1 /* -*- Mode: C; indent-tabs-mode:t ; c-basic-offset:8 -*- */
3 * Core functions for libusbx
4 * Copyright © 2012-2013 Nathan Hjelm <hjelmn@cs.unm.edu>
5 * Copyright © 2007-2008 Daniel Drake <dsd@gentoo.org>
6 * Copyright © 2001 Johannes Erdfelt <johannes@erdfelt.com>
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with this library; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
30 #ifdef HAVE_SYS_TYPES_H
31 #include <sys/types.h>
33 #ifdef HAVE_SYS_TIME_H
41 #include <android/log.h>
48 const struct usbi_os_backend * const usbi_backend = &linux_usbfs_backend;
49 #elif defined(OS_DARWIN)
50 const struct usbi_os_backend * const usbi_backend = &darwin_backend;
51 #elif defined(OS_OPENBSD)
52 const struct usbi_os_backend * const usbi_backend = &openbsd_backend;
53 #elif defined(OS_WINDOWS)
54 const struct usbi_os_backend * const usbi_backend = &windows_backend;
55 #elif defined(OS_WINCE)
56 const struct usbi_os_backend * const usbi_backend = &wince_backend;
58 #error "Unsupported OS"
61 struct libusb_context *usbi_default_context = NULL;
62 static const struct libusb_version libusb_version_internal =
63 { LIBUSB_MAJOR, LIBUSB_MINOR, LIBUSB_MICRO, LIBUSB_NANO,
64 LIBUSB_RC, "http://libusbx.org" };
65 static int default_context_refcnt = 0;
66 static usbi_mutex_static_t default_context_lock = USBI_MUTEX_INITIALIZER;
67 static struct timeval timestamp_origin = { 0, 0 };
69 usbi_mutex_static_t active_contexts_lock = USBI_MUTEX_INITIALIZER;
70 struct list_head active_contexts_list;
73 * \mainpage libusbx-1.0 API Reference
75 * \section intro Introduction
77 * libusbx is an open source library that allows you to communicate with USB
78 * devices from userspace. For more info, see the
79 * <a href="http://libusbx.org">libusbx homepage</a>.
81 * This documentation is aimed at application developers wishing to
82 * communicate with USB peripherals from their own software. After reviewing
83 * this documentation, feedback and questions can be sent to the
84 * <a href="http://mailing-list.libusbx.org">libusbx-devel mailing list</a>.
86 * This documentation assumes knowledge of how to operate USB devices from
87 * a software standpoint (descriptors, configurations, interfaces, endpoints,
88 * control/bulk/interrupt/isochronous transfers, etc). Full information
89 * can be found in the <a href="http://www.usb.org/developers/docs/">USB 3.0
90 * Specification</a> which is available for free download. You can probably
91 * find less verbose introductions by searching the web.
93 * \section features Library features
95 * - All transfer types supported (control/bulk/interrupt/isochronous)
96 * - 2 transfer interfaces:
97 * -# Synchronous (simple)
98 * -# Asynchronous (more complicated, but more powerful)
99 * - Thread safe (although the asynchronous interface means that you
100 * usually won't need to thread)
101 * - Lightweight with lean API
102 * - Compatible with libusb-0.1 through the libusb-compat-0.1 translation layer
103 * - Hotplug support (on some platforms). See \ref hotplug.
105 * \section gettingstarted Getting Started
107 * To begin reading the API documentation, start with the Modules page which
108 * links to the different categories of libusbx's functionality.
110 * One decision you will have to make is whether to use the synchronous
111 * or the asynchronous data transfer interface. The \ref io documentation
112 * provides some insight into this topic.
114 * Some example programs can be found in the libusbx source distribution under
115 * the "examples" subdirectory. The libusbx homepage includes a list of
116 * real-life project examples which use libusbx.
118 * \section errorhandling Error handling
120 * libusbx functions typically return 0 on success or a negative error code
121 * on failure. These negative error codes relate to LIBUSB_ERROR constants
122 * which are listed on the \ref misc "miscellaneous" documentation page.
124 * \section msglog Debug message logging
126 * libusbx uses stderr for all logging. By default, logging is set to NONE,
127 * which means that no output will be produced. However, unless the library
128 * has been compiled with logging disabled, then any application calls to
129 * libusb_set_debug(), or the setting of the environmental variable
130 * LIBUSB_DEBUG outside of the application, can result in logging being
131 * produced. Your application should therefore not close stderr, but instead
132 * direct it to the null device if its output is undesireable.
134 * The libusb_set_debug() function can be used to enable logging of certain
135 * messages. Under standard configuration, libusbx doesn't really log much
136 * so you are advised to use this function to enable all error/warning/
137 * informational messages. It will help debug problems with your software.
139 * The logged messages are unstructured. There is no one-to-one correspondence
140 * between messages being logged and success or failure return codes from
141 * libusbx functions. There is no format to the messages, so you should not
142 * try to capture or parse them. They are not and will not be localized.
143 * These messages are not intended to being passed to your application user;
144 * instead, you should interpret the error codes returned from libusbx functions
145 * and provide appropriate notification to the user. The messages are simply
146 * there to aid you as a programmer, and if you're confused because you're
147 * getting a strange error code from a libusbx function, enabling message
148 * logging may give you a suitable explanation.
150 * The LIBUSB_DEBUG environment variable can be used to enable message logging
151 * at run-time. This environment variable should be set to a log level number,
152 * which is interpreted the same as the libusb_set_debug() parameter. When this
153 * environment variable is set, the message logging verbosity level is fixed
154 * and libusb_set_debug() effectively does nothing.
156 * libusbx can be compiled without any logging functions, useful for embedded
157 * systems. In this case, libusb_set_debug() and the LIBUSB_DEBUG environment
158 * variable have no effects.
160 * libusbx can also be compiled with verbose debugging messages always. When
161 * the library is compiled in this way, all messages of all verbosities are
162 * always logged. libusb_set_debug() and the LIBUSB_DEBUG environment variable
165 * \section remarks Other remarks
167 * libusbx does have imperfections. The \ref caveats "caveats" page attempts
172 * \page caveats Caveats
174 * \section devresets Device resets
176 * The libusb_reset_device() function allows you to reset a device. If your
177 * program has to call such a function, it should obviously be aware that
178 * the reset will cause device state to change (e.g. register values may be
181 * The problem is that any other program could reset the device your program
182 * is working with, at any time. libusbx does not offer a mechanism to inform
183 * you when this has happened, so if someone else resets your device it will
184 * not be clear to your own program why the device state has changed.
186 * Ultimately, this is a limitation of writing drivers in userspace.
187 * Separation from the USB stack in the underlying kernel makes it difficult
188 * for the operating system to deliver such notifications to your program.
189 * The Linux kernel USB stack allows such reset notifications to be delivered
190 * to in-kernel USB drivers, but it is not clear how such notifications could
191 * be delivered to second-class drivers that live in userspace.
193 * \section blockonly Blocking-only functionality
195 * The functionality listed below is only available through synchronous,
196 * blocking functions. There are no asynchronous/non-blocking alternatives,
197 * and no clear ways of implementing these.
199 * - Configuration activation (libusb_set_configuration())
200 * - Interface/alternate setting activation (libusb_set_interface_alt_setting())
201 * - Releasing of interfaces (libusb_release_interface())
202 * - Clearing of halt/stall condition (libusb_clear_halt())
203 * - Device resets (libusb_reset_device())
205 * \section configsel Configuration selection and handling
207 * When libusbx presents a device handle to an application, there is a chance
208 * that the corresponding device may be in unconfigured state. For devices
209 * with multiple configurations, there is also a chance that the configuration
210 * currently selected is not the one that the application wants to use.
212 * The obvious solution is to add a call to libusb_set_configuration() early
213 * on during your device initialization routines, but there are caveats to
215 * -# If the device is already in the desired configuration, calling
216 * libusb_set_configuration() using the same configuration value will cause
217 * a lightweight device reset. This may not be desirable behaviour.
218 * -# libusbx will be unable to change configuration if the device is in
219 * another configuration and other programs or drivers have claimed
220 * interfaces under that configuration.
221 * -# In the case where the desired configuration is already active, libusbx
222 * may not even be able to perform a lightweight device reset. For example,
223 * take my USB keyboard with fingerprint reader: I'm interested in driving
224 * the fingerprint reader interface through libusbx, but the kernel's
225 * USB-HID driver will almost always have claimed the keyboard interface.
226 * Because the kernel has claimed an interface, it is not even possible to
227 * perform the lightweight device reset, so libusb_set_configuration() will
228 * fail. (Luckily the device in question only has a single configuration.)
230 * One solution to some of the above problems is to consider the currently
231 * active configuration. If the configuration we want is already active, then
232 * we don't have to select any configuration:
234 cfg = libusb_get_configuration(dev);
236 libusb_set_configuration(dev, desired);
239 * This is probably suitable for most scenarios, but is inherently racy:
240 * another application or driver may change the selected configuration
241 * <em>after</em> the libusb_get_configuration() call.
243 * Even in cases where libusb_set_configuration() succeeds, consider that other
244 * applications or drivers may change configuration after your application
245 * calls libusb_set_configuration().
247 * One possible way to lock your device into a specific configuration is as
249 * -# Set the desired configuration (or use the logic above to realise that
250 * it is already in the desired configuration)
251 * -# Claim the interface that you wish to use
252 * -# Check that the currently active configuration is the one that you want
255 * The above method works because once an interface is claimed, no application
256 * or driver is able to select another configuration.
258 * \section earlycomp Early transfer completion
260 * NOTE: This section is currently Linux-centric. I am not sure if any of these
261 * considerations apply to Darwin or other platforms.
263 * When a transfer completes early (i.e. when less data is received/sent in
264 * any one packet than the transfer buffer allows for) then libusbx is designed
265 * to terminate the transfer immediately, not transferring or receiving any
266 * more data unless other transfers have been queued by the user.
268 * On legacy platforms, libusbx is unable to do this in all situations. After
269 * the incomplete packet occurs, "surplus" data may be transferred. For recent
270 * versions of libusbx, this information is kept (the data length of the
271 * transfer is updated) and, for device-to-host transfers, any surplus data was
272 * added to the buffer. Still, this is not a nice solution because it loses the
273 * information about the end of the short packet, and the user probably wanted
274 * that surplus data to arrive in the next logical transfer.
277 * \section zlp Zero length packets
279 * - libusbx is able to send a packet of zero length to an endpoint simply by
280 * submitting a transfer of zero length.
281 * - The \ref libusb_transfer_flags::LIBUSB_TRANSFER_ADD_ZERO_PACKET
282 * "LIBUSB_TRANSFER_ADD_ZERO_PACKET" flag is currently only supported on Linux.
286 * \page contexts Contexts
288 * It is possible that libusbx may be used simultaneously from two independent
289 * libraries linked into the same executable. For example, if your application
290 * has a plugin-like system which allows the user to dynamically load a range
291 * of modules into your program, it is feasible that two independently
292 * developed modules may both use libusbx.
294 * libusbx is written to allow for these multiple user scenarios. The two
295 * "instances" of libusbx will not interfere: libusb_set_debug() calls
296 * from one user will not affect the same settings for other users, other
297 * users can continue using libusbx after one of them calls libusb_exit(), etc.
299 * This is made possible through libusbx's <em>context</em> concept. When you
300 * call libusb_init(), you are (optionally) given a context. You can then pass
301 * this context pointer back into future libusbx functions.
303 * In order to keep things simple for more simplistic applications, it is
304 * legal to pass NULL to all functions requiring a context pointer (as long as
305 * you're sure no other code will attempt to use libusbx from the same process).
306 * When you pass NULL, the default context will be used. The default context
307 * is created the first time a process calls libusb_init() when no other
308 * context is alive. Contexts are destroyed during libusb_exit().
310 * The default context is reference-counted and can be shared. That means that
311 * if libusb_init(NULL) is called twice within the same process, the two
312 * users end up sharing the same context. The deinitialization and freeing of
313 * the default context will only happen when the last user calls libusb_exit().
314 * In other words, the default context is created and initialized when its
315 * reference count goes from 0 to 1, and is deinitialized and destroyed when
316 * its reference count goes from 1 to 0.
318 * You may be wondering why only a subset of libusbx functions require a
319 * context pointer in their function definition. Internally, libusbx stores
320 * context pointers in other objects (e.g. libusb_device instances) and hence
321 * can infer the context from those objects.
325 * @defgroup lib Library initialization/deinitialization
326 * This page details how to initialize and deinitialize libusbx. Initialization
327 * must be performed before using any libusbx functionality, and similarly you
328 * must not call any libusbx functions after deinitialization.
332 * @defgroup dev Device handling and enumeration
333 * The functionality documented below is designed to help with the following
335 * - Enumerating the USB devices currently attached to the system
336 * - Choosing a device to operate from your software
337 * - Opening and closing the chosen device
339 * \section nutshell In a nutshell...
341 * The description below really makes things sound more complicated than they
342 * actually are. The following sequence of function calls will be suitable
343 * for almost all scenarios and does not require you to have such a deep
344 * understanding of the resource management issues:
347 libusb_device **list;
348 libusb_device *found = NULL;
349 ssize_t cnt = libusb_get_device_list(NULL, &list);
355 for (i = 0; i < cnt; i++) {
356 libusb_device *device = list[i];
357 if (is_interesting(device)) {
364 libusb_device_handle *handle;
366 err = libusb_open(found, &handle);
372 libusb_free_device_list(list, 1);
375 * The two important points:
376 * - You asked libusb_free_device_list() to unreference the devices (2nd
378 * - You opened the device before freeing the list and unreferencing the
381 * If you ended up with a handle, you can now proceed to perform I/O on the
384 * \section devshandles Devices and device handles
385 * libusbx has a concept of a USB device, represented by the
386 * \ref libusb_device opaque type. A device represents a USB device that
387 * is currently or was previously connected to the system. Using a reference
388 * to a device, you can determine certain information about the device (e.g.
389 * you can read the descriptor data).
391 * The libusb_get_device_list() function can be used to obtain a list of
392 * devices currently connected to the system. This is known as device
395 * Just because you have a reference to a device does not mean it is
396 * necessarily usable. The device may have been unplugged, you may not have
397 * permission to operate such device, or another program or driver may be
400 * When you've found a device that you'd like to operate, you must ask
401 * libusbx to open the device using the libusb_open() function. Assuming
402 * success, libusbx then returns you a <em>device handle</em>
403 * (a \ref libusb_device_handle pointer). All "real" I/O operations then
404 * operate on the handle rather than the original device pointer.
406 * \section devref Device discovery and reference counting
408 * Device discovery (i.e. calling libusb_get_device_list()) returns a
409 * freshly-allocated list of devices. The list itself must be freed when
410 * you are done with it. libusbx also needs to know when it is OK to free
411 * the contents of the list - the devices themselves.
413 * To handle these issues, libusbx provides you with two separate items:
414 * - A function to free the list itself
415 * - A reference counting system for the devices inside
417 * New devices presented by the libusb_get_device_list() function all have a
418 * reference count of 1. You can increase and decrease reference count using
419 * libusb_ref_device() and libusb_unref_device(). A device is destroyed when
420 * its reference count reaches 0.
422 * With the above information in mind, the process of opening a device can
423 * be viewed as follows:
424 * -# Discover devices using libusb_get_device_list().
425 * -# Choose the device that you want to operate, and call libusb_open().
426 * -# Unref all devices in the discovered device list.
427 * -# Free the discovered device list.
429 * The order is important - you must not unreference the device before
430 * attempting to open it, because unreferencing it may destroy the device.
432 * For convenience, the libusb_free_device_list() function includes a
433 * parameter to optionally unreference all the devices in the list before
434 * freeing the list itself. This combines steps 3 and 4 above.
436 * As an implementation detail, libusb_open() actually adds a reference to
437 * the device in question. This is because the device remains available
438 * through the handle via libusb_get_device(). The reference is deleted during
442 /** @defgroup misc Miscellaneous */
444 /* we traverse usbfs without knowing how many devices we are going to find.
445 * so we create this discovered_devs model which is similar to a linked-list
446 * which grows when required. it can be freed once discovery has completed,
447 * eliminating the need for a list node in the libusb_device structure
449 #define DISCOVERED_DEVICES_SIZE_STEP 8
451 static struct discovered_devs *discovered_devs_alloc(void)
453 struct discovered_devs *ret =
454 malloc(sizeof(*ret) + (sizeof(void *) * DISCOVERED_DEVICES_SIZE_STEP));
458 ret->capacity = DISCOVERED_DEVICES_SIZE_STEP;
463 /* append a device to the discovered devices collection. may realloc itself,
464 * returning new discdevs. returns NULL on realloc failure. */
465 struct discovered_devs *discovered_devs_append(
466 struct discovered_devs *discdevs, struct libusb_device *dev)
468 size_t len = discdevs->len;
471 /* if there is space, just append the device */
472 if (len < discdevs->capacity) {
473 discdevs->devices[len] = libusb_ref_device(dev);
478 /* exceeded capacity, need to grow */
479 usbi_dbg("need to increase capacity");
480 capacity = discdevs->capacity + DISCOVERED_DEVICES_SIZE_STEP;
481 discdevs = usbi_reallocf(discdevs,
482 sizeof(*discdevs) + (sizeof(void *) * capacity));
484 discdevs->capacity = capacity;
485 discdevs->devices[len] = libusb_ref_device(dev);
492 static void discovered_devs_free(struct discovered_devs *discdevs)
496 for (i = 0; i < discdevs->len; i++)
497 libusb_unref_device(discdevs->devices[i]);
502 /* Allocate a new device with a specific session ID. The returned device has
503 * a reference count of 1. */
504 struct libusb_device *usbi_alloc_device(struct libusb_context *ctx,
505 unsigned long session_id)
507 size_t priv_size = usbi_backend->device_priv_size;
508 struct libusb_device *dev = calloc(1, sizeof(*dev) + priv_size);
514 r = usbi_mutex_init(&dev->lock, NULL);
522 dev->session_data = session_id;
523 dev->speed = LIBUSB_SPEED_UNKNOWN;
525 if (!libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG)) {
526 usbi_connect_device (dev);
532 void usbi_connect_device(struct libusb_device *dev)
534 libusb_hotplug_message message;
537 memset(&message, 0, sizeof(message));
538 message.event = LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED;
539 message.device = dev;
542 usbi_mutex_lock(&dev->ctx->usb_devs_lock);
543 list_add(&dev->list, &dev->ctx->usb_devs);
544 usbi_mutex_unlock(&dev->ctx->usb_devs_lock);
546 /* Signal that an event has occurred for this device if we support hotplug AND
547 * the hotplug pipe is ready. This prevents an event from getting raised during
548 * initial enumeration. */
549 if (libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG) && dev->ctx->hotplug_pipe[1] > 0) {
550 ret = usbi_write(dev->ctx->hotplug_pipe[1], &message, sizeof(message));
551 if (sizeof (message) != ret) {
552 usbi_err(DEVICE_CTX(dev), "error writing hotplug message");
557 void usbi_disconnect_device(struct libusb_device *dev)
559 libusb_hotplug_message message;
560 struct libusb_context *ctx = dev->ctx;
563 memset(&message, 0, sizeof(message));
564 message.event = LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT;
565 message.device = dev;
566 usbi_mutex_lock(&dev->lock);
568 usbi_mutex_unlock(&dev->lock);
570 /* Signal that an event has occurred for this device if we support hotplug AND
571 * the hotplug pipe is ready. This prevents an event from getting raised during
572 * initial enumeration. libusb_handle_events will take care of dereferencing the
574 if (libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG) && dev->ctx->hotplug_pipe[1] > 0) {
575 ret = usbi_write(dev->ctx->hotplug_pipe[1], &message, sizeof(message));
576 if (sizeof(message) != ret) {
577 usbi_err(DEVICE_CTX(dev), "error writing hotplug message");
581 usbi_mutex_lock(&ctx->usb_devs_lock);
582 list_del(&dev->list);
583 usbi_mutex_unlock(&ctx->usb_devs_lock);
586 /* Perform some final sanity checks on a newly discovered device. If this
587 * function fails (negative return code), the device should not be added
588 * to the discovered device list. */
589 int usbi_sanitize_device(struct libusb_device *dev)
592 uint8_t num_configurations;
594 r = usbi_device_cache_descriptor(dev);
598 num_configurations = dev->device_descriptor.bNumConfigurations;
599 if (num_configurations > USB_MAXCONFIG) {
600 usbi_err(DEVICE_CTX(dev), "too many configurations");
601 return LIBUSB_ERROR_IO;
602 } else if (0 == num_configurations)
603 usbi_dbg("zero configurations, maybe an unauthorized device");
605 dev->num_configurations = num_configurations;
609 /* Examine libusbx's internal list of known devices, looking for one with
610 * a specific session ID. Returns the matching device if it was found, and
612 struct libusb_device *usbi_get_device_by_session_id(struct libusb_context *ctx,
613 unsigned long session_id)
615 struct libusb_device *dev;
616 struct libusb_device *ret = NULL;
618 usbi_mutex_lock(&ctx->usb_devs_lock);
619 list_for_each_entry(dev, &ctx->usb_devs, list, struct libusb_device)
620 if (dev->session_data == session_id) {
624 usbi_mutex_unlock(&ctx->usb_devs_lock);
630 * Returns a list of USB devices currently attached to the system. This is
631 * your entry point into finding a USB device to operate.
633 * You are expected to unreference all the devices when you are done with
634 * them, and then free the list with libusb_free_device_list(). Note that
635 * libusb_free_device_list() can unref all the devices for you. Be careful
636 * not to unreference a device you are about to open until after you have
639 * This return value of this function indicates the number of devices in
640 * the resultant list. The list is actually one element larger, as it is
643 * \param ctx the context to operate on, or NULL for the default context
644 * \param list output location for a list of devices. Must be later freed with
645 * libusb_free_device_list().
646 * \returns the number of devices in the outputted list, or any
647 * \ref libusb_error according to errors encountered by the backend.
649 ssize_t API_EXPORTED libusb_get_device_list(libusb_context *ctx,
650 libusb_device ***list)
652 struct discovered_devs *discdevs = discovered_devs_alloc();
653 struct libusb_device **ret;
656 USBI_GET_CONTEXT(ctx);
660 return LIBUSB_ERROR_NO_MEM;
662 if (libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG)) {
663 /* backend provides hotplug support */
664 struct libusb_device *dev;
666 if (usbi_backend->hotplug_poll)
667 usbi_backend->hotplug_poll();
669 usbi_mutex_lock(&ctx->usb_devs_lock);
670 list_for_each_entry(dev, &ctx->usb_devs, list, struct libusb_device) {
671 discdevs = discovered_devs_append(discdevs, dev);
674 r = LIBUSB_ERROR_NO_MEM;
678 usbi_mutex_unlock(&ctx->usb_devs_lock);
680 /* backend does not provide hotplug support */
681 r = usbi_backend->get_device_list(ctx, &discdevs);
689 /* convert discovered_devs into a list */
691 ret = calloc(len + 1, sizeof(struct libusb_device *));
693 len = LIBUSB_ERROR_NO_MEM;
698 for (i = 0; i < len; i++) {
699 struct libusb_device *dev = discdevs->devices[i];
700 ret[i] = libusb_ref_device(dev);
705 discovered_devs_free(discdevs);
710 * Frees a list of devices previously discovered using
711 * libusb_get_device_list(). If the unref_devices parameter is set, the
712 * reference count of each device in the list is decremented by 1.
713 * \param list the list to free
714 * \param unref_devices whether to unref the devices in the list
716 void API_EXPORTED libusb_free_device_list(libusb_device **list,
724 struct libusb_device *dev;
726 while ((dev = list[i++]) != NULL)
727 libusb_unref_device(dev);
733 * Get the number of the bus that a device is connected to.
734 * \param dev a device
735 * \returns the bus number
737 uint8_t API_EXPORTED libusb_get_bus_number(libusb_device *dev)
739 return dev->bus_number;
743 * Get the number of the port that a device is connected to.
744 * Unless the OS does something funky, or you are hot-plugging USB extension cards,
745 * the port number returned by this call is usually guaranteed to be uniquely tied
746 * to a physical port, meaning that different devices plugged on the same physical
747 * port should return the same port number.
749 * But outside of this, there is no guarantee that the port number returned by this
750 * call will remain the same, or even match the order in which ports have been
751 * numbered by the HUB/HCD manufacturer.
753 * \param dev a device
754 * \returns the port number (0 if not available)
756 uint8_t API_EXPORTED libusb_get_port_number(libusb_device *dev)
758 return dev->port_number;
762 * Get the list of all port numbers from root for the specified device
764 * Since version 1.0.16, \ref LIBUSBX_API_VERSION >= 0x01000102
765 * \param dev a device
766 * \param port_numbers the array that should contain the port numbers
767 * \param port_numbers_len the maximum length of the array. As per the USB 3.0
768 * specs, the current maximum limit for the depth is 7.
769 * \returns the number of elements filled
770 * \returns LIBUSB_ERROR_OVERFLOW if the array is too small
772 int API_EXPORTED libusb_get_port_numbers(libusb_device *dev,
773 uint8_t* port_numbers, int port_numbers_len)
775 int i = port_numbers_len;
778 // HCDs can be listed as devices and would have port #0
779 // TODO: see how the other backends want to implement HCDs as parents
780 if (dev->port_number == 0)
784 usbi_warn(DEVICE_CTX(dev),
785 "port numbers array too small");
786 return LIBUSB_ERROR_OVERFLOW;
788 port_numbers[i] = dev->port_number;
789 dev = dev->parent_dev;
791 memmove(port_numbers, &port_numbers[i], port_numbers_len - i);
792 return port_numbers_len - i;
796 * Deprecated please use libusb_get_port_numbers instead.
798 int API_EXPORTED libusb_get_port_path(libusb_context *ctx, libusb_device *dev,
799 uint8_t* port_numbers, uint8_t port_numbers_len)
803 return libusb_get_port_numbers(dev, port_numbers, port_numbers_len);
807 * Get the the parent from the specified device.
808 * \param dev a device
809 * \returns the device parent or NULL if not available
810 * You should issue a \ref libusb_get_device_list() before calling this
811 * function and make sure that you only access the parent before issuing
812 * \ref libusb_free_device_list(). The reason is that libusbx currently does
813 * not maintain a permanent list of device instances, and therefore can
814 * only guarantee that parents are fully instantiated within a
815 * libusb_get_device_list() - libusb_free_device_list() block.
818 libusb_device * LIBUSB_CALL libusb_get_parent(libusb_device *dev)
820 return dev->parent_dev;
824 * Get the address of the device on the bus it is connected to.
825 * \param dev a device
826 * \returns the device address
828 uint8_t API_EXPORTED libusb_get_device_address(libusb_device *dev)
830 return dev->device_address;
834 * Get the negotiated connection speed for a device.
835 * \param dev a device
836 * \returns a \ref libusb_speed code, where LIBUSB_SPEED_UNKNOWN means that
837 * the OS doesn't know or doesn't support returning the negotiated speed.
839 int API_EXPORTED libusb_get_device_speed(libusb_device *dev)
844 static const struct libusb_endpoint_descriptor *find_endpoint(
845 struct libusb_config_descriptor *config, unsigned char endpoint)
848 for (iface_idx = 0; iface_idx < config->bNumInterfaces; iface_idx++) {
849 const struct libusb_interface *iface = &config->interface[iface_idx];
852 for (altsetting_idx = 0; altsetting_idx < iface->num_altsetting;
854 const struct libusb_interface_descriptor *altsetting
855 = &iface->altsetting[altsetting_idx];
858 for (ep_idx = 0; ep_idx < altsetting->bNumEndpoints; ep_idx++) {
859 const struct libusb_endpoint_descriptor *ep =
860 &altsetting->endpoint[ep_idx];
861 if (ep->bEndpointAddress == endpoint)
870 * Convenience function to retrieve the wMaxPacketSize value for a particular
871 * endpoint in the active device configuration.
873 * This function was originally intended to be of assistance when setting up
874 * isochronous transfers, but a design mistake resulted in this function
875 * instead. It simply returns the wMaxPacketSize value without considering
876 * its contents. If you're dealing with isochronous transfers, you probably
877 * want libusb_get_max_iso_packet_size() instead.
879 * \param dev a device
880 * \param endpoint address of the endpoint in question
881 * \returns the wMaxPacketSize value
882 * \returns LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist
883 * \returns LIBUSB_ERROR_OTHER on other failure
885 int API_EXPORTED libusb_get_max_packet_size(libusb_device *dev,
886 unsigned char endpoint)
888 struct libusb_config_descriptor *config;
889 const struct libusb_endpoint_descriptor *ep;
892 r = libusb_get_active_config_descriptor(dev, &config);
894 usbi_err(DEVICE_CTX(dev),
895 "could not retrieve active config descriptor");
896 return LIBUSB_ERROR_OTHER;
899 ep = find_endpoint(config, endpoint);
901 return LIBUSB_ERROR_NOT_FOUND;
903 r = ep->wMaxPacketSize;
904 libusb_free_config_descriptor(config);
909 * Calculate the maximum packet size which a specific endpoint is capable is
910 * sending or receiving in the duration of 1 microframe
912 * Only the active configuration is examined. The calculation is based on the
913 * wMaxPacketSize field in the endpoint descriptor as described in section
914 * 9.6.6 in the USB 2.0 specifications.
916 * If acting on an isochronous or interrupt endpoint, this function will
917 * multiply the value found in bits 0:10 by the number of transactions per
918 * microframe (determined by bits 11:12). Otherwise, this function just
919 * returns the numeric value found in bits 0:10.
921 * This function is useful for setting up isochronous transfers, for example
922 * you might pass the return value from this function to
923 * libusb_set_iso_packet_lengths() in order to set the length field of every
924 * isochronous packet in a transfer.
928 * \param dev a device
929 * \param endpoint address of the endpoint in question
930 * \returns the maximum packet size which can be sent/received on this endpoint
931 * \returns LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist
932 * \returns LIBUSB_ERROR_OTHER on other failure
934 int API_EXPORTED libusb_get_max_iso_packet_size(libusb_device *dev,
935 unsigned char endpoint)
937 struct libusb_config_descriptor *config;
938 const struct libusb_endpoint_descriptor *ep;
939 enum libusb_transfer_type ep_type;
943 r = libusb_get_active_config_descriptor(dev, &config);
945 usbi_err(DEVICE_CTX(dev),
946 "could not retrieve active config descriptor");
947 return LIBUSB_ERROR_OTHER;
950 ep = find_endpoint(config, endpoint);
952 return LIBUSB_ERROR_NOT_FOUND;
954 val = ep->wMaxPacketSize;
955 ep_type = (enum libusb_transfer_type) (ep->bmAttributes & 0x3);
956 libusb_free_config_descriptor(config);
959 if (ep_type == LIBUSB_TRANSFER_TYPE_ISOCHRONOUS
960 || ep_type == LIBUSB_TRANSFER_TYPE_INTERRUPT)
961 r *= (1 + ((val >> 11) & 3));
966 * Increment the reference count of a device.
967 * \param dev the device to reference
968 * \returns the same device
971 libusb_device * LIBUSB_CALL libusb_ref_device(libusb_device *dev)
973 usbi_mutex_lock(&dev->lock);
975 usbi_mutex_unlock(&dev->lock);
980 * Decrement the reference count of a device. If the decrement operation
981 * causes the reference count to reach zero, the device shall be destroyed.
982 * \param dev the device to unreference
984 void API_EXPORTED libusb_unref_device(libusb_device *dev)
991 usbi_mutex_lock(&dev->lock);
992 refcnt = --dev->refcnt;
993 usbi_mutex_unlock(&dev->lock);
996 usbi_dbg("destroy device %d.%d", dev->bus_number, dev->device_address);
998 libusb_unref_device(dev->parent_dev);
1000 if (usbi_backend->destroy_device)
1001 usbi_backend->destroy_device(dev);
1003 if (!libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG)) {
1004 /* backend does not support hotplug */
1005 usbi_disconnect_device(dev);
1008 usbi_mutex_destroy(&dev->lock);
1014 * Interrupt the iteration of the event handling thread, so that it picks
1017 void usbi_fd_notification(struct libusb_context *ctx)
1019 unsigned char dummy = 1;
1025 /* record that we are messing with poll fds */
1026 usbi_mutex_lock(&ctx->pollfd_modify_lock);
1027 ctx->pollfd_modify++;
1028 usbi_mutex_unlock(&ctx->pollfd_modify_lock);
1030 /* write some data on control pipe to interrupt event handlers */
1031 r = usbi_write(ctx->ctrl_pipe[1], &dummy, sizeof(dummy));
1033 usbi_warn(ctx, "internal signalling write failed");
1034 usbi_mutex_lock(&ctx->pollfd_modify_lock);
1035 ctx->pollfd_modify--;
1036 usbi_mutex_unlock(&ctx->pollfd_modify_lock);
1040 /* take event handling lock */
1041 libusb_lock_events(ctx);
1043 /* read the dummy data */
1044 r = usbi_read(ctx->ctrl_pipe[0], &dummy, sizeof(dummy));
1046 usbi_warn(ctx, "internal signalling read failed");
1048 /* we're done with modifying poll fds */
1049 usbi_mutex_lock(&ctx->pollfd_modify_lock);
1050 ctx->pollfd_modify--;
1051 usbi_mutex_unlock(&ctx->pollfd_modify_lock);
1053 /* Release event handling lock and wake up event waiters */
1054 libusb_unlock_events(ctx);
1058 * Open a device and obtain a device handle. A handle allows you to perform
1059 * I/O on the device in question.
1061 * Internally, this function adds a reference to the device and makes it
1062 * available to you through libusb_get_device(). This reference is removed
1063 * during libusb_close().
1065 * This is a non-blocking function; no requests are sent over the bus.
1067 * \param dev the device to open
1068 * \param handle output location for the returned device handle pointer. Only
1069 * populated when the return code is 0.
1070 * \returns 0 on success
1071 * \returns LIBUSB_ERROR_NO_MEM on memory allocation failure
1072 * \returns LIBUSB_ERROR_ACCESS if the user has insufficient permissions
1073 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1074 * \returns another LIBUSB_ERROR code on other failure
1076 int API_EXPORTED libusb_open(libusb_device *dev,
1077 libusb_device_handle **handle)
1079 struct libusb_context *ctx = DEVICE_CTX(dev);
1080 struct libusb_device_handle *_handle;
1081 size_t priv_size = usbi_backend->device_handle_priv_size;
1083 usbi_dbg("open %d.%d", dev->bus_number, dev->device_address);
1085 if (!dev->attached) {
1086 return LIBUSB_ERROR_NO_DEVICE;
1089 _handle = malloc(sizeof(*_handle) + priv_size);
1091 return LIBUSB_ERROR_NO_MEM;
1093 r = usbi_mutex_init(&_handle->lock, NULL);
1096 return LIBUSB_ERROR_OTHER;
1099 _handle->dev = libusb_ref_device(dev);
1100 _handle->auto_detach_kernel_driver = 0;
1101 _handle->claimed_interfaces = 0;
1102 memset(&_handle->os_priv, 0, priv_size);
1104 r = usbi_backend->open(_handle);
1106 usbi_dbg("open %d.%d returns %d", dev->bus_number, dev->device_address, r);
1107 libusb_unref_device(dev);
1108 usbi_mutex_destroy(&_handle->lock);
1113 usbi_mutex_lock(&ctx->open_devs_lock);
1114 list_add(&_handle->list, &ctx->open_devs);
1115 usbi_mutex_unlock(&ctx->open_devs_lock);
1118 /* At this point, we want to interrupt any existing event handlers so
1119 * that they realise the addition of the new device's poll fd. One
1120 * example when this is desirable is if the user is running a separate
1121 * dedicated libusbx events handling thread, which is running with a long
1122 * or infinite timeout. We want to interrupt that iteration of the loop,
1123 * so that it picks up the new fd, and then continues. */
1124 usbi_fd_notification(ctx);
1130 * Convenience function for finding a device with a particular
1131 * <tt>idVendor</tt>/<tt>idProduct</tt> combination. This function is intended
1132 * for those scenarios where you are using libusbx to knock up a quick test
1133 * application - it allows you to avoid calling libusb_get_device_list() and
1134 * worrying about traversing/freeing the list.
1136 * This function has limitations and is hence not intended for use in real
1137 * applications: if multiple devices have the same IDs it will only
1138 * give you the first one, etc.
1140 * \param ctx the context to operate on, or NULL for the default context
1141 * \param vendor_id the idVendor value to search for
1142 * \param product_id the idProduct value to search for
1143 * \returns a handle for the first found device, or NULL on error or if the
1144 * device could not be found. */
1146 libusb_device_handle * LIBUSB_CALL libusb_open_device_with_vid_pid(
1147 libusb_context *ctx, uint16_t vendor_id, uint16_t product_id)
1149 struct libusb_device **devs;
1150 struct libusb_device *found = NULL;
1151 struct libusb_device *dev;
1152 struct libusb_device_handle *handle = NULL;
1156 if (libusb_get_device_list(ctx, &devs) < 0)
1159 while ((dev = devs[i++]) != NULL) {
1160 struct libusb_device_descriptor desc;
1161 r = libusb_get_device_descriptor(dev, &desc);
1164 if (desc.idVendor == vendor_id && desc.idProduct == product_id) {
1171 r = libusb_open(found, &handle);
1177 libusb_free_device_list(devs, 1);
1181 static void do_close(struct libusb_context *ctx,
1182 struct libusb_device_handle *dev_handle)
1184 struct usbi_transfer *itransfer;
1185 struct usbi_transfer *tmp;
1187 libusb_lock_events(ctx);
1189 /* remove any transfers in flight that are for this device */
1190 usbi_mutex_lock(&ctx->flying_transfers_lock);
1192 /* safe iteration because transfers may be being deleted */
1193 list_for_each_entry_safe(itransfer, tmp, &ctx->flying_transfers, list, struct usbi_transfer) {
1194 struct libusb_transfer *transfer =
1195 USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
1197 if (transfer->dev_handle != dev_handle)
1200 if (!(itransfer->flags & USBI_TRANSFER_DEVICE_DISAPPEARED)) {
1201 usbi_err(ctx, "Device handle closed while transfer was still being processed, but the device is still connected as far as we know");
1203 if (itransfer->flags & USBI_TRANSFER_CANCELLING)
1204 usbi_warn(ctx, "A cancellation for an in-flight transfer hasn't completed but closing the device handle");
1206 usbi_err(ctx, "A cancellation hasn't even been scheduled on the transfer for which the device is closing");
1209 /* remove from the list of in-flight transfers and make sure
1210 * we don't accidentally use the device handle in the future
1211 * (or that such accesses will be easily caught and identified as a crash)
1213 usbi_mutex_lock(&itransfer->lock);
1214 list_del(&itransfer->list);
1215 transfer->dev_handle = NULL;
1216 usbi_mutex_unlock(&itransfer->lock);
1218 /* it is up to the user to free up the actual transfer struct. this is
1219 * just making sure that we don't attempt to process the transfer after
1220 * the device handle is invalid
1222 usbi_dbg("Removed transfer %p from the in-flight list because device handle %p closed",
1223 transfer, dev_handle);
1225 usbi_mutex_unlock(&ctx->flying_transfers_lock);
1227 libusb_unlock_events(ctx);
1229 usbi_mutex_lock(&ctx->open_devs_lock);
1230 list_del(&dev_handle->list);
1231 usbi_mutex_unlock(&ctx->open_devs_lock);
1233 usbi_backend->close(dev_handle);
1234 libusb_unref_device(dev_handle->dev);
1235 usbi_mutex_destroy(&dev_handle->lock);
1240 * Close a device handle. Should be called on all open handles before your
1241 * application exits.
1243 * Internally, this function destroys the reference that was added by
1244 * libusb_open() on the given device.
1246 * This is a non-blocking function; no requests are sent over the bus.
1248 * \param dev_handle the handle to close
1250 void API_EXPORTED libusb_close(libusb_device_handle *dev_handle)
1252 struct libusb_context *ctx;
1253 unsigned char dummy = 1;
1260 ctx = HANDLE_CTX(dev_handle);
1262 /* Similarly to libusb_open(), we want to interrupt all event handlers
1263 * at this point. More importantly, we want to perform the actual close of
1264 * the device while holding the event handling lock (preventing any other
1265 * thread from doing event handling) because we will be removing a file
1266 * descriptor from the polling loop. */
1268 /* record that we are messing with poll fds */
1269 usbi_mutex_lock(&ctx->pollfd_modify_lock);
1270 ctx->pollfd_modify++;
1271 usbi_mutex_unlock(&ctx->pollfd_modify_lock);
1273 /* write some data on control pipe to interrupt event handlers */
1274 r = usbi_write(ctx->ctrl_pipe[1], &dummy, sizeof(dummy));
1276 usbi_warn(ctx, "internal signalling write failed, closing anyway");
1277 do_close(ctx, dev_handle);
1278 usbi_mutex_lock(&ctx->pollfd_modify_lock);
1279 ctx->pollfd_modify--;
1280 usbi_mutex_unlock(&ctx->pollfd_modify_lock);
1284 /* take event handling lock */
1285 libusb_lock_events(ctx);
1287 /* read the dummy data */
1288 r = usbi_read(ctx->ctrl_pipe[0], &dummy, sizeof(dummy));
1290 usbi_warn(ctx, "internal signalling read failed, closing anyway");
1292 /* Close the device */
1293 do_close(ctx, dev_handle);
1295 /* we're done with modifying poll fds */
1296 usbi_mutex_lock(&ctx->pollfd_modify_lock);
1297 ctx->pollfd_modify--;
1298 usbi_mutex_unlock(&ctx->pollfd_modify_lock);
1300 /* Release event handling lock and wake up event waiters */
1301 libusb_unlock_events(ctx);
1305 * Get the underlying device for a handle. This function does not modify
1306 * the reference count of the returned device, so do not feel compelled to
1307 * unreference it when you are done.
1308 * \param dev_handle a device handle
1309 * \returns the underlying device
1312 libusb_device * LIBUSB_CALL libusb_get_device(libusb_device_handle *dev_handle)
1314 return dev_handle->dev;
1318 * Determine the bConfigurationValue of the currently active configuration.
1320 * You could formulate your own control request to obtain this information,
1321 * but this function has the advantage that it may be able to retrieve the
1322 * information from operating system caches (no I/O involved).
1324 * If the OS does not cache this information, then this function will block
1325 * while a control transfer is submitted to retrieve the information.
1327 * This function will return a value of 0 in the <tt>config</tt> output
1328 * parameter if the device is in unconfigured state.
1330 * \param dev a device handle
1331 * \param config output location for the bConfigurationValue of the active
1332 * configuration (only valid for return code 0)
1333 * \returns 0 on success
1334 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1335 * \returns another LIBUSB_ERROR code on other failure
1337 int API_EXPORTED libusb_get_configuration(libusb_device_handle *dev,
1340 int r = LIBUSB_ERROR_NOT_SUPPORTED;
1343 if (usbi_backend->get_configuration)
1344 r = usbi_backend->get_configuration(dev, config);
1346 if (r == LIBUSB_ERROR_NOT_SUPPORTED) {
1348 usbi_dbg("falling back to control message");
1349 r = libusb_control_transfer(dev, LIBUSB_ENDPOINT_IN,
1350 LIBUSB_REQUEST_GET_CONFIGURATION, 0, 0, &tmp, 1, 1000);
1352 usbi_err(HANDLE_CTX(dev), "zero bytes returned in ctrl transfer?");
1353 r = LIBUSB_ERROR_IO;
1354 } else if (r == 1) {
1358 usbi_dbg("control failed, error %d", r);
1363 usbi_dbg("active config %d", *config);
1369 * Set the active configuration for a device.
1371 * The operating system may or may not have already set an active
1372 * configuration on the device. It is up to your application to ensure the
1373 * correct configuration is selected before you attempt to claim interfaces
1374 * and perform other operations.
1376 * If you call this function on a device already configured with the selected
1377 * configuration, then this function will act as a lightweight device reset:
1378 * it will issue a SET_CONFIGURATION request using the current configuration,
1379 * causing most USB-related device state to be reset (altsetting reset to zero,
1380 * endpoint halts cleared, toggles reset).
1382 * You cannot change/reset configuration if your application has claimed
1383 * interfaces. It is advised to set the desired configuration before claiming
1386 * Alternatively you can call libusb_release_interface() first. Note if you
1387 * do things this way you must ensure that auto_detach_kernel_driver for
1388 * <tt>dev</tt> is 0, otherwise the kernel driver will be re-attached when you
1389 * release the interface(s).
1391 * You cannot change/reset configuration if other applications or drivers have
1392 * claimed interfaces.
1394 * A configuration value of -1 will put the device in unconfigured state.
1395 * The USB specifications state that a configuration value of 0 does this,
1396 * however buggy devices exist which actually have a configuration 0.
1398 * You should always use this function rather than formulating your own
1399 * SET_CONFIGURATION control request. This is because the underlying operating
1400 * system needs to know when such changes happen.
1402 * This is a blocking function.
1404 * \param dev a device handle
1405 * \param configuration the bConfigurationValue of the configuration you
1406 * wish to activate, or -1 if you wish to put the device in unconfigured state
1407 * \returns 0 on success
1408 * \returns LIBUSB_ERROR_NOT_FOUND if the requested configuration does not exist
1409 * \returns LIBUSB_ERROR_BUSY if interfaces are currently claimed
1410 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1411 * \returns another LIBUSB_ERROR code on other failure
1412 * \see libusb_set_auto_detach_kernel_driver()
1414 int API_EXPORTED libusb_set_configuration(libusb_device_handle *dev,
1417 usbi_dbg("configuration %d", configuration);
1418 return usbi_backend->set_configuration(dev, configuration);
1422 * Claim an interface on a given device handle. You must claim the interface
1423 * you wish to use before you can perform I/O on any of its endpoints.
1425 * It is legal to attempt to claim an already-claimed interface, in which
1426 * case libusbx just returns 0 without doing anything.
1428 * If auto_detach_kernel_driver is set to 1 for <tt>dev</tt>, the kernel driver
1429 * will be detached if necessary, on failure the detach error is returned.
1431 * Claiming of interfaces is a purely logical operation; it does not cause
1432 * any requests to be sent over the bus. Interface claiming is used to
1433 * instruct the underlying operating system that your application wishes
1434 * to take ownership of the interface.
1436 * This is a non-blocking function.
1438 * \param dev a device handle
1439 * \param interface_number the <tt>bInterfaceNumber</tt> of the interface you
1441 * \returns 0 on success
1442 * \returns LIBUSB_ERROR_NOT_FOUND if the requested interface does not exist
1443 * \returns LIBUSB_ERROR_BUSY if another program or driver has claimed the
1445 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1446 * \returns a LIBUSB_ERROR code on other failure
1447 * \see libusb_set_auto_detach_kernel_driver()
1449 int API_EXPORTED libusb_claim_interface(libusb_device_handle *dev,
1450 int interface_number)
1454 usbi_dbg("interface %d", interface_number);
1455 if (interface_number >= USB_MAXINTERFACES)
1456 return LIBUSB_ERROR_INVALID_PARAM;
1458 if (!dev->dev->attached)
1459 return LIBUSB_ERROR_NO_DEVICE;
1461 usbi_mutex_lock(&dev->lock);
1462 if (dev->claimed_interfaces & (1 << interface_number))
1465 r = usbi_backend->claim_interface(dev, interface_number);
1467 dev->claimed_interfaces |= 1 << interface_number;
1470 usbi_mutex_unlock(&dev->lock);
1475 * Release an interface previously claimed with libusb_claim_interface(). You
1476 * should release all claimed interfaces before closing a device handle.
1478 * This is a blocking function. A SET_INTERFACE control request will be sent
1479 * to the device, resetting interface state to the first alternate setting.
1481 * If auto_detach_kernel_driver is set to 1 for <tt>dev</tt>, the kernel
1482 * driver will be re-attached after releasing the interface.
1484 * \param dev a device handle
1485 * \param interface_number the <tt>bInterfaceNumber</tt> of the
1486 * previously-claimed interface
1487 * \returns 0 on success
1488 * \returns LIBUSB_ERROR_NOT_FOUND if the interface was not claimed
1489 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1490 * \returns another LIBUSB_ERROR code on other failure
1491 * \see libusb_set_auto_detach_kernel_driver()
1493 int API_EXPORTED libusb_release_interface(libusb_device_handle *dev,
1494 int interface_number)
1498 usbi_dbg("interface %d", interface_number);
1499 if (interface_number >= USB_MAXINTERFACES)
1500 return LIBUSB_ERROR_INVALID_PARAM;
1502 usbi_mutex_lock(&dev->lock);
1503 if (!(dev->claimed_interfaces & (1 << interface_number))) {
1504 r = LIBUSB_ERROR_NOT_FOUND;
1508 r = usbi_backend->release_interface(dev, interface_number);
1510 dev->claimed_interfaces &= ~(1 << interface_number);
1513 usbi_mutex_unlock(&dev->lock);
1518 * Activate an alternate setting for an interface. The interface must have
1519 * been previously claimed with libusb_claim_interface().
1521 * You should always use this function rather than formulating your own
1522 * SET_INTERFACE control request. This is because the underlying operating
1523 * system needs to know when such changes happen.
1525 * This is a blocking function.
1527 * \param dev a device handle
1528 * \param interface_number the <tt>bInterfaceNumber</tt> of the
1529 * previously-claimed interface
1530 * \param alternate_setting the <tt>bAlternateSetting</tt> of the alternate
1531 * setting to activate
1532 * \returns 0 on success
1533 * \returns LIBUSB_ERROR_NOT_FOUND if the interface was not claimed, or the
1534 * requested alternate setting does not exist
1535 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1536 * \returns another LIBUSB_ERROR code on other failure
1538 int API_EXPORTED libusb_set_interface_alt_setting(libusb_device_handle *dev,
1539 int interface_number, int alternate_setting)
1541 usbi_dbg("interface %d altsetting %d",
1542 interface_number, alternate_setting);
1543 if (interface_number >= USB_MAXINTERFACES)
1544 return LIBUSB_ERROR_INVALID_PARAM;
1546 usbi_mutex_lock(&dev->lock);
1547 if (!dev->dev->attached) {
1548 usbi_mutex_unlock(&dev->lock);
1549 return LIBUSB_ERROR_NO_DEVICE;
1552 if (!(dev->claimed_interfaces & (1 << interface_number))) {
1553 usbi_mutex_unlock(&dev->lock);
1554 return LIBUSB_ERROR_NOT_FOUND;
1556 usbi_mutex_unlock(&dev->lock);
1558 return usbi_backend->set_interface_altsetting(dev, interface_number,
1563 * Clear the halt/stall condition for an endpoint. Endpoints with halt status
1564 * are unable to receive or transmit data until the halt condition is stalled.
1566 * You should cancel all pending transfers before attempting to clear the halt
1569 * This is a blocking function.
1571 * \param dev a device handle
1572 * \param endpoint the endpoint to clear halt status
1573 * \returns 0 on success
1574 * \returns LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist
1575 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1576 * \returns another LIBUSB_ERROR code on other failure
1578 int API_EXPORTED libusb_clear_halt(libusb_device_handle *dev,
1579 unsigned char endpoint)
1581 usbi_dbg("endpoint %x", endpoint);
1582 if (!dev->dev->attached)
1583 return LIBUSB_ERROR_NO_DEVICE;
1585 return usbi_backend->clear_halt(dev, endpoint);
1589 * Perform a USB port reset to reinitialize a device. The system will attempt
1590 * to restore the previous configuration and alternate settings after the
1591 * reset has completed.
1593 * If the reset fails, the descriptors change, or the previous state cannot be
1594 * restored, the device will appear to be disconnected and reconnected. This
1595 * means that the device handle is no longer valid (you should close it) and
1596 * rediscover the device. A return code of LIBUSB_ERROR_NOT_FOUND indicates
1597 * when this is the case.
1599 * This is a blocking function which usually incurs a noticeable delay.
1601 * \param dev a handle of the device to reset
1602 * \returns 0 on success
1603 * \returns LIBUSB_ERROR_NOT_FOUND if re-enumeration is required, or if the
1604 * device has been disconnected
1605 * \returns another LIBUSB_ERROR code on other failure
1607 int API_EXPORTED libusb_reset_device(libusb_device_handle *dev)
1610 if (!dev->dev->attached)
1611 return LIBUSB_ERROR_NO_DEVICE;
1613 return usbi_backend->reset_device(dev);
1617 * Determine if a kernel driver is active on an interface. If a kernel driver
1618 * is active, you cannot claim the interface, and libusbx will be unable to
1621 * This functionality is not available on Windows.
1623 * \param dev a device handle
1624 * \param interface_number the interface to check
1625 * \returns 0 if no kernel driver is active
1626 * \returns 1 if a kernel driver is active
1627 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1628 * \returns LIBUSB_ERROR_NOT_SUPPORTED on platforms where the functionality
1630 * \returns another LIBUSB_ERROR code on other failure
1631 * \see libusb_detach_kernel_driver()
1633 int API_EXPORTED libusb_kernel_driver_active(libusb_device_handle *dev,
1634 int interface_number)
1636 usbi_dbg("interface %d", interface_number);
1638 if (!dev->dev->attached)
1639 return LIBUSB_ERROR_NO_DEVICE;
1641 if (usbi_backend->kernel_driver_active)
1642 return usbi_backend->kernel_driver_active(dev, interface_number);
1644 return LIBUSB_ERROR_NOT_SUPPORTED;
1648 * Detach a kernel driver from an interface. If successful, you will then be
1649 * able to claim the interface and perform I/O.
1651 * This functionality is not available on Darwin or Windows.
1653 * Note that libusbx itself also talks to the device through a special kernel
1654 * driver, if this driver is already attached to the device, this call will
1655 * not detach it and return LIBUSB_ERROR_NOT_FOUND.
1657 * \param dev a device handle
1658 * \param interface_number the interface to detach the driver from
1659 * \returns 0 on success
1660 * \returns LIBUSB_ERROR_NOT_FOUND if no kernel driver was active
1661 * \returns LIBUSB_ERROR_INVALID_PARAM if the interface does not exist
1662 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1663 * \returns LIBUSB_ERROR_NOT_SUPPORTED on platforms where the functionality
1665 * \returns another LIBUSB_ERROR code on other failure
1666 * \see libusb_kernel_driver_active()
1668 int API_EXPORTED libusb_detach_kernel_driver(libusb_device_handle *dev,
1669 int interface_number)
1671 usbi_dbg("interface %d", interface_number);
1673 if (!dev->dev->attached)
1674 return LIBUSB_ERROR_NO_DEVICE;
1676 if (usbi_backend->detach_kernel_driver)
1677 return usbi_backend->detach_kernel_driver(dev, interface_number);
1679 return LIBUSB_ERROR_NOT_SUPPORTED;
1683 * Re-attach an interface's kernel driver, which was previously detached
1684 * using libusb_detach_kernel_driver(). This call is only effective on
1685 * Linux and returns LIBUSB_ERROR_NOT_SUPPORTED on all other platforms.
1687 * This functionality is not available on Darwin or Windows.
1689 * \param dev a device handle
1690 * \param interface_number the interface to attach the driver from
1691 * \returns 0 on success
1692 * \returns LIBUSB_ERROR_NOT_FOUND if no kernel driver was active
1693 * \returns LIBUSB_ERROR_INVALID_PARAM if the interface does not exist
1694 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1695 * \returns LIBUSB_ERROR_NOT_SUPPORTED on platforms where the functionality
1697 * \returns LIBUSB_ERROR_BUSY if the driver cannot be attached because the
1698 * interface is claimed by a program or driver
1699 * \returns another LIBUSB_ERROR code on other failure
1700 * \see libusb_kernel_driver_active()
1702 int API_EXPORTED libusb_attach_kernel_driver(libusb_device_handle *dev,
1703 int interface_number)
1705 usbi_dbg("interface %d", interface_number);
1707 if (!dev->dev->attached)
1708 return LIBUSB_ERROR_NO_DEVICE;
1710 if (usbi_backend->attach_kernel_driver)
1711 return usbi_backend->attach_kernel_driver(dev, interface_number);
1713 return LIBUSB_ERROR_NOT_SUPPORTED;
1717 * Enable/disable libusbx's automatic kernel driver detachment. When this is
1718 * enabled libusbx will automatically detach the kernel driver on an interface
1719 * when claiming the interface, and attach it when releasing the interface.
1721 * Automatic kernel driver detachment is disabled on newly opened device
1722 * handles by default.
1724 * On platforms which do not have LIBUSB_CAP_SUPPORTS_DETACH_KERNEL_DRIVER
1725 * this function will return LIBUSB_ERROR_NOT_SUPPORTED, and libusbx will
1726 * continue as if this function was never called.
1728 * \param dev a device handle
1729 * \param enable whether to enable or disable auto kernel driver detachment
1731 * \returns LIBUSB_SUCCESS on success
1732 * \returns LIBUSB_ERROR_NOT_SUPPORTED on platforms where the functionality
1734 * \see libusb_claim_interface()
1735 * \see libusb_release_interface()
1736 * \see libusb_set_configuration()
1738 int API_EXPORTED libusb_set_auto_detach_kernel_driver(
1739 libusb_device_handle *dev, int enable)
1741 if (!(usbi_backend->caps & USBI_CAP_SUPPORTS_DETACH_KERNEL_DRIVER))
1742 return LIBUSB_ERROR_NOT_SUPPORTED;
1744 dev->auto_detach_kernel_driver = enable;
1745 return LIBUSB_SUCCESS;
1749 * Set log message verbosity.
1751 * The default level is LIBUSB_LOG_LEVEL_NONE, which means no messages are ever
1752 * printed. If you choose to increase the message verbosity level, ensure
1753 * that your application does not close the stdout/stderr file descriptors.
1755 * You are advised to use level LIBUSB_LOG_LEVEL_WARNING. libusbx is conservative
1756 * with its message logging and most of the time, will only log messages that
1757 * explain error conditions and other oddities. This will help you debug
1760 * If the LIBUSB_DEBUG environment variable was set when libusbx was
1761 * initialized, this function does nothing: the message verbosity is fixed
1762 * to the value in the environment variable.
1764 * If libusbx was compiled without any message logging, this function does
1765 * nothing: you'll never get any messages.
1767 * If libusbx was compiled with verbose debug message logging, this function
1768 * does nothing: you'll always get messages from all levels.
1770 * \param ctx the context to operate on, or NULL for the default context
1771 * \param level debug level to set
1773 void API_EXPORTED libusb_set_debug(libusb_context *ctx, int level)
1775 USBI_GET_CONTEXT(ctx);
1776 if (!ctx->debug_fixed)
1781 * Initialize libusb. This function must be called before calling any other
1784 * If you do not provide an output location for a context pointer, a default
1785 * context will be created. If there was already a default context, it will
1786 * be reused (and nothing will be initialized/reinitialized).
1788 * \param context Optional output location for context pointer.
1789 * Only valid on return code 0.
1790 * \returns 0 on success, or a LIBUSB_ERROR code on failure
1793 int API_EXPORTED libusb_init(libusb_context **context)
1795 struct libusb_device *dev, *next;
1796 char *dbg = getenv("LIBUSB_DEBUG");
1797 struct libusb_context *ctx;
1798 static int first_init = 1;
1801 usbi_mutex_static_lock(&default_context_lock);
1803 if (!timestamp_origin.tv_sec) {
1804 usbi_gettimeofday(×tamp_origin, NULL);
1807 if (!context && usbi_default_context) {
1808 usbi_dbg("reusing default context");
1809 default_context_refcnt++;
1810 usbi_mutex_static_unlock(&default_context_lock);
1814 ctx = calloc(1, sizeof(*ctx));
1816 r = LIBUSB_ERROR_NO_MEM;
1820 #ifdef ENABLE_DEBUG_LOGGING
1821 ctx->debug = LIBUSB_LOG_LEVEL_DEBUG;
1825 ctx->debug = atoi(dbg);
1827 ctx->debug_fixed = 1;
1830 /* default context should be initialized before calling usbi_dbg */
1831 if (!usbi_default_context) {
1832 usbi_default_context = ctx;
1833 default_context_refcnt++;
1834 usbi_dbg("created default context");
1837 usbi_dbg("libusbx v%d.%d.%d.%d", libusb_version_internal.major, libusb_version_internal.minor,
1838 libusb_version_internal.micro, libusb_version_internal.nano);
1840 usbi_mutex_init(&ctx->usb_devs_lock, NULL);
1841 usbi_mutex_init(&ctx->open_devs_lock, NULL);
1842 usbi_mutex_init(&ctx->hotplug_cbs_lock, NULL);
1843 list_init(&ctx->usb_devs);
1844 list_init(&ctx->open_devs);
1845 list_init(&ctx->hotplug_cbs);
1847 usbi_mutex_static_lock(&active_contexts_lock);
1850 list_init (&active_contexts_list);
1852 list_add (&ctx->list, &active_contexts_list);
1853 usbi_mutex_static_unlock(&active_contexts_lock);
1855 if (usbi_backend->init) {
1856 r = usbi_backend->init(ctx);
1861 r = usbi_io_init(ctx);
1863 goto err_backend_exit;
1865 usbi_mutex_static_unlock(&default_context_lock);
1873 if (usbi_backend->exit)
1874 usbi_backend->exit();
1876 if (ctx == usbi_default_context)
1877 usbi_default_context = NULL;
1879 usbi_mutex_static_lock(&active_contexts_lock);
1880 list_del (&ctx->list);
1881 usbi_mutex_static_unlock(&active_contexts_lock);
1883 usbi_mutex_lock(&ctx->usb_devs_lock);
1884 list_for_each_entry_safe(dev, next, &ctx->usb_devs, list, struct libusb_device) {
1885 list_del(&dev->list);
1886 libusb_unref_device(dev);
1888 usbi_mutex_unlock(&ctx->usb_devs_lock);
1890 usbi_mutex_destroy(&ctx->open_devs_lock);
1891 usbi_mutex_destroy(&ctx->usb_devs_lock);
1892 usbi_mutex_destroy(&ctx->hotplug_cbs_lock);
1896 usbi_mutex_static_unlock(&default_context_lock);
1901 * Deinitialize libusb. Should be called after closing all open devices and
1902 * before your application terminates.
1903 * \param ctx the context to deinitialize, or NULL for the default context
1905 void API_EXPORTED libusb_exit(struct libusb_context *ctx)
1907 struct libusb_device *dev, *next;
1910 USBI_GET_CONTEXT(ctx);
1912 /* if working with default context, only actually do the deinitialization
1913 * if we're the last user */
1914 usbi_mutex_static_lock(&default_context_lock);
1915 if (ctx == usbi_default_context) {
1916 if (--default_context_refcnt > 0) {
1917 usbi_dbg("not destroying default context");
1918 usbi_mutex_static_unlock(&default_context_lock);
1921 usbi_dbg("destroying default context");
1922 usbi_default_context = NULL;
1924 usbi_mutex_static_unlock(&default_context_lock);
1926 usbi_mutex_static_lock(&active_contexts_lock);
1927 list_del (&ctx->list);
1928 usbi_mutex_static_unlock(&active_contexts_lock);
1930 if (libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG)) {
1931 usbi_hotplug_deregister_all(ctx);
1932 usbi_mutex_lock(&ctx->usb_devs_lock);
1933 list_for_each_entry_safe(dev, next, &ctx->usb_devs, list, struct libusb_device) {
1934 list_del(&dev->list);
1935 libusb_unref_device(dev);
1937 usbi_mutex_unlock(&ctx->usb_devs_lock);
1940 /* a few sanity checks. don't bother with locking because unless
1941 * there is an application bug, nobody will be accessing these. */
1942 if (!list_empty(&ctx->usb_devs))
1943 usbi_warn(ctx, "some libusb_devices were leaked");
1944 if (!list_empty(&ctx->open_devs))
1945 usbi_warn(ctx, "application left some devices open");
1948 if (usbi_backend->exit)
1949 usbi_backend->exit();
1951 usbi_mutex_destroy(&ctx->open_devs_lock);
1952 usbi_mutex_destroy(&ctx->usb_devs_lock);
1953 usbi_mutex_destroy(&ctx->hotplug_cbs_lock);
1958 * Check at runtime if the loaded library has a given capability.
1959 * This call should be performed after \ref libusb_init(), to ensure the
1960 * backend has updated its capability set.
1962 * \param capability the \ref libusb_capability to check for
1963 * \returns nonzero if the running library has the capability, 0 otherwise
1965 int API_EXPORTED libusb_has_capability(uint32_t capability)
1967 switch (capability) {
1968 case LIBUSB_CAP_HAS_CAPABILITY:
1970 case LIBUSB_CAP_HAS_HOTPLUG:
1971 return !(usbi_backend->get_device_list);
1972 case LIBUSB_CAP_HAS_HID_ACCESS:
1973 return (usbi_backend->caps & USBI_CAP_HAS_HID_ACCESS);
1974 case LIBUSB_CAP_SUPPORTS_DETACH_KERNEL_DRIVER:
1975 return (usbi_backend->caps & USBI_CAP_SUPPORTS_DETACH_KERNEL_DRIVER);
1980 /* this is defined in libusbi.h if needed */
1981 #ifdef LIBUSB_GETTIMEOFDAY_WIN32
1984 * Implementation according to:
1985 * The Open Group Base Specifications Issue 6
1986 * IEEE Std 1003.1, 2004 Edition
1990 * THIS SOFTWARE IS NOT COPYRIGHTED
1992 * This source code is offered for use in the public domain. You may
1993 * use, modify or distribute it freely.
1995 * This code is distributed in the hope that it will be useful but
1996 * WITHOUT ANY WARRANTY. ALL WARRANTIES, EXPRESS OR IMPLIED ARE HEREBY
1997 * DISCLAIMED. This includes but is not limited to warranties of
1998 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
2001 * Danny Smith <dannysmith@users.sourceforge.net>
2004 /* Offset between 1/1/1601 and 1/1/1970 in 100 nanosec units */
2005 #define _W32_FT_OFFSET (116444736000000000)
2007 int usbi_gettimeofday(struct timeval *tp, void *tzp)
2010 unsigned __int64 ns100; /* Time since 1 Jan 1601, in 100ns units */
2016 #if defined(OS_WINCE)
2019 SystemTimeToFileTime(&st, &_now.ft);
2021 GetSystemTimeAsFileTime (&_now.ft);
2023 tp->tv_usec=(long)((_now.ns100 / 10) % 1000000 );
2024 tp->tv_sec= (long)((_now.ns100 - _W32_FT_OFFSET) / 10000000);
2026 /* Always return 0 as per Open Group Base Specifications Issue 6.
2027 Do not set errno on error. */
2032 static void usbi_log_str(struct libusb_context *ctx,
2033 enum libusb_log_level level, const char * str)
2035 #if defined(USE_SYSTEM_LOGGING_FACILITY)
2036 #if defined(OS_WINDOWS) || defined(OS_WINCE)
2037 /* Windows CE only supports the Unicode version of OutputDebugString. */
2038 WCHAR wbuf[USBI_MAX_LOG_LEN];
2039 MultiByteToWideChar(CP_UTF8, 0, str, -1, wbuf, sizeof(wbuf));
2040 OutputDebugStringW(wbuf);
2041 #elif defined(__ANDROID__)
2042 int priority = ANDROID_LOG_UNKNOWN;
2044 case LIBUSB_LOG_LEVEL_INFO: priority = ANDROID_LOG_INFO; break;
2045 case LIBUSB_LOG_LEVEL_WARNING: priority = ANDROID_LOG_WARN; break;
2046 case LIBUSB_LOG_LEVEL_ERROR: priority = ANDROID_LOG_ERROR; break;
2047 case LIBUSB_LOG_LEVEL_DEBUG: priority = ANDROID_LOG_DEBUG; break;
2049 __android_log_write(priority, "libusb", str);
2050 #elif defined(HAVE_SYSLOG_FUNC)
2051 int syslog_level = LOG_INFO;
2053 case LIBUSB_LOG_LEVEL_INFO: syslog_level = LOG_INFO; break;
2054 case LIBUSB_LOG_LEVEL_WARNING: syslog_level = LOG_WARNING; break;
2055 case LIBUSB_LOG_LEVEL_ERROR: syslog_level = LOG_ERR; break;
2056 case LIBUSB_LOG_LEVEL_DEBUG: syslog_level = LOG_DEBUG; break;
2058 syslog(syslog_level, "%s", str);
2059 #else /* All of gcc, Clang, XCode seem to use #warning */
2060 #warning System logging is not supported on this platform. Logging to stderr will be used instead.
2065 #endif /* USE_SYSTEM_LOGGING_FACILITY */
2070 void usbi_log_v(struct libusb_context *ctx, enum libusb_log_level level,
2071 const char *function, const char *format, va_list args)
2073 const char *prefix = "";
2074 char buf[USBI_MAX_LOG_LEN];
2076 int global_debug, header_len, text_len;
2077 static int has_debug_header_been_displayed = 0;
2079 #ifdef ENABLE_DEBUG_LOGGING
2083 USBI_GET_CONTEXT(ctx);
2086 global_debug = (ctx->debug == LIBUSB_LOG_LEVEL_DEBUG);
2089 if (level == LIBUSB_LOG_LEVEL_WARNING && ctx->debug < LIBUSB_LOG_LEVEL_WARNING)
2091 if (level == LIBUSB_LOG_LEVEL_INFO && ctx->debug < LIBUSB_LOG_LEVEL_INFO)
2093 if (level == LIBUSB_LOG_LEVEL_DEBUG && ctx->debug < LIBUSB_LOG_LEVEL_DEBUG)
2097 usbi_gettimeofday(&now, NULL);
2098 if ((global_debug) && (!has_debug_header_been_displayed)) {
2099 has_debug_header_been_displayed = 1;
2100 usbi_log_str(ctx, LIBUSB_LOG_LEVEL_DEBUG, "[timestamp] [threadID] facility level [function call] <message>\n");
2101 usbi_log_str(ctx, LIBUSB_LOG_LEVEL_DEBUG, "--------------------------------------------------------------------------------\n");
2103 if (now.tv_usec < timestamp_origin.tv_usec) {
2105 now.tv_usec += 1000000;
2107 now.tv_sec -= timestamp_origin.tv_sec;
2108 now.tv_usec -= timestamp_origin.tv_usec;
2111 case LIBUSB_LOG_LEVEL_INFO:
2114 case LIBUSB_LOG_LEVEL_WARNING:
2117 case LIBUSB_LOG_LEVEL_ERROR:
2120 case LIBUSB_LOG_LEVEL_DEBUG:
2123 case LIBUSB_LOG_LEVEL_NONE:
2131 header_len = snprintf(buf, sizeof(buf),
2132 "[%2d.%06d] [%08x] libusbx: %s [%s] ",
2133 (int)now.tv_sec, (int)now.tv_usec, usbi_get_tid(), prefix, function);
2135 header_len = snprintf(buf, sizeof(buf),
2136 "libusbx: %s [%s] ", prefix, function);
2139 if (header_len < 0 || header_len >= sizeof(buf)) {
2140 /* Somehow snprintf failed to write to the buffer,
2141 * remove the header so something useful is output. */
2144 /* Make sure buffer is NUL terminated */
2145 buf[header_len] = '\0';
2146 text_len = vsnprintf(buf + header_len, sizeof(buf) - header_len,
2148 if (text_len < 0 || text_len + header_len >= sizeof(buf)) {
2149 /* Truncated log output. On some platforms a -1 return value means
2150 * that the output was truncated. */
2151 text_len = sizeof(buf) - header_len;
2153 if (header_len + text_len + sizeof(USBI_LOG_LINE_END) >= sizeof(buf)) {
2154 /* Need to truncate the text slightly to fit on the terminator. */
2155 text_len -= (header_len + text_len + sizeof(USBI_LOG_LINE_END)) - sizeof(buf);
2157 strcpy(buf + header_len + text_len, USBI_LOG_LINE_END);
2159 usbi_log_str(ctx, level, buf);
2162 void usbi_log(struct libusb_context *ctx, enum libusb_log_level level,
2163 const char *function, const char *format, ...)
2167 va_start (args, format);
2168 usbi_log_v(ctx, level, function, format, args);
2173 * Returns a constant NULL-terminated string with the ASCII name of a libusbx
2174 * error or transfer status code. The caller must not free() the returned
2177 * \param error_code The \ref libusb_error or libusb_transfer_status code to
2178 * return the name of.
2179 * \returns The error name, or the string **UNKNOWN** if the value of
2180 * error_code is not a known error / status code.
2182 DEFAULT_VISIBILITY const char * LIBUSB_CALL libusb_error_name(int error_code)
2184 switch (error_code) {
2185 case LIBUSB_ERROR_IO:
2186 return "LIBUSB_ERROR_IO";
2187 case LIBUSB_ERROR_INVALID_PARAM:
2188 return "LIBUSB_ERROR_INVALID_PARAM";
2189 case LIBUSB_ERROR_ACCESS:
2190 return "LIBUSB_ERROR_ACCESS";
2191 case LIBUSB_ERROR_NO_DEVICE:
2192 return "LIBUSB_ERROR_NO_DEVICE";
2193 case LIBUSB_ERROR_NOT_FOUND:
2194 return "LIBUSB_ERROR_NOT_FOUND";
2195 case LIBUSB_ERROR_BUSY:
2196 return "LIBUSB_ERROR_BUSY";
2197 case LIBUSB_ERROR_TIMEOUT:
2198 return "LIBUSB_ERROR_TIMEOUT";
2199 case LIBUSB_ERROR_OVERFLOW:
2200 return "LIBUSB_ERROR_OVERFLOW";
2201 case LIBUSB_ERROR_PIPE:
2202 return "LIBUSB_ERROR_PIPE";
2203 case LIBUSB_ERROR_INTERRUPTED:
2204 return "LIBUSB_ERROR_INTERRUPTED";
2205 case LIBUSB_ERROR_NO_MEM:
2206 return "LIBUSB_ERROR_NO_MEM";
2207 case LIBUSB_ERROR_NOT_SUPPORTED:
2208 return "LIBUSB_ERROR_NOT_SUPPORTED";
2209 case LIBUSB_ERROR_OTHER:
2210 return "LIBUSB_ERROR_OTHER";
2212 case LIBUSB_TRANSFER_ERROR:
2213 return "LIBUSB_TRANSFER_ERROR";
2214 case LIBUSB_TRANSFER_TIMED_OUT:
2215 return "LIBUSB_TRANSFER_TIMED_OUT";
2216 case LIBUSB_TRANSFER_CANCELLED:
2217 return "LIBUSB_TRANSFER_CANCELLED";
2218 case LIBUSB_TRANSFER_STALL:
2219 return "LIBUSB_TRANSFER_STALL";
2220 case LIBUSB_TRANSFER_NO_DEVICE:
2221 return "LIBUSB_TRANSFER_NO_DEVICE";
2222 case LIBUSB_TRANSFER_OVERFLOW:
2223 return "LIBUSB_TRANSFER_OVERFLOW";
2226 return "LIBUSB_SUCCESS / LIBUSB_TRANSFER_COMPLETED";
2228 return "**UNKNOWN**";
2233 * Returns a pointer to const struct libusb_version with the version
2234 * (major, minor, micro, nano and rc) of the running library.
2237 const struct libusb_version * LIBUSB_CALL libusb_get_version(void)
2239 return &libusb_version_internal;