Fix linux compilation

1 files changed, 0 insertions, 2807 deletions

diff --git a/src/os/linux_usbfs.c b/src/os/linux_usbfs.c
deleted file mode 100644
index c300675..0000000
--- a/src/os/linux_usbfs.c
+++ /dev/null
@@ -1,2807 +0,0 @@
-/* -*- Mode: C; c-basic-offset:8 ; indent-tabs-mode:t -*- */
-/*
- * Linux usbfs backend for libusb
- * Copyright © 2007-2009 Daniel Drake <dsd@gentoo.org>
- * Copyright © 2001 Johannes Erdfelt <johannes@erdfelt.com>
- * Copyright © 2013 Nathan Hjelm <hjelmn@mac.com>
- * Copyright © 2012-2013 Hans de Goede <hdegoede@redhat.com>
- * Copyright © 2020 Chris Dickens <christopher.a.dickens@gmail.com>
- *
- * 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 "libusbi.h"
-#include "linux_usbfs.h"
-
-#include <alloca.h>
-#include <ctype.h>
-#include <dirent.h>
-#include <errno.h>
-#include <fcntl.h>
-#include <stdio.h>
-#include <string.h>
-#include <sys/ioctl.h>
-#include <sys/mman.h>
-#include <sys/utsname.h>
-#include <sys/vfs.h>
-#include <unistd.h>
-
-/* sysfs vs usbfs:
- * opening a usbfs node causes the device to be resumed, so we attempt to
- * avoid this during enumeration.
- *
- * sysfs allows us to read the kernel's in-memory copies of device descriptors
- * and so forth, avoiding the need to open the device:
- *  - The binary "descriptors" file contains all config descriptors since
- *    2.6.26, commit 217a9081d8e69026186067711131b77f0ce219ed
- *  - The binary "descriptors" file was added in 2.6.23, commit
- *    69d42a78f935d19384d1f6e4f94b65bb162b36df, but it only contains the
- *    active config descriptors
- *  - The "busnum" file was added in 2.6.22, commit
- *    83f7d958eab2fbc6b159ee92bf1493924e1d0f72
- *  - The "devnum" file has been present since pre-2.6.18
- *  - the "bConfigurationValue" file has been present since pre-2.6.18
- *
- * If we have bConfigurationValue, busnum, and devnum, then we can determine
- * the active configuration without having to open the usbfs node in RDWR mode.
- * The busnum file is important as that is the only way we can relate sysfs
- * devices to usbfs nodes.
- *
- * If we also have all descriptors, we can obtain the device descriptor and
- * configuration without touching usbfs at all.
- */
-
-/* endianness for multi-byte fields:
- *
- * Descriptors exposed by usbfs have the multi-byte fields in the device
- * descriptor as host endian. Multi-byte fields in the other descriptors are
- * bus-endian. The kernel documentation says otherwise, but it is wrong.
- *
- * In sysfs all descriptors are bus-endian.
- */
-
-#define USBDEV_PATH		"/dev"
-#define USB_DEVTMPFS_PATH	"/dev/bus/usb"
-
-/* use usbdev*.* device names in /dev instead of the usbfs bus directories */
-static int usbdev_names = 0;
-
-/* Linux has changed the maximum length of an individual isochronous packet
- * over time.  Initially this limit was 1,023 bytes, but Linux 2.6.18
- * (commit 3612242e527eb47ee4756b5350f8bdf791aa5ede) increased this value to
- * 8,192 bytes to support higher bandwidth devices.  Linux 3.10
- * (commit e2e2f0ea1c935edcf53feb4c4c8fdb4f86d57dd9) further increased this
- * value to 49,152 bytes to support super speed devices.  Linux 5.2
- * (commit 8a1dbc8d91d3d1602282c7e6b4222c7759c916fa) even further increased
- * this value to 98,304 bytes to support super speed plus devices.
- */
-static unsigned int max_iso_packet_len = 0;
-
-/* is sysfs available (mounted) ? */
-static int sysfs_available = -1;
-
-/* how many times have we initted (and not exited) ? */
-static int init_count = 0;
-
-/* have no authority to operate usb device directly */
-static int no_enumeration = 0;
-
-/* Serialize scan-devices, event-thread, and poll */
-usbi_mutex_static_t linux_hotplug_lock = USBI_MUTEX_INITIALIZER;
-
-static int linux_scan_devices(struct libusb_context *ctx);
-static int detach_kernel_driver_and_claim(struct libusb_device_handle *, uint8_t);
-
-#if !defined(HAVE_LIBUDEV)
-static int linux_default_scan_devices(struct libusb_context *ctx);
-#endif
-
-struct kernel_version {
-	int major;
-	int minor;
-	int sublevel;
-};
-
-struct config_descriptor {
-	struct usbi_configuration_descriptor *desc;
-	size_t actual_len;
-};
-
-struct linux_device_priv {
-	char *sysfs_dir;
-	void *descriptors;
-	size_t descriptors_len;
-	struct config_descriptor *config_descriptors;
-	int active_config; /* cache val for !sysfs_available  */
-};
-
-struct linux_device_handle_priv {
-	int fd;
-	int fd_removed;
-	int fd_keep;
-	uint32_t caps;
-};
-
-enum reap_action {
-	NORMAL = 0,
-	/* submission failed after the first URB, so await cancellation/completion
-	 * of all the others */
-	SUBMIT_FAILED,
-
-	/* cancelled by user or timeout */
-	CANCELLED,
-
-	/* completed multi-URB transfer in non-final URB */
-	COMPLETED_EARLY,
-
-	/* one or more urbs encountered a low-level error */
-	ERROR,
-};
-
-struct linux_transfer_priv {
-	union {
-		struct usbfs_urb *urbs;
-		struct usbfs_urb **iso_urbs;
-	};
-
-	enum reap_action reap_action;
-	int num_urbs;
-	int num_retired;
-	enum libusb_transfer_status reap_status;
-
-	/* next iso packet in user-supplied transfer to be populated */
-	int iso_packet_offset;
-};
-
-static int dev_has_config0(struct libusb_device *dev)
-{
-	struct linux_device_priv *priv = usbi_get_device_priv(dev);
-	struct config_descriptor *config;
-	uint8_t idx;
-
-	for (idx = 0; idx < dev->device_descriptor.bNumConfigurations; idx++) {
-		config = &priv->config_descriptors[idx];
-		if (config->desc->bConfigurationValue == 0)
-			return 1;
-	}
-
-	return 0;
-}
-
-static int get_usbfs_fd(struct libusb_device *dev, mode_t mode, int silent)
-{
-	struct libusb_context *ctx = DEVICE_CTX(dev);
-	char path[24];
-	int fd;
-
-	if (usbdev_names)
-		sprintf(path, USBDEV_PATH "/usbdev%u.%u",
-			dev->bus_number, dev->device_address);
-	else
-		sprintf(path, USB_DEVTMPFS_PATH "/%03u/%03u",
-			dev->bus_number, dev->device_address);
-
-	fd = open(path, mode | O_CLOEXEC);
-	if (fd != -1)
-		return fd; /* Success */
-
-	if (errno == ENOENT) {
-		const long delay_ms = 10L;
-		const struct timespec delay_ts = { 0L, delay_ms * 1000L * 1000L };
-
-		if (!silent)
-			usbi_err(ctx, "File doesn't exist, wait %ld ms and try again", delay_ms);
-
-		/* Wait 10ms for USB device path creation.*/
-		nanosleep(&delay_ts, NULL);
-
-		fd = open(path, mode | O_CLOEXEC);
-		if (fd != -1)
-			return fd; /* Success */
-	}
-
-	if (!silent) {
-		usbi_err(ctx, "libusb couldn't open USB device %s, errno=%d", path, errno);
-		if (errno == EACCES && mode == O_RDWR)
-			usbi_err(ctx, "libusb requires write access to USB device nodes");
-	}
-
-	if (errno == EACCES)
-		return LIBUSB_ERROR_ACCESS;
-	if (errno == ENOENT)
-		return LIBUSB_ERROR_NO_DEVICE;
-	return LIBUSB_ERROR_IO;
-}
-
-/* check dirent for a /dev/usbdev%d.%d name
- * optionally return bus/device on success */
-static int is_usbdev_entry(const char *name, uint8_t *bus_p, uint8_t *dev_p)
-{
-	int busnum, devnum;
-
-	if (sscanf(name, "usbdev%d.%d", &busnum, &devnum) != 2)
-		return 0;
-	if (busnum < 0 || busnum > UINT8_MAX || devnum < 0 || devnum > UINT8_MAX) {
-		usbi_dbg(NULL, "invalid usbdev format '%s'", name);
-		return 0;
-	}
-
-	usbi_dbg(NULL, "found: %s", name);
-	if (bus_p)
-		*bus_p = (uint8_t)busnum;
-	if (dev_p)
-		*dev_p = (uint8_t)devnum;
-	return 1;
-}
-
-static const char *find_usbfs_path(void)
-{
-	const char *path;
-	DIR *dir;
-	struct dirent *entry;
-
-	path = USB_DEVTMPFS_PATH;
-	dir = opendir(path);
-	if (dir) {
-		while ((entry = readdir(dir))) {
-			if (entry->d_name[0] == '.')
-				continue;
-
-			/* We assume if we find any files that it must be the right place */
-			break;
-		}
-
-		closedir(dir);
-
-		if (entry)
-			return path;
-	}
-
-	/* look for /dev/usbdev*.* if the normal place fails */
-	path = USBDEV_PATH;
-	dir = opendir(path);
-	if (dir) {
-		while ((entry = readdir(dir))) {
-			if (entry->d_name[0] == '.')
-				continue;
-
-			if (is_usbdev_entry(entry->d_name, NULL, NULL)) {
-				/* found one; that's enough */
-				break;
-			}
-		}
-
-		closedir(dir);
-
-		if (entry) {
-			usbdev_names = 1;
-			return path;
-		}
-	}
-
-/* On udev based systems without any usb-devices /dev/bus/usb will not
- * exist. So if we've not found anything and we're using udev for hotplug
- * simply assume /dev/bus/usb rather then making libusb_init fail.
- * Make the same assumption for Android where SELinux policies might block us
- * from reading /dev on newer devices. */
-#if defined(HAVE_LIBUDEV) || defined(__ANDROID__)
-	return USB_DEVTMPFS_PATH;
-#else
-	return NULL;
-#endif
-}
-
-static int get_kernel_version(struct libusb_context *ctx,
-	struct kernel_version *ver)
-{
-	struct utsname uts;
-	int atoms;
-
-	if (uname(&uts) < 0) {
-		usbi_err(ctx, "uname failed, errno=%d", errno);
-		return -1;
-	}
-
-	atoms = sscanf(uts.release, "%d.%d.%d", &ver->major, &ver->minor, &ver->sublevel);
-	if (atoms < 2) {
-		usbi_err(ctx, "failed to parse uname release '%s'", uts.release);
-		return -1;
-	}
-
-	if (atoms < 3)
-		ver->sublevel = -1;
-
-	usbi_dbg(ctx, "reported kernel version is %s", uts.release);
-
-	return 0;
-}
-
-static int kernel_version_ge(const struct kernel_version *ver,
-	int major, int minor, int sublevel)
-{
-	if (ver->major > major)
-		return 1;
-	else if (ver->major < major)
-		return 0;
-
-	/* kmajor == major */
-	if (ver->minor > minor)
-		return 1;
-	else if (ver->minor < minor)
-		return 0;
-
-	/* kminor == minor */
-	if (ver->sublevel == -1)
-		return sublevel == 0;
-
-	return ver->sublevel >= sublevel;
-}
-
-static int op_init(struct libusb_context *ctx)
-{
-	struct kernel_version kversion;
-	const char *usbfs_path;
-	int r;
-
-	if (get_kernel_version(ctx, &kversion) < 0)
-		return LIBUSB_ERROR_OTHER;
-
-	if (!kernel_version_ge(&kversion, 2, 6, 32)) {
-		usbi_err(ctx, "kernel version is too old (reported as %d.%d.%d)",
-			 kversion.major, kversion.minor,
-			 kversion.sublevel != -1 ? kversion.sublevel : 0);
-		return LIBUSB_ERROR_NOT_SUPPORTED;
-	}
-
-	usbfs_path = find_usbfs_path();
-	if (!usbfs_path) {
-		usbi_err(ctx, "could not find usbfs");
-		return LIBUSB_ERROR_OTHER;
-	}
-
-	usbi_dbg(ctx, "found usbfs at %s", usbfs_path);
-
-	if (!max_iso_packet_len) {
-		if (kernel_version_ge(&kversion, 5, 2, 0))
-			max_iso_packet_len = 98304;
-		else if (kernel_version_ge(&kversion, 3, 10, 0))
-			max_iso_packet_len = 49152;
-		else
-			max_iso_packet_len = 8192;
-	}
-
-	usbi_dbg(ctx, "max iso packet length is (likely) %u bytes", max_iso_packet_len);
-
-	if (sysfs_available == -1) {
-		struct statfs statfsbuf;
-
-		r = statfs(SYSFS_MOUNT_PATH, &statfsbuf);
-		if (r == 0 && statfsbuf.f_type == SYSFS_MAGIC) {
-			usbi_dbg(ctx, "sysfs is available");
-			sysfs_available = 1;
-		} else {
-			usbi_warn(ctx, "sysfs not mounted");
-			sysfs_available = 0;
-		}
-	}
-
-	if (no_enumeration) {
-		return LIBUSB_SUCCESS;
-	}
-
-	r = LIBUSB_SUCCESS;
-	if (init_count == 0) {
-		/* start up hotplug event handler */
-		r = linux_start_event_monitor();
-	}
-	if (r == LIBUSB_SUCCESS) {
-		r = linux_scan_devices(ctx);
-		if (r == LIBUSB_SUCCESS)
-			init_count++;
-		else if (init_count == 0)
-			linux_stop_event_monitor();
-	} else {
-		usbi_err(ctx, "error starting hotplug event monitor");
-	}
-
-	return r;
-}
-
-static void op_exit(struct libusb_context *ctx)
-{
-	UNUSED(ctx);
-
-	if (no_enumeration) {
-		return;
-	}
-
-	assert(init_count != 0);
-	if (!--init_count) {
-		/* tear down event handler */
-		linux_stop_event_monitor();
-	}
-}
-
-static int op_set_option(struct libusb_context *ctx, enum libusb_option option, va_list ap)
-{
-	UNUSED(ctx);
-	UNUSED(ap);
-
-	if (option == LIBUSB_OPTION_NO_DEVICE_DISCOVERY) {
-		usbi_dbg(ctx, "no enumeration will be performed");
-		no_enumeration = 1;
-		return LIBUSB_SUCCESS;
-	}
-
-	return LIBUSB_ERROR_NOT_SUPPORTED;
-}
-
-static int linux_scan_devices(struct libusb_context *ctx)
-{
-	int ret;
-
-	usbi_mutex_static_lock(&linux_hotplug_lock);
-
-#if defined(HAVE_LIBUDEV)
-	ret = linux_udev_scan_devices(ctx);
-#else
-	ret = linux_default_scan_devices(ctx);
-#endif
-
-	usbi_mutex_static_unlock(&linux_hotplug_lock);
-
-	return ret;
-}
-
-static void op_hotplug_poll(void)
-{
-	linux_hotplug_poll();
-}
-
-static int open_sysfs_attr(struct libusb_context *ctx,
-	const char *sysfs_dir, const char *attr)
-{
-	char filename[256];
-	int fd;
-
-	snprintf(filename, sizeof(filename), SYSFS_DEVICE_PATH "/%s/%s", sysfs_dir, attr);
-	fd = open(filename, O_RDONLY | O_CLOEXEC);
-	if (fd < 0) {
-		if (errno == ENOENT) {
-			/* File doesn't exist. Assume the device has been
-			   disconnected (see trac ticket #70). */
-			return LIBUSB_ERROR_NO_DEVICE;
-		}
-		usbi_err(ctx, "open %s failed, errno=%d", filename, errno);
-		return LIBUSB_ERROR_IO;
-	}
-
-	return fd;
-}
-
-/* Note only suitable for attributes which always read >= 0, < 0 is error */
-static int read_sysfs_attr(struct libusb_context *ctx,
-	const char *sysfs_dir, const char *attr, int max_value, int *value_p)
-{
-	char buf[20], *endptr;
-	long value;
-	ssize_t r;
-	int fd;
-
-	fd = open_sysfs_attr(ctx, sysfs_dir, attr);
-	if (fd < 0)
-		return fd;
-
-	r = read(fd, buf, sizeof(buf) - 1);
-	if (r < 0) {
-		r = errno;
-		close(fd);
-		if (r == ENODEV)
-			return LIBUSB_ERROR_NO_DEVICE;
-		usbi_err(ctx, "attribute %s read failed, errno=%zd", attr, r);
-		return LIBUSB_ERROR_IO;
-	}
-	close(fd);
-
-	if (r == 0) {
-		/* Certain attributes (e.g. bConfigurationValue) are not
-		 * populated if the device is not configured. */
-		*value_p = -1;
-		return 0;
-	}
-
-	/* The kernel does *not* NUL-terminate the string, but every attribute
-	 * should be terminated with a newline character. */
-	if (!isdigit(buf[0])) {
-		usbi_err(ctx, "attribute %s doesn't have numeric value?", attr);
-		return LIBUSB_ERROR_IO;
-	} else if (buf[r - 1] != '\n') {
-		usbi_warn(ctx, "attribute %s doesn't end with newline?", attr);
-	} else {
-		/* Remove the terminating newline character */
-		r--;
-	}
-	buf[r] = '\0';
-
-	errno = 0;
-	value = strtol(buf, &endptr, 10);
-	if (value < 0 || value > (long)max_value || errno) {
-		usbi_err(ctx, "attribute %s contains an invalid value: '%s'", attr, buf);
-		return LIBUSB_ERROR_INVALID_PARAM;
-	} else if (*endptr != '\0') {
-		/* Consider the value to be valid if the remainder is a '.'
-		 * character followed by numbers.  This occurs, for example,
-		 * when reading the "speed" attribute for a low-speed device
-		 * (e.g. "1.5") */
-		if (*endptr == '.' && isdigit(*(endptr + 1))) {
-			endptr++;
-			while (isdigit(*endptr))
-				endptr++;
-		}
-		if (*endptr != '\0') {
-			usbi_err(ctx, "attribute %s contains an invalid value: '%s'", attr, buf);
-			return LIBUSB_ERROR_INVALID_PARAM;
-		}
-	}
-
-	*value_p = (int)value;
-	return 0;
-}
-
-static int sysfs_scan_device(struct libusb_context *ctx, const char *devname)
-{
-	uint8_t busnum, devaddr;
-	int ret;
-
-	ret = linux_get_device_address(ctx, 0, &busnum, &devaddr, NULL, devname, -1);
-	if (ret != LIBUSB_SUCCESS)
-		return ret;
-
-	return linux_enumerate_device(ctx, busnum, devaddr, devname);
-}
-
-/* read the bConfigurationValue for a device */
-static int sysfs_get_active_config(struct libusb_device *dev, int *config)
-{
-	struct linux_device_priv *priv = usbi_get_device_priv(dev);
-
-	return read_sysfs_attr(DEVICE_CTX(dev), priv->sysfs_dir, "bConfigurationValue",
-			UINT8_MAX, config);
-}
-
-int linux_get_device_address(struct libusb_context *ctx, int detached,
-	uint8_t *busnum, uint8_t *devaddr, const char *dev_node,
-	const char *sys_name, int fd)
-{
-	int sysfs_val;
-	int r;
-
-	usbi_dbg(ctx, "getting address for device: %s detached: %d", sys_name, detached);
-	/* can't use sysfs to read the bus and device number if the
-	 * device has been detached */
-	if (!sysfs_available || detached || !sys_name) {
-		if (!dev_node && fd >= 0) {
-			char *fd_path = alloca(PATH_MAX);
-			char proc_path[32];
-
-			/* try to retrieve the device node from fd */
-			sprintf(proc_path, "/proc/self/fd/%d", fd);
-			r = readlink(proc_path, fd_path, PATH_MAX - 1);
-			if (r > 0) {
-				fd_path[r] = '\0';
-				dev_node = fd_path;
-			}
-		}
-
-		if (!dev_node)
-			return LIBUSB_ERROR_OTHER;
-
-		/* will this work with all supported kernel versions? */
-		if (!strncmp(dev_node, "/dev/bus/usb", 12))
-			sscanf(dev_node, "/dev/bus/usb/%hhu/%hhu", busnum, devaddr);
-		else
-			return LIBUSB_ERROR_OTHER;
-
-		return LIBUSB_SUCCESS;
-	}
-
-	usbi_dbg(ctx, "scan %s", sys_name);
-
-	r = read_sysfs_attr(ctx, sys_name, "busnum", UINT8_MAX, &sysfs_val);
-	if (r < 0)
-		return r;
-	*busnum = (uint8_t)sysfs_val;
-
-	r = read_sysfs_attr(ctx, sys_name, "devnum", UINT8_MAX, &sysfs_val);
-	if (r < 0)
-		return r;
-	*devaddr = (uint8_t)sysfs_val;
-
-	usbi_dbg(ctx, "bus=%u dev=%u", *busnum, *devaddr);
-
-	return LIBUSB_SUCCESS;
-}
-
-/* Return offset of the next config descriptor */
-static int seek_to_next_config(struct libusb_context *ctx,
-	uint8_t *buffer, size_t len)
-{
-	struct usbi_descriptor_header *header;
-	int offset;
-
-	/* Start seeking past the config descriptor */
-	offset = LIBUSB_DT_CONFIG_SIZE;
-	buffer += LIBUSB_DT_CONFIG_SIZE;
-	len -= LIBUSB_DT_CONFIG_SIZE;
-
-	while (len > 0) {
-		if (len < 2) {
-			usbi_err(ctx, "short descriptor read %zu/2", len);
-			return LIBUSB_ERROR_IO;
-		}
-
-		header = (struct usbi_descriptor_header *)buffer;
-		if (header->bDescriptorType == LIBUSB_DT_CONFIG)
-			return offset;
-
-		if (len < header->bLength) {
-			usbi_err(ctx, "bLength overflow by %zu bytes",
-				 (size_t)header->bLength - len);
-			return LIBUSB_ERROR_IO;
-		}
-
-		offset += header->bLength;
-		buffer += header->bLength;
-		len -= header->bLength;
-	}
-
-	usbi_err(ctx, "config descriptor not found");
-	return LIBUSB_ERROR_IO;
-}
-
-static int parse_config_descriptors(struct libusb_device *dev)
-{
-	struct libusb_context *ctx = DEVICE_CTX(dev);
-	struct linux_device_priv *priv = usbi_get_device_priv(dev);
-	struct usbi_device_descriptor *device_desc;
-	uint8_t idx, num_configs;
-	uint8_t *buffer;
-	size_t remaining;
-
-	device_desc = priv->descriptors;
-	num_configs = device_desc->bNumConfigurations;
-
-	if (num_configs == 0)
-		return 0;	/* no configurations? */
-
-	priv->config_descriptors = malloc(num_configs * sizeof(priv->config_descriptors[0]));
-	if (!priv->config_descriptors)
-		return LIBUSB_ERROR_NO_MEM;
-
-	buffer = (uint8_t *)priv->descriptors + LIBUSB_DT_DEVICE_SIZE;
-	remaining = priv->descriptors_len - LIBUSB_DT_DEVICE_SIZE;
-
-	for (idx = 0; idx < num_configs; idx++) {
-		struct usbi_configuration_descriptor *config_desc;
-		uint16_t config_len;
-
-		if (remaining < LIBUSB_DT_CONFIG_SIZE) {
-			usbi_err(ctx, "short descriptor read %zu/%d",
-				 remaining, LIBUSB_DT_CONFIG_SIZE);
-			return LIBUSB_ERROR_IO;
-		}
-
-		config_desc = (struct usbi_configuration_descriptor *)buffer;
-		if (config_desc->bDescriptorType != LIBUSB_DT_CONFIG) {
-			usbi_err(ctx, "descriptor is not a config desc (type 0x%02x)",
-				 config_desc->bDescriptorType);
-			return LIBUSB_ERROR_IO;
-		} else if (config_desc->bLength < LIBUSB_DT_CONFIG_SIZE) {
-			usbi_err(ctx, "invalid descriptor bLength %u",
-				 config_desc->bLength);
-			return LIBUSB_ERROR_IO;
-		}
-
-		config_len = libusb_le16_to_cpu(config_desc->wTotalLength);
-		if (config_len < LIBUSB_DT_CONFIG_SIZE) {
-			usbi_err(ctx, "invalid wTotalLength %u", config_len);
-			return LIBUSB_ERROR_IO;
-		}
-
-		if (priv->sysfs_dir) {
-			/*
-			 * In sysfs wTotalLength is ignored, instead the kernel returns a
-			 * config descriptor with verified bLength fields, with descriptors
-			 * with an invalid bLength removed.
-			 */
-			uint16_t sysfs_config_len;
-			int offset;
-
-			if (num_configs > 1 && idx < num_configs - 1) {
-				offset = seek_to_next_config(ctx, buffer, remaining);
-				if (offset < 0)
-					return offset;
-				sysfs_config_len = (uint16_t)offset;
-			} else {
-				sysfs_config_len = (uint16_t)remaining;
-			}
-
-			if (config_len != sysfs_config_len) {
-				usbi_warn(ctx, "config length mismatch wTotalLength %u real %u",
-					  config_len, sysfs_config_len);
-				config_len = sysfs_config_len;
-			}
-		} else {
-			/*
-			 * In usbfs the config descriptors are wTotalLength bytes apart,
-			 * with any short reads from the device appearing as holes in the file.
-			 */
-			if (config_len > remaining) {
-				usbi_warn(ctx, "short descriptor read %zu/%u", remaining, config_len);
-				config_len = (uint16_t)remaining;
-			}
-		}
-
-		if (config_desc->bConfigurationValue == 0)
-			usbi_warn(ctx, "device has configuration 0");
-
-		priv->config_descriptors[idx].desc = config_desc;
-		priv->config_descriptors[idx].actual_len = config_len;
-
-		buffer += config_len;
-		remaining -= config_len;
-	}
-
-	return LIBUSB_SUCCESS;
-}
-
-static int op_get_config_descriptor_by_value(struct libusb_device *dev,
-	uint8_t value, void **buffer)
-{
-	struct linux_device_priv *priv = usbi_get_device_priv(dev);
-	struct config_descriptor *config;
-	uint8_t idx;
-
-	for (idx = 0; idx < dev->device_descriptor.bNumConfigurations; idx++) {
-		config = &priv->config_descriptors[idx];
-		if (config->desc->bConfigurationValue == value) {
-			*buffer = config->desc;
-			return (int)config->actual_len;
-		}
-	}
-
-	return LIBUSB_ERROR_NOT_FOUND;
-}
-
-static int op_get_active_config_descriptor(struct libusb_device *dev,
-	void *buffer, size_t len)
-{
-	struct linux_device_priv *priv = usbi_get_device_priv(dev);
-	void *config_desc;
-	int active_config;
-	int r;
-
-	if (priv->sysfs_dir) {
-		r = sysfs_get_active_config(dev, &active_config);
-		if (r < 0)
-			return r;
-	} else {
-		/* Use cached bConfigurationValue */
-		active_config = priv->active_config;
-	}
-
-	if (active_config == -1) {
-		usbi_err(DEVICE_CTX(dev), "device unconfigured");
-		return LIBUSB_ERROR_NOT_FOUND;
-	}
-
-	r = op_get_config_descriptor_by_value(dev, (uint8_t)active_config, &config_desc);
-	if (r < 0)
-		return r;
-
-	len = MIN(len, (size_t)r);
-	memcpy(buffer, config_desc, len);
-	return len;
-}
-
-static int op_get_config_descriptor(struct libusb_device *dev,
-	uint8_t config_index, void *buffer, size_t len)
-{
-	struct linux_device_priv *priv = usbi_get_device_priv(dev);
-	struct config_descriptor *config;
-
-	if (config_index >= dev->device_descriptor.bNumConfigurations)
-		return LIBUSB_ERROR_NOT_FOUND;
-
-	config = &priv->config_descriptors[config_index];
-	len = MIN(len, config->actual_len);
-	memcpy(buffer, config->desc, len);
-	return len;
-}
-
-/* send a control message to retrieve active configuration */
-static int usbfs_get_active_config(struct libusb_device *dev, int fd)
-{
-	struct linux_device_priv *priv = usbi_get_device_priv(dev);
-	uint8_t active_config = 0;
-	int r;
-
-	struct usbfs_ctrltransfer ctrl = {
-		.bmRequestType = LIBUSB_ENDPOINT_IN,
-		.bRequest = LIBUSB_REQUEST_GET_CONFIGURATION,
-		.wValue = 0,
-		.wIndex = 0,
-		.wLength = 1,
-		.timeout = 1000,
-		.data = &active_config
-	};
-
-	r = ioctl(fd, IOCTL_USBFS_CONTROL, &ctrl);
-	if (r < 0) {
-		if (errno == ENODEV)
-			return LIBUSB_ERROR_NO_DEVICE;
-
-		/* we hit this error path frequently with buggy devices :( */
-		usbi_warn(DEVICE_CTX(dev), "get configuration failed, errno=%d", errno);
-
-		/* assume the current configuration is the first one if we have
-		 * the configuration descriptors, otherwise treat the device
-		 * as unconfigured. */
-		if (priv->config_descriptors)
-			priv->active_config = (int)priv->config_descriptors[0].desc->bConfigurationValue;
-		else
-			priv->active_config = -1;
-	} else if (active_config == 0) {
-		if (dev_has_config0(dev)) {
-			/* some buggy devices have a configuration 0, but we're
-			 * reaching into the corner of a corner case here. */
-			priv->active_config = 0;
-		} else {
-			priv->active_config = -1;
-		}
-	} else {
-		priv->active_config = (int)active_config;
-	}
-
-	return LIBUSB_SUCCESS;
-}
-
-static enum libusb_speed usbfs_get_speed(struct libusb_context *ctx, int fd)
-{
-	int r;
-
-	r = ioctl(fd, IOCTL_USBFS_GET_SPEED, NULL);
-	switch (r) {
-	case USBFS_SPEED_UNKNOWN:	return LIBUSB_SPEED_UNKNOWN;
-	case USBFS_SPEED_LOW:		return LIBUSB_SPEED_LOW;
-	case USBFS_SPEED_FULL:		return LIBUSB_SPEED_FULL;
-	case USBFS_SPEED_HIGH:		return LIBUSB_SPEED_HIGH;
-	case USBFS_SPEED_WIRELESS:	return LIBUSB_SPEED_HIGH;
-	case USBFS_SPEED_SUPER:		return LIBUSB_SPEED_SUPER;
-	case USBFS_SPEED_SUPER_PLUS:	return LIBUSB_SPEED_SUPER_PLUS;
-	default:
-		usbi_warn(ctx, "Error getting device speed: %d", r);
-	}
-
-	return LIBUSB_SPEED_UNKNOWN;
-}
-
-static int initialize_device(struct libusb_device *dev, uint8_t busnum,
-	uint8_t devaddr, const char *sysfs_dir, int wrapped_fd)
-{
-	struct linux_device_priv *priv = usbi_get_device_priv(dev);
-	struct libusb_context *ctx = DEVICE_CTX(dev);
-	size_t alloc_len;
-	int fd, speed, r;
-	ssize_t nb;
-
-	dev->bus_number = busnum;
-	dev->device_address = devaddr;
-
-	if (sysfs_dir) {
-		priv->sysfs_dir = strdup(sysfs_dir);
-		if (!priv->sysfs_dir)
-			return LIBUSB_ERROR_NO_MEM;
-
-		/* Note speed can contain 1.5, in this case read_sysfs_attr()
-		   will stop parsing at the '.' and return 1 */
-		if (read_sysfs_attr(ctx, sysfs_dir, "speed", INT_MAX, &speed) == 0) {
-			switch (speed) {
-			case     1: dev->speed = LIBUSB_SPEED_LOW; break;
-			case    12: dev->speed = LIBUSB_SPEED_FULL; break;
-			case   480: dev->speed = LIBUSB_SPEED_HIGH; break;
-			case  5000: dev->speed = LIBUSB_SPEED_SUPER; break;
-			case 10000: dev->speed = LIBUSB_SPEED_SUPER_PLUS; break;
-			default:
-				usbi_warn(ctx, "unknown device speed: %d Mbps", speed);
-			}
-		}
-	} else if (wrapped_fd >= 0) {
-		dev->speed = usbfs_get_speed(ctx, wrapped_fd);
-	}
-
-	/* cache descriptors in memory */
-	if (sysfs_dir) {
-		fd = open_sysfs_attr(ctx, sysfs_dir, "descriptors");
-	} else if (wrapped_fd < 0) {
-		fd = get_usbfs_fd(dev, O_RDONLY, 0);
-	} else {
-		fd = wrapped_fd;
-		r = lseek(fd, 0, SEEK_SET);
-		if (r < 0) {
-			usbi_err(ctx, "lseek failed, errno=%d", errno);
-			return LIBUSB_ERROR_IO;
-		}
-	}
-	if (fd < 0)
-		return fd;
-
-	alloc_len = 0;
-	do {
-		const size_t desc_read_length = 256;
-		uint8_t *read_ptr;
-
-		alloc_len += desc_read_length;
-		priv->descriptors = usbi_reallocf(priv->descriptors, alloc_len);
-		if (!priv->descriptors) {
-			if (fd != wrapped_fd)
-				close(fd);
-			return LIBUSB_ERROR_NO_MEM;
-		}
-		read_ptr = (uint8_t *)priv->descriptors + priv->descriptors_len;
-		/* usbfs has holes in the file */
-		if (!sysfs_dir)
-			memset(read_ptr, 0, desc_read_length);
-		nb = read(fd, read_ptr, desc_read_length);
-		if (nb < 0) {
-			usbi_err(ctx, "read descriptor failed, errno=%d", errno);
-			if (fd != wrapped_fd)
-				close(fd);
-			return LIBUSB_ERROR_IO;
-		}
-		priv->descriptors_len += (size_t)nb;
-	} while (priv->descriptors_len == alloc_len);
-
-	if (fd != wrapped_fd)
-		close(fd);
-
-	if (priv->descriptors_len < LIBUSB_DT_DEVICE_SIZE) {
-		usbi_err(ctx, "short descriptor read (%zu)", priv->descriptors_len);
-		return LIBUSB_ERROR_IO;
-	}
-
-	r = parse_config_descriptors(dev);
-	if (r < 0)
-		return r;
-
-	memcpy(&dev->device_descriptor, priv->descriptors, LIBUSB_DT_DEVICE_SIZE);
-
-	if (sysfs_dir) {
-		/* sysfs descriptors are in bus-endian format */
-		usbi_localize_device_descriptor(&dev->device_descriptor);
-		return LIBUSB_SUCCESS;
-	}
-
-	/* cache active config */
-	if (wrapped_fd < 0)
-		fd = get_usbfs_fd(dev, O_RDWR, 1);
-	else
-		fd = wrapped_fd;
-	if (fd < 0) {
-		/* cannot send a control message to determine the active
-		 * config. just assume the first one is active. */
-		usbi_warn(ctx, "Missing rw usbfs access; cannot determine "
-			       "active configuration descriptor");
-		if (priv->config_descriptors)
-			priv->active_config = (int)priv->config_descriptors[0].desc->bConfigurationValue;
-		else
-			priv->active_config = -1; /* No config dt */
-
-		return LIBUSB_SUCCESS;
-	}
-
-	r = usbfs_get_active_config(dev, fd);
-	if (fd != wrapped_fd)
-		close(fd);
-
-	return r;
-}
-
-static int linux_get_parent_info(struct libusb_device *dev, const char *sysfs_dir)
-{
-	struct libusb_context *ctx = DEVICE_CTX(dev);
-	struct libusb_device *it;
-	char *parent_sysfs_dir, *tmp;
-	int ret, add_parent = 1;
-
-	/* XXX -- can we figure out the topology when using usbfs? */
-	if (!sysfs_dir || !strncmp(sysfs_dir, "usb", 3)) {
-		/* either using usbfs or finding the parent of a root hub */
-		return LIBUSB_SUCCESS;
-	}
-
-	parent_sysfs_dir = strdup(sysfs_dir);
-	if (!parent_sysfs_dir)
-		return LIBUSB_ERROR_NO_MEM;
-
-	if ((tmp = strrchr(parent_sysfs_dir, '.')) ||
-	    (tmp = strrchr(parent_sysfs_dir, '-'))) {
-	        dev->port_number = atoi(tmp + 1);
-		*tmp = '\0';
-	} else {
-		usbi_warn(ctx, "Can not parse sysfs_dir: %s, no parent info",
-			  parent_sysfs_dir);
-		free(parent_sysfs_dir);
-		return LIBUSB_SUCCESS;
-	}
-
-	/* is the parent a root hub? */
-	if (!strchr(parent_sysfs_dir, '-')) {
-		tmp = parent_sysfs_dir;
-		ret = asprintf(&parent_sysfs_dir, "usb%s", tmp);
-		free(tmp);
-		if (ret < 0)
-			return LIBUSB_ERROR_NO_MEM;
-	}
-
-retry:
-	/* find the parent in the context */
-	usbi_mutex_lock(&ctx->usb_devs_lock);
-	for_each_device(ctx, it) {
-		struct linux_device_priv *priv = usbi_get_device_priv(it);
-
-		if (priv->sysfs_dir) {
-			if (!strcmp(priv->sysfs_dir, parent_sysfs_dir)) {
-				dev->parent_dev = libusb_ref_device(it);
-				break;
-			}
-		}
-	}
-	usbi_mutex_unlock(&ctx->usb_devs_lock);
-
-	if (!dev->parent_dev && add_parent) {
-		usbi_dbg(ctx, "parent_dev %s not enumerated yet, enumerating now",
-			 parent_sysfs_dir);
-		sysfs_scan_device(ctx, parent_sysfs_dir);
-		add_parent = 0;
-		goto retry;
-	}
-
-	usbi_dbg(ctx, "dev %p (%s) has parent %p (%s) port %u", dev, sysfs_dir,
-		 dev->parent_dev, parent_sysfs_dir, dev->port_number);
-
-	free(parent_sysfs_dir);
-
-	return LIBUSB_SUCCESS;
-}
-
-int linux_enumerate_device(struct libusb_context *ctx,
-	uint8_t busnum, uint8_t devaddr, const char *sysfs_dir)
-{
-	unsigned long session_id;
-	struct libusb_device *dev;
-	int r;
-
-	/* FIXME: session ID is not guaranteed unique as addresses can wrap and
-	 * will be reused. instead we should add a simple sysfs attribute with
-	 * a session ID. */
-	session_id = busnum << 8 | devaddr;
-	usbi_dbg(ctx, "busnum %u devaddr %u session_id %lu", busnum, devaddr, session_id);
-
-	dev = usbi_get_device_by_session_id(ctx, session_id);
-	if (dev) {
-		/* device already exists in the context */
-		usbi_dbg(ctx, "session_id %lu already exists", session_id);
-		libusb_unref_device(dev);
-		return LIBUSB_SUCCESS;
-	}
-
-	usbi_dbg(ctx, "allocating new device for %u/%u (session %lu)",
-		 busnum, devaddr, session_id);
-	dev = usbi_alloc_device(ctx, session_id);
-	if (!dev)
-		return LIBUSB_ERROR_NO_MEM;
-
-	r = initialize_device(dev, busnum, devaddr, sysfs_dir, -1);
-	if (r < 0)
-		goto out;
-	r = usbi_sanitize_device(dev);
-	if (r < 0)
-		goto out;
-
-	r = linux_get_parent_info(dev, sysfs_dir);
-	if (r < 0)
-		goto out;
-out:
-	if (r < 0)
-		libusb_unref_device(dev);
-	else
-		usbi_connect_device(dev);
-
-	return r;
-}
-
-void linux_hotplug_enumerate(uint8_t busnum, uint8_t devaddr, const char *sys_name)
-{
-	struct libusb_context *ctx;
-
-	usbi_mutex_static_lock(&active_contexts_lock);
-	for_each_context(ctx) {
-		linux_enumerate_device(ctx, busnum, devaddr, sys_name);
-	}
-	usbi_mutex_static_unlock(&active_contexts_lock);
-}
-
-void linux_device_disconnected(uint8_t busnum, uint8_t devaddr)
-{
-	struct libusb_context *ctx;
-	struct libusb_device *dev;
-	unsigned long session_id = busnum << 8 | devaddr;
-
-	usbi_mutex_static_lock(&active_contexts_lock);
-	for_each_context(ctx) {
-		dev = usbi_get_device_by_session_id(ctx, session_id);
-		if (dev) {
-			usbi_disconnect_device(dev);
-			libusb_unref_device(dev);
-		} else {
-			usbi_dbg(ctx, "device not found for session %lx", session_id);
-		}
-	}
-	usbi_mutex_static_unlock(&active_contexts_lock);
-}
-
-#if !defined(HAVE_LIBUDEV)
-static int parse_u8(const char *str, uint8_t *val_p)
-{
-	char *endptr;
-	long num;
-
-	errno = 0;
-	num = strtol(str, &endptr, 10);
-	if (num < 0 || num > UINT8_MAX || errno)
-		return 0;
-	if (endptr == str || *endptr != '\0')
-		return 0;
-
-	*val_p = (uint8_t)num;
-	return 1;
-}
-
-/* open a bus directory and adds all discovered devices to the context */
-static int usbfs_scan_busdir(struct libusb_context *ctx, uint8_t busnum)
-{
-	DIR *dir;
-	char dirpath[20];
-	struct dirent *entry;
-	int r = LIBUSB_ERROR_IO;
-
-	sprintf(dirpath, USB_DEVTMPFS_PATH "/%03u", busnum);
-	usbi_dbg(ctx, "%s", dirpath);
-	dir = opendir(dirpath);
-	if (!dir) {
-		usbi_err(ctx, "opendir '%s' failed, errno=%d", dirpath, errno);
-		/* FIXME: should handle valid race conditions like hub unplugged
-		 * during directory iteration - this is not an error */
-		return r;
-	}
-
-	while ((entry = readdir(dir))) {
-		uint8_t devaddr;
-
-		if (entry->d_name[0] == '.')
-			continue;
-
-		if (!parse_u8(entry->d_name, &devaddr)) {
-			usbi_dbg(ctx, "unknown dir entry %s", entry->d_name);
-			continue;
-		}
-
-		if (linux_enumerate_device(ctx, busnum, devaddr, NULL)) {
-			usbi_dbg(ctx, "failed to enumerate dir entry %s", entry->d_name);
-			continue;
-		}
-
-		r = 0;
-	}
-
-	closedir(dir);
-	return r;
-}
-
-static int usbfs_get_device_list(struct libusb_context *ctx)
-{
-	struct dirent *entry;
-	DIR *buses;
-	uint8_t busnum, devaddr;
-	int r = 0;
-
-	if (usbdev_names)
-		buses = opendir(USBDEV_PATH);
-	else
-		buses = opendir(USB_DEVTMPFS_PATH);
-
-	if (!buses) {
-		usbi_err(ctx, "opendir buses failed, errno=%d", errno);
-		return LIBUSB_ERROR_IO;
-	}
-
-	while ((entry = readdir(buses))) {
-		if (entry->d_name[0] == '.')
-			continue;
-
-		if (usbdev_names) {
-			if (!is_usbdev_entry(entry->d_name, &busnum, &devaddr))
-				continue;
-
-			r = linux_enumerate_device(ctx, busnum, devaddr, NULL);
-			if (r < 0) {
-				usbi_dbg(ctx, "failed to enumerate dir entry %s", entry->d_name);
-				continue;
-			}
-		} else {
-			if (!parse_u8(entry->d_name, &busnum)) {
-				usbi_dbg(ctx, "unknown dir entry %s", entry->d_name);
-				continue;
-			}
-
-			r = usbfs_scan_busdir(ctx, busnum);
-			if (r < 0)
-				break;
-		}
-	}
-
-	closedir(buses);
-	return r;
-
-}
-
-static int sysfs_get_device_list(struct libusb_context *ctx)
-{
-	DIR *devices = opendir(SYSFS_DEVICE_PATH);
-	struct dirent *entry;
-	int num_devices = 0;
-	int num_enumerated = 0;
-
-	if (!devices) {
-		usbi_err(ctx, "opendir devices failed, errno=%d", errno);
-		return LIBUSB_ERROR_IO;
-	}
-
-	while ((entry = readdir(devices))) {
-		if ((!isdigit(entry->d_name[0]) && strncmp(entry->d_name, "usb", 3))
-		    || strchr(entry->d_name, ':'))
-			continue;
-
-		num_devices++;
-
-		if (sysfs_scan_device(ctx, entry->d_name)) {
-			usbi_dbg(ctx, "failed to enumerate dir entry %s", entry->d_name);
-			continue;
-		}
-
-		num_enumerated++;
-	}
-
-	closedir(devices);
-
-	/* successful if at least one device was enumerated or no devices were found */
-	if (num_enumerated || !num_devices)
-		return LIBUSB_SUCCESS;
-	else
-		return LIBUSB_ERROR_IO;
-}
-
-static int linux_default_scan_devices(struct libusb_context *ctx)
-{
-	/* we can retrieve device list and descriptors from sysfs or usbfs.
-	 * sysfs is preferable, because if we use usbfs we end up resuming
-	 * any autosuspended USB devices. however, sysfs is not available
-	 * everywhere, so we need a usbfs fallback too.
-	 */
-	if (sysfs_available)
-		return sysfs_get_device_list(ctx);
-	else
-		return usbfs_get_device_list(ctx);
-}
-#endif
-
-static int initialize_handle(struct libusb_device_handle *handle, int fd)
-{
-	struct linux_device_handle_priv *hpriv = usbi_get_device_handle_priv(handle);
-	int r;
-
-	hpriv->fd = fd;
-
-	r = ioctl(fd, IOCTL_USBFS_GET_CAPABILITIES, &hpriv->caps);
-	if (r < 0) {
-		if (errno == ENOTTY)
-			usbi_dbg(HANDLE_CTX(handle), "getcap not available");
-		else
-			usbi_err(HANDLE_CTX(handle), "getcap failed, errno=%d", errno);
-		hpriv->caps = USBFS_CAP_BULK_CONTINUATION;
-	}
-
-	return usbi_add_event_source(HANDLE_CTX(handle), hpriv->fd, POLLOUT);
-}
-
-static int op_wrap_sys_device(struct libusb_context *ctx,
-	struct libusb_device_handle *handle, intptr_t sys_dev)
-{
-	struct linux_device_handle_priv *hpriv = usbi_get_device_handle_priv(handle);
-	int fd = (int)sys_dev;
-	uint8_t busnum, devaddr;
-	struct usbfs_connectinfo ci;
-	struct libusb_device *dev;
-	int r;
-
-	r = linux_get_device_address(ctx, 1, &busnum, &devaddr, NULL, NULL, fd);
-	if (r < 0) {
-		r = ioctl(fd, IOCTL_USBFS_CONNECTINFO, &ci);
-		if (r < 0) {
-			usbi_err(ctx, "connectinfo failed, errno=%d", errno);
-			return LIBUSB_ERROR_IO;
-		}
-		/* There is no ioctl to get the bus number. We choose 0 here
-		 * as linux starts numbering buses from 1. */
-		busnum = 0;
-		devaddr = ci.devnum;
-	}
-
-	/* Session id is unused as we do not add the device to the list of
-	 * connected devices. */
-	usbi_dbg(ctx, "allocating new device for fd %d", fd);
-	dev = usbi_alloc_device(ctx, 0);
-	if (!dev)
-		return LIBUSB_ERROR_NO_MEM;
-
-	r = initialize_device(dev, busnum, devaddr, NULL, fd);
-	if (r < 0)
-		goto out;
-	r = usbi_sanitize_device(dev);
-	if (r < 0)
-		goto out;
-	/* Consider the device as connected, but do not add it to the managed
-	 * device list. */
-	usbi_atomic_store(&dev->attached, 1);
-	handle->dev = dev;
-
-	r = initialize_handle(handle, fd);
-	hpriv->fd_keep = 1;
-
-out:
-	if (r < 0)
-		libusb_unref_device(dev);
-	return r;
-}
-
-static int op_open(struct libusb_device_handle *handle)
-{
-	int fd, r;
-
-	fd = get_usbfs_fd(handle->dev, O_RDWR, 0);
-	if (fd < 0) {
-		if (fd == LIBUSB_ERROR_NO_DEVICE) {
-			/* device will still be marked as attached if hotplug monitor thread
-			 * hasn't processed remove event yet */
-			usbi_mutex_static_lock(&linux_hotplug_lock);
-			if (usbi_atomic_load(&handle->dev->attached)) {
-				usbi_dbg(HANDLE_CTX(handle), "open failed with no device, but device still attached");
-				linux_device_disconnected(handle->dev->bus_number,
-							  handle->dev->device_address);
-			}
-			usbi_mutex_static_unlock(&linux_hotplug_lock);
-		}
-		return fd;
-	}
-
-	r = initialize_handle(handle, fd);
-	if (r < 0)
-		close(fd);
-
-	return r;
-}
-
-static void op_close(struct libusb_device_handle *dev_handle)
-{
-	struct linux_device_handle_priv *hpriv = usbi_get_device_handle_priv(dev_handle);
-
-	/* fd may have already been removed by POLLERR condition in op_handle_events() */
-	if (!hpriv->fd_removed)
-		usbi_remove_event_source(HANDLE_CTX(dev_handle), hpriv->fd);
-	if (!hpriv->fd_keep)
-		close(hpriv->fd);
-}
-
-static int op_get_configuration(struct libusb_device_handle *handle,
-	uint8_t *config)
-{
-	struct linux_device_priv *priv = usbi_get_device_priv(handle->dev);
-	int active_config;
-	int r;
-
-	if (priv->sysfs_dir) {
-		r = sysfs_get_active_config(handle->dev, &active_config);
-	} else {
-		struct linux_device_handle_priv *hpriv = usbi_get_device_handle_priv(handle);
-
-		r = usbfs_get_active_config(handle->dev, hpriv->fd);
-		if (r == LIBUSB_SUCCESS)
-			active_config = priv->active_config;
-	}
-	if (r < 0)
-		return r;
-
-	if (active_config == -1) {
-		usbi_warn(HANDLE_CTX(handle), "device unconfigured");
-		active_config = 0;
-	}
-
-	*config = (uint8_t)active_config;
-
-	return 0;
-}
-
-static int op_set_configuration(struct libusb_device_handle *handle, int config)
-{
-	struct linux_device_priv *priv = usbi_get_device_priv(handle->dev);
-	struct linux_device_handle_priv *hpriv = usbi_get_device_handle_priv(handle);
-	int fd = hpriv->fd;
-	int r = ioctl(fd, IOCTL_USBFS_SETCONFIGURATION, &config);
-
-	if (r < 0) {
-		if (errno == EINVAL)
-			return LIBUSB_ERROR_NOT_FOUND;
-		else if (errno == EBUSY)
-			return LIBUSB_ERROR_BUSY;
-		else if (errno == ENODEV)
-			return LIBUSB_ERROR_NO_DEVICE;
-
-		usbi_err(HANDLE_CTX(handle), "set configuration failed, errno=%d", errno);
-		return LIBUSB_ERROR_OTHER;
-	}
-
-	/* if necessary, update our cached active config descriptor */
-	if (!priv->sysfs_dir) {
-		if (config == 0 && !dev_has_config0(handle->dev))
-			config = -1;
-
-		priv->active_config = config;
-	}
-
-	return LIBUSB_SUCCESS;
-}
-
-static int claim_interface(struct libusb_device_handle *handle, unsigned int iface)
-{
-	struct linux_device_handle_priv *hpriv = usbi_get_device_handle_priv(handle);
-	int fd = hpriv->fd;
-	int r = ioctl(fd, IOCTL_USBFS_CLAIMINTERFACE, &iface);
-
-	if (r < 0) {
-		if (errno == ENOENT)
-			return LIBUSB_ERROR_NOT_FOUND;
-		else if (errno == EBUSY)
-			return LIBUSB_ERROR_BUSY;
-		else if (errno == ENODEV)
-			return LIBUSB_ERROR_NO_DEVICE;
-
-		usbi_err(HANDLE_CTX(handle), "claim interface failed, errno=%d", errno);
-		return LIBUSB_ERROR_OTHER;
-	}
-	return 0;
-}
-
-static int release_interface(struct libusb_device_handle *handle, unsigned int iface)
-{
-	struct linux_device_handle_priv *hpriv = usbi_get_device_handle_priv(handle);
-	int fd = hpriv->fd;
-	int r = ioctl(fd, IOCTL_USBFS_RELEASEINTERFACE, &iface);
-
-	if (r < 0) {
-		if (errno == ENODEV)
-			return LIBUSB_ERROR_NO_DEVICE;
-
-		usbi_err(HANDLE_CTX(handle), "release interface failed, errno=%d", errno);
-		return LIBUSB_ERROR_OTHER;
-	}
-	return 0;
-}
-
-static int op_set_interface(struct libusb_device_handle *handle, uint8_t interface,
-	uint8_t altsetting)
-{
-	struct linux_device_handle_priv *hpriv = usbi_get_device_handle_priv(handle);
-	int fd = hpriv->fd;
-	struct usbfs_setinterface setintf;
-	int r;
-
-	setintf.interface = interface;
-	setintf.altsetting = altsetting;
-	r = ioctl(fd, IOCTL_USBFS_SETINTERFACE, &setintf);
-	if (r < 0) {
-		if (errno == EINVAL)
-			return LIBUSB_ERROR_NOT_FOUND;
-		else if (errno == ENODEV)
-			return LIBUSB_ERROR_NO_DEVICE;
-
-		usbi_err(HANDLE_CTX(handle), "set interface failed, errno=%d", errno);
-		return LIBUSB_ERROR_OTHER;
-	}
-
-	return 0;
-}
-
-static int op_clear_halt(struct libusb_device_handle *handle,
-	unsigned char endpoint)
-{
-	struct linux_device_handle_priv *hpriv = usbi_get_device_handle_priv(handle);
-	int fd = hpriv->fd;
-	unsigned int _endpoint = endpoint;
-	int r = ioctl(fd, IOCTL_USBFS_CLEAR_HALT, &_endpoint);
-
-	if (r < 0) {
-		if (errno == ENOENT)
-			return LIBUSB_ERROR_NOT_FOUND;
-		else if (errno == ENODEV)
-			return LIBUSB_ERROR_NO_DEVICE;
-
-		usbi_err(HANDLE_CTX(handle), "clear halt failed, errno=%d", errno);
-		return LIBUSB_ERROR_OTHER;
-	}
-
-	return 0;
-}
-
-static int op_reset_device(struct libusb_device_handle *handle)
-{
-	struct linux_device_handle_priv *hpriv = usbi_get_device_handle_priv(handle);
-	int fd = hpriv->fd;
-	int r, ret = 0;
-	uint8_t i;
-
-	/* Doing a device reset will cause the usbfs driver to get unbound
-	 * from any interfaces it is bound to. By voluntarily unbinding
-	 * the usbfs driver ourself, we stop the kernel from rebinding
-	 * the interface after reset (which would end up with the interface
-	 * getting bound to the in kernel driver if any). */
-	for (i = 0; i < USB_MAXINTERFACES; i++) {
-		if (handle->claimed_interfaces & (1UL << i))
-			release_interface(handle, i);
-	}
-
-	usbi_mutex_lock(&handle->lock);
-	r = ioctl(fd, IOCTL_USBFS_RESET, NULL);
-	if (r < 0) {
-		if (errno == ENODEV) {
-			ret = LIBUSB_ERROR_NOT_FOUND;
-			goto out;
-		}
-
-		usbi_err(HANDLE_CTX(handle), "reset failed, errno=%d", errno);
-		ret = LIBUSB_ERROR_OTHER;
-		goto out;
-	}
-
-	/* And re-claim any interfaces which were claimed before the reset */
-	for (i = 0; i < USB_MAXINTERFACES; i++) {
-		if (!(handle->claimed_interfaces & (1UL << i)))
-			continue;
-		/*
-		 * A driver may have completed modprobing during
-		 * IOCTL_USBFS_RESET, and bound itself as soon as
-		 * IOCTL_USBFS_RESET released the device lock
-		 */
-		r = detach_kernel_driver_and_claim(handle, i);
-		if (r) {
-			usbi_warn(HANDLE_CTX(handle), "failed to re-claim interface %u after reset: %s",
-				  i, libusb_error_name(r));
-			handle->claimed_interfaces &= ~(1UL << i);
-			ret = LIBUSB_ERROR_NOT_FOUND;
-		}
-	}
-out:
-	usbi_mutex_unlock(&handle->lock);
-	return ret;
-}
-
-static int do_streams_ioctl(struct libusb_device_handle *handle, long req,
-	uint32_t num_streams, unsigned char *endpoints, int num_endpoints)
-{
-	struct linux_device_handle_priv *hpriv = usbi_get_device_handle_priv(handle);
-	int r, fd = hpriv->fd;
-	struct usbfs_streams *streams;
-
-	if (num_endpoints > 30) /* Max 15 in + 15 out eps */
-		return LIBUSB_ERROR_INVALID_PARAM;
-
-	streams = malloc(sizeof(*streams) + num_endpoints);
-	if (!streams)
-		return LIBUSB_ERROR_NO_MEM;
-
-	streams->num_streams = num_streams;
-	streams->num_eps = num_endpoints;
-	memcpy(streams->eps, endpoints, num_endpoints);
-
-	r = ioctl(fd, req, streams);
-
-	free(streams);
-
-	if (r < 0) {
-		if (errno == ENOTTY)
-			return LIBUSB_ERROR_NOT_SUPPORTED;
-		else if (errno == EINVAL)
-			return LIBUSB_ERROR_INVALID_PARAM;
-		else if (errno == ENODEV)
-			return LIBUSB_ERROR_NO_DEVICE;
-
-		usbi_err(HANDLE_CTX(handle), "streams-ioctl failed, errno=%d", errno);
-		return LIBUSB_ERROR_OTHER;
-	}
-	return r;
-}
-
-static int op_alloc_streams(struct libusb_device_handle *handle,
-	uint32_t num_streams, unsigned char *endpoints, int num_endpoints)
-{
-	return do_streams_ioctl(handle, IOCTL_USBFS_ALLOC_STREAMS,
-				num_streams, endpoints, num_endpoints);
-}
-
-static int op_free_streams(struct libusb_device_handle *handle,
-		unsigned char *endpoints, int num_endpoints)
-{
-	return do_streams_ioctl(handle, IOCTL_USBFS_FREE_STREAMS, 0,
-				endpoints, num_endpoints);
-}
-
-static void *op_dev_mem_alloc(struct libusb_device_handle *handle, size_t len)
-{
-	struct linux_device_handle_priv *hpriv = usbi_get_device_handle_priv(handle);
-	void *buffer;
-
-	buffer = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_SHARED, hpriv->fd, 0);
-	if (buffer == MAP_FAILED) {
-		usbi_err(HANDLE_CTX(handle), "alloc dev mem failed, errno=%d", errno);
-		return NULL;
-	}
-	return buffer;
-}
-
-static int op_dev_mem_free(struct libusb_device_handle *handle, void *buffer,
-	size_t len)
-{
-	if (munmap(buffer, len) != 0) {
-		usbi_err(HANDLE_CTX(handle), "free dev mem failed, errno=%d", errno);
-		return LIBUSB_ERROR_OTHER;
-	} else {
-		return LIBUSB_SUCCESS;
-	}
-}
-
-static int op_kernel_driver_active(struct libusb_device_handle *handle,
-	uint8_t interface)
-{
-	struct linux_device_handle_priv *hpriv = usbi_get_device_handle_priv(handle);
-	int fd = hpriv->fd;
-	struct usbfs_getdriver getdrv;
-	int r;
-
-	getdrv.interface = interface;
-	r = ioctl(fd, IOCTL_USBFS_GETDRIVER, &getdrv);
-	if (r < 0) {
-		if (errno == ENODATA)
-			return 0;
-		else if (errno == ENODEV)
-			return LIBUSB_ERROR_NO_DEVICE;
-
-		usbi_err(HANDLE_CTX(handle), "get driver failed, errno=%d", errno);
-		return LIBUSB_ERROR_OTHER;
-	}
-
-	return strcmp(getdrv.driver, "usbfs") != 0;
-}
-
-static int op_detach_kernel_driver(struct libusb_device_handle *handle,
-	uint8_t interface)
-{
-	struct linux_device_handle_priv *hpriv = usbi_get_device_handle_priv(handle);
-	int fd = hpriv->fd;
-	struct usbfs_ioctl command;
-	struct usbfs_getdriver getdrv;
-	int r;
-
-	command.ifno = interface;
-	command.ioctl_code = IOCTL_USBFS_DISCONNECT;
-	command.data = NULL;
-
-	getdrv.interface = interface;
-	r = ioctl(fd, IOCTL_USBFS_GETDRIVER, &getdrv);
-	if (r == 0 && !strcmp(getdrv.driver, "usbfs"))
-		return LIBUSB_ERROR_NOT_FOUND;
-
-	r = ioctl(fd, IOCTL_USBFS_IOCTL, &command);
-	if (r < 0) {
-		if (errno == ENODATA)
-			return LIBUSB_ERROR_NOT_FOUND;
-		else if (errno == EINVAL)
-			return LIBUSB_ERROR_INVALID_PARAM;
-		else if (errno == ENODEV)
-			return LIBUSB_ERROR_NO_DEVICE;
-
-		usbi_err(HANDLE_CTX(handle), "detach failed, errno=%d", errno);
-		return LIBUSB_ERROR_OTHER;
-	}
-
-	return 0;
-}
-
-static int op_attach_kernel_driver(struct libusb_device_handle *handle,
-	uint8_t interface)
-{
-	struct linux_device_handle_priv *hpriv = usbi_get_device_handle_priv(handle);
-	int fd = hpriv->fd;
-	struct usbfs_ioctl command;
-	int r;
-
-	command.ifno = interface;
-	command.ioctl_code = IOCTL_USBFS_CONNECT;
-	command.data = NULL;
-
-	r = ioctl(fd, IOCTL_USBFS_IOCTL, &command);
-	if (r < 0) {
-		if (errno == ENODATA)
-			return LIBUSB_ERROR_NOT_FOUND;
-		else if (errno == EINVAL)
-			return LIBUSB_ERROR_INVALID_PARAM;
-		else if (errno == ENODEV)
-			return LIBUSB_ERROR_NO_DEVICE;
-		else if (errno == EBUSY)
-			return LIBUSB_ERROR_BUSY;
-
-		usbi_err(HANDLE_CTX(handle), "attach failed, errno=%d", errno);
-		return LIBUSB_ERROR_OTHER;
-	} else if (r == 0) {
-		return LIBUSB_ERROR_NOT_FOUND;
-	}
-
-	return 0;
-}
-
-static int detach_kernel_driver_and_claim(struct libusb_device_handle *handle,
-	uint8_t interface)
-{
-	struct linux_device_handle_priv *hpriv = usbi_get_device_handle_priv(handle);
-	struct usbfs_disconnect_claim dc;
-	int r, fd = hpriv->fd;
-
-	dc.interface = interface;
-	strcpy(dc.driver, "usbfs");
-	dc.flags = USBFS_DISCONNECT_CLAIM_EXCEPT_DRIVER;
-	r = ioctl(fd, IOCTL_USBFS_DISCONNECT_CLAIM, &dc);
-	if (r == 0)
-		return 0;
-	switch (errno) {
-	case ENOTTY:
-		break;
-	case EBUSY:
-		return LIBUSB_ERROR_BUSY;
-	case EINVAL:
-		return LIBUSB_ERROR_INVALID_PARAM;
-	case ENODEV:
-		return LIBUSB_ERROR_NO_DEVICE;
-	default:
-		usbi_err(HANDLE_CTX(handle), "disconnect-and-claim failed, errno=%d", errno);
-		return LIBUSB_ERROR_OTHER;
-	}
-
-	/* Fallback code for kernels which don't support the
-	   disconnect-and-claim ioctl */
-	r = op_detach_kernel_driver(handle, interface);
-	if (r != 0 && r != LIBUSB_ERROR_NOT_FOUND)
-		return r;
-
-	return claim_interface(handle, interface);
-}
-
-static int op_claim_interface(struct libusb_device_handle *handle, uint8_t interface)
-{
-	if (handle->auto_detach_kernel_driver)
-		return detach_kernel_driver_and_claim(handle, interface);
-	else
-		return claim_interface(handle, interface);
-}
-
-static int op_release_interface(struct libusb_device_handle *handle, uint8_t interface)
-{
-	int r;
-
-	r = release_interface(handle, interface);
-	if (r)
-		return r;
-
-	if (handle->auto_detach_kernel_driver)
-		op_attach_kernel_driver(handle, interface);
-
-	return 0;
-}
-
-static void op_destroy_device(struct libusb_device *dev)
-{
-	struct linux_device_priv *priv = usbi_get_device_priv(dev);
-
-	free(priv->config_descriptors);
-	free(priv->descriptors);
-	free(priv->sysfs_dir);
-}
-
-/* URBs are discarded in reverse order of submission to avoid races. */
-static int discard_urbs(struct usbi_transfer *itransfer, int first, int last_plus_one)
-{
-	struct libusb_transfer *transfer =
-		USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
-	struct linux_transfer_priv *tpriv = usbi_get_transfer_priv(itransfer);
-	struct linux_device_handle_priv *hpriv =
-		usbi_get_device_handle_priv(transfer->dev_handle);
-	int i, ret = 0;
-	struct usbfs_urb *urb;
-
-	for (i = last_plus_one - 1; i >= first; i--) {
-		if (transfer->type == LIBUSB_TRANSFER_TYPE_ISOCHRONOUS)
-			urb = tpriv->iso_urbs[i];
-		else
-			urb = &tpriv->urbs[i];
-
-		if (ioctl(hpriv->fd, IOCTL_USBFS_DISCARDURB, urb) == 0)
-			continue;
-
-		if (errno == EINVAL) {
-			usbi_dbg(TRANSFER_CTX(transfer), "URB not found --> assuming ready to be reaped");
-			if (i == (last_plus_one - 1))
-				ret = LIBUSB_ERROR_NOT_FOUND;
-		} else if (errno == ENODEV) {
-			usbi_dbg(TRANSFER_CTX(transfer), "Device not found for URB --> assuming ready to be reaped");
-			ret = LIBUSB_ERROR_NO_DEVICE;
-		} else {
-			usbi_warn(TRANSFER_CTX(transfer), "unrecognised discard errno %d", errno);
-			ret = LIBUSB_ERROR_OTHER;
-		}
-	}
-	return ret;
-}
-
-static void free_iso_urbs(struct linux_transfer_priv *tpriv)
-{
-	int i;
-
-	for (i = 0; i < tpriv->num_urbs; i++) {
-		struct usbfs_urb *urb = tpriv->iso_urbs[i];
-
-		if (!urb)
-			break;
-		free(urb);
-	}
-
-	free(tpriv->iso_urbs);
-	tpriv->iso_urbs = NULL;
-}
-
-static int submit_bulk_transfer(struct usbi_transfer *itransfer)
-{
-	struct libusb_transfer *transfer =
-		USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
-	struct linux_transfer_priv *tpriv = usbi_get_transfer_priv(itransfer);
-	struct linux_device_handle_priv *hpriv =
-		usbi_get_device_handle_priv(transfer->dev_handle);
-	struct usbfs_urb *urbs;
-	int is_out = IS_XFEROUT(transfer);
-	int bulk_buffer_len, use_bulk_continuation;
-	int num_urbs;
-	int last_urb_partial = 0;
-	int r;
-	int i;
-
-	/*
-	 * Older versions of usbfs place a 16kb limit on bulk URBs. We work
-	 * around this by splitting large transfers into 16k blocks, and then
-	 * submit all urbs at once. it would be simpler to submit one urb at
-	 * a time, but there is a big performance gain doing it this way.
-	 *
-	 * Newer versions lift the 16k limit (USBFS_CAP_NO_PACKET_SIZE_LIM),
-	 * using arbitrary large transfers can still be a bad idea though, as
-	 * the kernel needs to allocate physical contiguous memory for this,
-	 * which may fail for large buffers.
-	 *
-	 * The kernel solves this problem by splitting the transfer into
-	 * blocks itself when the host-controller is scatter-gather capable
-	 * (USBFS_CAP_BULK_SCATTER_GATHER), which most controllers are.
-	 *
-	 * Last, there is the issue of short-transfers when splitting, for
-	 * short split-transfers to work reliable USBFS_CAP_BULK_CONTINUATION
-	 * is needed, but this is not always available.
-	 */
-	if (hpriv->caps & USBFS_CAP_BULK_SCATTER_GATHER) {
-		/* Good! Just submit everything in one go */
-		bulk_buffer_len = transfer->length ? transfer->length : 1;
-		use_bulk_continuation = 0;
-	} else if (hpriv->caps & USBFS_CAP_BULK_CONTINUATION) {
-		/* Split the transfers and use bulk-continuation to
-		   avoid issues with short-transfers */
-		bulk_buffer_len = MAX_BULK_BUFFER_LENGTH;
-		use_bulk_continuation = 1;
-	} else if (hpriv->caps & USBFS_CAP_NO_PACKET_SIZE_LIM) {
-		/* Don't split, assume the kernel can alloc the buffer
-		   (otherwise the submit will fail with -ENOMEM) */
-		bulk_buffer_len = transfer->length ? transfer->length : 1;
-		use_bulk_continuation = 0;
-	} else {
-		/* Bad, splitting without bulk-continuation, short transfers
-		   which end before the last urb will not work reliable! */
-		/* Note we don't warn here as this is "normal" on kernels <
-		   2.6.32 and not a problem for most applications */
-		bulk_buffer_len = MAX_BULK_BUFFER_LENGTH;
-		use_bulk_continuation = 0;
-	}
-
-	num_urbs = transfer->length / bulk_buffer_len;
-
-	if (transfer->length == 0) {
-		num_urbs = 1;
-	} else if ((transfer->length % bulk_buffer_len) > 0) {
-		last_urb_partial = 1;
-		num_urbs++;
-	}
-	usbi_dbg(TRANSFER_CTX(transfer), "need %d urbs for new transfer with length %d", num_urbs, transfer->length);
-	urbs = calloc(num_urbs, sizeof(*urbs));
-	if (!urbs)
-		return LIBUSB_ERROR_NO_MEM;
-	tpriv->urbs = urbs;
-	tpriv->num_urbs = num_urbs;
-	tpriv->num_retired = 0;
-	tpriv->reap_action = NORMAL;
-	tpriv->reap_status = LIBUSB_TRANSFER_COMPLETED;
-
-	for (i = 0; i < num_urbs; i++) {
-		struct usbfs_urb *urb = &urbs[i];
-
-		urb->usercontext = itransfer;
-		switch (transfer->type) {
-		case LIBUSB_TRANSFER_TYPE_BULK:
-			urb->type = USBFS_URB_TYPE_BULK;
-			urb->stream_id = 0;
-			break;
-		case LIBUSB_TRANSFER_TYPE_BULK_STREAM:
-			urb->type = USBFS_URB_TYPE_BULK;
-			urb->stream_id = itransfer->stream_id;
-			break;
-		case LIBUSB_TRANSFER_TYPE_INTERRUPT:
-			urb->type = USBFS_URB_TYPE_INTERRUPT;
-			break;
-		}
-		urb->endpoint = transfer->endpoint;
-		urb->buffer = transfer->buffer + (i * bulk_buffer_len);
-
-		/* don't set the short not ok flag for the last URB */
-		if (use_bulk_continuation && !is_out && (i < num_urbs - 1))
-			urb->flags = USBFS_URB_SHORT_NOT_OK;
-
-		if (i == num_urbs - 1 && last_urb_partial)
-			urb->buffer_length = transfer->length % bulk_buffer_len;
-		else if (transfer->length == 0)
-			urb->buffer_length = 0;
-		else
-			urb->buffer_length = bulk_buffer_len;
-
-		if (i > 0 && use_bulk_continuation)
-			urb->flags |= USBFS_URB_BULK_CONTINUATION;
-
-		/* we have already checked that the flag is supported */
-		if (is_out && i == num_urbs - 1 &&
-		    (transfer->flags & LIBUSB_TRANSFER_ADD_ZERO_PACKET))
-			urb->flags |= USBFS_URB_ZERO_PACKET;
-
-		r = ioctl(hpriv->fd, IOCTL_USBFS_SUBMITURB, urb);
-		if (r == 0)
-			continue;
-
-		if (errno == ENODEV) {
-			r = LIBUSB_ERROR_NO_DEVICE;
-		} else if (errno == ENOMEM) {
-			r = LIBUSB_ERROR_NO_MEM;
-		} else {
-			usbi_err(TRANSFER_CTX(transfer), "submiturb failed, errno=%d", errno);
-			r = LIBUSB_ERROR_IO;
-		}
-
-		/* if the first URB submission fails, we can simply free up and
-		 * return failure immediately. */
-		if (i == 0) {
-			usbi_dbg(TRANSFER_CTX(transfer), "first URB failed, easy peasy");
-			free(urbs);
-			tpriv->urbs = NULL;
-			return r;
-		}
-
-		/* if it's not the first URB that failed, the situation is a bit
-		 * tricky. we may need to discard all previous URBs. there are
-		 * complications:
-		 *  - discarding is asynchronous - discarded urbs will be reaped
-		 *    later. the user must not have freed the transfer when the
-		 *    discarded URBs are reaped, otherwise libusb will be using
-		 *    freed memory.
-		 *  - the earlier URBs may have completed successfully and we do
-		 *    not want to throw away any data.
-		 *  - this URB failing may be no error; EREMOTEIO means that
-		 *    this transfer simply didn't need all the URBs we submitted
-		 * so, we report that the transfer was submitted successfully and
-		 * in case of error we discard all previous URBs. later when
-		 * the final reap completes we can report error to the user,
-		 * or success if an earlier URB was completed successfully.
-		 */
-		tpriv->reap_action = errno == EREMOTEIO ? COMPLETED_EARLY : SUBMIT_FAILED;
-
-		/* The URBs we haven't submitted yet we count as already
-		 * retired. */
-		tpriv->num_retired += num_urbs - i;
-
-		/* If we completed short then don't try to discard. */
-		if (tpriv->reap_action == COMPLETED_EARLY)
-			return 0;
-
-		discard_urbs(itransfer, 0, i);
-
-		usbi_dbg(TRANSFER_CTX(transfer), "reporting successful submission but waiting for %d "
-			 "discards before reporting error", i);
-		return 0;
-	}
-
-	return 0;
-}
-
-static int submit_iso_transfer(struct usbi_transfer *itransfer)
-{
-	struct libusb_transfer *transfer =
-		USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
-	struct linux_transfer_priv *tpriv = usbi_get_transfer_priv(itransfer);
-	struct linux_device_handle_priv *hpriv =
-		usbi_get_device_handle_priv(transfer->dev_handle);
-	struct usbfs_urb **urbs;
-	int num_packets = transfer->num_iso_packets;
-	int num_packets_remaining;
-	int i, j;
-	int num_urbs;
-	unsigned int packet_len;
-	unsigned int total_len = 0;
-	unsigned char *urb_buffer = transfer->buffer;
-
-	if (num_packets < 1)
-		return LIBUSB_ERROR_INVALID_PARAM;
-
-	/* usbfs places arbitrary limits on iso URBs. this limit has changed
-	 * at least three times, but we attempt to detect this limit during
-	 * init and check it here. if the kernel rejects the request due to
-	 * its size, we return an error indicating such to the user.
-	 */
-	for (i = 0; i < num_packets; i++) {
-		packet_len = transfer->iso_packet_desc[i].length;
-
-		if (packet_len > max_iso_packet_len) {
-			usbi_warn(TRANSFER_CTX(transfer),
-				  "iso packet length of %u bytes exceeds maximum of %u bytes",
-				  packet_len, max_iso_packet_len);
-			return LIBUSB_ERROR_INVALID_PARAM;
-		}
-
-		total_len += packet_len;
-	}
-
-	if (transfer->length < (int)total_len)
-		return LIBUSB_ERROR_INVALID_PARAM;
-
-	/* usbfs limits the number of iso packets per URB */
-	num_urbs = (num_packets + (MAX_ISO_PACKETS_PER_URB - 1)) / MAX_ISO_PACKETS_PER_URB;
-
-	usbi_dbg(TRANSFER_CTX(transfer), "need %d urbs for new transfer with length %d", num_urbs, transfer->length);
-
-	urbs = calloc(num_urbs, sizeof(*urbs));
-	if (!urbs)
-		return LIBUSB_ERROR_NO_MEM;
-
-	tpriv->iso_urbs = urbs;
-	tpriv->num_urbs = num_urbs;
-	tpriv->num_retired = 0;
-	tpriv->reap_action = NORMAL;
-	tpriv->iso_packet_offset = 0;
-
-	/* allocate + initialize each URB with the correct number of packets */
-	num_packets_remaining = num_packets;
-	for (i = 0, j = 0; i < num_urbs; i++) {
-		int num_packets_in_urb = MIN(num_packets_remaining, MAX_ISO_PACKETS_PER_URB);
-		struct usbfs_urb *urb;
-		size_t alloc_size;
-		int k;
-
-		alloc_size = sizeof(*urb)
-			+ (num_packets_in_urb * sizeof(struct usbfs_iso_packet_desc));
-		urb = calloc(1, alloc_size);
-		if (!urb) {
-			free_iso_urbs(tpriv);
-			return LIBUSB_ERROR_NO_MEM;
-		}
-		urbs[i] = urb;
-
-		/* populate packet lengths */
-		for (k = 0; k < num_packets_in_urb; j++, k++) {
-			packet_len = transfer->iso_packet_desc[j].length;
-			urb->buffer_length += packet_len;
-			urb->iso_frame_desc[k].length = packet_len;
-		}
-
-		urb->usercontext = itransfer;
-		urb->type = USBFS_URB_TYPE_ISO;
-		/* FIXME: interface for non-ASAP data? */
-		urb->flags = USBFS_URB_ISO_ASAP;
-		urb->endpoint = transfer->endpoint;
-		urb->number_of_packets = num_packets_in_urb;
-		urb->buffer = urb_buffer;
-
-		urb_buffer += urb->buffer_length;
-		num_packets_remaining -= num_packets_in_urb;
-	}
-
-	/* submit URBs */
-	for (i = 0; i < num_urbs; i++) {
-		int r = ioctl(hpriv->fd, IOCTL_USBFS_SUBMITURB, urbs[i]);
-
-		if (r == 0)
-			continue;
-
-		if (errno == ENODEV) {
-			r = LIBUSB_ERROR_NO_DEVICE;
-		} else if (errno == EINVAL) {
-			usbi_warn(TRANSFER_CTX(transfer), "submiturb failed, transfer too large");
-			r = LIBUSB_ERROR_INVALID_PARAM;
-		} else if (errno == EMSGSIZE) {
-			usbi_warn(TRANSFER_CTX(transfer), "submiturb failed, iso packet length too large");
-			r = LIBUSB_ERROR_INVALID_PARAM;
-		} else {
-			usbi_err(TRANSFER_CTX(transfer), "submiturb failed, errno=%d", errno);
-			r = LIBUSB_ERROR_IO;
-		}
-
-		/* if the first URB submission fails, we can simply free up and
-		 * return failure immediately. */
-		if (i == 0) {
-			usbi_dbg(TRANSFER_CTX(transfer), "first URB failed, easy peasy");
-			free_iso_urbs(tpriv);
-			return r;
-		}
-
-		/* if it's not the first URB that failed, the situation is a bit
-		 * tricky. we must discard all previous URBs. there are
-		 * complications:
-		 *  - discarding is asynchronous - discarded urbs will be reaped
-		 *    later. the user must not have freed the transfer when the
-		 *    discarded URBs are reaped, otherwise libusb will be using
-		 *    freed memory.
-		 *  - the earlier URBs may have completed successfully and we do
-		 *    not want to throw away any data.
-		 * so, in this case we discard all the previous URBs BUT we report
-		 * that the transfer was submitted successfully. then later when
-		 * the final discard completes we can report error to the user.
-		 */
-		tpriv->reap_action = SUBMIT_FAILED;
-
-		/* The URBs we haven't submitted yet we count as already
-		 * retired. */
-		tpriv->num_retired = num_urbs - i;
-		discard_urbs(itransfer, 0, i);
-
-		usbi_dbg(TRANSFER_CTX(transfer), "reporting successful submission but waiting for %d "
-			 "discards before reporting error", i);
-		return 0;
-	}
-
-	return 0;
-}
-
-static int submit_control_transfer(struct usbi_transfer *itransfer)
-{
-	struct linux_transfer_priv *tpriv = usbi_get_transfer_priv(itransfer);
-	struct libusb_transfer *transfer =
-		USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
-	struct linux_device_handle_priv *hpriv =
-		usbi_get_device_handle_priv(transfer->dev_handle);
-	struct usbfs_urb *urb;
-	int r;
-
-	if (transfer->length - LIBUSB_CONTROL_SETUP_SIZE > MAX_CTRL_BUFFER_LENGTH)
-		return LIBUSB_ERROR_INVALID_PARAM;
-
-	urb = calloc(1, sizeof(*urb));
-	if (!urb)
-		return LIBUSB_ERROR_NO_MEM;
-	tpriv->urbs = urb;
-	tpriv->num_urbs = 1;
-	tpriv->reap_action = NORMAL;
-
-	urb->usercontext = itransfer;
-	urb->type = USBFS_URB_TYPE_CONTROL;
-	urb->endpoint = transfer->endpoint;
-	urb->buffer = transfer->buffer;
-	urb->buffer_length = transfer->length;
-
-	r = ioctl(hpriv->fd, IOCTL_USBFS_SUBMITURB, urb);
-	if (r < 0) {
-		free(urb);
-		tpriv->urbs = NULL;
-		if (errno == ENODEV)
-			return LIBUSB_ERROR_NO_DEVICE;
-
-		usbi_err(TRANSFER_CTX(transfer), "submiturb failed, errno=%d", errno);
-		return LIBUSB_ERROR_IO;
-	}
-	return 0;
-}
-
-static int op_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_BULK_STREAM:
-		return submit_bulk_transfer(itransfer);
-	case LIBUSB_TRANSFER_TYPE_INTERRUPT:
-		return submit_bulk_transfer(itransfer);
-	case LIBUSB_TRANSFER_TYPE_ISOCHRONOUS:
-		return submit_iso_transfer(itransfer);
-	default:
-		usbi_err(TRANSFER_CTX(transfer), "unknown transfer type %u", transfer->type);
-		return LIBUSB_ERROR_INVALID_PARAM;
-	}
-}
-
-static int op_cancel_transfer(struct usbi_transfer *itransfer)
-{
-	struct linux_transfer_priv *tpriv = usbi_get_transfer_priv(itransfer);
-	struct libusb_transfer *transfer =
-		USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
-	int r;
-
-	if (!tpriv->urbs)
-		return LIBUSB_ERROR_NOT_FOUND;
-
-	r = discard_urbs(itransfer, 0, tpriv->num_urbs);
-	if (r != 0)
-		return r;
-
-	switch (transfer->type) {
-	case LIBUSB_TRANSFER_TYPE_BULK:
-	case LIBUSB_TRANSFER_TYPE_BULK_STREAM:
-		if (tpriv->reap_action == ERROR)
-			break;
-		/* else, fall through */
-	default:
-		tpriv->reap_action = CANCELLED;
-	}
-
-	return 0;
-}
-
-static void op_clear_transfer_priv(struct usbi_transfer *itransfer)
-{
-	struct libusb_transfer *transfer =
-		USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
-	struct linux_transfer_priv *tpriv = usbi_get_transfer_priv(itransfer);
-
-	switch (transfer->type) {
-	case LIBUSB_TRANSFER_TYPE_CONTROL:
-	case LIBUSB_TRANSFER_TYPE_BULK:
-	case LIBUSB_TRANSFER_TYPE_BULK_STREAM:
-	case LIBUSB_TRANSFER_TYPE_INTERRUPT:
-		if (tpriv->urbs) {
-			free(tpriv->urbs);
-			tpriv->urbs = NULL;
-		}
-		break;
-	case LIBUSB_TRANSFER_TYPE_ISOCHRONOUS:
-		if (tpriv->iso_urbs) {
-			free_iso_urbs(tpriv);
-			tpriv->iso_urbs = NULL;
-		}
-		break;
-	default:
-		usbi_err(TRANSFER_CTX(transfer), "unknown transfer type %u", transfer->type);
-	}
-}
-
-static int handle_bulk_completion(struct usbi_transfer *itransfer,
-	struct usbfs_urb *urb)
-{
-	struct linux_transfer_priv *tpriv = usbi_get_transfer_priv(itransfer);
-	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
-	int urb_idx = urb - tpriv->urbs;
-
-	usbi_mutex_lock(&itransfer->lock);
-	usbi_dbg(TRANSFER_CTX(transfer), "handling completion status %d of bulk urb %d/%d", urb->status,
-		 urb_idx + 1, tpriv->num_urbs);
-
-	tpriv->num_retired++;
-
-	if (tpriv->reap_action != NORMAL) {
-		/* cancelled, submit_fail, or completed early */
-		usbi_dbg(TRANSFER_CTX(transfer), "abnormal reap: urb status %d", urb->status);
-
-		/* even though we're in the process of cancelling, it's possible that
-		 * we may receive some data in these URBs that we don't want to lose.
-		 * examples:
-		 * 1. while the kernel is cancelling all the packets that make up an
-		 *    URB, a few of them might complete. so we get back a successful
-		 *    cancellation *and* some data.
-		 * 2. we receive a short URB which marks the early completion condition,
-		 *    so we start cancelling the remaining URBs. however, we're too
-		 *    slow and another URB completes (or at least completes partially).
-		 *    (this can't happen since we always use BULK_CONTINUATION.)
-		 *
-		 * When this happens, our objectives are not to lose any "surplus" data,
-		 * and also to stick it at the end of the previously-received data
-		 * (closing any holes), so that libusb reports the total amount of
-		 * transferred data and presents it in a contiguous chunk.
-		 */
-		if (urb->actual_length > 0) {
-			unsigned char *target = transfer->buffer + itransfer->transferred;
-
-			usbi_dbg(TRANSFER_CTX(transfer), "received %d bytes of surplus data", urb->actual_length);
-			if (urb->buffer != target) {
-				usbi_dbg(TRANSFER_CTX(transfer), "moving surplus data from offset %zu to offset %zu",
-					 (unsigned char *)urb->buffer - transfer->buffer,
-					 target - transfer->buffer);
-				memmove(target, urb->buffer, urb->actual_length);
-			}
-			itransfer->transferred += urb->actual_length;
-		}
-
-		if (tpriv->num_retired == tpriv->num_urbs) {
-			usbi_dbg(TRANSFER_CTX(transfer), "abnormal reap: last URB handled, reporting");
-			if (tpriv->reap_action != COMPLETED_EARLY &&
-			    tpriv->reap_status == LIBUSB_TRANSFER_COMPLETED)
-				tpriv->reap_status = LIBUSB_TRANSFER_ERROR;
-			goto completed;
-		}
-		goto out_unlock;
-	}
-
-	itransfer->transferred += urb->actual_length;
-
-	/* Many of these errors can occur on *any* urb of a multi-urb
-	 * transfer.  When they do, we tear down the rest of the transfer.
-	 */
-	switch (urb->status) {
-	case 0:
-		break;
-	case -EREMOTEIO: /* short transfer */
-		break;
-	case -ENOENT: /* cancelled */
-	case -ECONNRESET:
-		break;
-	case -ENODEV:
-	case -ESHUTDOWN:
-		usbi_dbg(TRANSFER_CTX(transfer), "device removed");
-		tpriv->reap_status = LIBUSB_TRANSFER_NO_DEVICE;
-		goto cancel_remaining;
-	case -EPIPE:
-		usbi_dbg(TRANSFER_CTX(transfer), "detected endpoint stall");
-		if (tpriv->reap_status == LIBUSB_TRANSFER_COMPLETED)
-			tpriv->reap_status = LIBUSB_TRANSFER_STALL;
-		goto cancel_remaining;
-	case -EOVERFLOW:
-		/* overflow can only ever occur in the last urb */
-		usbi_dbg(TRANSFER_CTX(transfer), "overflow, actual_length=%d", urb->actual_length);
-		if (tpriv->reap_status == LIBUSB_TRANSFER_COMPLETED)
-			tpriv->reap_status = LIBUSB_TRANSFER_OVERFLOW;
-		goto completed;
-	case -ETIME:
-	case -EPROTO:
-	case -EILSEQ:
-	case -ECOMM:
-	case -ENOSR:
-		usbi_dbg(TRANSFER_CTX(transfer), "low-level bus error %d", urb->status);
-		tpriv->reap_action = ERROR;
-		goto cancel_remaining;
-	default:
-		usbi_warn(ITRANSFER_CTX(itransfer), "unrecognised urb status %d", urb->status);
-		tpriv->reap_action = ERROR;
-		goto cancel_remaining;
-	}
-
-	/* if we've reaped all urbs or we got less data than requested then we're
-	 * done */
-	if (tpriv->num_retired == tpriv->num_urbs) {
-		usbi_dbg(TRANSFER_CTX(transfer), "all URBs in transfer reaped --> complete!");
-		goto completed;
-	} else if (urb->actual_length < urb->buffer_length) {
-		usbi_dbg(TRANSFER_CTX(transfer), "short transfer %d/%d --> complete!",
-			 urb->actual_length, urb->buffer_length);
-		if (tpriv->reap_action == NORMAL)
-			tpriv->reap_action = COMPLETED_EARLY;
-	} else {
-		goto out_unlock;
-	}
-
-cancel_remaining:
-	if (tpriv->reap_action == ERROR && tpriv->reap_status == LIBUSB_TRANSFER_COMPLETED)
-		tpriv->reap_status = LIBUSB_TRANSFER_ERROR;
-
-	if (tpriv->num_retired == tpriv->num_urbs) /* nothing to cancel */
-		goto completed;
-
-	/* cancel remaining urbs and wait for their completion before
-	 * reporting results */
-	discard_urbs(itransfer, urb_idx + 1, tpriv->num_urbs);
-
-out_unlock:
-	usbi_mutex_unlock(&itransfer->lock);
-	return 0;
-
-completed:
-	free(tpriv->urbs);
-	tpriv->urbs = NULL;
-	usbi_mutex_unlock(&itransfer->lock);
-	return tpriv->reap_action == CANCELLED ?
-		usbi_handle_transfer_cancellation(itransfer) :
-		usbi_handle_transfer_completion(itransfer, tpriv->reap_status);
-}
-
-static int handle_iso_completion(struct usbi_transfer *itransfer,
-	struct usbfs_urb *urb)
-{
-	struct libusb_transfer *transfer =
-		USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
-	struct linux_transfer_priv *tpriv = usbi_get_transfer_priv(itransfer);
-	int num_urbs = tpriv->num_urbs;
-	int urb_idx = 0;
-	int i;
-	enum libusb_transfer_status status = LIBUSB_TRANSFER_COMPLETED;
-
-	usbi_mutex_lock(&itransfer->lock);
-	for (i = 0; i < num_urbs; i++) {
-		if (urb == tpriv->iso_urbs[i]) {
-			urb_idx = i + 1;
-			break;
-		}
-	}
-	if (urb_idx == 0) {
-		usbi_err(TRANSFER_CTX(transfer), "could not locate urb!");
-		usbi_mutex_unlock(&itransfer->lock);
-		return LIBUSB_ERROR_NOT_FOUND;
-	}
-
-	usbi_dbg(TRANSFER_CTX(transfer), "handling completion status %d of iso urb %d/%d", urb->status,
-		 urb_idx, num_urbs);
-
-	/* copy isochronous results back in */
-
-	for (i = 0; i < urb->number_of_packets; i++) {
-		struct usbfs_iso_packet_desc *urb_desc = &urb->iso_frame_desc[i];
-		struct libusb_iso_packet_descriptor *lib_desc =
-			&transfer->iso_packet_desc[tpriv->iso_packet_offset++];
-
-		lib_desc->status = LIBUSB_TRANSFER_COMPLETED;
-		switch (urb_desc->status) {
-		case 0:
-			break;
-		case -ENOENT: /* cancelled */
-		case -ECONNRESET:
-			break;
-		case -ENODEV:
-		case -ESHUTDOWN:
-			usbi_dbg(TRANSFER_CTX(transfer), "packet %d - device removed", i);
-			lib_desc->status = LIBUSB_TRANSFER_NO_DEVICE;
-			break;
-		case -EPIPE:
-			usbi_dbg(TRANSFER_CTX(transfer), "packet %d - detected endpoint stall", i);
-			lib_desc->status = LIBUSB_TRANSFER_STALL;
-			break;
-		case -EOVERFLOW:
-			usbi_dbg(TRANSFER_CTX(transfer), "packet %d - overflow error", i);
-			lib_desc->status = LIBUSB_TRANSFER_OVERFLOW;
-			break;
-		case -ETIME:
-		case -EPROTO:
-		case -EILSEQ:
-		case -ECOMM:
-		case -ENOSR:
-		case -EXDEV:
-			usbi_dbg(TRANSFER_CTX(transfer), "packet %d - low-level USB error %d", i, urb_desc->status);
-			lib_desc->status = LIBUSB_TRANSFER_ERROR;
-			break;
-		default:
-			usbi_warn(TRANSFER_CTX(transfer), "packet %d - unrecognised urb status %d",
-				  i, urb_desc->status);
-			lib_desc->status = LIBUSB_TRANSFER_ERROR;
-			break;
-		}
-		lib_desc->actual_length = urb_desc->actual_length;
-	}
-
-	tpriv->num_retired++;
-
-	if (tpriv->reap_action != NORMAL) { /* cancelled or submit_fail */
-		usbi_dbg(TRANSFER_CTX(transfer), "CANCEL: urb status %d", urb->status);
-
-		if (tpriv->num_retired == num_urbs) {
-			usbi_dbg(TRANSFER_CTX(transfer), "CANCEL: last URB handled, reporting");
-			free_iso_urbs(tpriv);
-			if (tpriv->reap_action == CANCELLED) {
-				usbi_mutex_unlock(&itransfer->lock);
-				return usbi_handle_transfer_cancellation(itransfer);
-			} else {
-				usbi_mutex_unlock(&itransfer->lock);
-				return usbi_handle_transfer_completion(itransfer, LIBUSB_TRANSFER_ERROR);
-			}
-		}
-		goto out;
-	}
-
-	switch (urb->status) {
-	case 0:
-		break;
-	case -ENOENT: /* cancelled */
-	case -ECONNRESET:
-		break;
-	case -ESHUTDOWN:
-		usbi_dbg(TRANSFER_CTX(transfer), "device removed");
-		status = LIBUSB_TRANSFER_NO_DEVICE;
-		break;
-	default:
-		usbi_warn(TRANSFER_CTX(transfer), "unrecognised urb status %d", urb->status);
-		status = LIBUSB_TRANSFER_ERROR;
-		break;
-	}
-
-	/* if we've reaped all urbs then we're done */
-	if (tpriv->num_retired == num_urbs) {
-		usbi_dbg(TRANSFER_CTX(transfer), "all URBs in transfer reaped --> complete!");
-		free_iso_urbs(tpriv);
-		usbi_mutex_unlock(&itransfer->lock);
-		return usbi_handle_transfer_completion(itransfer, status);
-	}
-
-out:
-	usbi_mutex_unlock(&itransfer->lock);
-	return 0;
-}
-
-static int handle_control_completion(struct usbi_transfer *itransfer,
-	struct usbfs_urb *urb)
-{
-	struct linux_transfer_priv *tpriv = usbi_get_transfer_priv(itransfer);
-	int status;
-
-	usbi_mutex_lock(&itransfer->lock);
-	usbi_dbg(ITRANSFER_CTX(itransfer), "handling completion status %d", urb->status);
-
-	itransfer->transferred += urb->actual_length;
-
-	if (tpriv->reap_action == CANCELLED) {
-		if (urb->status && urb->status != -ENOENT)
-			usbi_warn(ITRANSFER_CTX(itransfer), "cancel: unrecognised urb status %d",
-				  urb->status);
-		free(tpriv->urbs);
-		tpriv->urbs = NULL;
-		usbi_mutex_unlock(&itransfer->lock);
-		return usbi_handle_transfer_cancellation(itransfer);
-	}
-
-	switch (urb->status) {
-	case 0:
-		status = LIBUSB_TRANSFER_COMPLETED;
-		break;
-	case -ENOENT: /* cancelled */
-		status = LIBUSB_TRANSFER_CANCELLED;
-		break;
-	case -ENODEV:
-	case -ESHUTDOWN:
-		usbi_dbg(ITRANSFER_CTX(itransfer), "device removed");
-		status = LIBUSB_TRANSFER_NO_DEVICE;
-		break;
-	case -EPIPE:
-		usbi_dbg(ITRANSFER_CTX(itransfer), "unsupported control request");
-		status = LIBUSB_TRANSFER_STALL;
-		break;
-	case -EOVERFLOW:
-		usbi_dbg(ITRANSFER_CTX(itransfer), "overflow, actual_length=%d", urb->actual_length);
-		status = LIBUSB_TRANSFER_OVERFLOW;
-		break;
-	case -ETIME:
-	case -EPROTO:
-	case -EILSEQ:
-	case -ECOMM:
-	case -ENOSR:
-		usbi_dbg(ITRANSFER_CTX(itransfer), "low-level bus error %d", urb->status);
-		status = LIBUSB_TRANSFER_ERROR;
-		break;
-	default:
-		usbi_warn(ITRANSFER_CTX(itransfer), "unrecognised urb status %d", urb->status);
-		status = LIBUSB_TRANSFER_ERROR;
-		break;
-	}
-
-	free(tpriv->urbs);
-	tpriv->urbs = NULL;
-	usbi_mutex_unlock(&itransfer->lock);
-	return usbi_handle_transfer_completion(itransfer, status);
-}
-
-static int reap_for_handle(struct libusb_device_handle *handle)
-{
-	struct linux_device_handle_priv *hpriv = usbi_get_device_handle_priv(handle);
-	int r;
-	struct usbfs_urb *urb = NULL;
-	struct usbi_transfer *itransfer;
-	struct libusb_transfer *transfer;
-
-	r = ioctl(hpriv->fd, IOCTL_USBFS_REAPURBNDELAY, &urb);
-	if (r < 0) {
-		if (errno == EAGAIN)
-			return 1;
-		if (errno == ENODEV)
-			return LIBUSB_ERROR_NO_DEVICE;
-
-		usbi_err(HANDLE_CTX(handle), "reap failed, errno=%d", errno);
-		return LIBUSB_ERROR_IO;
-	}
-
-	itransfer = urb->usercontext;
-	transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
-
-	usbi_dbg(HANDLE_CTX(handle), "urb type=%u status=%d transferred=%d", urb->type, urb->status, urb->actual_length);
-
-	switch (transfer->type) {
-	case LIBUSB_TRANSFER_TYPE_ISOCHRONOUS:
-		return handle_iso_completion(itransfer, urb);
-	case LIBUSB_TRANSFER_TYPE_BULK:
-	case LIBUSB_TRANSFER_TYPE_BULK_STREAM:
-	case LIBUSB_TRANSFER_TYPE_INTERRUPT:
-		return handle_bulk_completion(itransfer, urb);
-	case LIBUSB_TRANSFER_TYPE_CONTROL:
-		return handle_control_completion(itransfer, urb);
-	default:
-		usbi_err(HANDLE_CTX(handle), "unrecognised transfer type %u", transfer->type);
-		return LIBUSB_ERROR_OTHER;
-	}
-}
-
-static int op_handle_events(struct libusb_context *ctx,
-	void *event_data, unsigned int count, unsigned int num_ready)
-{
-	struct pollfd *fds = event_data;
-	unsigned int n;
-	int r;
-
-	usbi_mutex_lock(&ctx->open_devs_lock);
-	for (n = 0; n < count && num_ready > 0; n++) {
-		struct pollfd *pollfd = &fds[n];
-		struct libusb_device_handle *handle;
-		struct linux_device_handle_priv *hpriv = NULL;
-		int reap_count;
-
-		if (!pollfd->revents)
-			continue;
-
-		num_ready--;
-		for_each_open_device(ctx, handle) {
-			hpriv = usbi_get_device_handle_priv(handle);
-			if (hpriv->fd == pollfd->fd)
-				break;
-		}
-
-		if (!hpriv || hpriv->fd != pollfd->fd) {
-			usbi_err(ctx, "cannot find handle for fd %d",
-				 pollfd->fd);
-			continue;
-		}
-
-		if (pollfd->revents & POLLERR) {
-			/* remove the fd from the pollfd set so that it doesn't continuously
-			 * trigger an event, and flag that it has been removed so op_close()
-			 * doesn't try to remove it a second time */
-			usbi_remove_event_source(HANDLE_CTX(handle), hpriv->fd);
-			hpriv->fd_removed = 1;
-
-			/* device will still be marked as attached if hotplug monitor thread
-			 * hasn't processed remove event yet */
-			usbi_mutex_static_lock(&linux_hotplug_lock);
-			if (usbi_atomic_load(&handle->dev->attached))
-				linux_device_disconnected(handle->dev->bus_number,
-							  handle->dev->device_address);
-			usbi_mutex_static_unlock(&linux_hotplug_lock);
-
-			if (hpriv->caps & USBFS_CAP_REAP_AFTER_DISCONNECT) {
-				do {
-					r = reap_for_handle(handle);
-				} while (r == 0);
-			}
-
-			usbi_handle_disconnect(handle);
-			continue;
-		}
-
-		reap_count = 0;
-		do {
-			r = reap_for_handle(handle);
-		} while (r == 0 && ++reap_count <= 25);
-
-		if (r == 1 || r == LIBUSB_ERROR_NO_DEVICE)
-			continue;
-		else if (r < 0)
-			goto out;
-	}
-
-	r = 0;
-out:
-	usbi_mutex_unlock(&ctx->open_devs_lock);
-	return r;
-}
-
-const struct usbi_os_backend usbi_backend = {
-	.name = "Linux usbfs",
-	.caps = USBI_CAP_HAS_HID_ACCESS|USBI_CAP_SUPPORTS_DETACH_KERNEL_DRIVER,
-	.init = op_init,
-	.exit = op_exit,
-	.set_option = op_set_option,
-	.hotplug_poll = op_hotplug_poll,
-	.get_active_config_descriptor = op_get_active_config_descriptor,
-	.get_config_descriptor = op_get_config_descriptor,
-	.get_config_descriptor_by_value = op_get_config_descriptor_by_value,
-
-	.wrap_sys_device = op_wrap_sys_device,
-	.open = op_open,
-	.close = op_close,
-	.get_configuration = op_get_configuration,
-	.set_configuration = op_set_configuration,
-	.claim_interface = op_claim_interface,
-	.release_interface = op_release_interface,
-
-	.set_interface_altsetting = op_set_interface,
-	.clear_halt = op_clear_halt,
-	.reset_device = op_reset_device,
-
-	.alloc_streams = op_alloc_streams,
-	.free_streams = op_free_streams,
-
-	.dev_mem_alloc = op_dev_mem_alloc,
-	.dev_mem_free = op_dev_mem_free,
-
-	.kernel_driver_active = op_kernel_driver_active,
-	.detach_kernel_driver = op_detach_kernel_driver,
-	.attach_kernel_driver = op_attach_kernel_driver,
-
-	.destroy_device = op_destroy_device,
-
-	.submit_transfer = op_submit_transfer,
-	.cancel_transfer = op_cancel_transfer,
-	.clear_transfer_priv = op_clear_transfer_priv,
-
-	.handle_events = op_handle_events,
-
-	.device_priv_size = sizeof(struct linux_device_priv),
-	.device_handle_priv_size = sizeof(struct linux_device_handle_priv),
-	.transfer_priv_size = sizeof(struct linux_transfer_priv),
-};