1 /* -*- Mode: C; indent-tabs-mode:t ; c-basic-offset:8 -*- */
3 * Core functions for libusb
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_NETBSD)
54 const struct usbi_os_backend * const usbi_backend = &netbsd_backend;
55 #elif defined(OS_WINDOWS)
56 const struct usbi_os_backend * const usbi_backend = &windows_backend;
57 #elif defined(OS_WINCE)
58 const struct usbi_os_backend * const usbi_backend = &wince_backend;
59 #elif defined(OS_HAIKU)
60 const struct usbi_os_backend * const usbi_backend = &haiku_usb_raw_backend;
62 #error "Unsupported OS"
65 struct libusb_context *usbi_default_context = NULL;
66 static const struct libusb_version libusb_version_internal =
67 { LIBUSB_MAJOR, LIBUSB_MINOR, LIBUSB_MICRO, LIBUSB_NANO,
68 LIBUSB_RC, "http://libusb.info" };
69 static int default_context_refcnt = 0;
70 static usbi_mutex_static_t default_context_lock = USBI_MUTEX_INITIALIZER;
71 static struct timeval timestamp_origin = { 0, 0 };
73 usbi_mutex_static_t active_contexts_lock = USBI_MUTEX_INITIALIZER;
74 struct list_head active_contexts_list;
77 * \mainpage libusb-1.0 API Reference
79 * \section intro Introduction
81 * libusb is an open source library that allows you to communicate with USB
82 * devices from userspace. For more info, see the
83 * <a href="http://libusb.info">libusb homepage</a>.
85 * This documentation is aimed at application developers wishing to
86 * communicate with USB peripherals from their own software. After reviewing
87 * this documentation, feedback and questions can be sent to the
88 * <a href="http://mailing-list.libusb.info">libusb-devel mailing list</a>.
90 * This documentation assumes knowledge of how to operate USB devices from
91 * a software standpoint (descriptors, configurations, interfaces, endpoints,
92 * control/bulk/interrupt/isochronous transfers, etc). Full information
93 * can be found in the <a href="http://www.usb.org/developers/docs/">USB 3.0
94 * Specification</a> which is available for free download. You can probably
95 * find less verbose introductions by searching the web.
97 * \section features Library features
99 * - All transfer types supported (control/bulk/interrupt/isochronous)
100 * - 2 transfer interfaces:
101 * -# Synchronous (simple)
102 * -# Asynchronous (more complicated, but more powerful)
103 * - Thread safe (although the asynchronous interface means that you
104 * usually won't need to thread)
105 * - Lightweight with lean API
106 * - Compatible with libusb-0.1 through the libusb-compat-0.1 translation layer
107 * - Hotplug support (on some platforms). See \ref hotplug.
109 * \section gettingstarted Getting Started
111 * To begin reading the API documentation, start with the Modules page which
112 * links to the different categories of libusb's functionality.
114 * One decision you will have to make is whether to use the synchronous
115 * or the asynchronous data transfer interface. The \ref io documentation
116 * provides some insight into this topic.
118 * Some example programs can be found in the libusb source distribution under
119 * the "examples" subdirectory. The libusb homepage includes a list of
120 * real-life project examples which use libusb.
122 * \section errorhandling Error handling
124 * libusb functions typically return 0 on success or a negative error code
125 * on failure. These negative error codes relate to LIBUSB_ERROR constants
126 * which are listed on the \ref misc "miscellaneous" documentation page.
128 * \section msglog Debug message logging
130 * libusb uses stderr for all logging. By default, logging is set to NONE,
131 * which means that no output will be produced. However, unless the library
132 * has been compiled with logging disabled, then any application calls to
133 * libusb_set_debug(), or the setting of the environmental variable
134 * LIBUSB_DEBUG outside of the application, can result in logging being
135 * produced. Your application should therefore not close stderr, but instead
136 * direct it to the null device if its output is undesireable.
138 * The libusb_set_debug() function can be used to enable logging of certain
139 * messages. Under standard configuration, libusb doesn't really log much
140 * so you are advised to use this function to enable all error/warning/
141 * informational messages. It will help debug problems with your software.
143 * The logged messages are unstructured. There is no one-to-one correspondence
144 * between messages being logged and success or failure return codes from
145 * libusb functions. There is no format to the messages, so you should not
146 * try to capture or parse them. They are not and will not be localized.
147 * These messages are not intended to being passed to your application user;
148 * instead, you should interpret the error codes returned from libusb functions
149 * and provide appropriate notification to the user. The messages are simply
150 * there to aid you as a programmer, and if you're confused because you're
151 * getting a strange error code from a libusb function, enabling message
152 * logging may give you a suitable explanation.
154 * The LIBUSB_DEBUG environment variable can be used to enable message logging
155 * at run-time. This environment variable should be set to a log level number,
156 * which is interpreted the same as the libusb_set_debug() parameter. When this
157 * environment variable is set, the message logging verbosity level is fixed
158 * and libusb_set_debug() effectively does nothing.
160 * libusb can be compiled without any logging functions, useful for embedded
161 * systems. In this case, libusb_set_debug() and the LIBUSB_DEBUG environment
162 * variable have no effects.
164 * libusb can also be compiled with verbose debugging messages always. When
165 * the library is compiled in this way, all messages of all verbosities are
166 * always logged. libusb_set_debug() and the LIBUSB_DEBUG environment variable
169 * \section remarks Other remarks
171 * libusb does have imperfections. The \ref caveats "caveats" page attempts
176 * \page caveats Caveats
178 * \section devresets Device resets
180 * The libusb_reset_device() function allows you to reset a device. If your
181 * program has to call such a function, it should obviously be aware that
182 * the reset will cause device state to change (e.g. register values may be
185 * The problem is that any other program could reset the device your program
186 * is working with, at any time. libusb does not offer a mechanism to inform
187 * you when this has happened, so if someone else resets your device it will
188 * not be clear to your own program why the device state has changed.
190 * Ultimately, this is a limitation of writing drivers in userspace.
191 * Separation from the USB stack in the underlying kernel makes it difficult
192 * for the operating system to deliver such notifications to your program.
193 * The Linux kernel USB stack allows such reset notifications to be delivered
194 * to in-kernel USB drivers, but it is not clear how such notifications could
195 * be delivered to second-class drivers that live in userspace.
197 * \section blockonly Blocking-only functionality
199 * The functionality listed below is only available through synchronous,
200 * blocking functions. There are no asynchronous/non-blocking alternatives,
201 * and no clear ways of implementing these.
203 * - Configuration activation (libusb_set_configuration())
204 * - Interface/alternate setting activation (libusb_set_interface_alt_setting())
205 * - Releasing of interfaces (libusb_release_interface())
206 * - Clearing of halt/stall condition (libusb_clear_halt())
207 * - Device resets (libusb_reset_device())
209 * \section configsel Configuration selection and handling
211 * When libusb presents a device handle to an application, there is a chance
212 * that the corresponding device may be in unconfigured state. For devices
213 * with multiple configurations, there is also a chance that the configuration
214 * currently selected is not the one that the application wants to use.
216 * The obvious solution is to add a call to libusb_set_configuration() early
217 * on during your device initialization routines, but there are caveats to
219 * -# If the device is already in the desired configuration, calling
220 * libusb_set_configuration() using the same configuration value will cause
221 * a lightweight device reset. This may not be desirable behaviour.
222 * -# libusb will be unable to change configuration if the device is in
223 * another configuration and other programs or drivers have claimed
224 * interfaces under that configuration.
225 * -# In the case where the desired configuration is already active, libusb
226 * may not even be able to perform a lightweight device reset. For example,
227 * take my USB keyboard with fingerprint reader: I'm interested in driving
228 * the fingerprint reader interface through libusb, but the kernel's
229 * USB-HID driver will almost always have claimed the keyboard interface.
230 * Because the kernel has claimed an interface, it is not even possible to
231 * perform the lightweight device reset, so libusb_set_configuration() will
232 * fail. (Luckily the device in question only has a single configuration.)
234 * One solution to some of the above problems is to consider the currently
235 * active configuration. If the configuration we want is already active, then
236 * we don't have to select any configuration:
238 cfg = libusb_get_configuration(dev);
240 libusb_set_configuration(dev, desired);
243 * This is probably suitable for most scenarios, but is inherently racy:
244 * another application or driver may change the selected configuration
245 * <em>after</em> the libusb_get_configuration() call.
247 * Even in cases where libusb_set_configuration() succeeds, consider that other
248 * applications or drivers may change configuration after your application
249 * calls libusb_set_configuration().
251 * One possible way to lock your device into a specific configuration is as
253 * -# Set the desired configuration (or use the logic above to realise that
254 * it is already in the desired configuration)
255 * -# Claim the interface that you wish to use
256 * -# Check that the currently active configuration is the one that you want
259 * The above method works because once an interface is claimed, no application
260 * or driver is able to select another configuration.
262 * \section earlycomp Early transfer completion
264 * NOTE: This section is currently Linux-centric. I am not sure if any of these
265 * considerations apply to Darwin or other platforms.
267 * When a transfer completes early (i.e. when less data is received/sent in
268 * any one packet than the transfer buffer allows for) then libusb is designed
269 * to terminate the transfer immediately, not transferring or receiving any
270 * more data unless other transfers have been queued by the user.
272 * On legacy platforms, libusb is unable to do this in all situations. After
273 * the incomplete packet occurs, "surplus" data may be transferred. For recent
274 * versions of libusb, this information is kept (the data length of the
275 * transfer is updated) and, for device-to-host transfers, any surplus data was
276 * added to the buffer. Still, this is not a nice solution because it loses the
277 * information about the end of the short packet, and the user probably wanted
278 * that surplus data to arrive in the next logical transfer.
281 * \section zlp Zero length packets
283 * - libusb is able to send a packet of zero length to an endpoint simply by
284 * submitting a transfer of zero length.
285 * - The \ref libusb_transfer_flags::LIBUSB_TRANSFER_ADD_ZERO_PACKET
286 * "LIBUSB_TRANSFER_ADD_ZERO_PACKET" flag is currently only supported on Linux.
290 * \page contexts Contexts
292 * It is possible that libusb may be used simultaneously from two independent
293 * libraries linked into the same executable. For example, if your application
294 * has a plugin-like system which allows the user to dynamically load a range
295 * of modules into your program, it is feasible that two independently
296 * developed modules may both use libusb.
298 * libusb is written to allow for these multiple user scenarios. The two
299 * "instances" of libusb will not interfere: libusb_set_debug() calls
300 * from one user will not affect the same settings for other users, other
301 * users can continue using libusb after one of them calls libusb_exit(), etc.
303 * This is made possible through libusb's <em>context</em> concept. When you
304 * call libusb_init(), you are (optionally) given a context. You can then pass
305 * this context pointer back into future libusb functions.
307 * In order to keep things simple for more simplistic applications, it is
308 * legal to pass NULL to all functions requiring a context pointer (as long as
309 * you're sure no other code will attempt to use libusb from the same process).
310 * When you pass NULL, the default context will be used. The default context
311 * is created the first time a process calls libusb_init() when no other
312 * context is alive. Contexts are destroyed during libusb_exit().
314 * The default context is reference-counted and can be shared. That means that
315 * if libusb_init(NULL) is called twice within the same process, the two
316 * users end up sharing the same context. The deinitialization and freeing of
317 * the default context will only happen when the last user calls libusb_exit().
318 * In other words, the default context is created and initialized when its
319 * reference count goes from 0 to 1, and is deinitialized and destroyed when
320 * its reference count goes from 1 to 0.
322 * You may be wondering why only a subset of libusb functions require a
323 * context pointer in their function definition. Internally, libusb stores
324 * context pointers in other objects (e.g. libusb_device instances) and hence
325 * can infer the context from those objects.
329 * @defgroup lib Library initialization/deinitialization
330 * This page details how to initialize and deinitialize libusb. Initialization
331 * must be performed before using any libusb functionality, and similarly you
332 * must not call any libusb functions after deinitialization.
336 * @defgroup dev Device handling and enumeration
337 * The functionality documented below is designed to help with the following
339 * - Enumerating the USB devices currently attached to the system
340 * - Choosing a device to operate from your software
341 * - Opening and closing the chosen device
343 * \section nutshell In a nutshell...
345 * The description below really makes things sound more complicated than they
346 * actually are. The following sequence of function calls will be suitable
347 * for almost all scenarios and does not require you to have such a deep
348 * understanding of the resource management issues:
351 libusb_device **list;
352 libusb_device *found = NULL;
353 ssize_t cnt = libusb_get_device_list(NULL, &list);
359 for (i = 0; i < cnt; i++) {
360 libusb_device *device = list[i];
361 if (is_interesting(device)) {
368 libusb_device_handle *handle;
370 err = libusb_open(found, &handle);
376 libusb_free_device_list(list, 1);
379 * The two important points:
380 * - You asked libusb_free_device_list() to unreference the devices (2nd
382 * - You opened the device before freeing the list and unreferencing the
385 * If you ended up with a handle, you can now proceed to perform I/O on the
388 * \section devshandles Devices and device handles
389 * libusb has a concept of a USB device, represented by the
390 * \ref libusb_device opaque type. A device represents a USB device that
391 * is currently or was previously connected to the system. Using a reference
392 * to a device, you can determine certain information about the device (e.g.
393 * you can read the descriptor data).
395 * The libusb_get_device_list() function can be used to obtain a list of
396 * devices currently connected to the system. This is known as device
399 * Just because you have a reference to a device does not mean it is
400 * necessarily usable. The device may have been unplugged, you may not have
401 * permission to operate such device, or another program or driver may be
404 * When you've found a device that you'd like to operate, you must ask
405 * libusb to open the device using the libusb_open() function. Assuming
406 * success, libusb then returns you a <em>device handle</em>
407 * (a \ref libusb_device_handle pointer). All "real" I/O operations then
408 * operate on the handle rather than the original device pointer.
410 * \section devref Device discovery and reference counting
412 * Device discovery (i.e. calling libusb_get_device_list()) returns a
413 * freshly-allocated list of devices. The list itself must be freed when
414 * you are done with it. libusb also needs to know when it is OK to free
415 * the contents of the list - the devices themselves.
417 * To handle these issues, libusb provides you with two separate items:
418 * - A function to free the list itself
419 * - A reference counting system for the devices inside
421 * New devices presented by the libusb_get_device_list() function all have a
422 * reference count of 1. You can increase and decrease reference count using
423 * libusb_ref_device() and libusb_unref_device(). A device is destroyed when
424 * its reference count reaches 0.
426 * With the above information in mind, the process of opening a device can
427 * be viewed as follows:
428 * -# Discover devices using libusb_get_device_list().
429 * -# Choose the device that you want to operate, and call libusb_open().
430 * -# Unref all devices in the discovered device list.
431 * -# Free the discovered device list.
433 * The order is important - you must not unreference the device before
434 * attempting to open it, because unreferencing it may destroy the device.
436 * For convenience, the libusb_free_device_list() function includes a
437 * parameter to optionally unreference all the devices in the list before
438 * freeing the list itself. This combines steps 3 and 4 above.
440 * As an implementation detail, libusb_open() actually adds a reference to
441 * the device in question. This is because the device remains available
442 * through the handle via libusb_get_device(). The reference is deleted during
446 /** @defgroup misc Miscellaneous */
448 /* we traverse usbfs without knowing how many devices we are going to find.
449 * so we create this discovered_devs model which is similar to a linked-list
450 * which grows when required. it can be freed once discovery has completed,
451 * eliminating the need for a list node in the libusb_device structure
453 #define DISCOVERED_DEVICES_SIZE_STEP 8
455 static struct discovered_devs *discovered_devs_alloc(void)
457 struct discovered_devs *ret =
458 malloc(sizeof(*ret) + (sizeof(void *) * DISCOVERED_DEVICES_SIZE_STEP));
462 ret->capacity = DISCOVERED_DEVICES_SIZE_STEP;
467 /* append a device to the discovered devices collection. may realloc itself,
468 * returning new discdevs. returns NULL on realloc failure. */
469 struct discovered_devs *discovered_devs_append(
470 struct discovered_devs *discdevs, struct libusb_device *dev)
472 size_t len = discdevs->len;
475 /* if there is space, just append the device */
476 if (len < discdevs->capacity) {
477 discdevs->devices[len] = libusb_ref_device(dev);
482 /* exceeded capacity, need to grow */
483 usbi_dbg("need to increase capacity");
484 capacity = discdevs->capacity + DISCOVERED_DEVICES_SIZE_STEP;
485 discdevs = usbi_reallocf(discdevs,
486 sizeof(*discdevs) + (sizeof(void *) * capacity));
488 discdevs->capacity = capacity;
489 discdevs->devices[len] = libusb_ref_device(dev);
496 static void discovered_devs_free(struct discovered_devs *discdevs)
500 for (i = 0; i < discdevs->len; i++)
501 libusb_unref_device(discdevs->devices[i]);
506 /* Allocate a new device with a specific session ID. The returned device has
507 * a reference count of 1. */
508 struct libusb_device *usbi_alloc_device(struct libusb_context *ctx,
509 unsigned long session_id)
511 size_t priv_size = usbi_backend->device_priv_size;
512 struct libusb_device *dev = calloc(1, sizeof(*dev) + priv_size);
518 r = usbi_mutex_init(&dev->lock, NULL);
526 dev->session_data = session_id;
527 dev->speed = LIBUSB_SPEED_UNKNOWN;
529 if (!libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG)) {
530 usbi_connect_device (dev);
536 void usbi_connect_device(struct libusb_device *dev)
538 libusb_hotplug_message message;
541 memset(&message, 0, sizeof(message));
542 message.event = LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED;
543 message.device = dev;
546 usbi_mutex_lock(&dev->ctx->usb_devs_lock);
547 list_add(&dev->list, &dev->ctx->usb_devs);
548 usbi_mutex_unlock(&dev->ctx->usb_devs_lock);
550 /* Signal that an event has occurred for this device if we support hotplug AND
551 * the hotplug pipe is ready. This prevents an event from getting raised during
552 * initial enumeration. */
553 if (libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG) && dev->ctx->hotplug_pipe[1] > 0) {
554 ret = usbi_write(dev->ctx->hotplug_pipe[1], &message, sizeof(message));
555 if (sizeof (message) != ret) {
556 usbi_err(DEVICE_CTX(dev), "error writing hotplug message");
561 void usbi_disconnect_device(struct libusb_device *dev)
563 libusb_hotplug_message message;
564 struct libusb_context *ctx = dev->ctx;
567 memset(&message, 0, sizeof(message));
568 message.event = LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT;
569 message.device = dev;
570 usbi_mutex_lock(&dev->lock);
572 usbi_mutex_unlock(&dev->lock);
574 usbi_mutex_lock(&ctx->usb_devs_lock);
575 list_del(&dev->list);
576 usbi_mutex_unlock(&ctx->usb_devs_lock);
578 /* Signal that an event has occurred for this device if we support hotplug AND
579 * the hotplug pipe is ready. This prevents an event from getting raised during
580 * initial enumeration. libusb_handle_events will take care of dereferencing the
582 if (libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG) && dev->ctx->hotplug_pipe[1] > 0) {
583 ret = usbi_write(dev->ctx->hotplug_pipe[1], &message, sizeof(message));
584 if (sizeof(message) != ret) {
585 usbi_err(DEVICE_CTX(dev), "error writing hotplug message");
590 /* Perform some final sanity checks on a newly discovered device. If this
591 * function fails (negative return code), the device should not be added
592 * to the discovered device list. */
593 int usbi_sanitize_device(struct libusb_device *dev)
596 uint8_t num_configurations;
598 r = usbi_device_cache_descriptor(dev);
602 num_configurations = dev->device_descriptor.bNumConfigurations;
603 if (num_configurations > USB_MAXCONFIG) {
604 usbi_err(DEVICE_CTX(dev), "too many configurations");
605 return LIBUSB_ERROR_IO;
606 } else if (0 == num_configurations)
607 usbi_dbg("zero configurations, maybe an unauthorized device");
609 dev->num_configurations = num_configurations;
613 /* Examine libusb's internal list of known devices, looking for one with
614 * a specific session ID. Returns the matching device if it was found, and
616 struct libusb_device *usbi_get_device_by_session_id(struct libusb_context *ctx,
617 unsigned long session_id)
619 struct libusb_device *dev;
620 struct libusb_device *ret = NULL;
622 usbi_mutex_lock(&ctx->usb_devs_lock);
623 list_for_each_entry(dev, &ctx->usb_devs, list, struct libusb_device)
624 if (dev->session_data == session_id) {
625 ret = libusb_ref_device(dev);
628 usbi_mutex_unlock(&ctx->usb_devs_lock);
634 * Returns a list of USB devices currently attached to the system. This is
635 * your entry point into finding a USB device to operate.
637 * You are expected to unreference all the devices when you are done with
638 * them, and then free the list with libusb_free_device_list(). Note that
639 * libusb_free_device_list() can unref all the devices for you. Be careful
640 * not to unreference a device you are about to open until after you have
643 * This return value of this function indicates the number of devices in
644 * the resultant list. The list is actually one element larger, as it is
647 * \param ctx the context to operate on, or NULL for the default context
648 * \param list output location for a list of devices. Must be later freed with
649 * libusb_free_device_list().
650 * \returns the number of devices in the outputted list, or any
651 * \ref libusb_error according to errors encountered by the backend.
653 ssize_t API_EXPORTED libusb_get_device_list(libusb_context *ctx,
654 libusb_device ***list)
656 struct discovered_devs *discdevs = discovered_devs_alloc();
657 struct libusb_device **ret;
660 USBI_GET_CONTEXT(ctx);
664 return LIBUSB_ERROR_NO_MEM;
666 if (libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG)) {
667 /* backend provides hotplug support */
668 struct libusb_device *dev;
670 if (usbi_backend->hotplug_poll)
671 usbi_backend->hotplug_poll();
673 usbi_mutex_lock(&ctx->usb_devs_lock);
674 list_for_each_entry(dev, &ctx->usb_devs, list, struct libusb_device) {
675 discdevs = discovered_devs_append(discdevs, dev);
678 r = LIBUSB_ERROR_NO_MEM;
682 usbi_mutex_unlock(&ctx->usb_devs_lock);
684 /* backend does not provide hotplug support */
685 r = usbi_backend->get_device_list(ctx, &discdevs);
693 /* convert discovered_devs into a list */
695 ret = calloc(len + 1, sizeof(struct libusb_device *));
697 len = LIBUSB_ERROR_NO_MEM;
702 for (i = 0; i < len; i++) {
703 struct libusb_device *dev = discdevs->devices[i];
704 ret[i] = libusb_ref_device(dev);
709 discovered_devs_free(discdevs);
714 * Frees a list of devices previously discovered using
715 * libusb_get_device_list(). If the unref_devices parameter is set, the
716 * reference count of each device in the list is decremented by 1.
717 * \param list the list to free
718 * \param unref_devices whether to unref the devices in the list
720 void API_EXPORTED libusb_free_device_list(libusb_device **list,
728 struct libusb_device *dev;
730 while ((dev = list[i++]) != NULL)
731 libusb_unref_device(dev);
737 * Get the number of the bus that a device is connected to.
738 * \param dev a device
739 * \returns the bus number
741 uint8_t API_EXPORTED libusb_get_bus_number(libusb_device *dev)
743 return dev->bus_number;
747 * Get the number of the port that a device is connected to.
748 * Unless the OS does something funky, or you are hot-plugging USB extension cards,
749 * the port number returned by this call is usually guaranteed to be uniquely tied
750 * to a physical port, meaning that different devices plugged on the same physical
751 * port should return the same port number.
753 * But outside of this, there is no guarantee that the port number returned by this
754 * call will remain the same, or even match the order in which ports have been
755 * numbered by the HUB/HCD manufacturer.
757 * \param dev a device
758 * \returns the port number (0 if not available)
760 uint8_t API_EXPORTED libusb_get_port_number(libusb_device *dev)
762 return dev->port_number;
766 * Get the list of all port numbers from root for the specified device
768 * Since version 1.0.16, \ref LIBUSB_API_VERSION >= 0x01000102
769 * \param dev a device
770 * \param port_numbers the array that should contain the port numbers
771 * \param port_numbers_len the maximum length of the array. As per the USB 3.0
772 * specs, the current maximum limit for the depth is 7.
773 * \returns the number of elements filled
774 * \returns LIBUSB_ERROR_OVERFLOW if the array is too small
776 int API_EXPORTED libusb_get_port_numbers(libusb_device *dev,
777 uint8_t* port_numbers, int port_numbers_len)
779 int i = port_numbers_len;
780 struct libusb_context *ctx = DEVICE_CTX(dev);
782 if (port_numbers_len <= 0)
783 return LIBUSB_ERROR_INVALID_PARAM;
785 // HCDs can be listed as devices with port #0
786 while((dev) && (dev->port_number != 0)) {
788 usbi_warn(ctx, "port numbers array is too small");
789 return LIBUSB_ERROR_OVERFLOW;
791 port_numbers[i] = dev->port_number;
792 dev = dev->parent_dev;
794 if (i < port_numbers_len)
795 memmove(port_numbers, &port_numbers[i], port_numbers_len - i);
796 return port_numbers_len - i;
800 * Deprecated please use libusb_get_port_numbers instead.
802 int API_EXPORTED libusb_get_port_path(libusb_context *ctx, libusb_device *dev,
803 uint8_t* port_numbers, uint8_t port_numbers_len)
807 return libusb_get_port_numbers(dev, port_numbers, port_numbers_len);
811 * Get the the parent from the specified device.
812 * \param dev a device
813 * \returns the device parent or NULL if not available
814 * You should issue a \ref libusb_get_device_list() before calling this
815 * function and make sure that you only access the parent before issuing
816 * \ref libusb_free_device_list(). The reason is that libusb currently does
817 * not maintain a permanent list of device instances, and therefore can
818 * only guarantee that parents are fully instantiated within a
819 * libusb_get_device_list() - libusb_free_device_list() block.
822 libusb_device * LIBUSB_CALL libusb_get_parent(libusb_device *dev)
824 return dev->parent_dev;
828 * Get the address of the device on the bus it is connected to.
829 * \param dev a device
830 * \returns the device address
832 uint8_t API_EXPORTED libusb_get_device_address(libusb_device *dev)
834 return dev->device_address;
838 * Get the negotiated connection speed for a device.
839 * \param dev a device
840 * \returns a \ref libusb_speed code, where LIBUSB_SPEED_UNKNOWN means that
841 * the OS doesn't know or doesn't support returning the negotiated speed.
843 int API_EXPORTED libusb_get_device_speed(libusb_device *dev)
848 static const struct libusb_endpoint_descriptor *find_endpoint(
849 struct libusb_config_descriptor *config, unsigned char endpoint)
852 for (iface_idx = 0; iface_idx < config->bNumInterfaces; iface_idx++) {
853 const struct libusb_interface *iface = &config->interface[iface_idx];
856 for (altsetting_idx = 0; altsetting_idx < iface->num_altsetting;
858 const struct libusb_interface_descriptor *altsetting
859 = &iface->altsetting[altsetting_idx];
862 for (ep_idx = 0; ep_idx < altsetting->bNumEndpoints; ep_idx++) {
863 const struct libusb_endpoint_descriptor *ep =
864 &altsetting->endpoint[ep_idx];
865 if (ep->bEndpointAddress == endpoint)
874 * Convenience function to retrieve the wMaxPacketSize value for a particular
875 * endpoint in the active device configuration.
877 * This function was originally intended to be of assistance when setting up
878 * isochronous transfers, but a design mistake resulted in this function
879 * instead. It simply returns the wMaxPacketSize value without considering
880 * its contents. If you're dealing with isochronous transfers, you probably
881 * want libusb_get_max_iso_packet_size() instead.
883 * \param dev a device
884 * \param endpoint address of the endpoint in question
885 * \returns the wMaxPacketSize value
886 * \returns LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist
887 * \returns LIBUSB_ERROR_OTHER on other failure
889 int API_EXPORTED libusb_get_max_packet_size(libusb_device *dev,
890 unsigned char endpoint)
892 struct libusb_config_descriptor *config;
893 const struct libusb_endpoint_descriptor *ep;
896 r = libusb_get_active_config_descriptor(dev, &config);
898 usbi_err(DEVICE_CTX(dev),
899 "could not retrieve active config descriptor");
900 return LIBUSB_ERROR_OTHER;
903 ep = find_endpoint(config, endpoint);
905 r = LIBUSB_ERROR_NOT_FOUND;
909 r = ep->wMaxPacketSize;
912 libusb_free_config_descriptor(config);
917 * Calculate the maximum packet size which a specific endpoint is capable is
918 * sending or receiving in the duration of 1 microframe
920 * Only the active configuration is examined. The calculation is based on the
921 * wMaxPacketSize field in the endpoint descriptor as described in section
922 * 9.6.6 in the USB 2.0 specifications.
924 * If acting on an isochronous or interrupt endpoint, this function will
925 * multiply the value found in bits 0:10 by the number of transactions per
926 * microframe (determined by bits 11:12). Otherwise, this function just
927 * returns the numeric value found in bits 0:10.
929 * This function is useful for setting up isochronous transfers, for example
930 * you might pass the return value from this function to
931 * libusb_set_iso_packet_lengths() in order to set the length field of every
932 * isochronous packet in a transfer.
936 * \param dev a device
937 * \param endpoint address of the endpoint in question
938 * \returns the maximum packet size which can be sent/received on this endpoint
939 * \returns LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist
940 * \returns LIBUSB_ERROR_OTHER on other failure
942 int API_EXPORTED libusb_get_max_iso_packet_size(libusb_device *dev,
943 unsigned char endpoint)
945 struct libusb_config_descriptor *config;
946 const struct libusb_endpoint_descriptor *ep;
947 enum libusb_transfer_type ep_type;
951 r = libusb_get_active_config_descriptor(dev, &config);
953 usbi_err(DEVICE_CTX(dev),
954 "could not retrieve active config descriptor");
955 return LIBUSB_ERROR_OTHER;
958 ep = find_endpoint(config, endpoint);
960 r = LIBUSB_ERROR_NOT_FOUND;
964 val = ep->wMaxPacketSize;
965 ep_type = (enum libusb_transfer_type) (ep->bmAttributes & 0x3);
968 if (ep_type == LIBUSB_TRANSFER_TYPE_ISOCHRONOUS
969 || ep_type == LIBUSB_TRANSFER_TYPE_INTERRUPT)
970 r *= (1 + ((val >> 11) & 3));
973 libusb_free_config_descriptor(config);
978 * Increment the reference count of a device.
979 * \param dev the device to reference
980 * \returns the same device
983 libusb_device * LIBUSB_CALL libusb_ref_device(libusb_device *dev)
985 usbi_mutex_lock(&dev->lock);
987 usbi_mutex_unlock(&dev->lock);
992 * Decrement the reference count of a device. If the decrement operation
993 * causes the reference count to reach zero, the device shall be destroyed.
994 * \param dev the device to unreference
996 void API_EXPORTED libusb_unref_device(libusb_device *dev)
1003 usbi_mutex_lock(&dev->lock);
1004 refcnt = --dev->refcnt;
1005 usbi_mutex_unlock(&dev->lock);
1008 usbi_dbg("destroy device %d.%d", dev->bus_number, dev->device_address);
1010 libusb_unref_device(dev->parent_dev);
1012 if (usbi_backend->destroy_device)
1013 usbi_backend->destroy_device(dev);
1015 if (!libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG)) {
1016 /* backend does not support hotplug */
1017 usbi_disconnect_device(dev);
1020 usbi_mutex_destroy(&dev->lock);
1026 * Interrupt the iteration of the event handling thread, so that it picks
1029 void usbi_fd_notification(struct libusb_context *ctx)
1031 unsigned char dummy = 1;
1037 /* record that we are messing with poll fds */
1038 usbi_mutex_lock(&ctx->pollfd_modify_lock);
1039 ctx->pollfd_modify++;
1040 usbi_mutex_unlock(&ctx->pollfd_modify_lock);
1042 /* write some data on control pipe to interrupt event handlers */
1043 r = usbi_write(ctx->ctrl_pipe[1], &dummy, sizeof(dummy));
1045 usbi_warn(ctx, "internal signalling write failed");
1046 usbi_mutex_lock(&ctx->pollfd_modify_lock);
1047 ctx->pollfd_modify--;
1048 usbi_mutex_unlock(&ctx->pollfd_modify_lock);
1052 /* take event handling lock */
1053 libusb_lock_events(ctx);
1055 /* read the dummy data */
1056 r = usbi_read(ctx->ctrl_pipe[0], &dummy, sizeof(dummy));
1058 usbi_warn(ctx, "internal signalling read failed");
1060 /* we're done with modifying poll fds */
1061 usbi_mutex_lock(&ctx->pollfd_modify_lock);
1062 ctx->pollfd_modify--;
1063 usbi_mutex_unlock(&ctx->pollfd_modify_lock);
1065 /* Release event handling lock and wake up event waiters */
1066 libusb_unlock_events(ctx);
1070 * Open a device and obtain a device handle. A handle allows you to perform
1071 * I/O on the device in question.
1073 * Internally, this function adds a reference to the device and makes it
1074 * available to you through libusb_get_device(). This reference is removed
1075 * during libusb_close().
1077 * This is a non-blocking function; no requests are sent over the bus.
1079 * \param dev the device to open
1080 * \param handle output location for the returned device handle pointer. Only
1081 * populated when the return code is 0.
1082 * \returns 0 on success
1083 * \returns LIBUSB_ERROR_NO_MEM on memory allocation failure
1084 * \returns LIBUSB_ERROR_ACCESS if the user has insufficient permissions
1085 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1086 * \returns another LIBUSB_ERROR code on other failure
1088 int API_EXPORTED libusb_open(libusb_device *dev,
1089 libusb_device_handle **handle)
1091 struct libusb_context *ctx = DEVICE_CTX(dev);
1092 struct libusb_device_handle *_handle;
1093 size_t priv_size = usbi_backend->device_handle_priv_size;
1095 usbi_dbg("open %d.%d", dev->bus_number, dev->device_address);
1097 if (!dev->attached) {
1098 return LIBUSB_ERROR_NO_DEVICE;
1101 _handle = malloc(sizeof(*_handle) + priv_size);
1103 return LIBUSB_ERROR_NO_MEM;
1105 r = usbi_mutex_init(&_handle->lock, NULL);
1108 return LIBUSB_ERROR_OTHER;
1111 _handle->dev = libusb_ref_device(dev);
1112 _handle->auto_detach_kernel_driver = 0;
1113 _handle->claimed_interfaces = 0;
1114 memset(&_handle->os_priv, 0, priv_size);
1116 r = usbi_backend->open(_handle);
1118 usbi_dbg("open %d.%d returns %d", dev->bus_number, dev->device_address, r);
1119 libusb_unref_device(dev);
1120 usbi_mutex_destroy(&_handle->lock);
1125 usbi_mutex_lock(&ctx->open_devs_lock);
1126 list_add(&_handle->list, &ctx->open_devs);
1127 usbi_mutex_unlock(&ctx->open_devs_lock);
1130 if (usbi_backend->caps & USBI_CAP_HAS_POLLABLE_DEVICE_FD) {
1131 /* At this point, we want to interrupt any existing event handlers so
1132 * that they realise the addition of the new device's poll fd. One
1133 * example when this is desirable is if the user is running a separate
1134 * dedicated libusb events handling thread, which is running with a long
1135 * or infinite timeout. We want to interrupt that iteration of the loop,
1136 * so that it picks up the new fd, and then continues. */
1137 usbi_fd_notification(ctx);
1144 * Convenience function for finding a device with a particular
1145 * <tt>idVendor</tt>/<tt>idProduct</tt> combination. This function is intended
1146 * for those scenarios where you are using libusb to knock up a quick test
1147 * application - it allows you to avoid calling libusb_get_device_list() and
1148 * worrying about traversing/freeing the list.
1150 * This function has limitations and is hence not intended for use in real
1151 * applications: if multiple devices have the same IDs it will only
1152 * give you the first one, etc.
1154 * \param ctx the context to operate on, or NULL for the default context
1155 * \param vendor_id the idVendor value to search for
1156 * \param product_id the idProduct value to search for
1157 * \returns a handle for the first found device, or NULL on error or if the
1158 * device could not be found. */
1160 libusb_device_handle * LIBUSB_CALL libusb_open_device_with_vid_pid(
1161 libusb_context *ctx, uint16_t vendor_id, uint16_t product_id)
1163 struct libusb_device **devs;
1164 struct libusb_device *found = NULL;
1165 struct libusb_device *dev;
1166 struct libusb_device_handle *handle = NULL;
1170 if (libusb_get_device_list(ctx, &devs) < 0)
1173 while ((dev = devs[i++]) != NULL) {
1174 struct libusb_device_descriptor desc;
1175 r = libusb_get_device_descriptor(dev, &desc);
1178 if (desc.idVendor == vendor_id && desc.idProduct == product_id) {
1185 r = libusb_open(found, &handle);
1191 libusb_free_device_list(devs, 1);
1195 static void do_close(struct libusb_context *ctx,
1196 struct libusb_device_handle *dev_handle)
1198 struct usbi_transfer *itransfer;
1199 struct usbi_transfer *tmp;
1201 libusb_lock_events(ctx);
1203 /* remove any transfers in flight that are for this device */
1204 usbi_mutex_lock(&ctx->flying_transfers_lock);
1206 /* safe iteration because transfers may be being deleted */
1207 list_for_each_entry_safe(itransfer, tmp, &ctx->flying_transfers, list, struct usbi_transfer) {
1208 struct libusb_transfer *transfer =
1209 USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
1211 if (transfer->dev_handle != dev_handle)
1214 if (!(itransfer->flags & USBI_TRANSFER_DEVICE_DISAPPEARED)) {
1215 usbi_err(ctx, "Device handle closed while transfer was still being processed, but the device is still connected as far as we know");
1217 if (itransfer->flags & USBI_TRANSFER_CANCELLING)
1218 usbi_warn(ctx, "A cancellation for an in-flight transfer hasn't completed but closing the device handle");
1220 usbi_err(ctx, "A cancellation hasn't even been scheduled on the transfer for which the device is closing");
1223 /* remove from the list of in-flight transfers and make sure
1224 * we don't accidentally use the device handle in the future
1225 * (or that such accesses will be easily caught and identified as a crash)
1227 usbi_mutex_lock(&itransfer->lock);
1228 list_del(&itransfer->list);
1229 transfer->dev_handle = NULL;
1230 usbi_mutex_unlock(&itransfer->lock);
1232 /* it is up to the user to free up the actual transfer struct. this is
1233 * just making sure that we don't attempt to process the transfer after
1234 * the device handle is invalid
1236 usbi_dbg("Removed transfer %p from the in-flight list because device handle %p closed",
1237 transfer, dev_handle);
1239 usbi_mutex_unlock(&ctx->flying_transfers_lock);
1241 libusb_unlock_events(ctx);
1243 usbi_mutex_lock(&ctx->open_devs_lock);
1244 list_del(&dev_handle->list);
1245 usbi_mutex_unlock(&ctx->open_devs_lock);
1247 usbi_backend->close(dev_handle);
1248 libusb_unref_device(dev_handle->dev);
1249 usbi_mutex_destroy(&dev_handle->lock);
1254 * Close a device handle. Should be called on all open handles before your
1255 * application exits.
1257 * Internally, this function destroys the reference that was added by
1258 * libusb_open() on the given device.
1260 * This is a non-blocking function; no requests are sent over the bus.
1262 * \param dev_handle the handle to close
1264 void API_EXPORTED libusb_close(libusb_device_handle *dev_handle)
1266 struct libusb_context *ctx;
1267 unsigned char dummy = 1;
1274 ctx = HANDLE_CTX(dev_handle);
1276 /* Similarly to libusb_open(), we want to interrupt all event handlers
1277 * at this point. More importantly, we want to perform the actual close of
1278 * the device while holding the event handling lock (preventing any other
1279 * thread from doing event handling) because we will be removing a file
1280 * descriptor from the polling loop. */
1282 /* record that we are messing with poll fds */
1283 usbi_mutex_lock(&ctx->pollfd_modify_lock);
1284 ctx->pollfd_modify++;
1285 usbi_mutex_unlock(&ctx->pollfd_modify_lock);
1287 /* write some data on control pipe to interrupt event handlers */
1288 r = usbi_write(ctx->ctrl_pipe[1], &dummy, sizeof(dummy));
1290 usbi_warn(ctx, "internal signalling write failed, closing anyway");
1291 do_close(ctx, dev_handle);
1292 usbi_mutex_lock(&ctx->pollfd_modify_lock);
1293 ctx->pollfd_modify--;
1294 usbi_mutex_unlock(&ctx->pollfd_modify_lock);
1298 /* take event handling lock */
1299 libusb_lock_events(ctx);
1301 /* read the dummy data */
1302 r = usbi_read(ctx->ctrl_pipe[0], &dummy, sizeof(dummy));
1304 usbi_warn(ctx, "internal signalling read failed, closing anyway");
1306 /* Close the device */
1307 do_close(ctx, dev_handle);
1309 /* we're done with modifying poll fds */
1310 usbi_mutex_lock(&ctx->pollfd_modify_lock);
1311 ctx->pollfd_modify--;
1312 usbi_mutex_unlock(&ctx->pollfd_modify_lock);
1314 /* Release event handling lock and wake up event waiters */
1315 libusb_unlock_events(ctx);
1319 * Get the underlying device for a handle. This function does not modify
1320 * the reference count of the returned device, so do not feel compelled to
1321 * unreference it when you are done.
1322 * \param dev_handle a device handle
1323 * \returns the underlying device
1326 libusb_device * LIBUSB_CALL libusb_get_device(libusb_device_handle *dev_handle)
1328 return dev_handle->dev;
1332 * Determine the bConfigurationValue of the currently active configuration.
1334 * You could formulate your own control request to obtain this information,
1335 * but this function has the advantage that it may be able to retrieve the
1336 * information from operating system caches (no I/O involved).
1338 * If the OS does not cache this information, then this function will block
1339 * while a control transfer is submitted to retrieve the information.
1341 * This function will return a value of 0 in the <tt>config</tt> output
1342 * parameter if the device is in unconfigured state.
1344 * \param dev a device handle
1345 * \param config output location for the bConfigurationValue of the active
1346 * configuration (only valid for return code 0)
1347 * \returns 0 on success
1348 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1349 * \returns another LIBUSB_ERROR code on other failure
1351 int API_EXPORTED libusb_get_configuration(libusb_device_handle *dev,
1354 int r = LIBUSB_ERROR_NOT_SUPPORTED;
1357 if (usbi_backend->get_configuration)
1358 r = usbi_backend->get_configuration(dev, config);
1360 if (r == LIBUSB_ERROR_NOT_SUPPORTED) {
1362 usbi_dbg("falling back to control message");
1363 r = libusb_control_transfer(dev, LIBUSB_ENDPOINT_IN,
1364 LIBUSB_REQUEST_GET_CONFIGURATION, 0, 0, &tmp, 1, 1000);
1366 usbi_err(HANDLE_CTX(dev), "zero bytes returned in ctrl transfer?");
1367 r = LIBUSB_ERROR_IO;
1368 } else if (r == 1) {
1372 usbi_dbg("control failed, error %d", r);
1377 usbi_dbg("active config %d", *config);
1383 * Set the active configuration for a device.
1385 * The operating system may or may not have already set an active
1386 * configuration on the device. It is up to your application to ensure the
1387 * correct configuration is selected before you attempt to claim interfaces
1388 * and perform other operations.
1390 * If you call this function on a device already configured with the selected
1391 * configuration, then this function will act as a lightweight device reset:
1392 * it will issue a SET_CONFIGURATION request using the current configuration,
1393 * causing most USB-related device state to be reset (altsetting reset to zero,
1394 * endpoint halts cleared, toggles reset).
1396 * You cannot change/reset configuration if your application has claimed
1397 * interfaces. It is advised to set the desired configuration before claiming
1400 * Alternatively you can call libusb_release_interface() first. Note if you
1401 * do things this way you must ensure that auto_detach_kernel_driver for
1402 * <tt>dev</tt> is 0, otherwise the kernel driver will be re-attached when you
1403 * release the interface(s).
1405 * You cannot change/reset configuration if other applications or drivers have
1406 * claimed interfaces.
1408 * A configuration value of -1 will put the device in unconfigured state.
1409 * The USB specifications state that a configuration value of 0 does this,
1410 * however buggy devices exist which actually have a configuration 0.
1412 * You should always use this function rather than formulating your own
1413 * SET_CONFIGURATION control request. This is because the underlying operating
1414 * system needs to know when such changes happen.
1416 * This is a blocking function.
1418 * \param dev a device handle
1419 * \param configuration the bConfigurationValue of the configuration you
1420 * wish to activate, or -1 if you wish to put the device in unconfigured state
1421 * \returns 0 on success
1422 * \returns LIBUSB_ERROR_NOT_FOUND if the requested configuration does not exist
1423 * \returns LIBUSB_ERROR_BUSY if interfaces are currently claimed
1424 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1425 * \returns another LIBUSB_ERROR code on other failure
1426 * \see libusb_set_auto_detach_kernel_driver()
1428 int API_EXPORTED libusb_set_configuration(libusb_device_handle *dev,
1431 usbi_dbg("configuration %d", configuration);
1432 return usbi_backend->set_configuration(dev, configuration);
1436 * Claim an interface on a given device handle. You must claim the interface
1437 * you wish to use before you can perform I/O on any of its endpoints.
1439 * It is legal to attempt to claim an already-claimed interface, in which
1440 * case libusb just returns 0 without doing anything.
1442 * If auto_detach_kernel_driver is set to 1 for <tt>dev</tt>, the kernel driver
1443 * will be detached if necessary, on failure the detach error is returned.
1445 * Claiming of interfaces is a purely logical operation; it does not cause
1446 * any requests to be sent over the bus. Interface claiming is used to
1447 * instruct the underlying operating system that your application wishes
1448 * to take ownership of the interface.
1450 * This is a non-blocking function.
1452 * \param dev a device handle
1453 * \param interface_number the <tt>bInterfaceNumber</tt> of the interface you
1455 * \returns 0 on success
1456 * \returns LIBUSB_ERROR_NOT_FOUND if the requested interface does not exist
1457 * \returns LIBUSB_ERROR_BUSY if another program or driver has claimed the
1459 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1460 * \returns a LIBUSB_ERROR code on other failure
1461 * \see libusb_set_auto_detach_kernel_driver()
1463 int API_EXPORTED libusb_claim_interface(libusb_device_handle *dev,
1464 int interface_number)
1468 usbi_dbg("interface %d", interface_number);
1469 if (interface_number >= USB_MAXINTERFACES)
1470 return LIBUSB_ERROR_INVALID_PARAM;
1472 if (!dev->dev->attached)
1473 return LIBUSB_ERROR_NO_DEVICE;
1475 usbi_mutex_lock(&dev->lock);
1476 if (dev->claimed_interfaces & (1 << interface_number))
1479 r = usbi_backend->claim_interface(dev, interface_number);
1481 dev->claimed_interfaces |= 1 << interface_number;
1484 usbi_mutex_unlock(&dev->lock);
1489 * Release an interface previously claimed with libusb_claim_interface(). You
1490 * should release all claimed interfaces before closing a device handle.
1492 * This is a blocking function. A SET_INTERFACE control request will be sent
1493 * to the device, resetting interface state to the first alternate setting.
1495 * If auto_detach_kernel_driver is set to 1 for <tt>dev</tt>, the kernel
1496 * driver will be re-attached after releasing the interface.
1498 * \param dev a device handle
1499 * \param interface_number the <tt>bInterfaceNumber</tt> of the
1500 * previously-claimed interface
1501 * \returns 0 on success
1502 * \returns LIBUSB_ERROR_NOT_FOUND if the interface was not claimed
1503 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1504 * \returns another LIBUSB_ERROR code on other failure
1505 * \see libusb_set_auto_detach_kernel_driver()
1507 int API_EXPORTED libusb_release_interface(libusb_device_handle *dev,
1508 int interface_number)
1512 usbi_dbg("interface %d", interface_number);
1513 if (interface_number >= USB_MAXINTERFACES)
1514 return LIBUSB_ERROR_INVALID_PARAM;
1516 usbi_mutex_lock(&dev->lock);
1517 if (!(dev->claimed_interfaces & (1 << interface_number))) {
1518 r = LIBUSB_ERROR_NOT_FOUND;
1522 r = usbi_backend->release_interface(dev, interface_number);
1524 dev->claimed_interfaces &= ~(1 << interface_number);
1527 usbi_mutex_unlock(&dev->lock);
1532 * Activate an alternate setting for an interface. The interface must have
1533 * been previously claimed with libusb_claim_interface().
1535 * You should always use this function rather than formulating your own
1536 * SET_INTERFACE control request. This is because the underlying operating
1537 * system needs to know when such changes happen.
1539 * This is a blocking function.
1541 * \param dev a device handle
1542 * \param interface_number the <tt>bInterfaceNumber</tt> of the
1543 * previously-claimed interface
1544 * \param alternate_setting the <tt>bAlternateSetting</tt> of the alternate
1545 * setting to activate
1546 * \returns 0 on success
1547 * \returns LIBUSB_ERROR_NOT_FOUND if the interface was not claimed, or the
1548 * requested alternate setting does not exist
1549 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1550 * \returns another LIBUSB_ERROR code on other failure
1552 int API_EXPORTED libusb_set_interface_alt_setting(libusb_device_handle *dev,
1553 int interface_number, int alternate_setting)
1555 usbi_dbg("interface %d altsetting %d",
1556 interface_number, alternate_setting);
1557 if (interface_number >= USB_MAXINTERFACES)
1558 return LIBUSB_ERROR_INVALID_PARAM;
1560 usbi_mutex_lock(&dev->lock);
1561 if (!dev->dev->attached) {
1562 usbi_mutex_unlock(&dev->lock);
1563 return LIBUSB_ERROR_NO_DEVICE;
1566 if (!(dev->claimed_interfaces & (1 << interface_number))) {
1567 usbi_mutex_unlock(&dev->lock);
1568 return LIBUSB_ERROR_NOT_FOUND;
1570 usbi_mutex_unlock(&dev->lock);
1572 return usbi_backend->set_interface_altsetting(dev, interface_number,
1577 * Clear the halt/stall condition for an endpoint. Endpoints with halt status
1578 * are unable to receive or transmit data until the halt condition is stalled.
1580 * You should cancel all pending transfers before attempting to clear the halt
1583 * This is a blocking function.
1585 * \param dev a device handle
1586 * \param endpoint the endpoint to clear halt status
1587 * \returns 0 on success
1588 * \returns LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist
1589 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1590 * \returns another LIBUSB_ERROR code on other failure
1592 int API_EXPORTED libusb_clear_halt(libusb_device_handle *dev,
1593 unsigned char endpoint)
1595 usbi_dbg("endpoint %x", endpoint);
1596 if (!dev->dev->attached)
1597 return LIBUSB_ERROR_NO_DEVICE;
1599 return usbi_backend->clear_halt(dev, endpoint);
1603 * Perform a USB port reset to reinitialize a device. The system will attempt
1604 * to restore the previous configuration and alternate settings after the
1605 * reset has completed.
1607 * If the reset fails, the descriptors change, or the previous state cannot be
1608 * restored, the device will appear to be disconnected and reconnected. This
1609 * means that the device handle is no longer valid (you should close it) and
1610 * rediscover the device. A return code of LIBUSB_ERROR_NOT_FOUND indicates
1611 * when this is the case.
1613 * This is a blocking function which usually incurs a noticeable delay.
1615 * \param dev a handle of the device to reset
1616 * \returns 0 on success
1617 * \returns LIBUSB_ERROR_NOT_FOUND if re-enumeration is required, or if the
1618 * device has been disconnected
1619 * \returns another LIBUSB_ERROR code on other failure
1621 int API_EXPORTED libusb_reset_device(libusb_device_handle *dev)
1624 if (!dev->dev->attached)
1625 return LIBUSB_ERROR_NO_DEVICE;
1627 return usbi_backend->reset_device(dev);
1630 /** \ingroup asyncio
1631 * Allocate up to num_streams usb bulk streams on the specified endpoints. This
1632 * function takes an array of endpoints rather then a single endpoint because
1633 * some protocols require that endpoints are setup with similar stream ids.
1634 * All endpoints passed in must belong to the same interface.
1636 * Note this function may return less streams then requested. Also note that the
1637 * same number of streams are allocated for each endpoint in the endpoint array.
1639 * Stream id 0 is reserved, and should not be used to communicate with devices.
1640 * If libusb_alloc_streams() returns with a value of N, you may use stream ids
1643 * Since version 1.0.19, \ref LIBUSB_API_VERSION >= 0x01000103
1645 * \param dev a device handle
1646 * \param num_streams number of streams to try to allocate
1647 * \param endpoints array of endpoints to allocate streams on
1648 * \param num_endpoints length of the endpoints array
1649 * \returns number of streams allocated, or a LIBUSB_ERROR code on failure
1651 int API_EXPORTED libusb_alloc_streams(libusb_device_handle *dev,
1652 uint32_t num_streams, unsigned char *endpoints, int num_endpoints)
1654 usbi_dbg("streams %u eps %d", (unsigned) num_streams, num_endpoints);
1656 if (!dev->dev->attached)
1657 return LIBUSB_ERROR_NO_DEVICE;
1659 if (usbi_backend->alloc_streams)
1660 return usbi_backend->alloc_streams(dev, num_streams, endpoints,
1663 return LIBUSB_ERROR_NOT_SUPPORTED;
1666 /** \ingroup asyncio
1667 * Free usb bulk streams allocated with libusb_alloc_streams().
1669 * Note streams are automatically free-ed when releasing an interface.
1671 * Since version 1.0.19, \ref LIBUSB_API_VERSION >= 0x01000103
1673 * \param dev a device handle
1674 * \param endpoints array of endpoints to free streams on
1675 * \param num_endpoints length of the endpoints array
1676 * \returns LIBUSB_SUCCESS, or a LIBUSB_ERROR code on failure
1678 int API_EXPORTED libusb_free_streams(libusb_device_handle *dev,
1679 unsigned char *endpoints, int num_endpoints)
1681 usbi_dbg("eps %d", num_endpoints);
1683 if (!dev->dev->attached)
1684 return LIBUSB_ERROR_NO_DEVICE;
1686 if (usbi_backend->free_streams)
1687 return usbi_backend->free_streams(dev, endpoints,
1690 return LIBUSB_ERROR_NOT_SUPPORTED;
1694 * Determine if a kernel driver is active on an interface. If a kernel driver
1695 * is active, you cannot claim the interface, and libusb will be unable to
1698 * This functionality is not available on Windows.
1700 * \param dev a device handle
1701 * \param interface_number the interface to check
1702 * \returns 0 if no kernel driver is active
1703 * \returns 1 if a kernel driver is active
1704 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1705 * \returns LIBUSB_ERROR_NOT_SUPPORTED on platforms where the functionality
1707 * \returns another LIBUSB_ERROR code on other failure
1708 * \see libusb_detach_kernel_driver()
1710 int API_EXPORTED libusb_kernel_driver_active(libusb_device_handle *dev,
1711 int interface_number)
1713 usbi_dbg("interface %d", interface_number);
1715 if (!dev->dev->attached)
1716 return LIBUSB_ERROR_NO_DEVICE;
1718 if (usbi_backend->kernel_driver_active)
1719 return usbi_backend->kernel_driver_active(dev, interface_number);
1721 return LIBUSB_ERROR_NOT_SUPPORTED;
1725 * Detach a kernel driver from an interface. If successful, you will then be
1726 * able to claim the interface and perform I/O.
1728 * This functionality is not available on Darwin or Windows.
1730 * Note that libusb itself also talks to the device through a special kernel
1731 * driver, if this driver is already attached to the device, this call will
1732 * not detach it and return LIBUSB_ERROR_NOT_FOUND.
1734 * \param dev a device handle
1735 * \param interface_number the interface to detach the driver from
1736 * \returns 0 on success
1737 * \returns LIBUSB_ERROR_NOT_FOUND if no kernel driver was active
1738 * \returns LIBUSB_ERROR_INVALID_PARAM if the interface does not exist
1739 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1740 * \returns LIBUSB_ERROR_NOT_SUPPORTED on platforms where the functionality
1742 * \returns another LIBUSB_ERROR code on other failure
1743 * \see libusb_kernel_driver_active()
1745 int API_EXPORTED libusb_detach_kernel_driver(libusb_device_handle *dev,
1746 int interface_number)
1748 usbi_dbg("interface %d", interface_number);
1750 if (!dev->dev->attached)
1751 return LIBUSB_ERROR_NO_DEVICE;
1753 if (usbi_backend->detach_kernel_driver)
1754 return usbi_backend->detach_kernel_driver(dev, interface_number);
1756 return LIBUSB_ERROR_NOT_SUPPORTED;
1760 * Re-attach an interface's kernel driver, which was previously detached
1761 * using libusb_detach_kernel_driver(). This call is only effective on
1762 * Linux and returns LIBUSB_ERROR_NOT_SUPPORTED on all other platforms.
1764 * This functionality is not available on Darwin or Windows.
1766 * \param dev a device handle
1767 * \param interface_number the interface to attach the driver from
1768 * \returns 0 on success
1769 * \returns LIBUSB_ERROR_NOT_FOUND if no kernel driver was active
1770 * \returns LIBUSB_ERROR_INVALID_PARAM if the interface does not exist
1771 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1772 * \returns LIBUSB_ERROR_NOT_SUPPORTED on platforms where the functionality
1774 * \returns LIBUSB_ERROR_BUSY if the driver cannot be attached because the
1775 * interface is claimed by a program or driver
1776 * \returns another LIBUSB_ERROR code on other failure
1777 * \see libusb_kernel_driver_active()
1779 int API_EXPORTED libusb_attach_kernel_driver(libusb_device_handle *dev,
1780 int interface_number)
1782 usbi_dbg("interface %d", interface_number);
1784 if (!dev->dev->attached)
1785 return LIBUSB_ERROR_NO_DEVICE;
1787 if (usbi_backend->attach_kernel_driver)
1788 return usbi_backend->attach_kernel_driver(dev, interface_number);
1790 return LIBUSB_ERROR_NOT_SUPPORTED;
1794 * Enable/disable libusb's automatic kernel driver detachment. When this is
1795 * enabled libusb will automatically detach the kernel driver on an interface
1796 * when claiming the interface, and attach it when releasing the interface.
1798 * Automatic kernel driver detachment is disabled on newly opened device
1799 * handles by default.
1801 * On platforms which do not have LIBUSB_CAP_SUPPORTS_DETACH_KERNEL_DRIVER
1802 * this function will return LIBUSB_ERROR_NOT_SUPPORTED, and libusb will
1803 * continue as if this function was never called.
1805 * \param dev a device handle
1806 * \param enable whether to enable or disable auto kernel driver detachment
1808 * \returns LIBUSB_SUCCESS on success
1809 * \returns LIBUSB_ERROR_NOT_SUPPORTED on platforms where the functionality
1811 * \see libusb_claim_interface()
1812 * \see libusb_release_interface()
1813 * \see libusb_set_configuration()
1815 int API_EXPORTED libusb_set_auto_detach_kernel_driver(
1816 libusb_device_handle *dev, int enable)
1818 if (!(usbi_backend->caps & USBI_CAP_SUPPORTS_DETACH_KERNEL_DRIVER))
1819 return LIBUSB_ERROR_NOT_SUPPORTED;
1821 dev->auto_detach_kernel_driver = enable;
1822 return LIBUSB_SUCCESS;
1826 * Set log message verbosity.
1828 * The default level is LIBUSB_LOG_LEVEL_NONE, which means no messages are ever
1829 * printed. If you choose to increase the message verbosity level, ensure
1830 * that your application does not close the stdout/stderr file descriptors.
1832 * You are advised to use level LIBUSB_LOG_LEVEL_WARNING. libusb is conservative
1833 * with its message logging and most of the time, will only log messages that
1834 * explain error conditions and other oddities. This will help you debug
1837 * If the LIBUSB_DEBUG environment variable was set when libusb was
1838 * initialized, this function does nothing: the message verbosity is fixed
1839 * to the value in the environment variable.
1841 * If libusb was compiled without any message logging, this function does
1842 * nothing: you'll never get any messages.
1844 * If libusb was compiled with verbose debug message logging, this function
1845 * does nothing: you'll always get messages from all levels.
1847 * \param ctx the context to operate on, or NULL for the default context
1848 * \param level debug level to set
1850 void API_EXPORTED libusb_set_debug(libusb_context *ctx, int level)
1852 USBI_GET_CONTEXT(ctx);
1853 if (!ctx->debug_fixed)
1858 * Initialize libusb. This function must be called before calling any other
1861 * If you do not provide an output location for a context pointer, a default
1862 * context will be created. If there was already a default context, it will
1863 * be reused (and nothing will be initialized/reinitialized).
1865 * \param context Optional output location for context pointer.
1866 * Only valid on return code 0.
1867 * \returns 0 on success, or a LIBUSB_ERROR code on failure
1870 int API_EXPORTED libusb_init(libusb_context **context)
1872 struct libusb_device *dev, *next;
1873 char *dbg = getenv("LIBUSB_DEBUG");
1874 struct libusb_context *ctx;
1875 static int first_init = 1;
1878 usbi_mutex_static_lock(&default_context_lock);
1880 if (!timestamp_origin.tv_sec) {
1881 usbi_gettimeofday(×tamp_origin, NULL);
1884 if (!context && usbi_default_context) {
1885 usbi_dbg("reusing default context");
1886 default_context_refcnt++;
1887 usbi_mutex_static_unlock(&default_context_lock);
1891 ctx = calloc(1, sizeof(*ctx));
1893 r = LIBUSB_ERROR_NO_MEM;
1897 #ifdef ENABLE_DEBUG_LOGGING
1898 ctx->debug = LIBUSB_LOG_LEVEL_DEBUG;
1902 ctx->debug = atoi(dbg);
1904 ctx->debug_fixed = 1;
1907 /* default context should be initialized before calling usbi_dbg */
1908 if (!usbi_default_context) {
1909 usbi_default_context = ctx;
1910 default_context_refcnt++;
1911 usbi_dbg("created default context");
1914 usbi_dbg("libusb v%d.%d.%d.%d", libusb_version_internal.major, libusb_version_internal.minor,
1915 libusb_version_internal.micro, libusb_version_internal.nano);
1917 usbi_mutex_init(&ctx->usb_devs_lock, NULL);
1918 usbi_mutex_init(&ctx->open_devs_lock, NULL);
1919 usbi_mutex_init(&ctx->hotplug_cbs_lock, NULL);
1920 list_init(&ctx->usb_devs);
1921 list_init(&ctx->open_devs);
1922 list_init(&ctx->hotplug_cbs);
1924 usbi_mutex_static_lock(&active_contexts_lock);
1927 list_init (&active_contexts_list);
1929 list_add (&ctx->list, &active_contexts_list);
1930 usbi_mutex_static_unlock(&active_contexts_lock);
1932 if (usbi_backend->init) {
1933 r = usbi_backend->init(ctx);
1938 r = usbi_io_init(ctx);
1940 goto err_backend_exit;
1942 usbi_mutex_static_unlock(&default_context_lock);
1950 if (usbi_backend->exit)
1951 usbi_backend->exit();
1953 if (ctx == usbi_default_context) {
1954 usbi_default_context = NULL;
1955 default_context_refcnt--;
1958 usbi_mutex_static_lock(&active_contexts_lock);
1959 list_del (&ctx->list);
1960 usbi_mutex_static_unlock(&active_contexts_lock);
1962 usbi_mutex_lock(&ctx->usb_devs_lock);
1963 list_for_each_entry_safe(dev, next, &ctx->usb_devs, list, struct libusb_device) {
1964 list_del(&dev->list);
1965 libusb_unref_device(dev);
1967 usbi_mutex_unlock(&ctx->usb_devs_lock);
1969 usbi_mutex_destroy(&ctx->open_devs_lock);
1970 usbi_mutex_destroy(&ctx->usb_devs_lock);
1971 usbi_mutex_destroy(&ctx->hotplug_cbs_lock);
1975 usbi_mutex_static_unlock(&default_context_lock);
1980 * Deinitialize libusb. Should be called after closing all open devices and
1981 * before your application terminates.
1982 * \param ctx the context to deinitialize, or NULL for the default context
1984 void API_EXPORTED libusb_exit(struct libusb_context *ctx)
1986 struct libusb_device *dev, *next;
1987 struct timeval tv = { 0, 0 };
1990 USBI_GET_CONTEXT(ctx);
1992 /* if working with default context, only actually do the deinitialization
1993 * if we're the last user */
1994 usbi_mutex_static_lock(&default_context_lock);
1995 if (ctx == usbi_default_context) {
1996 if (--default_context_refcnt > 0) {
1997 usbi_dbg("not destroying default context");
1998 usbi_mutex_static_unlock(&default_context_lock);
2001 usbi_dbg("destroying default context");
2002 usbi_default_context = NULL;
2004 usbi_mutex_static_unlock(&default_context_lock);
2006 usbi_mutex_static_lock(&active_contexts_lock);
2007 list_del (&ctx->list);
2008 usbi_mutex_static_unlock(&active_contexts_lock);
2010 if (libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG)) {
2011 usbi_hotplug_deregister_all(ctx);
2014 * Ensure any pending unplug events are read from the hotplug
2015 * pipe. The usb_device-s hold in the events are no longer part
2016 * of usb_devs, but the events still hold a reference!
2018 * Note we don't do this if the application has left devices
2019 * open (which implies a buggy app) to avoid packet completion
2020 * handlers running when the app does not expect them to run.
2022 if (list_empty(&ctx->open_devs))
2023 libusb_handle_events_timeout(ctx, &tv);
2025 usbi_mutex_lock(&ctx->usb_devs_lock);
2026 list_for_each_entry_safe(dev, next, &ctx->usb_devs, list, struct libusb_device) {
2027 list_del(&dev->list);
2028 libusb_unref_device(dev);
2030 usbi_mutex_unlock(&ctx->usb_devs_lock);
2033 /* a few sanity checks. don't bother with locking because unless
2034 * there is an application bug, nobody will be accessing these. */
2035 if (!list_empty(&ctx->usb_devs))
2036 usbi_warn(ctx, "some libusb_devices were leaked");
2037 if (!list_empty(&ctx->open_devs))
2038 usbi_warn(ctx, "application left some devices open");
2041 if (usbi_backend->exit)
2042 usbi_backend->exit();
2044 usbi_mutex_destroy(&ctx->open_devs_lock);
2045 usbi_mutex_destroy(&ctx->usb_devs_lock);
2046 usbi_mutex_destroy(&ctx->hotplug_cbs_lock);
2051 * Check at runtime if the loaded library has a given capability.
2052 * This call should be performed after \ref libusb_init(), to ensure the
2053 * backend has updated its capability set.
2055 * \param capability the \ref libusb_capability to check for
2056 * \returns nonzero if the running library has the capability, 0 otherwise
2058 int API_EXPORTED libusb_has_capability(uint32_t capability)
2060 switch (capability) {
2061 case LIBUSB_CAP_HAS_CAPABILITY:
2063 case LIBUSB_CAP_HAS_HOTPLUG:
2064 return !(usbi_backend->get_device_list);
2065 case LIBUSB_CAP_HAS_HID_ACCESS:
2066 return (usbi_backend->caps & USBI_CAP_HAS_HID_ACCESS);
2067 case LIBUSB_CAP_SUPPORTS_DETACH_KERNEL_DRIVER:
2068 return (usbi_backend->caps & USBI_CAP_SUPPORTS_DETACH_KERNEL_DRIVER);
2073 /* this is defined in libusbi.h if needed */
2074 #ifdef LIBUSB_GETTIMEOFDAY_WIN32
2077 * Implementation according to:
2078 * The Open Group Base Specifications Issue 6
2079 * IEEE Std 1003.1, 2004 Edition
2083 * THIS SOFTWARE IS NOT COPYRIGHTED
2085 * This source code is offered for use in the public domain. You may
2086 * use, modify or distribute it freely.
2088 * This code is distributed in the hope that it will be useful but
2089 * WITHOUT ANY WARRANTY. ALL WARRANTIES, EXPRESS OR IMPLIED ARE HEREBY
2090 * DISCLAIMED. This includes but is not limited to warranties of
2091 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
2094 * Danny Smith <dannysmith@users.sourceforge.net>
2097 /* Offset between 1/1/1601 and 1/1/1970 in 100 nanosec units */
2098 #define _W32_FT_OFFSET (116444736000000000)
2100 int usbi_gettimeofday(struct timeval *tp, void *tzp)
2103 unsigned __int64 ns100; /* Time since 1 Jan 1601, in 100ns units */
2109 #if defined(OS_WINCE)
2112 SystemTimeToFileTime(&st, &_now.ft);
2114 GetSystemTimeAsFileTime (&_now.ft);
2116 tp->tv_usec=(long)((_now.ns100 / 10) % 1000000 );
2117 tp->tv_sec= (long)((_now.ns100 - _W32_FT_OFFSET) / 10000000);
2119 /* Always return 0 as per Open Group Base Specifications Issue 6.
2120 Do not set errno on error. */
2125 static void usbi_log_str(struct libusb_context *ctx,
2126 enum libusb_log_level level, const char * str)
2128 #if defined(USE_SYSTEM_LOGGING_FACILITY)
2129 #if defined(OS_WINDOWS) || defined(OS_WINCE)
2130 /* Windows CE only supports the Unicode version of OutputDebugString. */
2131 WCHAR wbuf[USBI_MAX_LOG_LEN];
2132 MultiByteToWideChar(CP_UTF8, 0, str, -1, wbuf, sizeof(wbuf));
2133 OutputDebugStringW(wbuf);
2134 #elif defined(__ANDROID__)
2135 int priority = ANDROID_LOG_UNKNOWN;
2137 case LIBUSB_LOG_LEVEL_INFO: priority = ANDROID_LOG_INFO; break;
2138 case LIBUSB_LOG_LEVEL_WARNING: priority = ANDROID_LOG_WARN; break;
2139 case LIBUSB_LOG_LEVEL_ERROR: priority = ANDROID_LOG_ERROR; break;
2140 case LIBUSB_LOG_LEVEL_DEBUG: priority = ANDROID_LOG_DEBUG; break;
2142 __android_log_write(priority, "libusb", str);
2143 #elif defined(HAVE_SYSLOG_FUNC)
2144 int syslog_level = LOG_INFO;
2146 case LIBUSB_LOG_LEVEL_INFO: syslog_level = LOG_INFO; break;
2147 case LIBUSB_LOG_LEVEL_WARNING: syslog_level = LOG_WARNING; break;
2148 case LIBUSB_LOG_LEVEL_ERROR: syslog_level = LOG_ERR; break;
2149 case LIBUSB_LOG_LEVEL_DEBUG: syslog_level = LOG_DEBUG; break;
2151 syslog(syslog_level, "%s", str);
2152 #else /* All of gcc, Clang, XCode seem to use #warning */
2153 #warning System logging is not supported on this platform. Logging to stderr will be used instead.
2158 #endif /* USE_SYSTEM_LOGGING_FACILITY */
2163 void usbi_log_v(struct libusb_context *ctx, enum libusb_log_level level,
2164 const char *function, const char *format, va_list args)
2166 const char *prefix = "";
2167 char buf[USBI_MAX_LOG_LEN];
2169 int global_debug, header_len, text_len;
2170 static int has_debug_header_been_displayed = 0;
2172 #ifdef ENABLE_DEBUG_LOGGING
2178 USBI_GET_CONTEXT(ctx);
2180 ctx_level = ctx->debug;
2182 char *dbg = getenv("LIBUSB_DEBUG");
2184 ctx_level = atoi(dbg);
2186 global_debug = (ctx_level == LIBUSB_LOG_LEVEL_DEBUG);
2189 if (level == LIBUSB_LOG_LEVEL_WARNING && ctx_level < LIBUSB_LOG_LEVEL_WARNING)
2191 if (level == LIBUSB_LOG_LEVEL_INFO && ctx_level < LIBUSB_LOG_LEVEL_INFO)
2193 if (level == LIBUSB_LOG_LEVEL_DEBUG && ctx_level < LIBUSB_LOG_LEVEL_DEBUG)
2197 usbi_gettimeofday(&now, NULL);
2198 if ((global_debug) && (!has_debug_header_been_displayed)) {
2199 has_debug_header_been_displayed = 1;
2200 usbi_log_str(ctx, LIBUSB_LOG_LEVEL_DEBUG, "[timestamp] [threadID] facility level [function call] <message>\n");
2201 usbi_log_str(ctx, LIBUSB_LOG_LEVEL_DEBUG, "--------------------------------------------------------------------------------\n");
2203 if (now.tv_usec < timestamp_origin.tv_usec) {
2205 now.tv_usec += 1000000;
2207 now.tv_sec -= timestamp_origin.tv_sec;
2208 now.tv_usec -= timestamp_origin.tv_usec;
2211 case LIBUSB_LOG_LEVEL_INFO:
2214 case LIBUSB_LOG_LEVEL_WARNING:
2217 case LIBUSB_LOG_LEVEL_ERROR:
2220 case LIBUSB_LOG_LEVEL_DEBUG:
2223 case LIBUSB_LOG_LEVEL_NONE:
2231 header_len = snprintf(buf, sizeof(buf),
2232 "[%2d.%06d] [%08x] libusb: %s [%s] ",
2233 (int)now.tv_sec, (int)now.tv_usec, usbi_get_tid(), prefix, function);
2235 header_len = snprintf(buf, sizeof(buf),
2236 "libusb: %s [%s] ", prefix, function);
2239 if (header_len < 0 || header_len >= sizeof(buf)) {
2240 /* Somehow snprintf failed to write to the buffer,
2241 * remove the header so something useful is output. */
2244 /* Make sure buffer is NUL terminated */
2245 buf[header_len] = '\0';
2246 text_len = vsnprintf(buf + header_len, sizeof(buf) - header_len,
2248 if (text_len < 0 || text_len + header_len >= sizeof(buf)) {
2249 /* Truncated log output. On some platforms a -1 return value means
2250 * that the output was truncated. */
2251 text_len = sizeof(buf) - header_len;
2253 if (header_len + text_len + sizeof(USBI_LOG_LINE_END) >= sizeof(buf)) {
2254 /* Need to truncate the text slightly to fit on the terminator. */
2255 text_len -= (header_len + text_len + sizeof(USBI_LOG_LINE_END)) - sizeof(buf);
2257 strcpy(buf + header_len + text_len, USBI_LOG_LINE_END);
2259 usbi_log_str(ctx, level, buf);
2262 void usbi_log(struct libusb_context *ctx, enum libusb_log_level level,
2263 const char *function, const char *format, ...)
2267 va_start (args, format);
2268 usbi_log_v(ctx, level, function, format, args);
2273 * Returns a constant NULL-terminated string with the ASCII name of a libusb
2274 * error or transfer status code. The caller must not free() the returned
2277 * \param error_code The \ref libusb_error or libusb_transfer_status code to
2278 * return the name of.
2279 * \returns The error name, or the string **UNKNOWN** if the value of
2280 * error_code is not a known error / status code.
2282 DEFAULT_VISIBILITY const char * LIBUSB_CALL libusb_error_name(int error_code)
2284 switch (error_code) {
2285 case LIBUSB_ERROR_IO:
2286 return "LIBUSB_ERROR_IO";
2287 case LIBUSB_ERROR_INVALID_PARAM:
2288 return "LIBUSB_ERROR_INVALID_PARAM";
2289 case LIBUSB_ERROR_ACCESS:
2290 return "LIBUSB_ERROR_ACCESS";
2291 case LIBUSB_ERROR_NO_DEVICE:
2292 return "LIBUSB_ERROR_NO_DEVICE";
2293 case LIBUSB_ERROR_NOT_FOUND:
2294 return "LIBUSB_ERROR_NOT_FOUND";
2295 case LIBUSB_ERROR_BUSY:
2296 return "LIBUSB_ERROR_BUSY";
2297 case LIBUSB_ERROR_TIMEOUT:
2298 return "LIBUSB_ERROR_TIMEOUT";
2299 case LIBUSB_ERROR_OVERFLOW:
2300 return "LIBUSB_ERROR_OVERFLOW";
2301 case LIBUSB_ERROR_PIPE:
2302 return "LIBUSB_ERROR_PIPE";
2303 case LIBUSB_ERROR_INTERRUPTED:
2304 return "LIBUSB_ERROR_INTERRUPTED";
2305 case LIBUSB_ERROR_NO_MEM:
2306 return "LIBUSB_ERROR_NO_MEM";
2307 case LIBUSB_ERROR_NOT_SUPPORTED:
2308 return "LIBUSB_ERROR_NOT_SUPPORTED";
2309 case LIBUSB_ERROR_OTHER:
2310 return "LIBUSB_ERROR_OTHER";
2312 case LIBUSB_TRANSFER_ERROR:
2313 return "LIBUSB_TRANSFER_ERROR";
2314 case LIBUSB_TRANSFER_TIMED_OUT:
2315 return "LIBUSB_TRANSFER_TIMED_OUT";
2316 case LIBUSB_TRANSFER_CANCELLED:
2317 return "LIBUSB_TRANSFER_CANCELLED";
2318 case LIBUSB_TRANSFER_STALL:
2319 return "LIBUSB_TRANSFER_STALL";
2320 case LIBUSB_TRANSFER_NO_DEVICE:
2321 return "LIBUSB_TRANSFER_NO_DEVICE";
2322 case LIBUSB_TRANSFER_OVERFLOW:
2323 return "LIBUSB_TRANSFER_OVERFLOW";
2326 return "LIBUSB_SUCCESS / LIBUSB_TRANSFER_COMPLETED";
2328 return "**UNKNOWN**";
2333 * Returns a pointer to const struct libusb_version with the version
2334 * (major, minor, micro, nano and rc) of the running library.
2337 const struct libusb_version * LIBUSB_CALL libusb_get_version(void)
2339 return &libusb_version_internal;