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 API Application Programming Interface (API)
99 * See the \ref api page for a complete list of the libusb functions.
101 * \section features Library features
103 * - All transfer types supported (control/bulk/interrupt/isochronous)
104 * - 2 transfer interfaces:
105 * -# Synchronous (simple)
106 * -# Asynchronous (more complicated, but more powerful)
107 * - Thread safe (although the asynchronous interface means that you
108 * usually won't need to thread)
109 * - Lightweight with lean API
110 * - Compatible with libusb-0.1 through the libusb-compat-0.1 translation layer
111 * - Hotplug support (on some platforms). See \ref hotplug.
113 * \section gettingstarted Getting Started
115 * To begin reading the API documentation, start with the Modules page which
116 * links to the different categories of libusb's functionality.
118 * One decision you will have to make is whether to use the synchronous
119 * or the asynchronous data transfer interface. The \ref io documentation
120 * provides some insight into this topic.
122 * Some example programs can be found in the libusb source distribution under
123 * the "examples" subdirectory. The libusb homepage includes a list of
124 * real-life project examples which use libusb.
126 * \section errorhandling Error handling
128 * libusb functions typically return 0 on success or a negative error code
129 * on failure. These negative error codes relate to LIBUSB_ERROR constants
130 * which are listed on the \ref misc "miscellaneous" documentation page.
132 * \section msglog Debug message logging
134 * libusb uses stderr for all logging. By default, logging is set to NONE,
135 * which means that no output will be produced. However, unless the library
136 * has been compiled with logging disabled, then any application calls to
137 * libusb_set_debug(), or the setting of the environmental variable
138 * LIBUSB_DEBUG outside of the application, can result in logging being
139 * produced. Your application should therefore not close stderr, but instead
140 * direct it to the null device if its output is undesireable.
142 * The libusb_set_debug() function can be used to enable logging of certain
143 * messages. Under standard configuration, libusb doesn't really log much
144 * so you are advised to use this function to enable all error/warning/
145 * informational messages. It will help debug problems with your software.
147 * The logged messages are unstructured. There is no one-to-one correspondence
148 * between messages being logged and success or failure return codes from
149 * libusb functions. There is no format to the messages, so you should not
150 * try to capture or parse them. They are not and will not be localized.
151 * These messages are not intended to being passed to your application user;
152 * instead, you should interpret the error codes returned from libusb functions
153 * and provide appropriate notification to the user. The messages are simply
154 * there to aid you as a programmer, and if you're confused because you're
155 * getting a strange error code from a libusb function, enabling message
156 * logging may give you a suitable explanation.
158 * The LIBUSB_DEBUG environment variable can be used to enable message logging
159 * at run-time. This environment variable should be set to a log level number,
160 * which is interpreted the same as the libusb_set_debug() parameter. When this
161 * environment variable is set, the message logging verbosity level is fixed
162 * and libusb_set_debug() effectively does nothing.
164 * libusb can be compiled without any logging functions, useful for embedded
165 * systems. In this case, libusb_set_debug() and the LIBUSB_DEBUG environment
166 * variable have no effects.
168 * libusb can also be compiled with verbose debugging messages always. When
169 * the library is compiled in this way, all messages of all verbosities are
170 * always logged. libusb_set_debug() and the LIBUSB_DEBUG environment variable
173 * \section remarks Other remarks
175 * libusb does have imperfections. The \ref caveats "caveats" page attempts
180 * \page caveats Caveats
182 * \section devresets Device resets
184 * The libusb_reset_device() function allows you to reset a device. If your
185 * program has to call such a function, it should obviously be aware that
186 * the reset will cause device state to change (e.g. register values may be
189 * The problem is that any other program could reset the device your program
190 * is working with, at any time. libusb does not offer a mechanism to inform
191 * you when this has happened, so if someone else resets your device it will
192 * not be clear to your own program why the device state has changed.
194 * Ultimately, this is a limitation of writing drivers in userspace.
195 * Separation from the USB stack in the underlying kernel makes it difficult
196 * for the operating system to deliver such notifications to your program.
197 * The Linux kernel USB stack allows such reset notifications to be delivered
198 * to in-kernel USB drivers, but it is not clear how such notifications could
199 * be delivered to second-class drivers that live in userspace.
201 * \section blockonly Blocking-only functionality
203 * The functionality listed below is only available through synchronous,
204 * blocking functions. There are no asynchronous/non-blocking alternatives,
205 * and no clear ways of implementing these.
207 * - Configuration activation (libusb_set_configuration())
208 * - Interface/alternate setting activation (libusb_set_interface_alt_setting())
209 * - Releasing of interfaces (libusb_release_interface())
210 * - Clearing of halt/stall condition (libusb_clear_halt())
211 * - Device resets (libusb_reset_device())
213 * \section configsel Configuration selection and handling
215 * When libusb presents a device handle to an application, there is a chance
216 * that the corresponding device may be in unconfigured state. For devices
217 * with multiple configurations, there is also a chance that the configuration
218 * currently selected is not the one that the application wants to use.
220 * The obvious solution is to add a call to libusb_set_configuration() early
221 * on during your device initialization routines, but there are caveats to
223 * -# If the device is already in the desired configuration, calling
224 * libusb_set_configuration() using the same configuration value will cause
225 * a lightweight device reset. This may not be desirable behaviour.
226 * -# libusb will be unable to change configuration if the device is in
227 * another configuration and other programs or drivers have claimed
228 * interfaces under that configuration.
229 * -# In the case where the desired configuration is already active, libusb
230 * may not even be able to perform a lightweight device reset. For example,
231 * take my USB keyboard with fingerprint reader: I'm interested in driving
232 * the fingerprint reader interface through libusb, but the kernel's
233 * USB-HID driver will almost always have claimed the keyboard interface.
234 * Because the kernel has claimed an interface, it is not even possible to
235 * perform the lightweight device reset, so libusb_set_configuration() will
236 * fail. (Luckily the device in question only has a single configuration.)
238 * One solution to some of the above problems is to consider the currently
239 * active configuration. If the configuration we want is already active, then
240 * we don't have to select any configuration:
242 cfg = libusb_get_configuration(dev);
244 libusb_set_configuration(dev, desired);
247 * This is probably suitable for most scenarios, but is inherently racy:
248 * another application or driver may change the selected configuration
249 * <em>after</em> the libusb_get_configuration() call.
251 * Even in cases where libusb_set_configuration() succeeds, consider that other
252 * applications or drivers may change configuration after your application
253 * calls libusb_set_configuration().
255 * One possible way to lock your device into a specific configuration is as
257 * -# Set the desired configuration (or use the logic above to realise that
258 * it is already in the desired configuration)
259 * -# Claim the interface that you wish to use
260 * -# Check that the currently active configuration is the one that you want
263 * The above method works because once an interface is claimed, no application
264 * or driver is able to select another configuration.
266 * \section earlycomp Early transfer completion
268 * NOTE: This section is currently Linux-centric. I am not sure if any of these
269 * considerations apply to Darwin or other platforms.
271 * When a transfer completes early (i.e. when less data is received/sent in
272 * any one packet than the transfer buffer allows for) then libusb is designed
273 * to terminate the transfer immediately, not transferring or receiving any
274 * more data unless other transfers have been queued by the user.
276 * On legacy platforms, libusb is unable to do this in all situations. After
277 * the incomplete packet occurs, "surplus" data may be transferred. For recent
278 * versions of libusb, this information is kept (the data length of the
279 * transfer is updated) and, for device-to-host transfers, any surplus data was
280 * added to the buffer. Still, this is not a nice solution because it loses the
281 * information about the end of the short packet, and the user probably wanted
282 * that surplus data to arrive in the next logical transfer.
285 * \section zlp Zero length packets
287 * - libusb is able to send a packet of zero length to an endpoint simply by
288 * submitting a transfer of zero length.
289 * - The \ref libusb_transfer_flags::LIBUSB_TRANSFER_ADD_ZERO_PACKET
290 * "LIBUSB_TRANSFER_ADD_ZERO_PACKET" flag is currently only supported on Linux.
294 * \page contexts Contexts
296 * It is possible that libusb may be used simultaneously from two independent
297 * libraries linked into the same executable. For example, if your application
298 * has a plugin-like system which allows the user to dynamically load a range
299 * of modules into your program, it is feasible that two independently
300 * developed modules may both use libusb.
302 * libusb is written to allow for these multiple user scenarios. The two
303 * "instances" of libusb will not interfere: libusb_set_debug() calls
304 * from one user will not affect the same settings for other users, other
305 * users can continue using libusb after one of them calls libusb_exit(), etc.
307 * This is made possible through libusb's <em>context</em> concept. When you
308 * call libusb_init(), you are (optionally) given a context. You can then pass
309 * this context pointer back into future libusb functions.
311 * In order to keep things simple for more simplistic applications, it is
312 * legal to pass NULL to all functions requiring a context pointer (as long as
313 * you're sure no other code will attempt to use libusb from the same process).
314 * When you pass NULL, the default context will be used. The default context
315 * is created the first time a process calls libusb_init() when no other
316 * context is alive. Contexts are destroyed during libusb_exit().
318 * The default context is reference-counted and can be shared. That means that
319 * if libusb_init(NULL) is called twice within the same process, the two
320 * users end up sharing the same context. The deinitialization and freeing of
321 * the default context will only happen when the last user calls libusb_exit().
322 * In other words, the default context is created and initialized when its
323 * reference count goes from 0 to 1, and is deinitialized and destroyed when
324 * its reference count goes from 1 to 0.
326 * You may be wondering why only a subset of libusb functions require a
327 * context pointer in their function definition. Internally, libusb stores
328 * context pointers in other objects (e.g. libusb_device instances) and hence
329 * can infer the context from those objects.
333 * \page api Application Programming Interface
335 * This is the complete list of libusb functions, structures and
336 * enumerations in alphabetical order.
339 * - libusb_alloc_streams()
340 * - libusb_alloc_transfer()
341 * - libusb_attach_kernel_driver()
342 * - libusb_bulk_transfer()
343 * - libusb_cancel_transfer()
344 * - libusb_claim_interface()
345 * - libusb_clear_halt()
347 * - libusb_control_transfer()
348 * - libusb_control_transfer_get_data()
349 * - libusb_control_transfer_get_setup()
350 * - libusb_cpu_to_le16()
351 * - libusb_detach_kernel_driver()
352 * - libusb_error_name()
353 * - libusb_event_handler_active()
354 * - libusb_event_handling_ok()
356 * - libusb_fill_bulk_stream_transfer()
357 * - libusb_fill_bulk_transfer()
358 * - libusb_fill_control_setup()
359 * - libusb_fill_control_transfer()
360 * - libusb_fill_interrupt_transfer()
361 * - libusb_fill_iso_transfer()
362 * - libusb_free_bos_descriptor()
363 * - libusb_free_config_descriptor()
364 * - libusb_free_container_id_descriptor()
365 * - libusb_free_device_list()
366 * - libusb_free_ss_endpoint_companion_descriptor()
367 * - libusb_free_ss_usb_device_capability_descriptor()
368 * - libusb_free_streams()
369 * - libusb_free_transfer()
370 * - libusb_free_usb_2_0_extension_descriptor()
371 * - libusb_get_active_config_descriptor()
372 * - libusb_get_bos_descriptor()
373 * - libusb_get_bus_number()
374 * - libusb_get_config_descriptor()
375 * - libusb_get_config_descriptor_by_value()
376 * - libusb_get_configuration()
377 * - libusb_get_container_id_descriptor()
378 * - libusb_get_descriptor()
379 * - libusb_get_device()
380 * - libusb_get_device_address()
381 * - libusb_get_device_descriptor()
382 * - libusb_get_device_list()
383 * - libusb_get_device_speed()
384 * - libusb_get_iso_packet_buffer()
385 * - libusb_get_iso_packet_buffer_simple()
386 * - libusb_get_max_iso_packet_size()
387 * - libusb_get_max_packet_size()
388 * - libusb_get_next_timeout()
389 * - libusb_get_parent()
390 * - libusb_get_port_number()
391 * - libusb_get_port_numbers()
392 * - libusb_get_ss_endpoint_companion_descriptor()
393 * - libusb_get_ss_usb_device_capability_descriptor()
394 * - libusb_get_string_descriptor()
395 * - libusb_get_string_descriptor_ascii()
396 * - libusb_get_usb_2_0_extension_descriptor()
397 * - libusb_get_version()
398 * - libusb_handle_events()
399 * - libusb_handle_events_completed()
400 * - libusb_handle_events_locked()
401 * - libusb_handle_events_timeout()
402 * - libusb_handle_events_timeout_completed()
403 * - libusb_has_capability()
404 * - libusb_hotplug_deregister_callback()
405 * - libusb_hotplug_register_callback()
407 * - libusb_interrupt_transfer()
408 * - libusb_kernel_driver_active()
409 * - libusb_lock_events()
410 * - libusb_lock_event_waiters()
412 * - libusb_open_device_with_vid_pid()
413 * - libusb_pollfds_handle_timeouts()
414 * - libusb_ref_device()
415 * - libusb_release_interface()
416 * - libusb_reset_device()
417 * - libusb_set_auto_detach_kernel_driver()
418 * - libusb_set_configuration()
419 * - libusb_set_debug()
420 * - libusb_set_interface_alt_setting()
421 * - libusb_set_iso_packet_lengths()
422 * - libusb_setlocale()
423 * - libusb_set_pollfd_notifiers()
424 * - libusb_strerror()
425 * - libusb_submit_transfer()
426 * - libusb_transfer_get_stream_id()
427 * - libusb_transfer_set_stream_id()
428 * - libusb_try_lock_events()
429 * - libusb_unlock_events()
430 * - libusb_unlock_event_waiters()
431 * - libusb_unref_device()
432 * - libusb_wait_for_event()
434 * \section Structures
435 * - libusb_bos_descriptor
436 * - libusb_bos_dev_capability_descriptor
437 * - libusb_config_descriptor
438 * - libusb_container_id_descriptor
439 * - \ref libusb_context
440 * - libusb_control_setup
441 * - \ref libusb_device
442 * - libusb_device_descriptor
443 * - \ref libusb_device_handle
444 * - libusb_endpoint_descriptor
446 * - libusb_interface_descriptor
447 * - libusb_iso_packet_descriptor
449 * - libusb_ss_endpoint_companion_descriptor
450 * - libusb_ss_usb_device_capability_descriptor
452 * - libusb_usb_2_0_extension_descriptor
456 * - \ref libusb_bos_type
457 * - \ref libusb_capability
458 * - \ref libusb_class_code
459 * - \ref libusb_descriptor_type
460 * - \ref libusb_endpoint_direction
461 * - \ref libusb_error
462 * - \ref libusb_iso_sync_type
463 * - \ref libusb_iso_usage_type
464 * - \ref libusb_log_level
465 * - \ref libusb_request_recipient
466 * - \ref libusb_request_type
467 * - \ref libusb_speed
468 * - \ref libusb_ss_usb_device_capability_attributes
469 * - \ref libusb_standard_request
470 * - \ref libusb_supported_speed
471 * - \ref libusb_transfer_flags
472 * - \ref libusb_transfer_status
473 * - \ref libusb_transfer_type
474 * - \ref libusb_usb_2_0_extension_attributes
478 * @defgroup lib Library initialization/deinitialization
479 * This page details how to initialize and deinitialize libusb. Initialization
480 * must be performed before using any libusb functionality, and similarly you
481 * must not call any libusb functions after deinitialization.
485 * @defgroup dev Device handling and enumeration
486 * The functionality documented below is designed to help with the following
488 * - Enumerating the USB devices currently attached to the system
489 * - Choosing a device to operate from your software
490 * - Opening and closing the chosen device
492 * \section nutshell In a nutshell...
494 * The description below really makes things sound more complicated than they
495 * actually are. The following sequence of function calls will be suitable
496 * for almost all scenarios and does not require you to have such a deep
497 * understanding of the resource management issues:
500 libusb_device **list;
501 libusb_device *found = NULL;
502 ssize_t cnt = libusb_get_device_list(NULL, &list);
508 for (i = 0; i < cnt; i++) {
509 libusb_device *device = list[i];
510 if (is_interesting(device)) {
517 libusb_device_handle *handle;
519 err = libusb_open(found, &handle);
525 libusb_free_device_list(list, 1);
528 * The two important points:
529 * - You asked libusb_free_device_list() to unreference the devices (2nd
531 * - You opened the device before freeing the list and unreferencing the
534 * If you ended up with a handle, you can now proceed to perform I/O on the
537 * \section devshandles Devices and device handles
538 * libusb has a concept of a USB device, represented by the
539 * \ref libusb_device opaque type. A device represents a USB device that
540 * is currently or was previously connected to the system. Using a reference
541 * to a device, you can determine certain information about the device (e.g.
542 * you can read the descriptor data).
544 * The libusb_get_device_list() function can be used to obtain a list of
545 * devices currently connected to the system. This is known as device
548 * Just because you have a reference to a device does not mean it is
549 * necessarily usable. The device may have been unplugged, you may not have
550 * permission to operate such device, or another program or driver may be
553 * When you've found a device that you'd like to operate, you must ask
554 * libusb to open the device using the libusb_open() function. Assuming
555 * success, libusb then returns you a <em>device handle</em>
556 * (a \ref libusb_device_handle pointer). All "real" I/O operations then
557 * operate on the handle rather than the original device pointer.
559 * \section devref Device discovery and reference counting
561 * Device discovery (i.e. calling libusb_get_device_list()) returns a
562 * freshly-allocated list of devices. The list itself must be freed when
563 * you are done with it. libusb also needs to know when it is OK to free
564 * the contents of the list - the devices themselves.
566 * To handle these issues, libusb provides you with two separate items:
567 * - A function to free the list itself
568 * - A reference counting system for the devices inside
570 * New devices presented by the libusb_get_device_list() function all have a
571 * reference count of 1. You can increase and decrease reference count using
572 * libusb_ref_device() and libusb_unref_device(). A device is destroyed when
573 * its reference count reaches 0.
575 * With the above information in mind, the process of opening a device can
576 * be viewed as follows:
577 * -# Discover devices using libusb_get_device_list().
578 * -# Choose the device that you want to operate, and call libusb_open().
579 * -# Unref all devices in the discovered device list.
580 * -# Free the discovered device list.
582 * The order is important - you must not unreference the device before
583 * attempting to open it, because unreferencing it may destroy the device.
585 * For convenience, the libusb_free_device_list() function includes a
586 * parameter to optionally unreference all the devices in the list before
587 * freeing the list itself. This combines steps 3 and 4 above.
589 * As an implementation detail, libusb_open() actually adds a reference to
590 * the device in question. This is because the device remains available
591 * through the handle via libusb_get_device(). The reference is deleted during
595 /** @defgroup misc Miscellaneous */
597 /* we traverse usbfs without knowing how many devices we are going to find.
598 * so we create this discovered_devs model which is similar to a linked-list
599 * which grows when required. it can be freed once discovery has completed,
600 * eliminating the need for a list node in the libusb_device structure
602 #define DISCOVERED_DEVICES_SIZE_STEP 8
604 static struct discovered_devs *discovered_devs_alloc(void)
606 struct discovered_devs *ret =
607 malloc(sizeof(*ret) + (sizeof(void *) * DISCOVERED_DEVICES_SIZE_STEP));
611 ret->capacity = DISCOVERED_DEVICES_SIZE_STEP;
616 /* append a device to the discovered devices collection. may realloc itself,
617 * returning new discdevs. returns NULL on realloc failure. */
618 struct discovered_devs *discovered_devs_append(
619 struct discovered_devs *discdevs, struct libusb_device *dev)
621 size_t len = discdevs->len;
624 /* if there is space, just append the device */
625 if (len < discdevs->capacity) {
626 discdevs->devices[len] = libusb_ref_device(dev);
631 /* exceeded capacity, need to grow */
632 usbi_dbg("need to increase capacity");
633 capacity = discdevs->capacity + DISCOVERED_DEVICES_SIZE_STEP;
634 discdevs = usbi_reallocf(discdevs,
635 sizeof(*discdevs) + (sizeof(void *) * capacity));
637 discdevs->capacity = capacity;
638 discdevs->devices[len] = libusb_ref_device(dev);
645 static void discovered_devs_free(struct discovered_devs *discdevs)
649 for (i = 0; i < discdevs->len; i++)
650 libusb_unref_device(discdevs->devices[i]);
655 /* Allocate a new device with a specific session ID. The returned device has
656 * a reference count of 1. */
657 struct libusb_device *usbi_alloc_device(struct libusb_context *ctx,
658 unsigned long session_id)
660 size_t priv_size = usbi_backend->device_priv_size;
661 struct libusb_device *dev = calloc(1, sizeof(*dev) + priv_size);
667 r = usbi_mutex_init(&dev->lock, NULL);
675 dev->session_data = session_id;
676 dev->speed = LIBUSB_SPEED_UNKNOWN;
678 if (!libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG)) {
679 usbi_connect_device (dev);
685 void usbi_connect_device(struct libusb_device *dev)
687 struct libusb_context *ctx = DEVICE_CTX(dev);
691 usbi_mutex_lock(&dev->ctx->usb_devs_lock);
692 list_add(&dev->list, &dev->ctx->usb_devs);
693 usbi_mutex_unlock(&dev->ctx->usb_devs_lock);
695 /* Signal that an event has occurred for this device if we support hotplug AND
696 * the hotplug message list is ready. This prevents an event from getting raised
697 * during initial enumeration. */
698 if (libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG) && dev->ctx->hotplug_msgs.next) {
699 usbi_hotplug_notification(ctx, dev, LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED);
703 void usbi_disconnect_device(struct libusb_device *dev)
705 struct libusb_context *ctx = DEVICE_CTX(dev);
707 usbi_mutex_lock(&dev->lock);
709 usbi_mutex_unlock(&dev->lock);
711 usbi_mutex_lock(&ctx->usb_devs_lock);
712 list_del(&dev->list);
713 usbi_mutex_unlock(&ctx->usb_devs_lock);
715 /* Signal that an event has occurred for this device if we support hotplug AND
716 * the hotplug message list is ready. This prevents an event from getting raised
717 * during initial enumeration. libusb_handle_events will take care of dereferencing
719 if (libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG) && dev->ctx->hotplug_msgs.next) {
720 usbi_hotplug_notification(ctx, dev, LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT);
724 /* Perform some final sanity checks on a newly discovered device. If this
725 * function fails (negative return code), the device should not be added
726 * to the discovered device list. */
727 int usbi_sanitize_device(struct libusb_device *dev)
730 uint8_t num_configurations;
732 r = usbi_device_cache_descriptor(dev);
736 num_configurations = dev->device_descriptor.bNumConfigurations;
737 if (num_configurations > USB_MAXCONFIG) {
738 usbi_err(DEVICE_CTX(dev), "too many configurations");
739 return LIBUSB_ERROR_IO;
740 } else if (0 == num_configurations)
741 usbi_dbg("zero configurations, maybe an unauthorized device");
743 dev->num_configurations = num_configurations;
747 /* Examine libusb's internal list of known devices, looking for one with
748 * a specific session ID. Returns the matching device if it was found, and
750 struct libusb_device *usbi_get_device_by_session_id(struct libusb_context *ctx,
751 unsigned long session_id)
753 struct libusb_device *dev;
754 struct libusb_device *ret = NULL;
756 usbi_mutex_lock(&ctx->usb_devs_lock);
757 list_for_each_entry(dev, &ctx->usb_devs, list, struct libusb_device)
758 if (dev->session_data == session_id) {
759 ret = libusb_ref_device(dev);
762 usbi_mutex_unlock(&ctx->usb_devs_lock);
768 * Returns a list of USB devices currently attached to the system. This is
769 * your entry point into finding a USB device to operate.
771 * You are expected to unreference all the devices when you are done with
772 * them, and then free the list with libusb_free_device_list(). Note that
773 * libusb_free_device_list() can unref all the devices for you. Be careful
774 * not to unreference a device you are about to open until after you have
777 * This return value of this function indicates the number of devices in
778 * the resultant list. The list is actually one element larger, as it is
781 * \param ctx the context to operate on, or NULL for the default context
782 * \param list output location for a list of devices. Must be later freed with
783 * libusb_free_device_list().
784 * \returns the number of devices in the outputted list, or any
785 * \ref libusb_error according to errors encountered by the backend.
787 ssize_t API_EXPORTED libusb_get_device_list(libusb_context *ctx,
788 libusb_device ***list)
790 struct discovered_devs *discdevs = discovered_devs_alloc();
791 struct libusb_device **ret;
794 USBI_GET_CONTEXT(ctx);
798 return LIBUSB_ERROR_NO_MEM;
800 if (libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG)) {
801 /* backend provides hotplug support */
802 struct libusb_device *dev;
804 if (usbi_backend->hotplug_poll)
805 usbi_backend->hotplug_poll();
807 usbi_mutex_lock(&ctx->usb_devs_lock);
808 list_for_each_entry(dev, &ctx->usb_devs, list, struct libusb_device) {
809 discdevs = discovered_devs_append(discdevs, dev);
812 r = LIBUSB_ERROR_NO_MEM;
816 usbi_mutex_unlock(&ctx->usb_devs_lock);
818 /* backend does not provide hotplug support */
819 r = usbi_backend->get_device_list(ctx, &discdevs);
827 /* convert discovered_devs into a list */
829 ret = calloc(len + 1, sizeof(struct libusb_device *));
831 len = LIBUSB_ERROR_NO_MEM;
836 for (i = 0; i < len; i++) {
837 struct libusb_device *dev = discdevs->devices[i];
838 ret[i] = libusb_ref_device(dev);
843 discovered_devs_free(discdevs);
848 * Frees a list of devices previously discovered using
849 * libusb_get_device_list(). If the unref_devices parameter is set, the
850 * reference count of each device in the list is decremented by 1.
851 * \param list the list to free
852 * \param unref_devices whether to unref the devices in the list
854 void API_EXPORTED libusb_free_device_list(libusb_device **list,
862 struct libusb_device *dev;
864 while ((dev = list[i++]) != NULL)
865 libusb_unref_device(dev);
871 * Get the number of the bus that a device is connected to.
872 * \param dev a device
873 * \returns the bus number
875 uint8_t API_EXPORTED libusb_get_bus_number(libusb_device *dev)
877 return dev->bus_number;
881 * Get the number of the port that a device is connected to.
882 * Unless the OS does something funky, or you are hot-plugging USB extension cards,
883 * the port number returned by this call is usually guaranteed to be uniquely tied
884 * to a physical port, meaning that different devices plugged on the same physical
885 * port should return the same port number.
887 * But outside of this, there is no guarantee that the port number returned by this
888 * call will remain the same, or even match the order in which ports have been
889 * numbered by the HUB/HCD manufacturer.
891 * \param dev a device
892 * \returns the port number (0 if not available)
894 uint8_t API_EXPORTED libusb_get_port_number(libusb_device *dev)
896 return dev->port_number;
900 * Get the list of all port numbers from root for the specified device
902 * Since version 1.0.16, \ref LIBUSB_API_VERSION >= 0x01000102
903 * \param dev a device
904 * \param port_numbers the array that should contain the port numbers
905 * \param port_numbers_len the maximum length of the array. As per the USB 3.0
906 * specs, the current maximum limit for the depth is 7.
907 * \returns the number of elements filled
908 * \returns LIBUSB_ERROR_OVERFLOW if the array is too small
910 int API_EXPORTED libusb_get_port_numbers(libusb_device *dev,
911 uint8_t* port_numbers, int port_numbers_len)
913 int i = port_numbers_len;
914 struct libusb_context *ctx = DEVICE_CTX(dev);
916 if (port_numbers_len <= 0)
917 return LIBUSB_ERROR_INVALID_PARAM;
919 // HCDs can be listed as devices with port #0
920 while((dev) && (dev->port_number != 0)) {
922 usbi_warn(ctx, "port numbers array is too small");
923 return LIBUSB_ERROR_OVERFLOW;
925 port_numbers[i] = dev->port_number;
926 dev = dev->parent_dev;
928 if (i < port_numbers_len)
929 memmove(port_numbers, &port_numbers[i], port_numbers_len - i);
930 return port_numbers_len - i;
934 * Deprecated please use libusb_get_port_numbers instead.
936 int API_EXPORTED libusb_get_port_path(libusb_context *ctx, libusb_device *dev,
937 uint8_t* port_numbers, uint8_t port_numbers_len)
941 return libusb_get_port_numbers(dev, port_numbers, port_numbers_len);
945 * Get the the parent from the specified device.
946 * \param dev a device
947 * \returns the device parent or NULL if not available
948 * You should issue a \ref libusb_get_device_list() before calling this
949 * function and make sure that you only access the parent before issuing
950 * \ref libusb_free_device_list(). The reason is that libusb currently does
951 * not maintain a permanent list of device instances, and therefore can
952 * only guarantee that parents are fully instantiated within a
953 * libusb_get_device_list() - libusb_free_device_list() block.
956 libusb_device * LIBUSB_CALL libusb_get_parent(libusb_device *dev)
958 return dev->parent_dev;
962 * Get the address of the device on the bus it is connected to.
963 * \param dev a device
964 * \returns the device address
966 uint8_t API_EXPORTED libusb_get_device_address(libusb_device *dev)
968 return dev->device_address;
972 * Get the negotiated connection speed for a device.
973 * \param dev a device
974 * \returns a \ref libusb_speed code, where LIBUSB_SPEED_UNKNOWN means that
975 * the OS doesn't know or doesn't support returning the negotiated speed.
977 int API_EXPORTED libusb_get_device_speed(libusb_device *dev)
982 static const struct libusb_endpoint_descriptor *find_endpoint(
983 struct libusb_config_descriptor *config, unsigned char endpoint)
986 for (iface_idx = 0; iface_idx < config->bNumInterfaces; iface_idx++) {
987 const struct libusb_interface *iface = &config->interface[iface_idx];
990 for (altsetting_idx = 0; altsetting_idx < iface->num_altsetting;
992 const struct libusb_interface_descriptor *altsetting
993 = &iface->altsetting[altsetting_idx];
996 for (ep_idx = 0; ep_idx < altsetting->bNumEndpoints; ep_idx++) {
997 const struct libusb_endpoint_descriptor *ep =
998 &altsetting->endpoint[ep_idx];
999 if (ep->bEndpointAddress == endpoint)
1008 * Convenience function to retrieve the wMaxPacketSize value for a particular
1009 * endpoint in the active device configuration.
1011 * This function was originally intended to be of assistance when setting up
1012 * isochronous transfers, but a design mistake resulted in this function
1013 * instead. It simply returns the wMaxPacketSize value without considering
1014 * its contents. If you're dealing with isochronous transfers, you probably
1015 * want libusb_get_max_iso_packet_size() instead.
1017 * \param dev a device
1018 * \param endpoint address of the endpoint in question
1019 * \returns the wMaxPacketSize value
1020 * \returns LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist
1021 * \returns LIBUSB_ERROR_OTHER on other failure
1023 int API_EXPORTED libusb_get_max_packet_size(libusb_device *dev,
1024 unsigned char endpoint)
1026 struct libusb_config_descriptor *config;
1027 const struct libusb_endpoint_descriptor *ep;
1030 r = libusb_get_active_config_descriptor(dev, &config);
1032 usbi_err(DEVICE_CTX(dev),
1033 "could not retrieve active config descriptor");
1034 return LIBUSB_ERROR_OTHER;
1037 ep = find_endpoint(config, endpoint);
1039 r = LIBUSB_ERROR_NOT_FOUND;
1043 r = ep->wMaxPacketSize;
1046 libusb_free_config_descriptor(config);
1051 * Calculate the maximum packet size which a specific endpoint is capable is
1052 * sending or receiving in the duration of 1 microframe
1054 * Only the active configuration is examined. The calculation is based on the
1055 * wMaxPacketSize field in the endpoint descriptor as described in section
1056 * 9.6.6 in the USB 2.0 specifications.
1058 * If acting on an isochronous or interrupt endpoint, this function will
1059 * multiply the value found in bits 0:10 by the number of transactions per
1060 * microframe (determined by bits 11:12). Otherwise, this function just
1061 * returns the numeric value found in bits 0:10.
1063 * This function is useful for setting up isochronous transfers, for example
1064 * you might pass the return value from this function to
1065 * libusb_set_iso_packet_lengths() in order to set the length field of every
1066 * isochronous packet in a transfer.
1070 * \param dev a device
1071 * \param endpoint address of the endpoint in question
1072 * \returns the maximum packet size which can be sent/received on this endpoint
1073 * \returns LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist
1074 * \returns LIBUSB_ERROR_OTHER on other failure
1076 int API_EXPORTED libusb_get_max_iso_packet_size(libusb_device *dev,
1077 unsigned char endpoint)
1079 struct libusb_config_descriptor *config;
1080 const struct libusb_endpoint_descriptor *ep;
1081 enum libusb_transfer_type ep_type;
1085 r = libusb_get_active_config_descriptor(dev, &config);
1087 usbi_err(DEVICE_CTX(dev),
1088 "could not retrieve active config descriptor");
1089 return LIBUSB_ERROR_OTHER;
1092 ep = find_endpoint(config, endpoint);
1094 r = LIBUSB_ERROR_NOT_FOUND;
1098 val = ep->wMaxPacketSize;
1099 ep_type = (enum libusb_transfer_type) (ep->bmAttributes & 0x3);
1102 if (ep_type == LIBUSB_TRANSFER_TYPE_ISOCHRONOUS
1103 || ep_type == LIBUSB_TRANSFER_TYPE_INTERRUPT)
1104 r *= (1 + ((val >> 11) & 3));
1107 libusb_free_config_descriptor(config);
1112 * Increment the reference count of a device.
1113 * \param dev the device to reference
1114 * \returns the same device
1117 libusb_device * LIBUSB_CALL libusb_ref_device(libusb_device *dev)
1119 usbi_mutex_lock(&dev->lock);
1121 usbi_mutex_unlock(&dev->lock);
1126 * Decrement the reference count of a device. If the decrement operation
1127 * causes the reference count to reach zero, the device shall be destroyed.
1128 * \param dev the device to unreference
1130 void API_EXPORTED libusb_unref_device(libusb_device *dev)
1137 usbi_mutex_lock(&dev->lock);
1138 refcnt = --dev->refcnt;
1139 usbi_mutex_unlock(&dev->lock);
1142 usbi_dbg("destroy device %d.%d", dev->bus_number, dev->device_address);
1144 libusb_unref_device(dev->parent_dev);
1146 if (usbi_backend->destroy_device)
1147 usbi_backend->destroy_device(dev);
1149 if (!libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG)) {
1150 /* backend does not support hotplug */
1151 usbi_disconnect_device(dev);
1154 usbi_mutex_destroy(&dev->lock);
1160 * Signal the event pipe so that the event handling thread will be
1161 * interrupted to process an internal event.
1163 int usbi_signal_event(struct libusb_context *ctx)
1165 unsigned char dummy = 1;
1168 /* write some data on event pipe to interrupt event handlers */
1169 r = usbi_write(ctx->event_pipe[1], &dummy, sizeof(dummy));
1170 if (r != sizeof(dummy)) {
1171 usbi_warn(ctx, "internal signalling write failed");
1172 return LIBUSB_ERROR_IO;
1179 * Clear the event pipe so that the event handling will no longer be
1182 int usbi_clear_event(struct libusb_context *ctx)
1184 unsigned char dummy;
1187 /* read some data on event pipe to clear it */
1188 r = usbi_read(ctx->event_pipe[0], &dummy, sizeof(dummy));
1189 if (r != sizeof(dummy)) {
1190 usbi_warn(ctx, "internal signalling read failed");
1191 return LIBUSB_ERROR_IO;
1198 * Open a device and obtain a device handle. A handle allows you to perform
1199 * I/O on the device in question.
1201 * Internally, this function adds a reference to the device and makes it
1202 * available to you through libusb_get_device(). This reference is removed
1203 * during libusb_close().
1205 * This is a non-blocking function; no requests are sent over the bus.
1207 * \param dev the device to open
1208 * \param handle output location for the returned device handle pointer. Only
1209 * populated when the return code is 0.
1210 * \returns 0 on success
1211 * \returns LIBUSB_ERROR_NO_MEM on memory allocation failure
1212 * \returns LIBUSB_ERROR_ACCESS if the user has insufficient permissions
1213 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1214 * \returns another LIBUSB_ERROR code on other failure
1216 int API_EXPORTED libusb_open(libusb_device *dev,
1217 libusb_device_handle **handle)
1219 struct libusb_context *ctx = DEVICE_CTX(dev);
1220 struct libusb_device_handle *_handle;
1221 size_t priv_size = usbi_backend->device_handle_priv_size;
1223 usbi_dbg("open %d.%d", dev->bus_number, dev->device_address);
1225 if (!dev->attached) {
1226 return LIBUSB_ERROR_NO_DEVICE;
1229 _handle = malloc(sizeof(*_handle) + priv_size);
1231 return LIBUSB_ERROR_NO_MEM;
1233 r = usbi_mutex_init(&_handle->lock, NULL);
1236 return LIBUSB_ERROR_OTHER;
1239 _handle->dev = libusb_ref_device(dev);
1240 _handle->auto_detach_kernel_driver = 0;
1241 _handle->claimed_interfaces = 0;
1242 memset(&_handle->os_priv, 0, priv_size);
1244 r = usbi_backend->open(_handle);
1246 usbi_dbg("open %d.%d returns %d", dev->bus_number, dev->device_address, r);
1247 libusb_unref_device(dev);
1248 usbi_mutex_destroy(&_handle->lock);
1253 usbi_mutex_lock(&ctx->open_devs_lock);
1254 list_add(&_handle->list, &ctx->open_devs);
1255 usbi_mutex_unlock(&ctx->open_devs_lock);
1262 * Convenience function for finding a device with a particular
1263 * <tt>idVendor</tt>/<tt>idProduct</tt> combination. This function is intended
1264 * for those scenarios where you are using libusb to knock up a quick test
1265 * application - it allows you to avoid calling libusb_get_device_list() and
1266 * worrying about traversing/freeing the list.
1268 * This function has limitations and is hence not intended for use in real
1269 * applications: if multiple devices have the same IDs it will only
1270 * give you the first one, etc.
1272 * \param ctx the context to operate on, or NULL for the default context
1273 * \param vendor_id the idVendor value to search for
1274 * \param product_id the idProduct value to search for
1275 * \returns a handle for the first found device, or NULL on error or if the
1276 * device could not be found. */
1278 libusb_device_handle * LIBUSB_CALL libusb_open_device_with_vid_pid(
1279 libusb_context *ctx, uint16_t vendor_id, uint16_t product_id)
1281 struct libusb_device **devs;
1282 struct libusb_device *found = NULL;
1283 struct libusb_device *dev;
1284 struct libusb_device_handle *handle = NULL;
1288 if (libusb_get_device_list(ctx, &devs) < 0)
1291 while ((dev = devs[i++]) != NULL) {
1292 struct libusb_device_descriptor desc;
1293 r = libusb_get_device_descriptor(dev, &desc);
1296 if (desc.idVendor == vendor_id && desc.idProduct == product_id) {
1303 r = libusb_open(found, &handle);
1309 libusb_free_device_list(devs, 1);
1313 static void do_close(struct libusb_context *ctx,
1314 struct libusb_device_handle *dev_handle)
1316 struct usbi_transfer *itransfer;
1317 struct usbi_transfer *tmp;
1319 libusb_lock_events(ctx);
1321 /* remove any transfers in flight that are for this device */
1322 usbi_mutex_lock(&ctx->flying_transfers_lock);
1324 /* safe iteration because transfers may be being deleted */
1325 list_for_each_entry_safe(itransfer, tmp, &ctx->flying_transfers, list, struct usbi_transfer) {
1326 struct libusb_transfer *transfer =
1327 USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
1329 if (transfer->dev_handle != dev_handle)
1332 if (!(itransfer->flags & USBI_TRANSFER_DEVICE_DISAPPEARED)) {
1333 usbi_err(ctx, "Device handle closed while transfer was still being processed, but the device is still connected as far as we know");
1335 if (itransfer->flags & USBI_TRANSFER_CANCELLING)
1336 usbi_warn(ctx, "A cancellation for an in-flight transfer hasn't completed but closing the device handle");
1338 usbi_err(ctx, "A cancellation hasn't even been scheduled on the transfer for which the device is closing");
1341 /* remove from the list of in-flight transfers and make sure
1342 * we don't accidentally use the device handle in the future
1343 * (or that such accesses will be easily caught and identified as a crash)
1345 usbi_mutex_lock(&itransfer->lock);
1346 list_del(&itransfer->list);
1347 transfer->dev_handle = NULL;
1348 usbi_mutex_unlock(&itransfer->lock);
1350 /* it is up to the user to free up the actual transfer struct. this is
1351 * just making sure that we don't attempt to process the transfer after
1352 * the device handle is invalid
1354 usbi_dbg("Removed transfer %p from the in-flight list because device handle %p closed",
1355 transfer, dev_handle);
1357 usbi_mutex_unlock(&ctx->flying_transfers_lock);
1359 libusb_unlock_events(ctx);
1361 usbi_mutex_lock(&ctx->open_devs_lock);
1362 list_del(&dev_handle->list);
1363 usbi_mutex_unlock(&ctx->open_devs_lock);
1365 usbi_backend->close(dev_handle);
1366 libusb_unref_device(dev_handle->dev);
1367 usbi_mutex_destroy(&dev_handle->lock);
1372 * Close a device handle. Should be called on all open handles before your
1373 * application exits.
1375 * Internally, this function destroys the reference that was added by
1376 * libusb_open() on the given device.
1378 * This is a non-blocking function; no requests are sent over the bus.
1380 * \param dev_handle the handle to close
1382 void API_EXPORTED libusb_close(libusb_device_handle *dev_handle)
1384 struct libusb_context *ctx;
1391 ctx = HANDLE_CTX(dev_handle);
1393 /* Similarly to libusb_open(), we want to interrupt all event handlers
1394 * at this point. More importantly, we want to perform the actual close of
1395 * the device while holding the event handling lock (preventing any other
1396 * thread from doing event handling) because we will be removing a file
1397 * descriptor from the polling loop. */
1399 /* Record that we are closing a device.
1400 * Only signal an event if there are no prior pending events. */
1401 usbi_mutex_lock(&ctx->event_data_lock);
1402 pending_events = usbi_pending_events(ctx);
1403 ctx->device_close++;
1404 if (!pending_events)
1405 usbi_signal_event(ctx);
1406 usbi_mutex_unlock(&ctx->event_data_lock);
1408 /* take event handling lock */
1409 libusb_lock_events(ctx);
1411 /* Close the device */
1412 do_close(ctx, dev_handle);
1414 /* We're done with closing this device.
1415 * Clear the event pipe if there are no further pending events. */
1416 usbi_mutex_lock(&ctx->event_data_lock);
1417 ctx->device_close--;
1418 pending_events = usbi_pending_events(ctx);
1419 if (!pending_events)
1420 usbi_clear_event(ctx);
1421 usbi_mutex_unlock(&ctx->event_data_lock);
1423 /* Release event handling lock and wake up event waiters */
1424 libusb_unlock_events(ctx);
1428 * Get the underlying device for a handle. This function does not modify
1429 * the reference count of the returned device, so do not feel compelled to
1430 * unreference it when you are done.
1431 * \param dev_handle a device handle
1432 * \returns the underlying device
1435 libusb_device * LIBUSB_CALL libusb_get_device(libusb_device_handle *dev_handle)
1437 return dev_handle->dev;
1441 * Determine the bConfigurationValue of the currently active configuration.
1443 * You could formulate your own control request to obtain this information,
1444 * but this function has the advantage that it may be able to retrieve the
1445 * information from operating system caches (no I/O involved).
1447 * If the OS does not cache this information, then this function will block
1448 * while a control transfer is submitted to retrieve the information.
1450 * This function will return a value of 0 in the <tt>config</tt> output
1451 * parameter if the device is in unconfigured state.
1453 * \param dev a device handle
1454 * \param config output location for the bConfigurationValue of the active
1455 * configuration (only valid for return code 0)
1456 * \returns 0 on success
1457 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1458 * \returns another LIBUSB_ERROR code on other failure
1460 int API_EXPORTED libusb_get_configuration(libusb_device_handle *dev,
1463 int r = LIBUSB_ERROR_NOT_SUPPORTED;
1466 if (usbi_backend->get_configuration)
1467 r = usbi_backend->get_configuration(dev, config);
1469 if (r == LIBUSB_ERROR_NOT_SUPPORTED) {
1471 usbi_dbg("falling back to control message");
1472 r = libusb_control_transfer(dev, LIBUSB_ENDPOINT_IN,
1473 LIBUSB_REQUEST_GET_CONFIGURATION, 0, 0, &tmp, 1, 1000);
1475 usbi_err(HANDLE_CTX(dev), "zero bytes returned in ctrl transfer?");
1476 r = LIBUSB_ERROR_IO;
1477 } else if (r == 1) {
1481 usbi_dbg("control failed, error %d", r);
1486 usbi_dbg("active config %d", *config);
1492 * Set the active configuration for a device.
1494 * The operating system may or may not have already set an active
1495 * configuration on the device. It is up to your application to ensure the
1496 * correct configuration is selected before you attempt to claim interfaces
1497 * and perform other operations.
1499 * If you call this function on a device already configured with the selected
1500 * configuration, then this function will act as a lightweight device reset:
1501 * it will issue a SET_CONFIGURATION request using the current configuration,
1502 * causing most USB-related device state to be reset (altsetting reset to zero,
1503 * endpoint halts cleared, toggles reset).
1505 * You cannot change/reset configuration if your application has claimed
1506 * interfaces. It is advised to set the desired configuration before claiming
1509 * Alternatively you can call libusb_release_interface() first. Note if you
1510 * do things this way you must ensure that auto_detach_kernel_driver for
1511 * <tt>dev</tt> is 0, otherwise the kernel driver will be re-attached when you
1512 * release the interface(s).
1514 * You cannot change/reset configuration if other applications or drivers have
1515 * claimed interfaces.
1517 * A configuration value of -1 will put the device in unconfigured state.
1518 * The USB specifications state that a configuration value of 0 does this,
1519 * however buggy devices exist which actually have a configuration 0.
1521 * You should always use this function rather than formulating your own
1522 * SET_CONFIGURATION 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 configuration the bConfigurationValue of the configuration you
1529 * wish to activate, or -1 if you wish to put the device in an unconfigured
1531 * \returns 0 on success
1532 * \returns LIBUSB_ERROR_NOT_FOUND if the requested configuration does not exist
1533 * \returns LIBUSB_ERROR_BUSY if interfaces are currently claimed
1534 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1535 * \returns another LIBUSB_ERROR code on other failure
1536 * \see libusb_set_auto_detach_kernel_driver()
1538 int API_EXPORTED libusb_set_configuration(libusb_device_handle *dev,
1541 usbi_dbg("configuration %d", configuration);
1542 return usbi_backend->set_configuration(dev, configuration);
1546 * Claim an interface on a given device handle. You must claim the interface
1547 * you wish to use before you can perform I/O on any of its endpoints.
1549 * It is legal to attempt to claim an already-claimed interface, in which
1550 * case libusb just returns 0 without doing anything.
1552 * If auto_detach_kernel_driver is set to 1 for <tt>dev</tt>, the kernel driver
1553 * will be detached if necessary, on failure the detach error is returned.
1555 * Claiming of interfaces is a purely logical operation; it does not cause
1556 * any requests to be sent over the bus. Interface claiming is used to
1557 * instruct the underlying operating system that your application wishes
1558 * to take ownership of the interface.
1560 * This is a non-blocking function.
1562 * \param dev a device handle
1563 * \param interface_number the <tt>bInterfaceNumber</tt> of the interface you
1565 * \returns 0 on success
1566 * \returns LIBUSB_ERROR_NOT_FOUND if the requested interface does not exist
1567 * \returns LIBUSB_ERROR_BUSY if another program or driver has claimed the
1569 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1570 * \returns a LIBUSB_ERROR code on other failure
1571 * \see libusb_set_auto_detach_kernel_driver()
1573 int API_EXPORTED libusb_claim_interface(libusb_device_handle *dev,
1574 int interface_number)
1578 usbi_dbg("interface %d", interface_number);
1579 if (interface_number >= USB_MAXINTERFACES)
1580 return LIBUSB_ERROR_INVALID_PARAM;
1582 if (!dev->dev->attached)
1583 return LIBUSB_ERROR_NO_DEVICE;
1585 usbi_mutex_lock(&dev->lock);
1586 if (dev->claimed_interfaces & (1 << interface_number))
1589 r = usbi_backend->claim_interface(dev, interface_number);
1591 dev->claimed_interfaces |= 1 << interface_number;
1594 usbi_mutex_unlock(&dev->lock);
1599 * Release an interface previously claimed with libusb_claim_interface(). You
1600 * should release all claimed interfaces before closing a device handle.
1602 * This is a blocking function. A SET_INTERFACE control request will be sent
1603 * to the device, resetting interface state to the first alternate setting.
1605 * If auto_detach_kernel_driver is set to 1 for <tt>dev</tt>, the kernel
1606 * driver will be re-attached after releasing the interface.
1608 * \param dev a device handle
1609 * \param interface_number the <tt>bInterfaceNumber</tt> of the
1610 * previously-claimed interface
1611 * \returns 0 on success
1612 * \returns LIBUSB_ERROR_NOT_FOUND if the interface was not claimed
1613 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1614 * \returns another LIBUSB_ERROR code on other failure
1615 * \see libusb_set_auto_detach_kernel_driver()
1617 int API_EXPORTED libusb_release_interface(libusb_device_handle *dev,
1618 int interface_number)
1622 usbi_dbg("interface %d", interface_number);
1623 if (interface_number >= USB_MAXINTERFACES)
1624 return LIBUSB_ERROR_INVALID_PARAM;
1626 usbi_mutex_lock(&dev->lock);
1627 if (!(dev->claimed_interfaces & (1 << interface_number))) {
1628 r = LIBUSB_ERROR_NOT_FOUND;
1632 r = usbi_backend->release_interface(dev, interface_number);
1634 dev->claimed_interfaces &= ~(1 << interface_number);
1637 usbi_mutex_unlock(&dev->lock);
1642 * Activate an alternate setting for an interface. The interface must have
1643 * been previously claimed with libusb_claim_interface().
1645 * You should always use this function rather than formulating your own
1646 * SET_INTERFACE control request. This is because the underlying operating
1647 * system needs to know when such changes happen.
1649 * This is a blocking function.
1651 * \param dev a device handle
1652 * \param interface_number the <tt>bInterfaceNumber</tt> of the
1653 * previously-claimed interface
1654 * \param alternate_setting the <tt>bAlternateSetting</tt> of the alternate
1655 * setting to activate
1656 * \returns 0 on success
1657 * \returns LIBUSB_ERROR_NOT_FOUND if the interface was not claimed, or the
1658 * requested alternate setting does not exist
1659 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1660 * \returns another LIBUSB_ERROR code on other failure
1662 int API_EXPORTED libusb_set_interface_alt_setting(libusb_device_handle *dev,
1663 int interface_number, int alternate_setting)
1665 usbi_dbg("interface %d altsetting %d",
1666 interface_number, alternate_setting);
1667 if (interface_number >= USB_MAXINTERFACES)
1668 return LIBUSB_ERROR_INVALID_PARAM;
1670 usbi_mutex_lock(&dev->lock);
1671 if (!dev->dev->attached) {
1672 usbi_mutex_unlock(&dev->lock);
1673 return LIBUSB_ERROR_NO_DEVICE;
1676 if (!(dev->claimed_interfaces & (1 << interface_number))) {
1677 usbi_mutex_unlock(&dev->lock);
1678 return LIBUSB_ERROR_NOT_FOUND;
1680 usbi_mutex_unlock(&dev->lock);
1682 return usbi_backend->set_interface_altsetting(dev, interface_number,
1687 * Clear the halt/stall condition for an endpoint. Endpoints with halt status
1688 * are unable to receive or transmit data until the halt condition is stalled.
1690 * You should cancel all pending transfers before attempting to clear the halt
1693 * This is a blocking function.
1695 * \param dev a device handle
1696 * \param endpoint the endpoint to clear halt status
1697 * \returns 0 on success
1698 * \returns LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist
1699 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1700 * \returns another LIBUSB_ERROR code on other failure
1702 int API_EXPORTED libusb_clear_halt(libusb_device_handle *dev,
1703 unsigned char endpoint)
1705 usbi_dbg("endpoint %x", endpoint);
1706 if (!dev->dev->attached)
1707 return LIBUSB_ERROR_NO_DEVICE;
1709 return usbi_backend->clear_halt(dev, endpoint);
1713 * Perform a USB port reset to reinitialize a device. The system will attempt
1714 * to restore the previous configuration and alternate settings after the
1715 * reset has completed.
1717 * If the reset fails, the descriptors change, or the previous state cannot be
1718 * restored, the device will appear to be disconnected and reconnected. This
1719 * means that the device handle is no longer valid (you should close it) and
1720 * rediscover the device. A return code of LIBUSB_ERROR_NOT_FOUND indicates
1721 * when this is the case.
1723 * This is a blocking function which usually incurs a noticeable delay.
1725 * \param dev a handle of the device to reset
1726 * \returns 0 on success
1727 * \returns LIBUSB_ERROR_NOT_FOUND if re-enumeration is required, or if the
1728 * device has been disconnected
1729 * \returns another LIBUSB_ERROR code on other failure
1731 int API_EXPORTED libusb_reset_device(libusb_device_handle *dev)
1734 if (!dev->dev->attached)
1735 return LIBUSB_ERROR_NO_DEVICE;
1737 return usbi_backend->reset_device(dev);
1740 /** \ingroup asyncio
1741 * Allocate up to num_streams usb bulk streams on the specified endpoints. This
1742 * function takes an array of endpoints rather then a single endpoint because
1743 * some protocols require that endpoints are setup with similar stream ids.
1744 * All endpoints passed in must belong to the same interface.
1746 * Note this function may return less streams then requested. Also note that the
1747 * same number of streams are allocated for each endpoint in the endpoint array.
1749 * Stream id 0 is reserved, and should not be used to communicate with devices.
1750 * If libusb_alloc_streams() returns with a value of N, you may use stream ids
1753 * Since version 1.0.19, \ref LIBUSB_API_VERSION >= 0x01000103
1755 * \param dev a device handle
1756 * \param num_streams number of streams to try to allocate
1757 * \param endpoints array of endpoints to allocate streams on
1758 * \param num_endpoints length of the endpoints array
1759 * \returns number of streams allocated, or a LIBUSB_ERROR code on failure
1761 int API_EXPORTED libusb_alloc_streams(libusb_device_handle *dev,
1762 uint32_t num_streams, unsigned char *endpoints, int num_endpoints)
1764 usbi_dbg("streams %u eps %d", (unsigned) num_streams, num_endpoints);
1766 if (!dev->dev->attached)
1767 return LIBUSB_ERROR_NO_DEVICE;
1769 if (usbi_backend->alloc_streams)
1770 return usbi_backend->alloc_streams(dev, num_streams, endpoints,
1773 return LIBUSB_ERROR_NOT_SUPPORTED;
1776 /** \ingroup asyncio
1777 * Free usb bulk streams allocated with libusb_alloc_streams().
1779 * Note streams are automatically free-ed when releasing an interface.
1781 * Since version 1.0.19, \ref LIBUSB_API_VERSION >= 0x01000103
1783 * \param dev a device handle
1784 * \param endpoints array of endpoints to free streams on
1785 * \param num_endpoints length of the endpoints array
1786 * \returns LIBUSB_SUCCESS, or a LIBUSB_ERROR code on failure
1788 int API_EXPORTED libusb_free_streams(libusb_device_handle *dev,
1789 unsigned char *endpoints, int num_endpoints)
1791 usbi_dbg("eps %d", num_endpoints);
1793 if (!dev->dev->attached)
1794 return LIBUSB_ERROR_NO_DEVICE;
1796 if (usbi_backend->free_streams)
1797 return usbi_backend->free_streams(dev, endpoints,
1800 return LIBUSB_ERROR_NOT_SUPPORTED;
1804 * Determine if a kernel driver is active on an interface. If a kernel driver
1805 * is active, you cannot claim the interface, and libusb will be unable to
1808 * This functionality is not available on Windows.
1810 * \param dev a device handle
1811 * \param interface_number the interface to check
1812 * \returns 0 if no kernel driver is active
1813 * \returns 1 if a kernel driver is active
1814 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1815 * \returns LIBUSB_ERROR_NOT_SUPPORTED on platforms where the functionality
1817 * \returns another LIBUSB_ERROR code on other failure
1818 * \see libusb_detach_kernel_driver()
1820 int API_EXPORTED libusb_kernel_driver_active(libusb_device_handle *dev,
1821 int interface_number)
1823 usbi_dbg("interface %d", interface_number);
1825 if (!dev->dev->attached)
1826 return LIBUSB_ERROR_NO_DEVICE;
1828 if (usbi_backend->kernel_driver_active)
1829 return usbi_backend->kernel_driver_active(dev, interface_number);
1831 return LIBUSB_ERROR_NOT_SUPPORTED;
1835 * Detach a kernel driver from an interface. If successful, you will then be
1836 * able to claim the interface and perform I/O.
1838 * This functionality is not available on Darwin or Windows.
1840 * Note that libusb itself also talks to the device through a special kernel
1841 * driver, if this driver is already attached to the device, this call will
1842 * not detach it and return LIBUSB_ERROR_NOT_FOUND.
1844 * \param dev a device handle
1845 * \param interface_number the interface to detach the driver from
1846 * \returns 0 on success
1847 * \returns LIBUSB_ERROR_NOT_FOUND if no kernel driver was active
1848 * \returns LIBUSB_ERROR_INVALID_PARAM if the interface does not exist
1849 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1850 * \returns LIBUSB_ERROR_NOT_SUPPORTED on platforms where the functionality
1852 * \returns another LIBUSB_ERROR code on other failure
1853 * \see libusb_kernel_driver_active()
1855 int API_EXPORTED libusb_detach_kernel_driver(libusb_device_handle *dev,
1856 int interface_number)
1858 usbi_dbg("interface %d", interface_number);
1860 if (!dev->dev->attached)
1861 return LIBUSB_ERROR_NO_DEVICE;
1863 if (usbi_backend->detach_kernel_driver)
1864 return usbi_backend->detach_kernel_driver(dev, interface_number);
1866 return LIBUSB_ERROR_NOT_SUPPORTED;
1870 * Re-attach an interface's kernel driver, which was previously detached
1871 * using libusb_detach_kernel_driver(). This call is only effective on
1872 * Linux and returns LIBUSB_ERROR_NOT_SUPPORTED on all other platforms.
1874 * This functionality is not available on Darwin or Windows.
1876 * \param dev a device handle
1877 * \param interface_number the interface to attach the driver from
1878 * \returns 0 on success
1879 * \returns LIBUSB_ERROR_NOT_FOUND if no kernel driver was active
1880 * \returns LIBUSB_ERROR_INVALID_PARAM if the interface does not exist
1881 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1882 * \returns LIBUSB_ERROR_NOT_SUPPORTED on platforms where the functionality
1884 * \returns LIBUSB_ERROR_BUSY if the driver cannot be attached because the
1885 * interface is claimed by a program or driver
1886 * \returns another LIBUSB_ERROR code on other failure
1887 * \see libusb_kernel_driver_active()
1889 int API_EXPORTED libusb_attach_kernel_driver(libusb_device_handle *dev,
1890 int interface_number)
1892 usbi_dbg("interface %d", interface_number);
1894 if (!dev->dev->attached)
1895 return LIBUSB_ERROR_NO_DEVICE;
1897 if (usbi_backend->attach_kernel_driver)
1898 return usbi_backend->attach_kernel_driver(dev, interface_number);
1900 return LIBUSB_ERROR_NOT_SUPPORTED;
1904 * Enable/disable libusb's automatic kernel driver detachment. When this is
1905 * enabled libusb will automatically detach the kernel driver on an interface
1906 * when claiming the interface, and attach it when releasing the interface.
1908 * Automatic kernel driver detachment is disabled on newly opened device
1909 * handles by default.
1911 * On platforms which do not have LIBUSB_CAP_SUPPORTS_DETACH_KERNEL_DRIVER
1912 * this function will return LIBUSB_ERROR_NOT_SUPPORTED, and libusb will
1913 * continue as if this function was never called.
1915 * \param dev a device handle
1916 * \param enable whether to enable or disable auto kernel driver detachment
1918 * \returns LIBUSB_SUCCESS on success
1919 * \returns LIBUSB_ERROR_NOT_SUPPORTED on platforms where the functionality
1921 * \see libusb_claim_interface()
1922 * \see libusb_release_interface()
1923 * \see libusb_set_configuration()
1925 int API_EXPORTED libusb_set_auto_detach_kernel_driver(
1926 libusb_device_handle *dev, int enable)
1928 if (!(usbi_backend->caps & USBI_CAP_SUPPORTS_DETACH_KERNEL_DRIVER))
1929 return LIBUSB_ERROR_NOT_SUPPORTED;
1931 dev->auto_detach_kernel_driver = enable;
1932 return LIBUSB_SUCCESS;
1936 * Set log message verbosity.
1938 * The default level is LIBUSB_LOG_LEVEL_NONE, which means no messages are ever
1939 * printed. If you choose to increase the message verbosity level, ensure
1940 * that your application does not close the stdout/stderr file descriptors.
1942 * You are advised to use level LIBUSB_LOG_LEVEL_WARNING. libusb is conservative
1943 * with its message logging and most of the time, will only log messages that
1944 * explain error conditions and other oddities. This will help you debug
1947 * If the LIBUSB_DEBUG environment variable was set when libusb was
1948 * initialized, this function does nothing: the message verbosity is fixed
1949 * to the value in the environment variable.
1951 * If libusb was compiled without any message logging, this function does
1952 * nothing: you'll never get any messages.
1954 * If libusb was compiled with verbose debug message logging, this function
1955 * does nothing: you'll always get messages from all levels.
1957 * \param ctx the context to operate on, or NULL for the default context
1958 * \param level debug level to set
1960 void API_EXPORTED libusb_set_debug(libusb_context *ctx, int level)
1962 USBI_GET_CONTEXT(ctx);
1963 if (!ctx->debug_fixed)
1968 * Initialize libusb. This function must be called before calling any other
1971 * If you do not provide an output location for a context pointer, a default
1972 * context will be created. If there was already a default context, it will
1973 * be reused (and nothing will be initialized/reinitialized).
1975 * \param context Optional output location for context pointer.
1976 * Only valid on return code 0.
1977 * \returns 0 on success, or a LIBUSB_ERROR code on failure
1980 int API_EXPORTED libusb_init(libusb_context **context)
1982 struct libusb_device *dev, *next;
1983 char *dbg = getenv("LIBUSB_DEBUG");
1984 struct libusb_context *ctx;
1985 static int first_init = 1;
1988 usbi_mutex_static_lock(&default_context_lock);
1990 if (!timestamp_origin.tv_sec) {
1991 usbi_gettimeofday(×tamp_origin, NULL);
1994 if (!context && usbi_default_context) {
1995 usbi_dbg("reusing default context");
1996 default_context_refcnt++;
1997 usbi_mutex_static_unlock(&default_context_lock);
2001 ctx = calloc(1, sizeof(*ctx));
2003 r = LIBUSB_ERROR_NO_MEM;
2007 #ifdef ENABLE_DEBUG_LOGGING
2008 ctx->debug = LIBUSB_LOG_LEVEL_DEBUG;
2012 ctx->debug = atoi(dbg);
2014 ctx->debug_fixed = 1;
2017 /* default context should be initialized before calling usbi_dbg */
2018 if (!usbi_default_context) {
2019 usbi_default_context = ctx;
2020 default_context_refcnt++;
2021 usbi_dbg("created default context");
2024 usbi_dbg("libusb v%d.%d.%d.%d", libusb_version_internal.major, libusb_version_internal.minor,
2025 libusb_version_internal.micro, libusb_version_internal.nano);
2027 usbi_mutex_init(&ctx->usb_devs_lock, NULL);
2028 usbi_mutex_init(&ctx->open_devs_lock, NULL);
2029 usbi_mutex_init(&ctx->hotplug_cbs_lock, NULL);
2030 list_init(&ctx->usb_devs);
2031 list_init(&ctx->open_devs);
2032 list_init(&ctx->hotplug_cbs);
2034 usbi_mutex_static_lock(&active_contexts_lock);
2037 list_init (&active_contexts_list);
2039 list_add (&ctx->list, &active_contexts_list);
2040 usbi_mutex_static_unlock(&active_contexts_lock);
2042 if (usbi_backend->init) {
2043 r = usbi_backend->init(ctx);
2048 r = usbi_io_init(ctx);
2050 goto err_backend_exit;
2052 usbi_mutex_static_unlock(&default_context_lock);
2060 if (usbi_backend->exit)
2061 usbi_backend->exit();
2063 if (ctx == usbi_default_context) {
2064 usbi_default_context = NULL;
2065 default_context_refcnt--;
2068 usbi_mutex_static_lock(&active_contexts_lock);
2069 list_del (&ctx->list);
2070 usbi_mutex_static_unlock(&active_contexts_lock);
2072 usbi_mutex_lock(&ctx->usb_devs_lock);
2073 list_for_each_entry_safe(dev, next, &ctx->usb_devs, list, struct libusb_device) {
2074 list_del(&dev->list);
2075 libusb_unref_device(dev);
2077 usbi_mutex_unlock(&ctx->usb_devs_lock);
2079 usbi_mutex_destroy(&ctx->open_devs_lock);
2080 usbi_mutex_destroy(&ctx->usb_devs_lock);
2081 usbi_mutex_destroy(&ctx->hotplug_cbs_lock);
2085 usbi_mutex_static_unlock(&default_context_lock);
2090 * Deinitialize libusb. Should be called after closing all open devices and
2091 * before your application terminates.
2092 * \param ctx the context to deinitialize, or NULL for the default context
2094 void API_EXPORTED libusb_exit(struct libusb_context *ctx)
2096 struct libusb_device *dev, *next;
2097 struct timeval tv = { 0, 0 };
2100 USBI_GET_CONTEXT(ctx);
2102 /* if working with default context, only actually do the deinitialization
2103 * if we're the last user */
2104 usbi_mutex_static_lock(&default_context_lock);
2105 if (ctx == usbi_default_context) {
2106 if (--default_context_refcnt > 0) {
2107 usbi_dbg("not destroying default context");
2108 usbi_mutex_static_unlock(&default_context_lock);
2111 usbi_dbg("destroying default context");
2112 usbi_default_context = NULL;
2114 usbi_mutex_static_unlock(&default_context_lock);
2116 usbi_mutex_static_lock(&active_contexts_lock);
2117 list_del (&ctx->list);
2118 usbi_mutex_static_unlock(&active_contexts_lock);
2120 if (libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG)) {
2121 usbi_hotplug_deregister_all(ctx);
2124 * Ensure any pending unplug events are read from the hotplug
2125 * pipe. The usb_device-s hold in the events are no longer part
2126 * of usb_devs, but the events still hold a reference!
2128 * Note we don't do this if the application has left devices
2129 * open (which implies a buggy app) to avoid packet completion
2130 * handlers running when the app does not expect them to run.
2132 if (list_empty(&ctx->open_devs))
2133 libusb_handle_events_timeout(ctx, &tv);
2135 usbi_mutex_lock(&ctx->usb_devs_lock);
2136 list_for_each_entry_safe(dev, next, &ctx->usb_devs, list, struct libusb_device) {
2137 list_del(&dev->list);
2138 libusb_unref_device(dev);
2140 usbi_mutex_unlock(&ctx->usb_devs_lock);
2143 /* a few sanity checks. don't bother with locking because unless
2144 * there is an application bug, nobody will be accessing these. */
2145 if (!list_empty(&ctx->usb_devs))
2146 usbi_warn(ctx, "some libusb_devices were leaked");
2147 if (!list_empty(&ctx->open_devs))
2148 usbi_warn(ctx, "application left some devices open");
2151 if (usbi_backend->exit)
2152 usbi_backend->exit();
2154 usbi_mutex_destroy(&ctx->open_devs_lock);
2155 usbi_mutex_destroy(&ctx->usb_devs_lock);
2156 usbi_mutex_destroy(&ctx->hotplug_cbs_lock);
2161 * Check at runtime if the loaded library has a given capability.
2162 * This call should be performed after \ref libusb_init(), to ensure the
2163 * backend has updated its capability set.
2165 * \param capability the \ref libusb_capability to check for
2166 * \returns nonzero if the running library has the capability, 0 otherwise
2168 int API_EXPORTED libusb_has_capability(uint32_t capability)
2170 switch (capability) {
2171 case LIBUSB_CAP_HAS_CAPABILITY:
2173 case LIBUSB_CAP_HAS_HOTPLUG:
2174 return !(usbi_backend->get_device_list);
2175 case LIBUSB_CAP_HAS_HID_ACCESS:
2176 return (usbi_backend->caps & USBI_CAP_HAS_HID_ACCESS);
2177 case LIBUSB_CAP_SUPPORTS_DETACH_KERNEL_DRIVER:
2178 return (usbi_backend->caps & USBI_CAP_SUPPORTS_DETACH_KERNEL_DRIVER);
2183 /* this is defined in libusbi.h if needed */
2184 #ifdef LIBUSB_GETTIMEOFDAY_WIN32
2187 * Implementation according to:
2188 * The Open Group Base Specifications Issue 6
2189 * IEEE Std 1003.1, 2004 Edition
2193 * THIS SOFTWARE IS NOT COPYRIGHTED
2195 * This source code is offered for use in the public domain. You may
2196 * use, modify or distribute it freely.
2198 * This code is distributed in the hope that it will be useful but
2199 * WITHOUT ANY WARRANTY. ALL WARRANTIES, EXPRESS OR IMPLIED ARE HEREBY
2200 * DISCLAIMED. This includes but is not limited to warranties of
2201 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
2204 * Danny Smith <dannysmith@users.sourceforge.net>
2207 /* Offset between 1/1/1601 and 1/1/1970 in 100 nanosec units */
2208 #define _W32_FT_OFFSET (116444736000000000)
2210 int usbi_gettimeofday(struct timeval *tp, void *tzp)
2213 unsigned __int64 ns100; /* Time since 1 Jan 1601, in 100ns units */
2219 #if defined(OS_WINCE)
2222 SystemTimeToFileTime(&st, &_now.ft);
2224 GetSystemTimeAsFileTime (&_now.ft);
2226 tp->tv_usec=(long)((_now.ns100 / 10) % 1000000 );
2227 tp->tv_sec= (long)((_now.ns100 - _W32_FT_OFFSET) / 10000000);
2229 /* Always return 0 as per Open Group Base Specifications Issue 6.
2230 Do not set errno on error. */
2235 static void usbi_log_str(struct libusb_context *ctx,
2236 enum libusb_log_level level, const char * str)
2238 #if defined(USE_SYSTEM_LOGGING_FACILITY)
2239 #if defined(OS_WINDOWS) || defined(OS_WINCE)
2240 /* Windows CE only supports the Unicode version of OutputDebugString. */
2241 WCHAR wbuf[USBI_MAX_LOG_LEN];
2242 MultiByteToWideChar(CP_UTF8, 0, str, -1, wbuf, sizeof(wbuf));
2243 OutputDebugStringW(wbuf);
2244 #elif defined(__ANDROID__)
2245 int priority = ANDROID_LOG_UNKNOWN;
2247 case LIBUSB_LOG_LEVEL_INFO: priority = ANDROID_LOG_INFO; break;
2248 case LIBUSB_LOG_LEVEL_WARNING: priority = ANDROID_LOG_WARN; break;
2249 case LIBUSB_LOG_LEVEL_ERROR: priority = ANDROID_LOG_ERROR; break;
2250 case LIBUSB_LOG_LEVEL_DEBUG: priority = ANDROID_LOG_DEBUG; break;
2252 __android_log_write(priority, "libusb", str);
2253 #elif defined(HAVE_SYSLOG_FUNC)
2254 int syslog_level = LOG_INFO;
2256 case LIBUSB_LOG_LEVEL_INFO: syslog_level = LOG_INFO; break;
2257 case LIBUSB_LOG_LEVEL_WARNING: syslog_level = LOG_WARNING; break;
2258 case LIBUSB_LOG_LEVEL_ERROR: syslog_level = LOG_ERR; break;
2259 case LIBUSB_LOG_LEVEL_DEBUG: syslog_level = LOG_DEBUG; break;
2261 syslog(syslog_level, "%s", str);
2262 #else /* All of gcc, Clang, XCode seem to use #warning */
2263 #warning System logging is not supported on this platform. Logging to stderr will be used instead.
2268 #endif /* USE_SYSTEM_LOGGING_FACILITY */
2273 void usbi_log_v(struct libusb_context *ctx, enum libusb_log_level level,
2274 const char *function, const char *format, va_list args)
2276 const char *prefix = "";
2277 char buf[USBI_MAX_LOG_LEN];
2279 int global_debug, header_len, text_len;
2280 static int has_debug_header_been_displayed = 0;
2282 #ifdef ENABLE_DEBUG_LOGGING
2288 USBI_GET_CONTEXT(ctx);
2290 ctx_level = ctx->debug;
2292 char *dbg = getenv("LIBUSB_DEBUG");
2294 ctx_level = atoi(dbg);
2296 global_debug = (ctx_level == LIBUSB_LOG_LEVEL_DEBUG);
2299 if (level == LIBUSB_LOG_LEVEL_WARNING && ctx_level < LIBUSB_LOG_LEVEL_WARNING)
2301 if (level == LIBUSB_LOG_LEVEL_INFO && ctx_level < LIBUSB_LOG_LEVEL_INFO)
2303 if (level == LIBUSB_LOG_LEVEL_DEBUG && ctx_level < LIBUSB_LOG_LEVEL_DEBUG)
2307 usbi_gettimeofday(&now, NULL);
2308 if ((global_debug) && (!has_debug_header_been_displayed)) {
2309 has_debug_header_been_displayed = 1;
2310 usbi_log_str(ctx, LIBUSB_LOG_LEVEL_DEBUG, "[timestamp] [threadID] facility level [function call] <message>\n");
2311 usbi_log_str(ctx, LIBUSB_LOG_LEVEL_DEBUG, "--------------------------------------------------------------------------------\n");
2313 if (now.tv_usec < timestamp_origin.tv_usec) {
2315 now.tv_usec += 1000000;
2317 now.tv_sec -= timestamp_origin.tv_sec;
2318 now.tv_usec -= timestamp_origin.tv_usec;
2321 case LIBUSB_LOG_LEVEL_INFO:
2324 case LIBUSB_LOG_LEVEL_WARNING:
2327 case LIBUSB_LOG_LEVEL_ERROR:
2330 case LIBUSB_LOG_LEVEL_DEBUG:
2333 case LIBUSB_LOG_LEVEL_NONE:
2341 header_len = snprintf(buf, sizeof(buf),
2342 "[%2d.%06d] [%08x] libusb: %s [%s] ",
2343 (int)now.tv_sec, (int)now.tv_usec, usbi_get_tid(), prefix, function);
2345 header_len = snprintf(buf, sizeof(buf),
2346 "libusb: %s [%s] ", prefix, function);
2349 if (header_len < 0 || header_len >= sizeof(buf)) {
2350 /* Somehow snprintf failed to write to the buffer,
2351 * remove the header so something useful is output. */
2354 /* Make sure buffer is NUL terminated */
2355 buf[header_len] = '\0';
2356 text_len = vsnprintf(buf + header_len, sizeof(buf) - header_len,
2358 if (text_len < 0 || text_len + header_len >= sizeof(buf)) {
2359 /* Truncated log output. On some platforms a -1 return value means
2360 * that the output was truncated. */
2361 text_len = sizeof(buf) - header_len;
2363 if (header_len + text_len + sizeof(USBI_LOG_LINE_END) >= sizeof(buf)) {
2364 /* Need to truncate the text slightly to fit on the terminator. */
2365 text_len -= (header_len + text_len + sizeof(USBI_LOG_LINE_END)) - sizeof(buf);
2367 strcpy(buf + header_len + text_len, USBI_LOG_LINE_END);
2369 usbi_log_str(ctx, level, buf);
2372 void usbi_log(struct libusb_context *ctx, enum libusb_log_level level,
2373 const char *function, const char *format, ...)
2377 va_start (args, format);
2378 usbi_log_v(ctx, level, function, format, args);
2383 * Returns a constant NULL-terminated string with the ASCII name of a libusb
2384 * error or transfer status code. The caller must not free() the returned
2387 * \param error_code The \ref libusb_error or libusb_transfer_status code to
2388 * return the name of.
2389 * \returns The error name, or the string **UNKNOWN** if the value of
2390 * error_code is not a known error / status code.
2392 DEFAULT_VISIBILITY const char * LIBUSB_CALL libusb_error_name(int error_code)
2394 switch (error_code) {
2395 case LIBUSB_ERROR_IO:
2396 return "LIBUSB_ERROR_IO";
2397 case LIBUSB_ERROR_INVALID_PARAM:
2398 return "LIBUSB_ERROR_INVALID_PARAM";
2399 case LIBUSB_ERROR_ACCESS:
2400 return "LIBUSB_ERROR_ACCESS";
2401 case LIBUSB_ERROR_NO_DEVICE:
2402 return "LIBUSB_ERROR_NO_DEVICE";
2403 case LIBUSB_ERROR_NOT_FOUND:
2404 return "LIBUSB_ERROR_NOT_FOUND";
2405 case LIBUSB_ERROR_BUSY:
2406 return "LIBUSB_ERROR_BUSY";
2407 case LIBUSB_ERROR_TIMEOUT:
2408 return "LIBUSB_ERROR_TIMEOUT";
2409 case LIBUSB_ERROR_OVERFLOW:
2410 return "LIBUSB_ERROR_OVERFLOW";
2411 case LIBUSB_ERROR_PIPE:
2412 return "LIBUSB_ERROR_PIPE";
2413 case LIBUSB_ERROR_INTERRUPTED:
2414 return "LIBUSB_ERROR_INTERRUPTED";
2415 case LIBUSB_ERROR_NO_MEM:
2416 return "LIBUSB_ERROR_NO_MEM";
2417 case LIBUSB_ERROR_NOT_SUPPORTED:
2418 return "LIBUSB_ERROR_NOT_SUPPORTED";
2419 case LIBUSB_ERROR_OTHER:
2420 return "LIBUSB_ERROR_OTHER";
2422 case LIBUSB_TRANSFER_ERROR:
2423 return "LIBUSB_TRANSFER_ERROR";
2424 case LIBUSB_TRANSFER_TIMED_OUT:
2425 return "LIBUSB_TRANSFER_TIMED_OUT";
2426 case LIBUSB_TRANSFER_CANCELLED:
2427 return "LIBUSB_TRANSFER_CANCELLED";
2428 case LIBUSB_TRANSFER_STALL:
2429 return "LIBUSB_TRANSFER_STALL";
2430 case LIBUSB_TRANSFER_NO_DEVICE:
2431 return "LIBUSB_TRANSFER_NO_DEVICE";
2432 case LIBUSB_TRANSFER_OVERFLOW:
2433 return "LIBUSB_TRANSFER_OVERFLOW";
2436 return "LIBUSB_SUCCESS / LIBUSB_TRANSFER_COMPLETED";
2438 return "**UNKNOWN**";
2443 * Returns a pointer to const struct libusb_version with the version
2444 * (major, minor, micro, nano and rc) of the running library.
2447 const struct libusb_version * LIBUSB_CALL libusb_get_version(void)
2449 return &libusb_version_internal;