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
27 #include <android/log.h>
35 static const struct libusb_version libusb_version_internal =
36 { LIBUSB_MAJOR, LIBUSB_MINOR, LIBUSB_MICRO, LIBUSB_NANO,
37 LIBUSB_RC, "http://libusb.info" };
38 static struct timespec timestamp_origin;
39 #if defined(ENABLE_LOGGING) && !defined(USE_SYSTEM_LOGGING_FACILITY)
40 static libusb_log_cb log_handler;
43 struct libusb_context *usbi_default_context;
44 static int default_context_refcnt;
45 static usbi_mutex_static_t default_context_lock = USBI_MUTEX_INITIALIZER;
46 static struct usbi_option default_context_options[LIBUSB_OPTION_MAX];
49 usbi_mutex_static_t active_contexts_lock = USBI_MUTEX_INITIALIZER;
50 struct list_head active_contexts_list;
53 * \mainpage libusb-1.0 API Reference
55 * \section intro Introduction
57 * libusb is an open source library that allows you to communicate with USB
58 * devices from user space. For more info, see the
59 * <a href="http://libusb.info">libusb homepage</a>.
61 * This documentation is aimed at application developers wishing to
62 * communicate with USB peripherals from their own software. After reviewing
63 * this documentation, feedback and questions can be sent to the
64 * <a href="http://mailing-list.libusb.info">libusb-devel mailing list</a>.
66 * This documentation assumes knowledge of how to operate USB devices from
67 * a software standpoint (descriptors, configurations, interfaces, endpoints,
68 * control/bulk/interrupt/isochronous transfers, etc). Full information
69 * can be found in the <a href="http://www.usb.org/developers/docs/">USB 3.0
70 * Specification</a> which is available for free download. You can probably
71 * find less verbose introductions by searching the web.
73 * \section API Application Programming Interface (API)
75 * See the \ref libusb_api page for a complete list of the libusb functions.
77 * \section features Library features
79 * - All transfer types supported (control/bulk/interrupt/isochronous)
80 * - 2 transfer interfaces:
81 * -# Synchronous (simple)
82 * -# Asynchronous (more complicated, but more powerful)
83 * - Thread safe (although the asynchronous interface means that you
84 * usually won't need to thread)
85 * - Lightweight with lean API
86 * - Compatible with libusb-0.1 through the libusb-compat-0.1 translation layer
87 * - Hotplug support (on some platforms). See \ref libusb_hotplug.
89 * \section gettingstarted Getting Started
91 * To begin reading the API documentation, start with the Modules page which
92 * links to the different categories of libusb's functionality.
94 * One decision you will have to make is whether to use the synchronous
95 * or the asynchronous data transfer interface. The \ref libusb_io documentation
96 * provides some insight into this topic.
98 * Some example programs can be found in the libusb source distribution under
99 * the "examples" subdirectory. The libusb homepage includes a list of
100 * real-life project examples which use libusb.
102 * \section errorhandling Error handling
104 * libusb functions typically return 0 on success or a negative error code
105 * on failure. These negative error codes relate to LIBUSB_ERROR constants
106 * which are listed on the \ref libusb_misc "miscellaneous" documentation page.
108 * \section msglog Debug message logging
110 * libusb uses stderr for all logging. By default, logging is set to NONE,
111 * which means that no output will be produced. However, unless the library
112 * has been compiled with logging disabled, then any application calls to
113 * libusb_set_option(ctx, LIBUSB_OPTION_LOG_LEVEL, level), or the setting of the
114 * environmental variable LIBUSB_DEBUG outside of the application, can result
115 * in logging being produced. Your application should therefore not close
116 * stderr, but instead direct it to the null device if its output is
119 * The libusb_set_option(ctx, LIBUSB_OPTION_LOG_LEVEL, level) function can be
120 * used to enable logging of certain messages. Under standard configuration,
121 * libusb doesn't really log much so you are advised to use this function
122 * to enable all error/warning/ informational messages. It will help debug
123 * problems with your software.
125 * The logged messages are unstructured. There is no one-to-one correspondence
126 * between messages being logged and success or failure return codes from
127 * libusb functions. There is no format to the messages, so you should not
128 * try to capture or parse them. They are not and will not be localized.
129 * These messages are not intended to being passed to your application user;
130 * instead, you should interpret the error codes returned from libusb functions
131 * and provide appropriate notification to the user. The messages are simply
132 * there to aid you as a programmer, and if you're confused because you're
133 * getting a strange error code from a libusb function, enabling message
134 * logging may give you a suitable explanation.
136 * The LIBUSB_DEBUG environment variable can be used to enable message logging
137 * at run-time. This environment variable should be set to a log level number,
138 * which is interpreted the same as the
139 * libusb_set_option(ctx, LIBUSB_OPTION_LOG_LEVEL, level) parameter. When this
140 * environment variable is set, the message logging verbosity level is fixed
141 * and libusb_set_option(ctx, LIBUSB_OPTION_LOG_LEVEL, level) effectively does
144 * libusb can be compiled without any logging functions, useful for embedded
145 * systems. In this case, libusb_set_option(ctx, LIBUSB_OPTION_LOG_LEVEL, level)
146 * and the LIBUSB_DEBUG environment variable have no effects.
148 * libusb can also be compiled with verbose debugging messages always. When
149 * the library is compiled in this way, all messages of all verbosities are
150 * always logged. libusb_set_option(ctx, LIBUSB_OPTION_LOG_LEVEL, level) and
151 * the LIBUSB_DEBUG environment variable have no effects.
153 * \section remarks Other remarks
155 * libusb does have imperfections. The \ref libusb_caveats "caveats" page attempts
160 * \page libusb_caveats Caveats
162 * \section threadsafety Thread safety
164 * libusb is designed to be completely thread-safe, but as with any API it
165 * cannot prevent a user from sabotaging themselves, either intentionally or
168 * Observe the following general guidelines:
170 * - Calls to functions that release a resource (e.g. libusb_close(),
171 * libusb_free_config_descriptor()) should not be called concurrently on
172 * the same resource. This is no different than concurrently calling free()
173 * on the same allocated pointer.
174 * - Each individual \ref libusb_transfer should be prepared by a single
175 * thread. In other words, no two threads should ever be concurrently
176 * filling out the fields of a \ref libusb_transfer. You can liken this to
177 * calling sprintf() with the same destination buffer from multiple threads.
178 * The results will likely not be what you want unless the input parameters
179 * are all the same, but its best to avoid this situation entirely.
180 * - Both the \ref libusb_transfer structure and its associated data buffer
181 * should not be accessed between the time the transfer is submitted and the
182 * time the completion callback is invoked. You can think of "ownership" of
183 * these things as being transferred to libusb while the transfer is active.
184 * - The various "setter" functions (e.g. libusb_set_log_cb(),
185 * libusb_set_pollfd_notifiers()) should not be called concurrently on the
186 * resource. Though doing so will not lead to any undefined behavior, it
187 * will likely produce results that the application does not expect.
189 * Rules for multiple threads and asynchronous I/O are detailed
190 * \ref libusb_mtasync "here".
192 * \section fork Fork considerations
194 * libusb is <em>not</em> designed to work across fork() calls. Depending on
195 * the platform, there may be resources in the parent process that are not
196 * available to the child (e.g. the hotplug monitor thread on Linux). In
197 * addition, since the parent and child will share libusb's internal file
198 * descriptors, using libusb in any way from the child could cause the parent
199 * process's \ref libusb_context to get into an inconsistent state.
201 * On Linux, libusb's file descriptors will be marked as CLOEXEC, which means
202 * that it is safe to fork() and exec() without worrying about the child
203 * process needing to clean up state or having access to these file descriptors.
204 * Other platforms may not be so forgiving, so consider yourself warned!
206 * \section devresets Device resets
208 * The libusb_reset_device() function allows you to reset a device. If your
209 * program has to call such a function, it should obviously be aware that
210 * the reset will cause device state to change (e.g. register values may be
213 * The problem is that any other program could reset the device your program
214 * is working with, at any time. libusb does not offer a mechanism to inform
215 * you when this has happened, so if someone else resets your device it will
216 * not be clear to your own program why the device state has changed.
218 * Ultimately, this is a limitation of writing drivers in user space.
219 * Separation from the USB stack in the underlying kernel makes it difficult
220 * for the operating system to deliver such notifications to your program.
221 * The Linux kernel USB stack allows such reset notifications to be delivered
222 * to in-kernel USB drivers, but it is not clear how such notifications could
223 * be delivered to second-class drivers that live in user space.
225 * \section blockonly Blocking-only functionality
227 * The functionality listed below is only available through synchronous,
228 * blocking functions. There are no asynchronous/non-blocking alternatives,
229 * and no clear ways of implementing these.
231 * - Configuration activation (libusb_set_configuration())
232 * - Interface/alternate setting activation (libusb_set_interface_alt_setting())
233 * - Releasing of interfaces (libusb_release_interface())
234 * - Clearing of halt/stall condition (libusb_clear_halt())
235 * - Device resets (libusb_reset_device())
237 * \section configsel Configuration selection and handling
239 * When libusb presents a device handle to an application, there is a chance
240 * that the corresponding device may be in unconfigured state. For devices
241 * with multiple configurations, there is also a chance that the configuration
242 * currently selected is not the one that the application wants to use.
244 * The obvious solution is to add a call to libusb_set_configuration() early
245 * on during your device initialization routines, but there are caveats to
247 * -# If the device is already in the desired configuration, calling
248 * libusb_set_configuration() using the same configuration value will cause
249 * a lightweight device reset. This may not be desirable behaviour.
250 * -# In the case where the desired configuration is already active, libusb
251 * may not even be able to perform a lightweight device reset. For example,
252 * take my USB keyboard with fingerprint reader: I'm interested in driving
253 * the fingerprint reader interface through libusb, but the kernel's
254 * USB-HID driver will almost always have claimed the keyboard interface.
255 * Because the kernel has claimed an interface, it is not even possible to
256 * perform the lightweight device reset, so libusb_set_configuration() will
257 * fail. (Luckily the device in question only has a single configuration.)
258 * -# libusb will be unable to set a configuration if other programs or
259 * drivers have claimed interfaces. In particular, this means that kernel
260 * drivers must be detached from all the interfaces before
261 * libusb_set_configuration() may succeed.
263 * One solution to some of the above problems is to consider the currently
264 * active configuration. If the configuration we want is already active, then
265 * we don't have to select any configuration:
268 libusb_get_configuration(dev, &cfg);
270 libusb_set_configuration(dev, desired);
273 * This is probably suitable for most scenarios, but is inherently racy:
274 * another application or driver may change the selected configuration
275 * <em>after</em> the libusb_get_configuration() call.
277 * Even in cases where libusb_set_configuration() succeeds, consider that other
278 * applications or drivers may change configuration after your application
279 * calls libusb_set_configuration().
281 * One possible way to lock your device into a specific configuration is as
283 * -# Set the desired configuration (or use the logic above to realise that
284 * it is already in the desired configuration)
285 * -# Claim the interface that you wish to use
286 * -# Check that the currently active configuration is the one that you want
289 * The above method works because once an interface is claimed, no application
290 * or driver is able to select another configuration.
292 * \section earlycomp Early transfer completion
294 * NOTE: This section is currently Linux-centric. I am not sure if any of these
295 * considerations apply to Darwin or other platforms.
297 * When a transfer completes early (i.e. when less data is received/sent in
298 * any one packet than the transfer buffer allows for) then libusb is designed
299 * to terminate the transfer immediately, not transferring or receiving any
300 * more data unless other transfers have been queued by the user.
302 * On legacy platforms, libusb is unable to do this in all situations. After
303 * the incomplete packet occurs, "surplus" data may be transferred. For recent
304 * versions of libusb, this information is kept (the data length of the
305 * transfer is updated) and, for device-to-host transfers, any surplus data was
306 * added to the buffer. Still, this is not a nice solution because it loses the
307 * information about the end of the short packet, and the user probably wanted
308 * that surplus data to arrive in the next logical transfer.
310 * \section zlp Zero length packets
312 * - libusb is able to send a packet of zero length to an endpoint simply by
313 * submitting a transfer of zero length.
314 * - The \ref libusb_transfer_flags::LIBUSB_TRANSFER_ADD_ZERO_PACKET
315 * "LIBUSB_TRANSFER_ADD_ZERO_PACKET" flag is currently only supported on Linux.
319 * \page libusb_contexts Contexts
321 * It is possible that libusb may be used simultaneously from two independent
322 * libraries linked into the same executable. For example, if your application
323 * has a plugin-like system which allows the user to dynamically load a range
324 * of modules into your program, it is feasible that two independently
325 * developed modules may both use libusb.
327 * libusb is written to allow for these multiple user scenarios. The two
328 * "instances" of libusb will not interfere: libusb_set_option() calls
329 * from one user will not affect the same settings for other users, other
330 * users can continue using libusb after one of them calls libusb_exit(), etc.
332 * This is made possible through libusb's <em>context</em> concept. When you
333 * call libusb_init(), you are (optionally) given a context. You can then pass
334 * this context pointer back into future libusb functions.
336 * In order to keep things simple for more simplistic applications, it is
337 * legal to pass NULL to all functions requiring a context pointer (as long as
338 * you're sure no other code will attempt to use libusb from the same process).
339 * When you pass NULL, the default context will be used. The default context
340 * is created the first time a process calls libusb_init() when no other
341 * context is alive. Contexts are destroyed during libusb_exit().
343 * The default context is reference-counted and can be shared. That means that
344 * if libusb_init(NULL) is called twice within the same process, the two
345 * users end up sharing the same context. The deinitialization and freeing of
346 * the default context will only happen when the last user calls libusb_exit().
347 * In other words, the default context is created and initialized when its
348 * reference count goes from 0 to 1, and is deinitialized and destroyed when
349 * its reference count goes from 1 to 0.
351 * You may be wondering why only a subset of libusb functions require a
352 * context pointer in their function definition. Internally, libusb stores
353 * context pointers in other objects (e.g. libusb_device instances) and hence
354 * can infer the context from those objects.
358 * \page libusb_api Application Programming Interface
360 * This is the complete list of libusb functions, structures and
361 * enumerations in alphabetical order.
364 * - libusb_alloc_streams()
365 * - libusb_alloc_transfer()
366 * - libusb_attach_kernel_driver()
367 * - libusb_bulk_transfer()
368 * - libusb_cancel_transfer()
369 * - libusb_claim_interface()
370 * - libusb_clear_halt()
372 * - libusb_control_transfer()
373 * - libusb_control_transfer_get_data()
374 * - libusb_control_transfer_get_setup()
375 * - libusb_cpu_to_le16()
376 * - libusb_detach_kernel_driver()
377 * - libusb_dev_mem_alloc()
378 * - libusb_dev_mem_free()
379 * - libusb_error_name()
380 * - libusb_event_handler_active()
381 * - libusb_event_handling_ok()
383 * - libusb_fill_bulk_stream_transfer()
384 * - libusb_fill_bulk_transfer()
385 * - libusb_fill_control_setup()
386 * - libusb_fill_control_transfer()
387 * - libusb_fill_interrupt_transfer()
388 * - libusb_fill_iso_transfer()
389 * - libusb_free_bos_descriptor()
390 * - libusb_free_config_descriptor()
391 * - libusb_free_container_id_descriptor()
392 * - libusb_free_device_list()
393 * - libusb_free_pollfds()
394 * - libusb_free_ss_endpoint_companion_descriptor()
395 * - libusb_free_ss_usb_device_capability_descriptor()
396 * - libusb_free_streams()
397 * - libusb_free_transfer()
398 * - libusb_free_usb_2_0_extension_descriptor()
399 * - libusb_get_active_config_descriptor()
400 * - libusb_get_bos_descriptor()
401 * - libusb_get_bus_number()
402 * - libusb_get_config_descriptor()
403 * - libusb_get_config_descriptor_by_value()
404 * - libusb_get_configuration()
405 * - libusb_get_container_id_descriptor()
406 * - libusb_get_descriptor()
407 * - libusb_get_device()
408 * - libusb_get_device_address()
409 * - libusb_get_device_descriptor()
410 * - libusb_get_device_list()
411 * - libusb_get_device_speed()
412 * - libusb_get_iso_packet_buffer()
413 * - libusb_get_iso_packet_buffer_simple()
414 * - libusb_get_max_iso_packet_size()
415 * - libusb_get_max_packet_size()
416 * - libusb_get_next_timeout()
417 * - libusb_get_parent()
418 * - libusb_get_pollfds()
419 * - libusb_get_port_number()
420 * - libusb_get_port_numbers()
421 * - libusb_get_port_path()
422 * - libusb_get_ss_endpoint_companion_descriptor()
423 * - libusb_get_ss_usb_device_capability_descriptor()
424 * - libusb_get_string_descriptor()
425 * - libusb_get_string_descriptor_ascii()
426 * - libusb_get_usb_2_0_extension_descriptor()
427 * - libusb_get_version()
428 * - libusb_handle_events()
429 * - libusb_handle_events_completed()
430 * - libusb_handle_events_locked()
431 * - libusb_handle_events_timeout()
432 * - libusb_handle_events_timeout_completed()
433 * - libusb_has_capability()
434 * - libusb_hotplug_deregister_callback()
435 * - libusb_hotplug_register_callback()
437 * - libusb_interrupt_event_handler()
438 * - libusb_interrupt_transfer()
439 * - libusb_kernel_driver_active()
440 * - libusb_lock_events()
441 * - libusb_lock_event_waiters()
443 * - libusb_open_device_with_vid_pid()
444 * - libusb_pollfds_handle_timeouts()
445 * - libusb_ref_device()
446 * - libusb_release_interface()
447 * - libusb_reset_device()
448 * - libusb_set_auto_detach_kernel_driver()
449 * - libusb_set_configuration()
450 * - libusb_set_debug()
451 * - libusb_set_log_cb()
452 * - libusb_set_interface_alt_setting()
453 * - libusb_set_iso_packet_lengths()
454 * - libusb_set_option()
455 * - libusb_setlocale()
456 * - libusb_set_pollfd_notifiers()
457 * - libusb_strerror()
458 * - libusb_submit_transfer()
459 * - libusb_transfer_get_stream_id()
460 * - libusb_transfer_set_stream_id()
461 * - libusb_try_lock_events()
462 * - libusb_unlock_events()
463 * - libusb_unlock_event_waiters()
464 * - libusb_unref_device()
465 * - libusb_wait_for_event()
466 * - libusb_wrap_sys_device()
468 * \section Structures
469 * - libusb_bos_descriptor
470 * - libusb_bos_dev_capability_descriptor
471 * - libusb_config_descriptor
472 * - libusb_container_id_descriptor
473 * - \ref libusb_context
474 * - libusb_control_setup
475 * - \ref libusb_device
476 * - libusb_device_descriptor
477 * - \ref libusb_device_handle
478 * - libusb_endpoint_descriptor
480 * - libusb_interface_descriptor
481 * - libusb_iso_packet_descriptor
483 * - libusb_ss_endpoint_companion_descriptor
484 * - libusb_ss_usb_device_capability_descriptor
486 * - libusb_usb_2_0_extension_descriptor
490 * - \ref libusb_bos_type
491 * - \ref libusb_capability
492 * - \ref libusb_class_code
493 * - \ref libusb_descriptor_type
494 * - \ref libusb_endpoint_direction
495 * - \ref libusb_endpoint_transfer_type
496 * - \ref libusb_error
497 * - \ref libusb_iso_sync_type
498 * - \ref libusb_iso_usage_type
499 * - \ref libusb_log_level
500 * - \ref libusb_option
501 * - \ref libusb_request_recipient
502 * - \ref libusb_request_type
503 * - \ref libusb_speed
504 * - \ref libusb_ss_usb_device_capability_attributes
505 * - \ref libusb_standard_request
506 * - \ref libusb_supported_speed
507 * - \ref libusb_transfer_flags
508 * - \ref libusb_transfer_status
509 * - \ref libusb_transfer_type
510 * - \ref libusb_usb_2_0_extension_attributes
514 * @defgroup libusb_lib Library initialization/deinitialization
515 * This page details how to initialize and deinitialize libusb. Initialization
516 * must be performed before using any libusb functionality, and similarly you
517 * must not call any libusb functions after deinitialization.
521 * @defgroup libusb_dev Device handling and enumeration
522 * The functionality documented below is designed to help with the following
524 * - Enumerating the USB devices currently attached to the system
525 * - Choosing a device to operate from your software
526 * - Opening and closing the chosen device
528 * \section nutshell In a nutshell...
530 * The description below really makes things sound more complicated than they
531 * actually are. The following sequence of function calls will be suitable
532 * for almost all scenarios and does not require you to have such a deep
533 * understanding of the resource management issues:
536 libusb_device **list;
537 libusb_device *found = NULL;
538 ssize_t cnt = libusb_get_device_list(NULL, &list);
544 for (i = 0; i < cnt; i++) {
545 libusb_device *device = list[i];
546 if (is_interesting(device)) {
553 libusb_device_handle *handle;
555 err = libusb_open(found, &handle);
561 libusb_free_device_list(list, 1);
564 * The two important points:
565 * - You asked libusb_free_device_list() to unreference the devices (2nd
567 * - You opened the device before freeing the list and unreferencing the
570 * If you ended up with a handle, you can now proceed to perform I/O on the
573 * \section devshandles Devices and device handles
574 * libusb has a concept of a USB device, represented by the
575 * \ref libusb_device opaque type. A device represents a USB device that
576 * is currently or was previously connected to the system. Using a reference
577 * to a device, you can determine certain information about the device (e.g.
578 * you can read the descriptor data).
580 * The libusb_get_device_list() function can be used to obtain a list of
581 * devices currently connected to the system. This is known as device
584 * Just because you have a reference to a device does not mean it is
585 * necessarily usable. The device may have been unplugged, you may not have
586 * permission to operate such device, or another program or driver may be
589 * When you've found a device that you'd like to operate, you must ask
590 * libusb to open the device using the libusb_open() function. Assuming
591 * success, libusb then returns you a <em>device handle</em>
592 * (a \ref libusb_device_handle pointer). All "real" I/O operations then
593 * operate on the handle rather than the original device pointer.
595 * \section devref Device discovery and reference counting
597 * Device discovery (i.e. calling libusb_get_device_list()) returns a
598 * freshly-allocated list of devices. The list itself must be freed when
599 * you are done with it. libusb also needs to know when it is OK to free
600 * the contents of the list - the devices themselves.
602 * To handle these issues, libusb provides you with two separate items:
603 * - A function to free the list itself
604 * - A reference counting system for the devices inside
606 * New devices presented by the libusb_get_device_list() function all have a
607 * reference count of 1. You can increase and decrease reference count using
608 * libusb_ref_device() and libusb_unref_device(). A device is destroyed when
609 * its reference count reaches 0.
611 * With the above information in mind, the process of opening a device can
612 * be viewed as follows:
613 * -# Discover devices using libusb_get_device_list().
614 * -# Choose the device that you want to operate, and call libusb_open().
615 * -# Unref all devices in the discovered device list.
616 * -# Free the discovered device list.
618 * The order is important - you must not unreference the device before
619 * attempting to open it, because unreferencing it may destroy the device.
621 * For convenience, the libusb_free_device_list() function includes a
622 * parameter to optionally unreference all the devices in the list before
623 * freeing the list itself. This combines steps 3 and 4 above.
625 * As an implementation detail, libusb_open() actually adds a reference to
626 * the device in question. This is because the device remains available
627 * through the handle via libusb_get_device(). The reference is deleted during
631 /** @defgroup libusb_misc Miscellaneous */
633 /* we traverse usbfs without knowing how many devices we are going to find.
634 * so we create this discovered_devs model which is similar to a linked-list
635 * which grows when required. it can be freed once discovery has completed,
636 * eliminating the need for a list node in the libusb_device structure
638 #define DISCOVERED_DEVICES_SIZE_STEP 16
640 static struct discovered_devs *discovered_devs_alloc(void)
642 struct discovered_devs *ret =
643 malloc(sizeof(*ret) + (sizeof(void *) * DISCOVERED_DEVICES_SIZE_STEP));
647 ret->capacity = DISCOVERED_DEVICES_SIZE_STEP;
652 static void discovered_devs_free(struct discovered_devs *discdevs)
656 for (i = 0; i < discdevs->len; i++)
657 libusb_unref_device(discdevs->devices[i]);
662 /* append a device to the discovered devices collection. may realloc itself,
663 * returning new discdevs. returns NULL on realloc failure. */
664 struct discovered_devs *discovered_devs_append(
665 struct discovered_devs *discdevs, struct libusb_device *dev)
667 size_t len = discdevs->len;
669 struct discovered_devs *new_discdevs;
671 /* if there is space, just append the device */
672 if (len < discdevs->capacity) {
673 discdevs->devices[len] = libusb_ref_device(dev);
678 /* exceeded capacity, need to grow */
679 usbi_dbg(DEVICE_CTX(dev), "need to increase capacity");
680 capacity = discdevs->capacity + DISCOVERED_DEVICES_SIZE_STEP;
681 /* can't use usbi_reallocf here because in failure cases it would
682 * free the existing discdevs without unreferencing its devices. */
683 new_discdevs = realloc(discdevs,
684 sizeof(*discdevs) + (sizeof(void *) * capacity));
686 discovered_devs_free(discdevs);
690 discdevs = new_discdevs;
691 discdevs->capacity = capacity;
692 discdevs->devices[len] = libusb_ref_device(dev);
698 /* Allocate a new device with a specific session ID. The returned device has
699 * a reference count of 1. */
700 struct libusb_device *usbi_alloc_device(struct libusb_context *ctx,
701 unsigned long session_id)
703 size_t priv_size = usbi_backend.device_priv_size;
704 struct libusb_device *dev = calloc(1, PTR_ALIGN(sizeof(*dev)) + priv_size);
709 usbi_atomic_store(&dev->refcnt, 1);
712 dev->session_data = session_id;
713 dev->speed = LIBUSB_SPEED_UNKNOWN;
715 if (!libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG))
716 usbi_connect_device(dev);
721 void usbi_connect_device(struct libusb_device *dev)
723 struct libusb_context *ctx = DEVICE_CTX(dev);
725 usbi_atomic_store(&dev->attached, 1);
727 usbi_mutex_lock(&dev->ctx->usb_devs_lock);
728 list_add(&dev->list, &dev->ctx->usb_devs);
729 usbi_mutex_unlock(&dev->ctx->usb_devs_lock);
731 usbi_hotplug_notification(ctx, dev, LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED);
734 void usbi_disconnect_device(struct libusb_device *dev)
736 struct libusb_context *ctx = DEVICE_CTX(dev);
738 usbi_atomic_store(&dev->attached, 0);
740 usbi_mutex_lock(&ctx->usb_devs_lock);
741 list_del(&dev->list);
742 usbi_mutex_unlock(&ctx->usb_devs_lock);
744 usbi_hotplug_notification(ctx, dev, LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT);
747 /* Perform some final sanity checks on a newly discovered device. If this
748 * function fails (negative return code), the device should not be added
749 * to the discovered device list. */
750 int usbi_sanitize_device(struct libusb_device *dev)
752 uint8_t num_configurations;
754 if (dev->device_descriptor.bLength != LIBUSB_DT_DEVICE_SIZE ||
755 dev->device_descriptor.bDescriptorType != LIBUSB_DT_DEVICE) {
756 usbi_err(DEVICE_CTX(dev), "invalid device descriptor");
757 return LIBUSB_ERROR_IO;
760 num_configurations = dev->device_descriptor.bNumConfigurations;
761 if (num_configurations > USB_MAXCONFIG) {
762 usbi_err(DEVICE_CTX(dev), "too many configurations");
763 return LIBUSB_ERROR_IO;
764 } else if (0 == num_configurations) {
765 usbi_dbg(DEVICE_CTX(dev), "zero configurations, maybe an unauthorized device");
771 /* Examine libusb's internal list of known devices, looking for one with
772 * a specific session ID. Returns the matching device if it was found, and
774 struct libusb_device *usbi_get_device_by_session_id(struct libusb_context *ctx,
775 unsigned long session_id)
777 struct libusb_device *dev;
778 struct libusb_device *ret = NULL;
780 usbi_mutex_lock(&ctx->usb_devs_lock);
781 for_each_device(ctx, dev) {
782 if (dev->session_data == session_id) {
783 ret = libusb_ref_device(dev);
787 usbi_mutex_unlock(&ctx->usb_devs_lock);
792 /** @ingroup libusb_dev
793 * Returns a list of USB devices currently attached to the system. This is
794 * your entry point into finding a USB device to operate.
796 * You are expected to unreference all the devices when you are done with
797 * them, and then free the list with libusb_free_device_list(). Note that
798 * libusb_free_device_list() can unref all the devices for you. Be careful
799 * not to unreference a device you are about to open until after you have
802 * This return value of this function indicates the number of devices in
803 * the resultant list. The list is actually one element larger, as it is
806 * \param ctx the context to operate on, or NULL for the default context
807 * \param list output location for a list of devices. Must be later freed with
808 * libusb_free_device_list().
809 * \returns the number of devices in the outputted list, or any
810 * \ref libusb_error according to errors encountered by the backend.
812 ssize_t API_EXPORTED libusb_get_device_list(libusb_context *ctx,
813 libusb_device ***list)
815 struct discovered_devs *discdevs = discovered_devs_alloc();
816 struct libusb_device **ret;
823 return LIBUSB_ERROR_NO_MEM;
825 ctx = usbi_get_context(ctx);
827 if (libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG)) {
828 /* backend provides hotplug support */
829 struct libusb_device *dev;
831 if (usbi_backend.hotplug_poll)
832 usbi_backend.hotplug_poll();
834 usbi_mutex_lock(&ctx->usb_devs_lock);
835 for_each_device(ctx, dev) {
836 discdevs = discovered_devs_append(discdevs, dev);
839 r = LIBUSB_ERROR_NO_MEM;
843 usbi_mutex_unlock(&ctx->usb_devs_lock);
845 /* backend does not provide hotplug support */
846 r = usbi_backend.get_device_list(ctx, &discdevs);
854 /* convert discovered_devs into a list */
855 len = (ssize_t)discdevs->len;
856 ret = calloc((size_t)len + 1, sizeof(struct libusb_device *));
858 len = LIBUSB_ERROR_NO_MEM;
863 for (i = 0; i < len; i++) {
864 struct libusb_device *dev = discdevs->devices[i];
865 ret[i] = libusb_ref_device(dev);
871 discovered_devs_free(discdevs);
875 /** \ingroup libusb_dev
876 * Frees a list of devices previously discovered using
877 * libusb_get_device_list(). If the unref_devices parameter is set, the
878 * reference count of each device in the list is decremented by 1.
879 * \param list the list to free
880 * \param unref_devices whether to unref the devices in the list
882 void API_EXPORTED libusb_free_device_list(libusb_device **list,
890 struct libusb_device *dev;
892 while ((dev = list[i++]) != NULL)
893 libusb_unref_device(dev);
898 /** \ingroup libusb_dev
899 * Get the number of the bus that a device is connected to.
900 * \param dev a device
901 * \returns the bus number
903 uint8_t API_EXPORTED libusb_get_bus_number(libusb_device *dev)
905 return dev->bus_number;
908 /** \ingroup libusb_dev
909 * Get the number of the port that a device is connected to.
910 * Unless the OS does something funky, or you are hot-plugging USB extension cards,
911 * the port number returned by this call is usually guaranteed to be uniquely tied
912 * to a physical port, meaning that different devices plugged on the same physical
913 * port should return the same port number.
915 * But outside of this, there is no guarantee that the port number returned by this
916 * call will remain the same, or even match the order in which ports have been
917 * numbered by the HUB/HCD manufacturer.
919 * \param dev a device
920 * \returns the port number (0 if not available)
922 uint8_t API_EXPORTED libusb_get_port_number(libusb_device *dev)
924 return dev->port_number;
927 /** \ingroup libusb_dev
928 * Get the list of all port numbers from root for the specified device
930 * Since version 1.0.16, \ref LIBUSB_API_VERSION >= 0x01000102
931 * \param dev a device
932 * \param port_numbers the array that should contain the port numbers
933 * \param port_numbers_len the maximum length of the array. As per the USB 3.0
934 * specs, the current maximum limit for the depth is 7.
935 * \returns the number of elements filled
936 * \returns LIBUSB_ERROR_OVERFLOW if the array is too small
938 int API_EXPORTED libusb_get_port_numbers(libusb_device *dev,
939 uint8_t *port_numbers, int port_numbers_len)
941 int i = port_numbers_len;
942 struct libusb_context *ctx = DEVICE_CTX(dev);
944 if (port_numbers_len <= 0)
945 return LIBUSB_ERROR_INVALID_PARAM;
947 // HCDs can be listed as devices with port #0
948 while((dev) && (dev->port_number != 0)) {
950 usbi_warn(ctx, "port numbers array is too small");
951 return LIBUSB_ERROR_OVERFLOW;
953 port_numbers[i] = dev->port_number;
954 dev = dev->parent_dev;
956 if (i < port_numbers_len)
957 memmove(port_numbers, &port_numbers[i], port_numbers_len - i);
958 return port_numbers_len - i;
961 /** \ingroup libusb_dev
962 * \deprecated Please use \ref libusb_get_port_numbers() instead.
964 int API_EXPORTED libusb_get_port_path(libusb_context *ctx, libusb_device *dev,
965 uint8_t *port_numbers, uint8_t port_numbers_len)
969 return libusb_get_port_numbers(dev, port_numbers, port_numbers_len);
972 /** \ingroup libusb_dev
973 * Get the the parent from the specified device.
974 * \param dev a device
975 * \returns the device parent or NULL if not available
976 * You should issue a \ref libusb_get_device_list() before calling this
977 * function and make sure that you only access the parent before issuing
978 * \ref libusb_free_device_list(). The reason is that libusb currently does
979 * not maintain a permanent list of device instances, and therefore can
980 * only guarantee that parents are fully instantiated within a
981 * libusb_get_device_list() - libusb_free_device_list() block.
984 libusb_device * LIBUSB_CALL libusb_get_parent(libusb_device *dev)
986 return dev->parent_dev;
989 /** \ingroup libusb_dev
990 * Get the address of the device on the bus it is connected to.
991 * \param dev a device
992 * \returns the device address
994 uint8_t API_EXPORTED libusb_get_device_address(libusb_device *dev)
996 return dev->device_address;
999 /** \ingroup libusb_dev
1000 * Get the negotiated connection speed for a device.
1001 * \param dev a device
1002 * \returns a \ref libusb_speed code, where LIBUSB_SPEED_UNKNOWN means that
1003 * the OS doesn't know or doesn't support returning the negotiated speed.
1005 int API_EXPORTED libusb_get_device_speed(libusb_device *dev)
1010 static const struct libusb_endpoint_descriptor *find_endpoint(
1011 struct libusb_config_descriptor *config, unsigned char endpoint)
1014 for (iface_idx = 0; iface_idx < config->bNumInterfaces; iface_idx++) {
1015 const struct libusb_interface *iface = &config->interface[iface_idx];
1018 for (altsetting_idx = 0; altsetting_idx < iface->num_altsetting;
1020 const struct libusb_interface_descriptor *altsetting
1021 = &iface->altsetting[altsetting_idx];
1024 for (ep_idx = 0; ep_idx < altsetting->bNumEndpoints; ep_idx++) {
1025 const struct libusb_endpoint_descriptor *ep =
1026 &altsetting->endpoint[ep_idx];
1027 if (ep->bEndpointAddress == endpoint)
1035 /** \ingroup libusb_dev
1036 * Convenience function to retrieve the wMaxPacketSize value for a particular
1037 * endpoint in the active device configuration.
1039 * This function was originally intended to be of assistance when setting up
1040 * isochronous transfers, but a design mistake resulted in this function
1041 * instead. It simply returns the wMaxPacketSize value without considering
1042 * its contents. If you're dealing with isochronous transfers, you probably
1043 * want libusb_get_max_iso_packet_size() instead.
1045 * \param dev a device
1046 * \param endpoint address of the endpoint in question
1047 * \returns the wMaxPacketSize value
1048 * \returns LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist
1049 * \returns LIBUSB_ERROR_OTHER on other failure
1051 int API_EXPORTED libusb_get_max_packet_size(libusb_device *dev,
1052 unsigned char endpoint)
1054 struct libusb_config_descriptor *config;
1055 const struct libusb_endpoint_descriptor *ep;
1058 r = libusb_get_active_config_descriptor(dev, &config);
1060 usbi_err(DEVICE_CTX(dev),
1061 "could not retrieve active config descriptor");
1062 return LIBUSB_ERROR_OTHER;
1065 ep = find_endpoint(config, endpoint);
1067 r = LIBUSB_ERROR_NOT_FOUND;
1071 r = ep->wMaxPacketSize;
1074 libusb_free_config_descriptor(config);
1078 /** \ingroup libusb_dev
1079 * Calculate the maximum packet size which a specific endpoint is capable is
1080 * sending or receiving in the duration of 1 microframe
1082 * Only the active configuration is examined. The calculation is based on the
1083 * wMaxPacketSize field in the endpoint descriptor as described in section
1084 * 9.6.6 in the USB 2.0 specifications.
1086 * If acting on an isochronous or interrupt endpoint, this function will
1087 * multiply the value found in bits 0:10 by the number of transactions per
1088 * microframe (determined by bits 11:12). Otherwise, this function just
1089 * returns the numeric value found in bits 0:10. For USB 3.0 device, it
1090 * will attempts to retrieve the Endpoint Companion Descriptor to return
1091 * wBytesPerInterval.
1093 * This function is useful for setting up isochronous transfers, for example
1094 * you might pass the return value from this function to
1095 * libusb_set_iso_packet_lengths() in order to set the length field of every
1096 * isochronous packet in a transfer.
1100 * \param dev a device
1101 * \param endpoint address of the endpoint in question
1102 * \returns the maximum packet size which can be sent/received on this endpoint
1103 * \returns LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist
1104 * \returns LIBUSB_ERROR_OTHER on other failure
1106 int API_EXPORTED libusb_get_max_iso_packet_size(libusb_device *dev,
1107 unsigned char endpoint)
1109 struct libusb_config_descriptor *config;
1110 const struct libusb_endpoint_descriptor *ep;
1111 struct libusb_ss_endpoint_companion_descriptor *ss_ep_cmp;
1112 enum libusb_endpoint_transfer_type ep_type;
1117 r = libusb_get_active_config_descriptor(dev, &config);
1119 usbi_err(DEVICE_CTX(dev),
1120 "could not retrieve active config descriptor");
1121 return LIBUSB_ERROR_OTHER;
1124 ep = find_endpoint(config, endpoint);
1126 r = LIBUSB_ERROR_NOT_FOUND;
1130 speed = libusb_get_device_speed(dev);
1131 if (speed >= LIBUSB_SPEED_SUPER) {
1132 r = libusb_get_ss_endpoint_companion_descriptor(dev->ctx, ep, &ss_ep_cmp);
1133 if (r == LIBUSB_SUCCESS) {
1134 r = ss_ep_cmp->wBytesPerInterval;
1135 libusb_free_ss_endpoint_companion_descriptor(ss_ep_cmp);
1139 /* If the device isn't a SuperSpeed device or retrieving the SS endpoint didn't worked. */
1140 if (speed < LIBUSB_SPEED_SUPER || r < 0) {
1141 val = ep->wMaxPacketSize;
1142 ep_type = (enum libusb_endpoint_transfer_type) (ep->bmAttributes & 0x3);
1145 if (ep_type == LIBUSB_ENDPOINT_TRANSFER_TYPE_ISOCHRONOUS
1146 || ep_type == LIBUSB_ENDPOINT_TRANSFER_TYPE_INTERRUPT)
1147 r *= (1 + ((val >> 11) & 3));
1151 libusb_free_config_descriptor(config);
1155 /** \ingroup libusb_dev
1156 * Increment the reference count of a device.
1157 * \param dev the device to reference
1158 * \returns the same device
1161 libusb_device * LIBUSB_CALL libusb_ref_device(libusb_device *dev)
1165 refcnt = usbi_atomic_inc(&dev->refcnt);
1166 assert(refcnt >= 2);
1171 /** \ingroup libusb_dev
1172 * Decrement the reference count of a device. If the decrement operation
1173 * causes the reference count to reach zero, the device shall be destroyed.
1174 * \param dev the device to unreference
1176 void API_EXPORTED libusb_unref_device(libusb_device *dev)
1183 refcnt = usbi_atomic_dec(&dev->refcnt);
1184 assert(refcnt >= 0);
1187 usbi_dbg(DEVICE_CTX(dev), "destroy device %d.%d", dev->bus_number, dev->device_address);
1189 libusb_unref_device(dev->parent_dev);
1191 if (usbi_backend.destroy_device)
1192 usbi_backend.destroy_device(dev);
1194 if (!libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG)) {
1195 /* backend does not support hotplug */
1196 usbi_disconnect_device(dev);
1203 /** \ingroup libusb_dev
1204 * Wrap a platform-specific system device handle and obtain a libusb device
1205 * handle for the underlying device. The handle allows you to use libusb to
1206 * perform I/O on the device in question.
1208 * Call libusb_set_option(NULL, LIBUSB_OPTION_NO_DEVICE_DISCOVERY) before
1209 * libusb_init() if you want to skip enumeration of USB devices. In particular,
1210 * this might be needed on Android if you don't have authority to access USB
1211 * devices in general.
1213 * On Linux, the system device handle must be a valid file descriptor opened
1214 * on the device node.
1216 * The system device handle must remain open until libusb_close() is called.
1217 * The system device handle will not be closed by libusb_close().
1219 * Internally, this function creates a temporary device and makes it
1220 * available to you through libusb_get_device(). This device is destroyed
1221 * during libusb_close(). The device shall not be opened through libusb_open().
1223 * This is a non-blocking function; no requests are sent over the bus.
1225 * Since version 1.0.23, \ref LIBUSB_API_VERSION >= 0x01000107
1227 * \param ctx the context to operate on, or NULL for the default context
1228 * \param sys_dev the platform-specific system device handle
1229 * \param dev_handle output location for the returned device handle pointer. Only
1230 * populated when the return code is 0.
1231 * \returns 0 on success
1232 * \returns LIBUSB_ERROR_NO_MEM on memory allocation failure
1233 * \returns LIBUSB_ERROR_ACCESS if the user has insufficient permissions
1234 * \returns LIBUSB_ERROR_NOT_SUPPORTED if the operation is not supported on this
1236 * \returns another LIBUSB_ERROR code on other failure
1238 int API_EXPORTED libusb_wrap_sys_device(libusb_context *ctx, intptr_t sys_dev,
1239 libusb_device_handle **dev_handle)
1241 struct libusb_device_handle *_dev_handle;
1242 size_t priv_size = usbi_backend.device_handle_priv_size;
1245 usbi_dbg(ctx, "wrap_sys_device 0x%" PRIxPTR, (uintptr_t)sys_dev);
1247 ctx = usbi_get_context(ctx);
1249 if (!usbi_backend.wrap_sys_device)
1250 return LIBUSB_ERROR_NOT_SUPPORTED;
1252 _dev_handle = calloc(1, PTR_ALIGN(sizeof(*_dev_handle)) + priv_size);
1254 return LIBUSB_ERROR_NO_MEM;
1256 usbi_mutex_init(&_dev_handle->lock);
1258 r = usbi_backend.wrap_sys_device(ctx, _dev_handle, sys_dev);
1260 usbi_dbg(ctx, "wrap_sys_device 0x%" PRIxPTR " returns %d", (uintptr_t)sys_dev, r);
1261 usbi_mutex_destroy(&_dev_handle->lock);
1266 usbi_mutex_lock(&ctx->open_devs_lock);
1267 list_add(&_dev_handle->list, &ctx->open_devs);
1268 usbi_mutex_unlock(&ctx->open_devs_lock);
1269 *dev_handle = _dev_handle;
1274 /** \ingroup libusb_dev
1275 * Open a device and obtain a device handle. A handle allows you to perform
1276 * I/O on the device in question.
1278 * Internally, this function adds a reference to the device and makes it
1279 * available to you through libusb_get_device(). This reference is removed
1280 * during libusb_close().
1282 * This is a non-blocking function; no requests are sent over the bus.
1284 * \param dev the device to open
1285 * \param dev_handle output location for the returned device handle pointer. Only
1286 * populated when the return code is 0.
1287 * \returns 0 on success
1288 * \returns LIBUSB_ERROR_NO_MEM on memory allocation failure
1289 * \returns LIBUSB_ERROR_ACCESS if the user has insufficient permissions
1290 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1291 * \returns another LIBUSB_ERROR code on other failure
1293 int API_EXPORTED libusb_open(libusb_device *dev,
1294 libusb_device_handle **dev_handle)
1296 struct libusb_context *ctx = DEVICE_CTX(dev);
1297 struct libusb_device_handle *_dev_handle;
1298 size_t priv_size = usbi_backend.device_handle_priv_size;
1301 usbi_dbg(DEVICE_CTX(dev), "open %d.%d", dev->bus_number, dev->device_address);
1303 if (!usbi_atomic_load(&dev->attached))
1304 return LIBUSB_ERROR_NO_DEVICE;
1306 _dev_handle = calloc(1, PTR_ALIGN(sizeof(*_dev_handle)) + priv_size);
1308 return LIBUSB_ERROR_NO_MEM;
1310 usbi_mutex_init(&_dev_handle->lock);
1312 _dev_handle->dev = libusb_ref_device(dev);
1314 r = usbi_backend.open(_dev_handle);
1316 usbi_dbg(DEVICE_CTX(dev), "open %d.%d returns %d", dev->bus_number, dev->device_address, r);
1317 libusb_unref_device(dev);
1318 usbi_mutex_destroy(&_dev_handle->lock);
1323 usbi_mutex_lock(&ctx->open_devs_lock);
1324 list_add(&_dev_handle->list, &ctx->open_devs);
1325 usbi_mutex_unlock(&ctx->open_devs_lock);
1326 *dev_handle = _dev_handle;
1331 /** \ingroup libusb_dev
1332 * Convenience function for finding a device with a particular
1333 * <tt>idVendor</tt>/<tt>idProduct</tt> combination. This function is intended
1334 * for those scenarios where you are using libusb to knock up a quick test
1335 * application - it allows you to avoid calling libusb_get_device_list() and
1336 * worrying about traversing/freeing the list.
1338 * This function has limitations and is hence not intended for use in real
1339 * applications: if multiple devices have the same IDs it will only
1340 * give you the first one, etc.
1342 * \param ctx the context to operate on, or NULL for the default context
1343 * \param vendor_id the idVendor value to search for
1344 * \param product_id the idProduct value to search for
1345 * \returns a device handle for the first found device, or NULL on error
1346 * or if the device could not be found. */
1348 libusb_device_handle * LIBUSB_CALL libusb_open_device_with_vid_pid(
1349 libusb_context *ctx, uint16_t vendor_id, uint16_t product_id)
1351 struct libusb_device **devs;
1352 struct libusb_device *found = NULL;
1353 struct libusb_device *dev;
1354 struct libusb_device_handle *dev_handle = NULL;
1358 if (libusb_get_device_list(ctx, &devs) < 0)
1361 while ((dev = devs[i++]) != NULL) {
1362 struct libusb_device_descriptor desc;
1363 r = libusb_get_device_descriptor(dev, &desc);
1366 if (desc.idVendor == vendor_id && desc.idProduct == product_id) {
1373 r = libusb_open(found, &dev_handle);
1379 libusb_free_device_list(devs, 1);
1383 static void do_close(struct libusb_context *ctx,
1384 struct libusb_device_handle *dev_handle)
1386 struct usbi_transfer *itransfer;
1387 struct usbi_transfer *tmp;
1389 /* remove any transfers in flight that are for this device */
1390 usbi_mutex_lock(&ctx->flying_transfers_lock);
1392 /* safe iteration because transfers may be being deleted */
1393 for_each_transfer_safe(ctx, itransfer, tmp) {
1394 struct libusb_transfer *transfer =
1395 USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
1397 if (transfer->dev_handle != dev_handle)
1400 usbi_mutex_lock(&itransfer->lock);
1401 if (!(itransfer->state_flags & USBI_TRANSFER_DEVICE_DISAPPEARED)) {
1402 usbi_err(ctx, "Device handle closed while transfer was still being processed, but the device is still connected as far as we know");
1404 if (itransfer->state_flags & USBI_TRANSFER_CANCELLING)
1405 usbi_warn(ctx, "A cancellation for an in-flight transfer hasn't completed but closing the device handle");
1407 usbi_err(ctx, "A cancellation hasn't even been scheduled on the transfer for which the device is closing");
1409 usbi_mutex_unlock(&itransfer->lock);
1411 /* remove from the list of in-flight transfers and make sure
1412 * we don't accidentally use the device handle in the future
1413 * (or that such accesses will be easily caught and identified as a crash)
1415 list_del(&itransfer->list);
1416 transfer->dev_handle = NULL;
1418 /* it is up to the user to free up the actual transfer struct. this is
1419 * just making sure that we don't attempt to process the transfer after
1420 * the device handle is invalid
1422 usbi_dbg(ctx, "Removed transfer %p from the in-flight list because device handle %p closed",
1423 transfer, dev_handle);
1425 usbi_mutex_unlock(&ctx->flying_transfers_lock);
1427 usbi_mutex_lock(&ctx->open_devs_lock);
1428 list_del(&dev_handle->list);
1429 usbi_mutex_unlock(&ctx->open_devs_lock);
1431 usbi_backend.close(dev_handle);
1432 libusb_unref_device(dev_handle->dev);
1433 usbi_mutex_destroy(&dev_handle->lock);
1437 /** \ingroup libusb_dev
1438 * Close a device handle. Should be called on all open handles before your
1439 * application exits.
1441 * Internally, this function destroys the reference that was added by
1442 * libusb_open() on the given device.
1444 * This is a non-blocking function; no requests are sent over the bus.
1446 * \param dev_handle the device handle to close
1448 void API_EXPORTED libusb_close(libusb_device_handle *dev_handle)
1450 struct libusb_context *ctx;
1451 unsigned int event_flags;
1452 int handling_events;
1456 ctx = HANDLE_CTX(dev_handle);
1459 handling_events = usbi_handling_events(ctx);
1461 /* Similarly to libusb_open(), we want to interrupt all event handlers
1462 * at this point. More importantly, we want to perform the actual close of
1463 * the device while holding the event handling lock (preventing any other
1464 * thread from doing event handling) because we will be removing a file
1465 * descriptor from the polling loop. If this is being called by the current
1466 * event handler, we can bypass the interruption code because we already
1467 * hold the event handling lock. */
1469 if (!handling_events) {
1470 /* Record that we are closing a device.
1471 * Only signal an event if there are no prior pending events. */
1472 usbi_mutex_lock(&ctx->event_data_lock);
1473 event_flags = ctx->event_flags;
1474 if (!ctx->device_close++)
1475 ctx->event_flags |= USBI_EVENT_DEVICE_CLOSE;
1477 usbi_signal_event(&ctx->event);
1478 usbi_mutex_unlock(&ctx->event_data_lock);
1480 /* take event handling lock */
1481 libusb_lock_events(ctx);
1484 /* Close the device */
1485 do_close(ctx, dev_handle);
1487 if (!handling_events) {
1488 /* We're done with closing this device.
1489 * Clear the event pipe if there are no further pending events. */
1490 usbi_mutex_lock(&ctx->event_data_lock);
1491 if (!--ctx->device_close)
1492 ctx->event_flags &= ~USBI_EVENT_DEVICE_CLOSE;
1493 if (!ctx->event_flags)
1494 usbi_clear_event(&ctx->event);
1495 usbi_mutex_unlock(&ctx->event_data_lock);
1497 /* Release event handling lock and wake up event waiters */
1498 libusb_unlock_events(ctx);
1502 /** \ingroup libusb_dev
1503 * Get the underlying device for a device handle. This function does not modify
1504 * the reference count of the returned device, so do not feel compelled to
1505 * unreference it when you are done.
1506 * \param dev_handle a device handle
1507 * \returns the underlying device
1510 libusb_device * LIBUSB_CALL libusb_get_device(libusb_device_handle *dev_handle)
1512 return dev_handle->dev;
1515 /** \ingroup libusb_dev
1516 * Determine the bConfigurationValue of the currently active configuration.
1518 * You could formulate your own control request to obtain this information,
1519 * but this function has the advantage that it may be able to retrieve the
1520 * information from operating system caches (no I/O involved).
1522 * If the OS does not cache this information, then this function will block
1523 * while a control transfer is submitted to retrieve the information.
1525 * This function will return a value of 0 in the <tt>config</tt> output
1526 * parameter if the device is in unconfigured state.
1528 * \param dev_handle a device handle
1529 * \param config output location for the bConfigurationValue of the active
1530 * configuration (only valid for return code 0)
1531 * \returns 0 on success
1532 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1533 * \returns another LIBUSB_ERROR code on other failure
1535 int API_EXPORTED libusb_get_configuration(libusb_device_handle *dev_handle,
1538 int r = LIBUSB_ERROR_NOT_SUPPORTED;
1540 struct libusb_context *ctx = HANDLE_CTX(dev_handle);
1543 if (usbi_backend.get_configuration)
1544 r = usbi_backend.get_configuration(dev_handle, &tmp);
1546 if (r == LIBUSB_ERROR_NOT_SUPPORTED) {
1547 usbi_dbg(ctx, "falling back to control message");
1548 r = libusb_control_transfer(dev_handle, LIBUSB_ENDPOINT_IN,
1549 LIBUSB_REQUEST_GET_CONFIGURATION, 0, 0, &tmp, 1, 1000);
1552 } else if (r == 0) {
1553 usbi_err(ctx, "zero bytes returned in ctrl transfer?");
1554 r = LIBUSB_ERROR_IO;
1556 usbi_dbg(ctx, "control failed, error %d", r);
1561 usbi_dbg(ctx, "active config %u", tmp);
1568 /** \ingroup libusb_dev
1569 * Set the active configuration for a device.
1571 * The operating system may or may not have already set an active
1572 * configuration on the device. It is up to your application to ensure the
1573 * correct configuration is selected before you attempt to claim interfaces
1574 * and perform other operations.
1576 * If you call this function on a device already configured with the selected
1577 * configuration, then this function will act as a lightweight device reset:
1578 * it will issue a SET_CONFIGURATION request using the current configuration,
1579 * causing most USB-related device state to be reset (altsetting reset to zero,
1580 * endpoint halts cleared, toggles reset).
1582 * Not all backends support setting the configuration from user space, which
1583 * will be indicated by the return code LIBUSB_ERROR_NOT_SUPPORTED. As this
1584 * suggests that the platform is handling the device configuration itself,
1585 * this error should generally be safe to ignore.
1587 * You cannot change/reset configuration if your application has claimed
1588 * interfaces. It is advised to set the desired configuration before claiming
1591 * Alternatively you can call libusb_release_interface() first. Note if you
1592 * do things this way you must ensure that auto_detach_kernel_driver for
1593 * <tt>dev</tt> is 0, otherwise the kernel driver will be re-attached when you
1594 * release the interface(s).
1596 * You cannot change/reset configuration if other applications or drivers have
1597 * claimed interfaces.
1599 * A configuration value of -1 will put the device in unconfigured state.
1600 * The USB specifications state that a configuration value of 0 does this,
1601 * however buggy devices exist which actually have a configuration 0.
1603 * You should always use this function rather than formulating your own
1604 * SET_CONFIGURATION control request. This is because the underlying operating
1605 * system needs to know when such changes happen.
1607 * This is a blocking function.
1609 * \param dev_handle a device handle
1610 * \param configuration the bConfigurationValue of the configuration you
1611 * wish to activate, or -1 if you wish to put the device in an unconfigured
1613 * \returns 0 on success
1614 * \returns LIBUSB_ERROR_NOT_FOUND if the requested configuration does not exist
1615 * \returns LIBUSB_ERROR_BUSY if interfaces are currently claimed
1616 * \returns LIBUSB_ERROR_NOT_SUPPORTED if setting or changing the configuration
1617 * is not supported by the backend
1618 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1619 * \returns another LIBUSB_ERROR code on other failure
1620 * \see libusb_set_auto_detach_kernel_driver()
1622 int API_EXPORTED libusb_set_configuration(libusb_device_handle *dev_handle,
1625 usbi_dbg(HANDLE_CTX(dev_handle), "configuration %d", configuration);
1626 if (configuration < -1 || configuration > (int)UINT8_MAX)
1627 return LIBUSB_ERROR_INVALID_PARAM;
1628 return usbi_backend.set_configuration(dev_handle, configuration);
1631 /** \ingroup libusb_dev
1632 * Claim an interface on a given device handle. You must claim the interface
1633 * you wish to use before you can perform I/O on any of its endpoints.
1635 * It is legal to attempt to claim an already-claimed interface, in which
1636 * case libusb just returns 0 without doing anything.
1638 * If auto_detach_kernel_driver is set to 1 for <tt>dev</tt>, the kernel driver
1639 * will be detached if necessary, on failure the detach error is returned.
1641 * Claiming of interfaces is a purely logical operation; it does not cause
1642 * any requests to be sent over the bus. Interface claiming is used to
1643 * instruct the underlying operating system that your application wishes
1644 * to take ownership of the interface.
1646 * This is a non-blocking function.
1648 * \param dev_handle a device handle
1649 * \param interface_number the <tt>bInterfaceNumber</tt> of the interface you
1651 * \returns 0 on success
1652 * \returns LIBUSB_ERROR_NOT_FOUND if the requested interface does not exist
1653 * \returns LIBUSB_ERROR_BUSY if another program or driver has claimed the
1655 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1656 * \returns a LIBUSB_ERROR code on other failure
1657 * \see libusb_set_auto_detach_kernel_driver()
1659 int API_EXPORTED libusb_claim_interface(libusb_device_handle *dev_handle,
1660 int interface_number)
1664 usbi_dbg(HANDLE_CTX(dev_handle), "interface %d", interface_number);
1665 if (interface_number < 0 || interface_number >= USB_MAXINTERFACES)
1666 return LIBUSB_ERROR_INVALID_PARAM;
1668 if (!usbi_atomic_load(&dev_handle->dev->attached))
1669 return LIBUSB_ERROR_NO_DEVICE;
1671 usbi_mutex_lock(&dev_handle->lock);
1672 if (dev_handle->claimed_interfaces & (1U << interface_number))
1675 r = usbi_backend.claim_interface(dev_handle, (uint8_t)interface_number);
1677 dev_handle->claimed_interfaces |= 1U << interface_number;
1680 usbi_mutex_unlock(&dev_handle->lock);
1684 /** \ingroup libusb_dev
1685 * Release an interface previously claimed with libusb_claim_interface(). You
1686 * should release all claimed interfaces before closing a device handle.
1688 * This is a blocking function. A SET_INTERFACE control request will be sent
1689 * to the device, resetting interface state to the first alternate setting.
1691 * If auto_detach_kernel_driver is set to 1 for <tt>dev</tt>, the kernel
1692 * driver will be re-attached after releasing the interface.
1694 * \param dev_handle a device handle
1695 * \param interface_number the <tt>bInterfaceNumber</tt> of the
1696 * previously-claimed interface
1697 * \returns 0 on success
1698 * \returns LIBUSB_ERROR_NOT_FOUND if the interface was not claimed
1699 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1700 * \returns another LIBUSB_ERROR code on other failure
1701 * \see libusb_set_auto_detach_kernel_driver()
1703 int API_EXPORTED libusb_release_interface(libusb_device_handle *dev_handle,
1704 int interface_number)
1708 usbi_dbg(HANDLE_CTX(dev_handle), "interface %d", interface_number);
1709 if (interface_number < 0 || interface_number >= USB_MAXINTERFACES)
1710 return LIBUSB_ERROR_INVALID_PARAM;
1712 usbi_mutex_lock(&dev_handle->lock);
1713 if (!(dev_handle->claimed_interfaces & (1U << interface_number))) {
1714 r = LIBUSB_ERROR_NOT_FOUND;
1718 r = usbi_backend.release_interface(dev_handle, (uint8_t)interface_number);
1720 dev_handle->claimed_interfaces &= ~(1U << interface_number);
1723 usbi_mutex_unlock(&dev_handle->lock);
1727 /** \ingroup libusb_dev
1728 * Activate an alternate setting for an interface. The interface must have
1729 * been previously claimed with libusb_claim_interface().
1731 * You should always use this function rather than formulating your own
1732 * SET_INTERFACE control request. This is because the underlying operating
1733 * system needs to know when such changes happen.
1735 * This is a blocking function.
1737 * \param dev_handle a device handle
1738 * \param interface_number the <tt>bInterfaceNumber</tt> of the
1739 * previously-claimed interface
1740 * \param alternate_setting the <tt>bAlternateSetting</tt> of the alternate
1741 * setting to activate
1742 * \returns 0 on success
1743 * \returns LIBUSB_ERROR_NOT_FOUND if the interface was not claimed, or the
1744 * requested alternate setting does not exist
1745 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1746 * \returns another LIBUSB_ERROR code on other failure
1748 int API_EXPORTED libusb_set_interface_alt_setting(libusb_device_handle *dev_handle,
1749 int interface_number, int alternate_setting)
1751 usbi_dbg(HANDLE_CTX(dev_handle), "interface %d altsetting %d",
1752 interface_number, alternate_setting);
1753 if (interface_number < 0 || interface_number >= USB_MAXINTERFACES)
1754 return LIBUSB_ERROR_INVALID_PARAM;
1755 if (alternate_setting < 0 || alternate_setting > (int)UINT8_MAX)
1756 return LIBUSB_ERROR_INVALID_PARAM;
1758 if (!usbi_atomic_load(&dev_handle->dev->attached)) {
1759 usbi_mutex_unlock(&dev_handle->lock);
1760 return LIBUSB_ERROR_NO_DEVICE;
1763 usbi_mutex_lock(&dev_handle->lock);
1764 if (!(dev_handle->claimed_interfaces & (1U << interface_number))) {
1765 usbi_mutex_unlock(&dev_handle->lock);
1766 return LIBUSB_ERROR_NOT_FOUND;
1768 usbi_mutex_unlock(&dev_handle->lock);
1770 return usbi_backend.set_interface_altsetting(dev_handle,
1771 (uint8_t)interface_number, (uint8_t)alternate_setting);
1774 /** \ingroup libusb_dev
1775 * Clear the halt/stall condition for an endpoint. Endpoints with halt status
1776 * are unable to receive or transmit data until the halt condition is stalled.
1778 * You should cancel all pending transfers before attempting to clear the halt
1781 * This is a blocking function.
1783 * \param dev_handle a device handle
1784 * \param endpoint the endpoint to clear halt status
1785 * \returns 0 on success
1786 * \returns LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist
1787 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1788 * \returns another LIBUSB_ERROR code on other failure
1790 int API_EXPORTED libusb_clear_halt(libusb_device_handle *dev_handle,
1791 unsigned char endpoint)
1793 usbi_dbg(HANDLE_CTX(dev_handle), "endpoint 0x%x", endpoint);
1794 if (!usbi_atomic_load(&dev_handle->dev->attached))
1795 return LIBUSB_ERROR_NO_DEVICE;
1797 return usbi_backend.clear_halt(dev_handle, endpoint);
1800 /** \ingroup libusb_dev
1801 * Perform a USB port reset to reinitialize a device. The system will attempt
1802 * to restore the previous configuration and alternate settings after the
1803 * reset has completed.
1805 * If the reset fails, the descriptors change, or the previous state cannot be
1806 * restored, the device will appear to be disconnected and reconnected. This
1807 * means that the device handle is no longer valid (you should close it) and
1808 * rediscover the device. A return code of LIBUSB_ERROR_NOT_FOUND indicates
1809 * when this is the case.
1811 * This is a blocking function which usually incurs a noticeable delay.
1813 * \param dev_handle a handle of the device to reset
1814 * \returns 0 on success
1815 * \returns LIBUSB_ERROR_NOT_FOUND if re-enumeration is required, or if the
1816 * device has been disconnected
1817 * \returns another LIBUSB_ERROR code on other failure
1819 int API_EXPORTED libusb_reset_device(libusb_device_handle *dev_handle)
1821 usbi_dbg(HANDLE_CTX(dev_handle), " ");
1822 if (!usbi_atomic_load(&dev_handle->dev->attached))
1823 return LIBUSB_ERROR_NO_DEVICE;
1825 if (usbi_backend.reset_device)
1826 return usbi_backend.reset_device(dev_handle);
1828 return LIBUSB_ERROR_NOT_SUPPORTED;
1831 /** \ingroup libusb_asyncio
1832 * Allocate up to num_streams usb bulk streams on the specified endpoints. This
1833 * function takes an array of endpoints rather then a single endpoint because
1834 * some protocols require that endpoints are setup with similar stream ids.
1835 * All endpoints passed in must belong to the same interface.
1837 * Note this function may return less streams then requested. Also note that the
1838 * same number of streams are allocated for each endpoint in the endpoint array.
1840 * Stream id 0 is reserved, and should not be used to communicate with devices.
1841 * If libusb_alloc_streams() returns with a value of N, you may use stream ids
1844 * Since version 1.0.19, \ref LIBUSB_API_VERSION >= 0x01000103
1846 * \param dev_handle a device handle
1847 * \param num_streams number of streams to try to allocate
1848 * \param endpoints array of endpoints to allocate streams on
1849 * \param num_endpoints length of the endpoints array
1850 * \returns number of streams allocated, or a LIBUSB_ERROR code on failure
1852 int API_EXPORTED libusb_alloc_streams(libusb_device_handle *dev_handle,
1853 uint32_t num_streams, unsigned char *endpoints, int num_endpoints)
1855 usbi_dbg(HANDLE_CTX(dev_handle), "streams %u eps %d", (unsigned)num_streams, num_endpoints);
1857 if (!num_streams || !endpoints || num_endpoints <= 0)
1858 return LIBUSB_ERROR_INVALID_PARAM;
1860 if (!usbi_atomic_load(&dev_handle->dev->attached))
1861 return LIBUSB_ERROR_NO_DEVICE;
1863 if (usbi_backend.alloc_streams)
1864 return usbi_backend.alloc_streams(dev_handle, num_streams, endpoints,
1867 return LIBUSB_ERROR_NOT_SUPPORTED;
1870 /** \ingroup libusb_asyncio
1871 * Free usb bulk streams allocated with libusb_alloc_streams().
1873 * Note streams are automatically free-ed when releasing an interface.
1875 * Since version 1.0.19, \ref LIBUSB_API_VERSION >= 0x01000103
1877 * \param dev_handle a device handle
1878 * \param endpoints array of endpoints to free streams on
1879 * \param num_endpoints length of the endpoints array
1880 * \returns LIBUSB_SUCCESS, or a LIBUSB_ERROR code on failure
1882 int API_EXPORTED libusb_free_streams(libusb_device_handle *dev_handle,
1883 unsigned char *endpoints, int num_endpoints)
1885 usbi_dbg(HANDLE_CTX(dev_handle), "eps %d", num_endpoints);
1887 if (!endpoints || num_endpoints <= 0)
1888 return LIBUSB_ERROR_INVALID_PARAM;
1890 if (!usbi_atomic_load(&dev_handle->dev->attached))
1891 return LIBUSB_ERROR_NO_DEVICE;
1893 if (usbi_backend.free_streams)
1894 return usbi_backend.free_streams(dev_handle, endpoints,
1897 return LIBUSB_ERROR_NOT_SUPPORTED;
1900 /** \ingroup libusb_asyncio
1901 * Attempts to allocate a block of persistent DMA memory suitable for transfers
1902 * against the given device. If successful, will return a block of memory
1903 * that is suitable for use as "buffer" in \ref libusb_transfer against this
1904 * device. Using this memory instead of regular memory means that the host
1905 * controller can use DMA directly into the buffer to increase performance, and
1906 * also that transfers can no longer fail due to kernel memory fragmentation.
1908 * Note that this means you should not modify this memory (or even data on
1909 * the same cache lines) when a transfer is in progress, although it is legal
1910 * to have several transfers going on within the same memory block.
1912 * Will return NULL on failure. Many systems do not support such zero-copy
1913 * and will always return NULL. Memory allocated with this function must be
1914 * freed with \ref libusb_dev_mem_free. Specifically, this means that the
1915 * flag \ref LIBUSB_TRANSFER_FREE_BUFFER cannot be used to free memory allocated
1916 * with this function.
1918 * Since version 1.0.21, \ref LIBUSB_API_VERSION >= 0x01000105
1920 * \param dev_handle a device handle
1921 * \param length size of desired data buffer
1922 * \returns a pointer to the newly allocated memory, or NULL on failure
1925 unsigned char * LIBUSB_CALL libusb_dev_mem_alloc(libusb_device_handle *dev_handle,
1928 if (!usbi_atomic_load(&dev_handle->dev->attached))
1931 if (usbi_backend.dev_mem_alloc)
1932 return usbi_backend.dev_mem_alloc(dev_handle, length);
1937 /** \ingroup libusb_asyncio
1938 * Free device memory allocated with libusb_dev_mem_alloc().
1940 * \param dev_handle a device handle
1941 * \param buffer pointer to the previously allocated memory
1942 * \param length size of previously allocated memory
1943 * \returns LIBUSB_SUCCESS, or a LIBUSB_ERROR code on failure
1945 int API_EXPORTED libusb_dev_mem_free(libusb_device_handle *dev_handle,
1946 unsigned char *buffer, size_t length)
1948 if (usbi_backend.dev_mem_free)
1949 return usbi_backend.dev_mem_free(dev_handle, buffer, length);
1951 return LIBUSB_ERROR_NOT_SUPPORTED;
1954 /** \ingroup libusb_dev
1955 * Determine if a kernel driver is active on an interface. If a kernel driver
1956 * is active, you cannot claim the interface, and libusb will be unable to
1959 * This functionality is not available on Windows.
1961 * \param dev_handle a device handle
1962 * \param interface_number the interface to check
1963 * \returns 0 if no kernel driver is active
1964 * \returns 1 if a kernel driver is active
1965 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1966 * \returns LIBUSB_ERROR_NOT_SUPPORTED on platforms where the functionality
1968 * \returns another LIBUSB_ERROR code on other failure
1969 * \see libusb_detach_kernel_driver()
1971 int API_EXPORTED libusb_kernel_driver_active(libusb_device_handle *dev_handle,
1972 int interface_number)
1974 usbi_dbg(HANDLE_CTX(dev_handle), "interface %d", interface_number);
1976 if (interface_number < 0 || interface_number >= USB_MAXINTERFACES)
1977 return LIBUSB_ERROR_INVALID_PARAM;
1979 if (!usbi_atomic_load(&dev_handle->dev->attached))
1980 return LIBUSB_ERROR_NO_DEVICE;
1982 if (usbi_backend.kernel_driver_active)
1983 return usbi_backend.kernel_driver_active(dev_handle, (uint8_t)interface_number);
1985 return LIBUSB_ERROR_NOT_SUPPORTED;
1988 /** \ingroup libusb_dev
1989 * Detach a kernel driver from an interface. If successful, you will then be
1990 * able to claim the interface and perform I/O.
1992 * This functionality is not available on Windows.
1994 * Note that libusb itself also talks to the device through a special kernel
1995 * driver, if this driver is already attached to the device, this call will
1996 * not detach it and return LIBUSB_ERROR_NOT_FOUND.
1998 * \param dev_handle a device handle
1999 * \param interface_number the interface to detach the driver from
2000 * \returns 0 on success
2001 * \returns LIBUSB_ERROR_NOT_FOUND if no kernel driver was active
2002 * \returns LIBUSB_ERROR_INVALID_PARAM if the interface does not exist
2003 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
2004 * \returns LIBUSB_ERROR_NOT_SUPPORTED on platforms where the functionality
2006 * \returns another LIBUSB_ERROR code on other failure
2007 * \see libusb_kernel_driver_active()
2009 int API_EXPORTED libusb_detach_kernel_driver(libusb_device_handle *dev_handle,
2010 int interface_number)
2012 usbi_dbg(HANDLE_CTX(dev_handle), "interface %d", interface_number);
2014 if (interface_number < 0 || interface_number >= USB_MAXINTERFACES)
2015 return LIBUSB_ERROR_INVALID_PARAM;
2017 if (!usbi_atomic_load(&dev_handle->dev->attached))
2018 return LIBUSB_ERROR_NO_DEVICE;
2020 if (usbi_backend.detach_kernel_driver)
2021 return usbi_backend.detach_kernel_driver(dev_handle, (uint8_t)interface_number);
2023 return LIBUSB_ERROR_NOT_SUPPORTED;
2026 /** \ingroup libusb_dev
2027 * Re-attach an interface's kernel driver, which was previously detached
2028 * using libusb_detach_kernel_driver().
2030 * This functionality is not available on Windows.
2032 * \param dev_handle a device handle
2033 * \param interface_number the interface to attach the driver from
2034 * \returns 0 on success
2035 * \returns LIBUSB_ERROR_NOT_FOUND if no kernel driver was active
2036 * \returns LIBUSB_ERROR_INVALID_PARAM if the interface does not exist
2037 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
2038 * \returns LIBUSB_ERROR_NOT_SUPPORTED on platforms where the functionality
2040 * \returns LIBUSB_ERROR_BUSY if the driver cannot be attached because the
2041 * interface is claimed by a program or driver
2042 * \returns another LIBUSB_ERROR code on other failure
2043 * \see libusb_kernel_driver_active()
2045 int API_EXPORTED libusb_attach_kernel_driver(libusb_device_handle *dev_handle,
2046 int interface_number)
2048 usbi_dbg(HANDLE_CTX(dev_handle), "interface %d", interface_number);
2050 if (interface_number < 0 || interface_number >= USB_MAXINTERFACES)
2051 return LIBUSB_ERROR_INVALID_PARAM;
2053 if (!usbi_atomic_load(&dev_handle->dev->attached))
2054 return LIBUSB_ERROR_NO_DEVICE;
2056 if (usbi_backend.attach_kernel_driver)
2057 return usbi_backend.attach_kernel_driver(dev_handle, (uint8_t)interface_number);
2059 return LIBUSB_ERROR_NOT_SUPPORTED;
2062 /** \ingroup libusb_dev
2063 * Enable/disable libusb's automatic kernel driver detachment. When this is
2064 * enabled libusb will automatically detach the kernel driver on an interface
2065 * when claiming the interface, and attach it when releasing the interface.
2067 * Automatic kernel driver detachment is disabled on newly opened device
2068 * handles by default.
2070 * On platforms which do not have LIBUSB_CAP_SUPPORTS_DETACH_KERNEL_DRIVER
2071 * this function will return LIBUSB_ERROR_NOT_SUPPORTED, and libusb will
2072 * continue as if this function was never called.
2074 * \param dev_handle a device handle
2075 * \param enable whether to enable or disable auto kernel driver detachment
2077 * \returns LIBUSB_SUCCESS on success
2078 * \returns LIBUSB_ERROR_NOT_SUPPORTED on platforms where the functionality
2080 * \see libusb_claim_interface()
2081 * \see libusb_release_interface()
2082 * \see libusb_set_configuration()
2084 int API_EXPORTED libusb_set_auto_detach_kernel_driver(
2085 libusb_device_handle *dev_handle, int enable)
2087 if (!(usbi_backend.caps & USBI_CAP_SUPPORTS_DETACH_KERNEL_DRIVER))
2088 return LIBUSB_ERROR_NOT_SUPPORTED;
2090 dev_handle->auto_detach_kernel_driver = enable;
2091 return LIBUSB_SUCCESS;
2094 /** \ingroup libusb_lib
2095 * \deprecated Use libusb_set_option() instead using the
2096 * \ref LIBUSB_OPTION_LOG_LEVEL option.
2098 void API_EXPORTED libusb_set_debug(libusb_context *ctx, int level)
2100 #if defined(ENABLE_LOGGING) && !defined(ENABLE_DEBUG_LOGGING)
2101 ctx = usbi_get_context(ctx);
2102 if (!ctx->debug_fixed) {
2103 level = CLAMP(level, LIBUSB_LOG_LEVEL_NONE, LIBUSB_LOG_LEVEL_DEBUG);
2104 ctx->debug = (enum libusb_log_level)level;
2112 /** \ingroup libusb_lib
2115 * libusb will redirect its log messages to the provided callback function.
2116 * libusb supports redirection of per context and global log messages.
2117 * Log messages sent to the context will be sent to the global log handler too.
2119 * If libusb is compiled without message logging or USE_SYSTEM_LOGGING_FACILITY
2120 * is defined then global callback function will never be called.
2121 * If ENABLE_DEBUG_LOGGING is defined then per context callback function will
2124 * Since version 1.0.23, \ref LIBUSB_API_VERSION >= 0x01000107
2126 * \param ctx context on which to assign log handler, or NULL for the default
2127 * context. Parameter ignored if only LIBUSB_LOG_CB_GLOBAL mode is requested.
2128 * \param cb pointer to the callback function, or NULL to stop log
2129 * messages redirection
2130 * \param mode mode of callback function operation. Several modes can be
2131 * selected for a single callback function, see \ref libusb_log_cb_mode for
2133 * \see libusb_log_cb, libusb_log_cb_mode
2135 void API_EXPORTED libusb_set_log_cb(libusb_context *ctx, libusb_log_cb cb,
2138 #if defined(ENABLE_LOGGING) && (!defined(ENABLE_DEBUG_LOGGING) || !defined(USE_SYSTEM_LOGGING_FACILITY))
2139 #if !defined(USE_SYSTEM_LOGGING_FACILITY)
2140 if (mode & LIBUSB_LOG_CB_GLOBAL)
2143 #if !defined(ENABLE_DEBUG_LOGGING)
2144 if (mode & LIBUSB_LOG_CB_CONTEXT) {
2145 ctx = usbi_get_context(ctx);
2146 ctx->log_handler = cb;
2158 /** \ingroup libusb_lib
2159 * Set an option in the library.
2161 * Use this function to configure a specific option within the library.
2163 * Some options require one or more arguments to be provided. Consult each
2164 * option's documentation for specific requirements.
2166 * Since version 1.0.22, \ref LIBUSB_API_VERSION >= 0x01000106
2168 * \param ctx context on which to operate
2169 * \param option which option to set
2170 * \param ... any required arguments for the specified option
2172 * \returns LIBUSB_SUCCESS on success
2173 * \returns LIBUSB_ERROR_INVALID_PARAM if the option or arguments are invalid
2174 * \returns LIBUSB_ERROR_NOT_SUPPORTED if the option is valid but not supported
2176 * \returns LIBUSB_ERROR_NOT_FOUND if LIBUSB_OPTION_USE_USBDK is valid on this platform but UsbDk is not available
2178 int API_EXPORTED libusb_set_option(libusb_context *ctx,
2179 enum libusb_option option, ...)
2181 int arg = 0, r = LIBUSB_SUCCESS;
2184 va_start(ap, option);
2185 if (LIBUSB_OPTION_LOG_LEVEL == option) {
2186 arg = va_arg(ap, int);
2187 if (arg < LIBUSB_LOG_LEVEL_NONE || arg > LIBUSB_LOG_LEVEL_DEBUG) {
2188 r = LIBUSB_ERROR_INVALID_PARAM;
2193 if (LIBUSB_SUCCESS != r) {
2197 if (option >= LIBUSB_OPTION_MAX) {
2198 return LIBUSB_ERROR_INVALID_PARAM;
2202 usbi_mutex_static_lock(&default_context_lock);
2203 default_context_options[option].is_set = 1;
2204 if (LIBUSB_OPTION_LOG_LEVEL == option) {
2205 default_context_options[option].arg.ival = arg;
2207 usbi_mutex_static_unlock(&default_context_lock);
2210 ctx = usbi_get_context(ctx);
2212 return LIBUSB_SUCCESS;
2216 case LIBUSB_OPTION_LOG_LEVEL:
2217 #if defined(ENABLE_LOGGING) && !defined(ENABLE_DEBUG_LOGGING)
2218 if (!ctx->debug_fixed)
2219 ctx->debug = (enum libusb_log_level)arg;
2223 /* Handle all backend-specific options here */
2224 case LIBUSB_OPTION_USE_USBDK:
2225 case LIBUSB_OPTION_NO_DEVICE_DISCOVERY:
2226 case LIBUSB_OPTION_WEAK_AUTHORITY:
2227 if (usbi_backend.set_option)
2228 return usbi_backend.set_option(ctx, option, ap);
2230 return LIBUSB_ERROR_NOT_SUPPORTED;
2233 case LIBUSB_OPTION_MAX:
2235 return LIBUSB_ERROR_INVALID_PARAM;
2238 return LIBUSB_SUCCESS;;
2241 #if defined(ENABLE_LOGGING) && !defined(ENABLE_DEBUG_LOGGING)
2242 /* returns the log level as defined in the LIBUSB_DEBUG environment variable.
2243 * if LIBUSB_DEBUG is not present or not a number, returns LIBUSB_LOG_LEVEL_NONE.
2244 * value is clamped to ensure it is within the valid range of possibilities.
2246 static enum libusb_log_level get_env_debug_level(void)
2248 const char *dbg = getenv("LIBUSB_DEBUG");
2249 enum libusb_log_level level;
2251 int dbg_level = atoi(dbg);
2252 dbg_level = CLAMP(dbg_level, LIBUSB_LOG_LEVEL_NONE, LIBUSB_LOG_LEVEL_DEBUG);
2253 level = (enum libusb_log_level)dbg_level;
2255 level = LIBUSB_LOG_LEVEL_NONE;
2261 /** \ingroup libusb_lib
2262 * Initialize libusb. This function must be called before calling any other
2265 * If you do not provide an output location for a context pointer, a default
2266 * context will be created. If there was already a default context, it will
2267 * be reused (and nothing will be initialized/reinitialized).
2269 * \param ctx Optional output location for context pointer.
2270 * Only valid on return code 0.
2271 * \returns 0 on success, or a LIBUSB_ERROR code on failure
2272 * \see libusb_contexts
2274 int API_EXPORTED libusb_init(libusb_context **ctx)
2276 size_t priv_size = usbi_backend.context_priv_size;
2277 struct libusb_context *_ctx;
2280 usbi_mutex_static_lock(&default_context_lock);
2282 if (!ctx && usbi_default_context) {
2283 usbi_dbg(usbi_default_context, "reusing default context");
2284 default_context_refcnt++;
2285 usbi_mutex_static_unlock(&default_context_lock);
2289 /* check for first init */
2290 if (!active_contexts_list.next) {
2291 list_init(&active_contexts_list);
2292 usbi_get_monotonic_time(×tamp_origin);
2295 _ctx = calloc(1, PTR_ALIGN(sizeof(*_ctx)) + priv_size);
2297 usbi_mutex_static_unlock(&default_context_lock);
2298 return LIBUSB_ERROR_NO_MEM;
2301 #if defined(ENABLE_LOGGING) && !defined(ENABLE_DEBUG_LOGGING)
2302 if (NULL == ctx && default_context_options[LIBUSB_OPTION_LOG_LEVEL].is_set) {
2303 _ctx->debug = default_context_options[LIBUSB_OPTION_LOG_LEVEL].arg.ival;
2305 _ctx->debug = get_env_debug_level();
2307 if (_ctx->debug != LIBUSB_LOG_LEVEL_NONE)
2308 _ctx->debug_fixed = 1;
2311 usbi_mutex_init(&_ctx->usb_devs_lock);
2312 usbi_mutex_init(&_ctx->open_devs_lock);
2313 list_init(&_ctx->usb_devs);
2314 list_init(&_ctx->open_devs);
2316 /* default context should be initialized before calling usbi_dbg */
2318 usbi_default_context = _ctx;
2319 default_context_refcnt = 1;
2320 usbi_dbg(usbi_default_context, "created default context");
2322 for (enum libusb_option option = 0 ; option < LIBUSB_OPTION_MAX ; option++) {
2323 if (LIBUSB_OPTION_LOG_LEVEL == option || !default_context_options[option].is_set) {
2326 r = libusb_set_option(_ctx, option);
2327 if (LIBUSB_SUCCESS != r)
2332 usbi_dbg(_ctx, "libusb v%u.%u.%u.%u%s", libusb_version_internal.major, libusb_version_internal.minor,
2333 libusb_version_internal.micro, libusb_version_internal.nano, libusb_version_internal.rc);
2335 r = usbi_io_init(_ctx);
2337 usbi_mutex_static_unlock(&default_context_lock);
2341 usbi_mutex_static_lock(&active_contexts_lock);
2342 list_add(&_ctx->list, &active_contexts_list);
2343 usbi_mutex_static_unlock(&active_contexts_lock);
2345 usbi_hotplug_init(_ctx);
2347 if (usbi_backend.init) {
2348 r = usbi_backend.init(_ctx);
2357 usbi_mutex_static_unlock(&default_context_lock);
2362 usbi_mutex_static_lock(&active_contexts_lock);
2363 list_del(&_ctx->list);
2364 usbi_mutex_static_unlock(&active_contexts_lock);
2367 usbi_default_context = NULL;
2368 default_context_refcnt = 0;
2371 usbi_mutex_static_unlock(&default_context_lock);
2373 usbi_hotplug_exit(_ctx);
2377 usbi_mutex_destroy(&_ctx->open_devs_lock);
2378 usbi_mutex_destroy(&_ctx->usb_devs_lock);
2385 /** \ingroup libusb_lib
2386 * Deinitialize libusb. Should be called after closing all open devices and
2387 * before your application terminates.
2388 * \param ctx the context to deinitialize, or NULL for the default context
2390 void API_EXPORTED libusb_exit(libusb_context *ctx)
2392 struct libusb_context *_ctx;
2393 struct libusb_device *dev;
2395 usbi_mutex_static_lock(&default_context_lock);
2397 /* if working with default context, only actually do the deinitialization
2398 * if we're the last user */
2400 if (!usbi_default_context) {
2401 usbi_dbg(ctx, "no default context, not initialized?");
2402 usbi_mutex_static_unlock(&default_context_lock);
2406 if (--default_context_refcnt > 0) {
2407 usbi_dbg(ctx, "not destroying default context");
2408 usbi_mutex_static_unlock(&default_context_lock);
2412 usbi_dbg(ctx, "destroying default context");
2413 _ctx = usbi_default_context;
2419 usbi_mutex_static_lock(&active_contexts_lock);
2420 list_del(&_ctx->list);
2421 usbi_mutex_static_unlock(&active_contexts_lock);
2423 if (usbi_backend.exit)
2424 usbi_backend.exit(_ctx);
2427 usbi_default_context = NULL;
2429 usbi_mutex_static_unlock(&default_context_lock);
2431 /* Don't bother with locking after this point because unless there is
2432 * an application bug, nobody will be accessing the context. */
2434 usbi_hotplug_exit(_ctx);
2437 for_each_device(_ctx, dev) {
2438 usbi_warn(_ctx, "device %d.%d still referenced",
2439 dev->bus_number, dev->device_address);
2442 if (!list_empty(&_ctx->open_devs))
2443 usbi_warn(_ctx, "application left some devices open");
2445 usbi_mutex_destroy(&_ctx->open_devs_lock);
2446 usbi_mutex_destroy(&_ctx->usb_devs_lock);
2451 /** \ingroup libusb_misc
2452 * Check at runtime if the loaded library has a given capability.
2453 * This call should be performed after \ref libusb_init(), to ensure the
2454 * backend has updated its capability set.
2456 * \param capability the \ref libusb_capability to check for
2457 * \returns nonzero if the running library has the capability, 0 otherwise
2459 int API_EXPORTED libusb_has_capability(uint32_t capability)
2461 switch (capability) {
2462 case LIBUSB_CAP_HAS_CAPABILITY:
2464 case LIBUSB_CAP_HAS_HOTPLUG:
2465 return !(usbi_backend.get_device_list);
2466 case LIBUSB_CAP_HAS_HID_ACCESS:
2467 return (usbi_backend.caps & USBI_CAP_HAS_HID_ACCESS);
2468 case LIBUSB_CAP_SUPPORTS_DETACH_KERNEL_DRIVER:
2469 return (usbi_backend.caps & USBI_CAP_SUPPORTS_DETACH_KERNEL_DRIVER);
2474 #ifdef ENABLE_LOGGING
2476 /* this is defined in libusbi.h if needed */
2477 #ifdef LIBUSB_PRINTF_WIN32
2479 * Prior to VS2015, Microsoft did not provide the snprintf() function and
2480 * provided a vsnprintf() that did not guarantee NUL-terminated output.
2481 * Microsoft did provide a _snprintf() function, but again it did not
2482 * guarantee NULL-terminated output.
2484 * The below implementations guarantee NUL-terminated output and are
2488 int usbi_snprintf(char *str, size_t size, const char *format, ...)
2493 va_start(args, format);
2494 ret = usbi_vsnprintf(str, size, format, args);
2500 int usbi_vsnprintf(char *str, size_t size, const char *format, va_list args)
2504 ret = _vsnprintf(str, size, format, args);
2505 if (ret < 0 || ret == (int)size) {
2506 /* Output is truncated, ensure buffer is NUL-terminated and
2507 * determine how many characters would have been written. */
2508 str[size - 1] = '\0';
2510 ret = _vsnprintf(NULL, 0, format, args);
2515 #endif /* LIBUSB_PRINTF_WIN32 */
2517 static void log_str(enum libusb_log_level level, const char *str)
2519 #if defined(USE_SYSTEM_LOGGING_FACILITY)
2520 #if defined(__ANDROID__)
2523 case LIBUSB_LOG_LEVEL_NONE: return; /* Impossible, but keeps compiler happy */
2524 case LIBUSB_LOG_LEVEL_ERROR: priority = ANDROID_LOG_ERROR; break;
2525 case LIBUSB_LOG_LEVEL_WARNING: priority = ANDROID_LOG_WARN; break;
2526 case LIBUSB_LOG_LEVEL_INFO: priority = ANDROID_LOG_INFO; break;
2527 case LIBUSB_LOG_LEVEL_DEBUG: priority = ANDROID_LOG_DEBUG; break;
2528 default: priority = ANDROID_LOG_UNKNOWN;
2530 __android_log_write(priority, "libusb", str);
2531 #elif defined(_WIN32)
2533 OutputDebugStringA(str);
2534 #elif defined(HAVE_SYSLOG)
2537 case LIBUSB_LOG_LEVEL_NONE: return; /* Impossible, but keeps compiler happy */
2538 case LIBUSB_LOG_LEVEL_ERROR: syslog_level = LOG_ERR; break;
2539 case LIBUSB_LOG_LEVEL_WARNING: syslog_level = LOG_WARNING; break;
2540 case LIBUSB_LOG_LEVEL_INFO: syslog_level = LOG_INFO; break;
2541 case LIBUSB_LOG_LEVEL_DEBUG: syslog_level = LOG_DEBUG; break;
2542 default: syslog_level = LOG_INFO;
2544 syslog(syslog_level, "%s", str);
2545 #else /* All of gcc, Clang, Xcode seem to use #warning */
2546 #warning System logging is not supported on this platform. Logging to stderr will be used instead.
2551 /* Global log handler */
2553 log_handler(NULL, level, str);
2556 #endif /* USE_SYSTEM_LOGGING_FACILITY */
2559 static void log_v(struct libusb_context *ctx, enum libusb_log_level level,
2560 const char *function, const char *format, va_list args)
2563 char buf[USBI_MAX_LOG_LEN];
2564 int global_debug, header_len, text_len;
2565 static int has_debug_header_been_displayed = 0;
2567 #ifdef ENABLE_DEBUG_LOGGING
2571 enum libusb_log_level ctx_level;
2573 ctx = usbi_get_context(ctx);
2575 ctx_level = ctx->debug;
2577 ctx_level = get_env_debug_level();
2579 if (ctx_level < level)
2582 global_debug = (ctx_level == LIBUSB_LOG_LEVEL_DEBUG);
2586 case LIBUSB_LOG_LEVEL_NONE: /* Impossible, but keeps compiler happy */
2588 case LIBUSB_LOG_LEVEL_ERROR:
2591 case LIBUSB_LOG_LEVEL_WARNING:
2594 case LIBUSB_LOG_LEVEL_INFO:
2597 case LIBUSB_LOG_LEVEL_DEBUG:
2606 struct timespec timestamp;
2608 if (!has_debug_header_been_displayed) {
2609 has_debug_header_been_displayed = 1;
2610 log_str(LIBUSB_LOG_LEVEL_DEBUG, "[timestamp] [threadID] facility level [function call] <message>" USBI_LOG_LINE_END);
2611 log_str(LIBUSB_LOG_LEVEL_DEBUG, "--------------------------------------------------------------------------------" USBI_LOG_LINE_END);
2614 usbi_get_monotonic_time(×tamp);
2615 TIMESPEC_SUB(×tamp, ×tamp_origin, ×tamp);
2617 header_len = snprintf(buf, sizeof(buf),
2618 "[%2ld.%06ld] [%08x] libusb: %s [%s] ",
2619 (long)timestamp.tv_sec, (long)(timestamp.tv_nsec / 1000L), usbi_get_tid(), prefix, function);
2621 header_len = snprintf(buf, sizeof(buf),
2622 "libusb: %s [%s] ", prefix, function);
2625 if (header_len < 0 || header_len >= (int)sizeof(buf)) {
2626 /* Somehow snprintf() failed to write to the buffer,
2627 * remove the header so something useful is output. */
2631 text_len = vsnprintf(buf + header_len, sizeof(buf) - (size_t)header_len,
2633 if (text_len < 0 || text_len + header_len >= (int)sizeof(buf)) {
2634 /* Truncated log output. On some platforms a -1 return value means
2635 * that the output was truncated. */
2636 text_len = (int)sizeof(buf) - header_len;
2638 if (header_len + text_len + (int)sizeof(USBI_LOG_LINE_END) >= (int)sizeof(buf)) {
2639 /* Need to truncate the text slightly to fit on the terminator. */
2640 text_len -= (header_len + text_len + (int)sizeof(USBI_LOG_LINE_END)) - (int)sizeof(buf);
2642 strcpy(buf + header_len + text_len, USBI_LOG_LINE_END);
2644 log_str(level, buf);
2646 /* Per-context log handler */
2647 #ifndef ENABLE_DEBUG_LOGGING
2648 if (ctx && ctx->log_handler)
2649 ctx->log_handler(ctx, level, buf);
2653 void usbi_log(struct libusb_context *ctx, enum libusb_log_level level,
2654 const char *function, const char *format, ...)
2658 va_start(args, format);
2659 log_v(ctx, level, function, format, args);
2663 #endif /* ENABLE_LOGGING */
2665 /** \ingroup libusb_misc
2666 * Returns a constant NULL-terminated string with the ASCII name of a libusb
2667 * error or transfer status code. The caller must not free() the returned
2670 * \param error_code The \ref libusb_error or libusb_transfer_status code to
2671 * return the name of.
2672 * \returns The error name, or the string **UNKNOWN** if the value of
2673 * error_code is not a known error / status code.
2675 DEFAULT_VISIBILITY const char * LIBUSB_CALL libusb_error_name(int error_code)
2677 switch (error_code) {
2678 case LIBUSB_ERROR_IO:
2679 return "LIBUSB_ERROR_IO";
2680 case LIBUSB_ERROR_INVALID_PARAM:
2681 return "LIBUSB_ERROR_INVALID_PARAM";
2682 case LIBUSB_ERROR_ACCESS:
2683 return "LIBUSB_ERROR_ACCESS";
2684 case LIBUSB_ERROR_NO_DEVICE:
2685 return "LIBUSB_ERROR_NO_DEVICE";
2686 case LIBUSB_ERROR_NOT_FOUND:
2687 return "LIBUSB_ERROR_NOT_FOUND";
2688 case LIBUSB_ERROR_BUSY:
2689 return "LIBUSB_ERROR_BUSY";
2690 case LIBUSB_ERROR_TIMEOUT:
2691 return "LIBUSB_ERROR_TIMEOUT";
2692 case LIBUSB_ERROR_OVERFLOW:
2693 return "LIBUSB_ERROR_OVERFLOW";
2694 case LIBUSB_ERROR_PIPE:
2695 return "LIBUSB_ERROR_PIPE";
2696 case LIBUSB_ERROR_INTERRUPTED:
2697 return "LIBUSB_ERROR_INTERRUPTED";
2698 case LIBUSB_ERROR_NO_MEM:
2699 return "LIBUSB_ERROR_NO_MEM";
2700 case LIBUSB_ERROR_NOT_SUPPORTED:
2701 return "LIBUSB_ERROR_NOT_SUPPORTED";
2702 case LIBUSB_ERROR_OTHER:
2703 return "LIBUSB_ERROR_OTHER";
2705 case LIBUSB_TRANSFER_ERROR:
2706 return "LIBUSB_TRANSFER_ERROR";
2707 case LIBUSB_TRANSFER_TIMED_OUT:
2708 return "LIBUSB_TRANSFER_TIMED_OUT";
2709 case LIBUSB_TRANSFER_CANCELLED:
2710 return "LIBUSB_TRANSFER_CANCELLED";
2711 case LIBUSB_TRANSFER_STALL:
2712 return "LIBUSB_TRANSFER_STALL";
2713 case LIBUSB_TRANSFER_NO_DEVICE:
2714 return "LIBUSB_TRANSFER_NO_DEVICE";
2715 case LIBUSB_TRANSFER_OVERFLOW:
2716 return "LIBUSB_TRANSFER_OVERFLOW";
2719 return "LIBUSB_SUCCESS / LIBUSB_TRANSFER_COMPLETED";
2721 return "**UNKNOWN**";
2725 /** \ingroup libusb_misc
2726 * Returns a pointer to const struct libusb_version with the version
2727 * (major, minor, micro, nano and rc) of the running library.
2730 const struct libusb_version * LIBUSB_CALL libusb_get_version(void)
2732 return &libusb_version_internal;