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 struct libusb_context *usbi_default_context = NULL;
36 static const struct libusb_version libusb_version_internal =
37 { LIBUSB_MAJOR, LIBUSB_MINOR, LIBUSB_MICRO, LIBUSB_NANO,
38 LIBUSB_RC, "http://libusb.info" };
39 static int default_context_refcnt = 0;
40 static usbi_mutex_static_t default_context_lock = USBI_MUTEX_INITIALIZER;
41 static struct timespec timestamp_origin = { 0, 0 };
42 #ifndef USE_SYSTEM_LOGGING_FACILITY
43 static libusb_log_cb log_handler = NULL;
46 usbi_mutex_static_t active_contexts_lock = USBI_MUTEX_INITIALIZER;
47 struct list_head active_contexts_list;
50 * \mainpage libusb-1.0 API Reference
52 * \section intro Introduction
54 * libusb is an open source library that allows you to communicate with USB
55 * devices from userspace. For more info, see the
56 * <a href="http://libusb.info">libusb homepage</a>.
58 * This documentation is aimed at application developers wishing to
59 * communicate with USB peripherals from their own software. After reviewing
60 * this documentation, feedback and questions can be sent to the
61 * <a href="http://mailing-list.libusb.info">libusb-devel mailing list</a>.
63 * This documentation assumes knowledge of how to operate USB devices from
64 * a software standpoint (descriptors, configurations, interfaces, endpoints,
65 * control/bulk/interrupt/isochronous transfers, etc). Full information
66 * can be found in the <a href="http://www.usb.org/developers/docs/">USB 3.0
67 * Specification</a> which is available for free download. You can probably
68 * find less verbose introductions by searching the web.
70 * \section API Application Programming Interface (API)
72 * See the \ref libusb_api page for a complete list of the libusb functions.
74 * \section features Library features
76 * - All transfer types supported (control/bulk/interrupt/isochronous)
77 * - 2 transfer interfaces:
78 * -# Synchronous (simple)
79 * -# Asynchronous (more complicated, but more powerful)
80 * - Thread safe (although the asynchronous interface means that you
81 * usually won't need to thread)
82 * - Lightweight with lean API
83 * - Compatible with libusb-0.1 through the libusb-compat-0.1 translation layer
84 * - Hotplug support (on some platforms). See \ref libusb_hotplug.
86 * \section gettingstarted Getting Started
88 * To begin reading the API documentation, start with the Modules page which
89 * links to the different categories of libusb's functionality.
91 * One decision you will have to make is whether to use the synchronous
92 * or the asynchronous data transfer interface. The \ref libusb_io documentation
93 * provides some insight into this topic.
95 * Some example programs can be found in the libusb source distribution under
96 * the "examples" subdirectory. The libusb homepage includes a list of
97 * real-life project examples which use libusb.
99 * \section errorhandling Error handling
101 * libusb functions typically return 0 on success or a negative error code
102 * on failure. These negative error codes relate to LIBUSB_ERROR constants
103 * which are listed on the \ref libusb_misc "miscellaneous" documentation page.
105 * \section msglog Debug message logging
107 * libusb uses stderr for all logging. By default, logging is set to NONE,
108 * which means that no output will be produced. However, unless the library
109 * has been compiled with logging disabled, then any application calls to
110 * libusb_set_option(ctx, LIBUSB_OPTION_LOG_LEVEL, level), or the setting of the
111 * environmental variable LIBUSB_DEBUG outside of the application, can result
112 * in logging being produced. Your application should therefore not close
113 * stderr, but instead direct it to the null device if its output is
116 * The libusb_set_option(ctx, LIBUSB_OPTION_LOG_LEVEL, level) function can be
117 * used to enable logging of certain messages. Under standard configuration,
118 * libusb doesn't really log much so you are advised to use this function
119 * to enable all error/warning/ informational messages. It will help debug
120 * problems with your software.
122 * The logged messages are unstructured. There is no one-to-one correspondence
123 * between messages being logged and success or failure return codes from
124 * libusb functions. There is no format to the messages, so you should not
125 * try to capture or parse them. They are not and will not be localized.
126 * These messages are not intended to being passed to your application user;
127 * instead, you should interpret the error codes returned from libusb functions
128 * and provide appropriate notification to the user. The messages are simply
129 * there to aid you as a programmer, and if you're confused because you're
130 * getting a strange error code from a libusb function, enabling message
131 * logging may give you a suitable explanation.
133 * The LIBUSB_DEBUG environment variable can be used to enable message logging
134 * at run-time. This environment variable should be set to a log level number,
135 * which is interpreted the same as the
136 * libusb_set_option(ctx, LIBUSB_OPTION_LOG_LEVEL, level) parameter. When this
137 * environment variable is set, the message logging verbosity level is fixed
138 * and libusb_set_option(ctx, LIBUSB_OPTION_LOG_LEVEL, level) effectively does
141 * libusb can be compiled without any logging functions, useful for embedded
142 * systems. In this case, libusb_set_option(ctx, LIBUSB_OPTION_LOG_LEVEL, level)
143 * and the LIBUSB_DEBUG environment variable have no effects.
145 * libusb can also be compiled with verbose debugging messages always. When
146 * the library is compiled in this way, all messages of all verbosities are
147 * always logged. libusb_set_option(ctx, LIBUSB_OPTION_LOG_LEVEL, level) and
148 * the LIBUSB_DEBUG environment variable have no effects.
150 * \section remarks Other remarks
152 * libusb does have imperfections. The \ref libusb_caveats "caveats" page attempts
157 * \page libusb_caveats Caveats
159 * \section fork Fork considerations
161 * libusb is <em>not</em> designed to work across fork() calls. Depending on
162 * the platform, there may be resources in the parent process that are not
163 * available to the child (e.g. the hotplug monitor thread on Linux). In
164 * addition, since the parent and child will share libusb's internal file
165 * descriptors, using libusb in any way from the child could cause the parent
166 * process's \ref libusb_context to get into an inconsistent state.
168 * On Linux, libusb's file descriptors will be marked as CLOEXEC, which means
169 * that it is safe to fork() and exec() without worrying about the child
170 * process needing to clean up state or having access to these file descriptors.
171 * Other platforms may not be so forgiving, so consider yourself warned!
173 * \section devresets Device resets
175 * The libusb_reset_device() function allows you to reset a device. If your
176 * program has to call such a function, it should obviously be aware that
177 * the reset will cause device state to change (e.g. register values may be
180 * The problem is that any other program could reset the device your program
181 * is working with, at any time. libusb does not offer a mechanism to inform
182 * you when this has happened, so if someone else resets your device it will
183 * not be clear to your own program why the device state has changed.
185 * Ultimately, this is a limitation of writing drivers in userspace.
186 * Separation from the USB stack in the underlying kernel makes it difficult
187 * for the operating system to deliver such notifications to your program.
188 * The Linux kernel USB stack allows such reset notifications to be delivered
189 * to in-kernel USB drivers, but it is not clear how such notifications could
190 * be delivered to second-class drivers that live in userspace.
192 * \section blockonly Blocking-only functionality
194 * The functionality listed below is only available through synchronous,
195 * blocking functions. There are no asynchronous/non-blocking alternatives,
196 * and no clear ways of implementing these.
198 * - Configuration activation (libusb_set_configuration())
199 * - Interface/alternate setting activation (libusb_set_interface_alt_setting())
200 * - Releasing of interfaces (libusb_release_interface())
201 * - Clearing of halt/stall condition (libusb_clear_halt())
202 * - Device resets (libusb_reset_device())
204 * \section configsel Configuration selection and handling
206 * When libusb presents a device handle to an application, there is a chance
207 * that the corresponding device may be in unconfigured state. For devices
208 * with multiple configurations, there is also a chance that the configuration
209 * currently selected is not the one that the application wants to use.
211 * The obvious solution is to add a call to libusb_set_configuration() early
212 * on during your device initialization routines, but there are caveats to
214 * -# If the device is already in the desired configuration, calling
215 * libusb_set_configuration() using the same configuration value will cause
216 * a lightweight device reset. This may not be desirable behaviour.
217 * -# In the case where the desired configuration is already active, libusb
218 * may not even be able to perform a lightweight device reset. For example,
219 * take my USB keyboard with fingerprint reader: I'm interested in driving
220 * the fingerprint reader interface through libusb, but the kernel's
221 * USB-HID driver will almost always have claimed the keyboard interface.
222 * Because the kernel has claimed an interface, it is not even possible to
223 * perform the lightweight device reset, so libusb_set_configuration() will
224 * fail. (Luckily the device in question only has a single configuration.)
225 * -# libusb will be unable to set a configuration if other programs or
226 * drivers have claimed interfaces. In particular, this means that kernel
227 * drivers must be detached from all the interfaces before
228 * libusb_set_configuration() may succeed.
230 * One solution to some of the above problems is to consider the currently
231 * active configuration. If the configuration we want is already active, then
232 * we don't have to select any configuration:
235 libusb_get_configuration(dev, &cfg);
237 libusb_set_configuration(dev, desired);
240 * This is probably suitable for most scenarios, but is inherently racy:
241 * another application or driver may change the selected configuration
242 * <em>after</em> the libusb_get_configuration() call.
244 * Even in cases where libusb_set_configuration() succeeds, consider that other
245 * applications or drivers may change configuration after your application
246 * calls libusb_set_configuration().
248 * One possible way to lock your device into a specific configuration is as
250 * -# Set the desired configuration (or use the logic above to realise that
251 * it is already in the desired configuration)
252 * -# Claim the interface that you wish to use
253 * -# Check that the currently active configuration is the one that you want
256 * The above method works because once an interface is claimed, no application
257 * or driver is able to select another configuration.
259 * \section earlycomp Early transfer completion
261 * NOTE: This section is currently Linux-centric. I am not sure if any of these
262 * considerations apply to Darwin or other platforms.
264 * When a transfer completes early (i.e. when less data is received/sent in
265 * any one packet than the transfer buffer allows for) then libusb is designed
266 * to terminate the transfer immediately, not transferring or receiving any
267 * more data unless other transfers have been queued by the user.
269 * On legacy platforms, libusb is unable to do this in all situations. After
270 * the incomplete packet occurs, "surplus" data may be transferred. For recent
271 * versions of libusb, this information is kept (the data length of the
272 * transfer is updated) and, for device-to-host transfers, any surplus data was
273 * added to the buffer. Still, this is not a nice solution because it loses the
274 * information about the end of the short packet, and the user probably wanted
275 * that surplus data to arrive in the next logical transfer.
277 * \section zlp Zero length packets
279 * - libusb is able to send a packet of zero length to an endpoint simply by
280 * submitting a transfer of zero length.
281 * - The \ref libusb_transfer_flags::LIBUSB_TRANSFER_ADD_ZERO_PACKET
282 * "LIBUSB_TRANSFER_ADD_ZERO_PACKET" flag is currently only supported on Linux.
286 * \page libusb_contexts Contexts
288 * It is possible that libusb may be used simultaneously from two independent
289 * libraries linked into the same executable. For example, if your application
290 * has a plugin-like system which allows the user to dynamically load a range
291 * of modules into your program, it is feasible that two independently
292 * developed modules may both use libusb.
294 * libusb is written to allow for these multiple user scenarios. The two
295 * "instances" of libusb will not interfere: libusb_set_option() calls
296 * from one user will not affect the same settings for other users, other
297 * users can continue using libusb after one of them calls libusb_exit(), etc.
299 * This is made possible through libusb's <em>context</em> concept. When you
300 * call libusb_init(), you are (optionally) given a context. You can then pass
301 * this context pointer back into future libusb functions.
303 * In order to keep things simple for more simplistic applications, it is
304 * legal to pass NULL to all functions requiring a context pointer (as long as
305 * you're sure no other code will attempt to use libusb from the same process).
306 * When you pass NULL, the default context will be used. The default context
307 * is created the first time a process calls libusb_init() when no other
308 * context is alive. Contexts are destroyed during libusb_exit().
310 * The default context is reference-counted and can be shared. That means that
311 * if libusb_init(NULL) is called twice within the same process, the two
312 * users end up sharing the same context. The deinitialization and freeing of
313 * the default context will only happen when the last user calls libusb_exit().
314 * In other words, the default context is created and initialized when its
315 * reference count goes from 0 to 1, and is deinitialized and destroyed when
316 * its reference count goes from 1 to 0.
318 * You may be wondering why only a subset of libusb functions require a
319 * context pointer in their function definition. Internally, libusb stores
320 * context pointers in other objects (e.g. libusb_device instances) and hence
321 * can infer the context from those objects.
325 * \page libusb_api Application Programming Interface
327 * This is the complete list of libusb functions, structures and
328 * enumerations in alphabetical order.
331 * - libusb_alloc_streams()
332 * - libusb_alloc_transfer()
333 * - libusb_attach_kernel_driver()
334 * - libusb_bulk_transfer()
335 * - libusb_cancel_transfer()
336 * - libusb_claim_interface()
337 * - libusb_clear_halt()
339 * - libusb_control_transfer()
340 * - libusb_control_transfer_get_data()
341 * - libusb_control_transfer_get_setup()
342 * - libusb_cpu_to_le16()
343 * - libusb_detach_kernel_driver()
344 * - libusb_dev_mem_alloc()
345 * - libusb_dev_mem_free()
346 * - libusb_error_name()
347 * - libusb_event_handler_active()
348 * - libusb_event_handling_ok()
350 * - libusb_fill_bulk_stream_transfer()
351 * - libusb_fill_bulk_transfer()
352 * - libusb_fill_control_setup()
353 * - libusb_fill_control_transfer()
354 * - libusb_fill_interrupt_transfer()
355 * - libusb_fill_iso_transfer()
356 * - libusb_free_bos_descriptor()
357 * - libusb_free_config_descriptor()
358 * - libusb_free_container_id_descriptor()
359 * - libusb_free_device_list()
360 * - libusb_free_pollfds()
361 * - libusb_free_ss_endpoint_companion_descriptor()
362 * - libusb_free_ss_usb_device_capability_descriptor()
363 * - libusb_free_streams()
364 * - libusb_free_transfer()
365 * - libusb_free_usb_2_0_extension_descriptor()
366 * - libusb_get_active_config_descriptor()
367 * - libusb_get_bos_descriptor()
368 * - libusb_get_bus_number()
369 * - libusb_get_config_descriptor()
370 * - libusb_get_config_descriptor_by_value()
371 * - libusb_get_configuration()
372 * - libusb_get_container_id_descriptor()
373 * - libusb_get_descriptor()
374 * - libusb_get_device()
375 * - libusb_get_device_address()
376 * - libusb_get_device_descriptor()
377 * - libusb_get_device_list()
378 * - libusb_get_device_speed()
379 * - libusb_get_iso_packet_buffer()
380 * - libusb_get_iso_packet_buffer_simple()
381 * - libusb_get_max_iso_packet_size()
382 * - libusb_get_max_packet_size()
383 * - libusb_get_next_timeout()
384 * - libusb_get_parent()
385 * - libusb_get_pollfds()
386 * - libusb_get_port_number()
387 * - libusb_get_port_numbers()
388 * - libusb_get_port_path()
389 * - libusb_get_ss_endpoint_companion_descriptor()
390 * - libusb_get_ss_usb_device_capability_descriptor()
391 * - libusb_get_string_descriptor()
392 * - libusb_get_string_descriptor_ascii()
393 * - libusb_get_usb_2_0_extension_descriptor()
394 * - libusb_get_version()
395 * - libusb_handle_events()
396 * - libusb_handle_events_completed()
397 * - libusb_handle_events_locked()
398 * - libusb_handle_events_timeout()
399 * - libusb_handle_events_timeout_completed()
400 * - libusb_has_capability()
401 * - libusb_hotplug_deregister_callback()
402 * - libusb_hotplug_register_callback()
404 * - libusb_interrupt_event_handler()
405 * - libusb_interrupt_transfer()
406 * - libusb_kernel_driver_active()
407 * - libusb_lock_events()
408 * - libusb_lock_event_waiters()
410 * - libusb_open_device_with_vid_pid()
411 * - libusb_pollfds_handle_timeouts()
412 * - libusb_ref_device()
413 * - libusb_release_interface()
414 * - libusb_reset_device()
415 * - libusb_set_auto_detach_kernel_driver()
416 * - libusb_set_configuration()
417 * - libusb_set_debug()
418 * - libusb_set_log_cb()
419 * - libusb_set_interface_alt_setting()
420 * - libusb_set_iso_packet_lengths()
421 * - libusb_set_option()
422 * - libusb_setlocale()
423 * - libusb_set_pollfd_notifiers()
424 * - libusb_strerror()
425 * - libusb_submit_transfer()
426 * - libusb_transfer_get_stream_id()
427 * - libusb_transfer_set_stream_id()
428 * - libusb_try_lock_events()
429 * - libusb_unlock_events()
430 * - libusb_unlock_event_waiters()
431 * - libusb_unref_device()
432 * - libusb_wait_for_event()
433 * - libusb_wrap_sys_device()
435 * \section Structures
436 * - libusb_bos_descriptor
437 * - libusb_bos_dev_capability_descriptor
438 * - libusb_config_descriptor
439 * - libusb_container_id_descriptor
440 * - \ref libusb_context
441 * - libusb_control_setup
442 * - \ref libusb_device
443 * - libusb_device_descriptor
444 * - \ref libusb_device_handle
445 * - libusb_endpoint_descriptor
447 * - libusb_interface_descriptor
448 * - libusb_iso_packet_descriptor
450 * - libusb_ss_endpoint_companion_descriptor
451 * - libusb_ss_usb_device_capability_descriptor
453 * - libusb_usb_2_0_extension_descriptor
457 * - \ref libusb_bos_type
458 * - \ref libusb_capability
459 * - \ref libusb_class_code
460 * - \ref libusb_descriptor_type
461 * - \ref libusb_endpoint_direction
462 * - \ref libusb_error
463 * - \ref libusb_iso_sync_type
464 * - \ref libusb_iso_usage_type
465 * - \ref libusb_log_level
466 * - \ref libusb_option
467 * - \ref libusb_request_recipient
468 * - \ref libusb_request_type
469 * - \ref libusb_speed
470 * - \ref libusb_ss_usb_device_capability_attributes
471 * - \ref libusb_standard_request
472 * - \ref libusb_supported_speed
473 * - \ref libusb_transfer_flags
474 * - \ref libusb_transfer_status
475 * - \ref libusb_transfer_type
476 * - \ref libusb_usb_2_0_extension_attributes
480 * @defgroup libusb_lib Library initialization/deinitialization
481 * This page details how to initialize and deinitialize libusb. Initialization
482 * must be performed before using any libusb functionality, and similarly you
483 * must not call any libusb functions after deinitialization.
487 * @defgroup libusb_dev Device handling and enumeration
488 * The functionality documented below is designed to help with the following
490 * - Enumerating the USB devices currently attached to the system
491 * - Choosing a device to operate from your software
492 * - Opening and closing the chosen device
494 * \section nutshell In a nutshell...
496 * The description below really makes things sound more complicated than they
497 * actually are. The following sequence of function calls will be suitable
498 * for almost all scenarios and does not require you to have such a deep
499 * understanding of the resource management issues:
502 libusb_device **list;
503 libusb_device *found = NULL;
504 ssize_t cnt = libusb_get_device_list(NULL, &list);
510 for (i = 0; i < cnt; i++) {
511 libusb_device *device = list[i];
512 if (is_interesting(device)) {
519 libusb_device_handle *handle;
521 err = libusb_open(found, &handle);
527 libusb_free_device_list(list, 1);
530 * The two important points:
531 * - You asked libusb_free_device_list() to unreference the devices (2nd
533 * - You opened the device before freeing the list and unreferencing the
536 * If you ended up with a handle, you can now proceed to perform I/O on the
539 * \section devshandles Devices and device handles
540 * libusb has a concept of a USB device, represented by the
541 * \ref libusb_device opaque type. A device represents a USB device that
542 * is currently or was previously connected to the system. Using a reference
543 * to a device, you can determine certain information about the device (e.g.
544 * you can read the descriptor data).
546 * The libusb_get_device_list() function can be used to obtain a list of
547 * devices currently connected to the system. This is known as device
550 * Just because you have a reference to a device does not mean it is
551 * necessarily usable. The device may have been unplugged, you may not have
552 * permission to operate such device, or another program or driver may be
555 * When you've found a device that you'd like to operate, you must ask
556 * libusb to open the device using the libusb_open() function. Assuming
557 * success, libusb then returns you a <em>device handle</em>
558 * (a \ref libusb_device_handle pointer). All "real" I/O operations then
559 * operate on the handle rather than the original device pointer.
561 * \section devref Device discovery and reference counting
563 * Device discovery (i.e. calling libusb_get_device_list()) returns a
564 * freshly-allocated list of devices. The list itself must be freed when
565 * you are done with it. libusb also needs to know when it is OK to free
566 * the contents of the list - the devices themselves.
568 * To handle these issues, libusb provides you with two separate items:
569 * - A function to free the list itself
570 * - A reference counting system for the devices inside
572 * New devices presented by the libusb_get_device_list() function all have a
573 * reference count of 1. You can increase and decrease reference count using
574 * libusb_ref_device() and libusb_unref_device(). A device is destroyed when
575 * its reference count reaches 0.
577 * With the above information in mind, the process of opening a device can
578 * be viewed as follows:
579 * -# Discover devices using libusb_get_device_list().
580 * -# Choose the device that you want to operate, and call libusb_open().
581 * -# Unref all devices in the discovered device list.
582 * -# Free the discovered device list.
584 * The order is important - you must not unreference the device before
585 * attempting to open it, because unreferencing it may destroy the device.
587 * For convenience, the libusb_free_device_list() function includes a
588 * parameter to optionally unreference all the devices in the list before
589 * freeing the list itself. This combines steps 3 and 4 above.
591 * As an implementation detail, libusb_open() actually adds a reference to
592 * the device in question. This is because the device remains available
593 * through the handle via libusb_get_device(). The reference is deleted during
597 /** @defgroup libusb_misc Miscellaneous */
599 /* we traverse usbfs without knowing how many devices we are going to find.
600 * so we create this discovered_devs model which is similar to a linked-list
601 * which grows when required. it can be freed once discovery has completed,
602 * eliminating the need for a list node in the libusb_device structure
604 #define DISCOVERED_DEVICES_SIZE_STEP 8
606 static struct discovered_devs *discovered_devs_alloc(void)
608 struct discovered_devs *ret =
609 malloc(sizeof(*ret) + (sizeof(void *) * DISCOVERED_DEVICES_SIZE_STEP));
613 ret->capacity = DISCOVERED_DEVICES_SIZE_STEP;
618 static void discovered_devs_free(struct discovered_devs *discdevs)
622 for (i = 0; i < discdevs->len; i++)
623 libusb_unref_device(discdevs->devices[i]);
628 /* append a device to the discovered devices collection. may realloc itself,
629 * returning new discdevs. returns NULL on realloc failure. */
630 struct discovered_devs *discovered_devs_append(
631 struct discovered_devs *discdevs, struct libusb_device *dev)
633 size_t len = discdevs->len;
635 struct discovered_devs *new_discdevs;
637 /* if there is space, just append the device */
638 if (len < discdevs->capacity) {
639 discdevs->devices[len] = libusb_ref_device(dev);
644 /* exceeded capacity, need to grow */
645 usbi_dbg("need to increase capacity");
646 capacity = discdevs->capacity + DISCOVERED_DEVICES_SIZE_STEP;
647 /* can't use usbi_reallocf here because in failure cases it would
648 * free the existing discdevs without unreferencing its devices. */
649 new_discdevs = realloc(discdevs,
650 sizeof(*discdevs) + (sizeof(void *) * capacity));
652 discovered_devs_free(discdevs);
656 discdevs = new_discdevs;
657 discdevs->capacity = capacity;
658 discdevs->devices[len] = libusb_ref_device(dev);
664 /* Allocate a new device with a specific session ID. The returned device has
665 * a reference count of 1. */
666 struct libusb_device *usbi_alloc_device(struct libusb_context *ctx,
667 unsigned long session_id)
669 size_t priv_size = usbi_backend.device_priv_size;
670 struct libusb_device *dev = calloc(1, sizeof(*dev) + priv_size);
676 r = usbi_mutex_init(&dev->lock);
684 dev->session_data = session_id;
685 dev->speed = LIBUSB_SPEED_UNKNOWN;
687 if (!libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG)) {
688 usbi_connect_device (dev);
694 void usbi_connect_device(struct libusb_device *dev)
696 struct libusb_context *ctx = DEVICE_CTX(dev);
700 usbi_mutex_lock(&dev->ctx->usb_devs_lock);
701 list_add(&dev->list, &dev->ctx->usb_devs);
702 usbi_mutex_unlock(&dev->ctx->usb_devs_lock);
704 /* Signal that an event has occurred for this device if we support hotplug AND
705 * the hotplug message list is ready. This prevents an event from getting raised
706 * during initial enumeration. */
707 if (libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG) && dev->ctx->hotplug_msgs.next) {
708 usbi_hotplug_notification(ctx, dev, LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED);
712 void usbi_disconnect_device(struct libusb_device *dev)
714 struct libusb_context *ctx = DEVICE_CTX(dev);
716 usbi_mutex_lock(&dev->lock);
718 usbi_mutex_unlock(&dev->lock);
720 usbi_mutex_lock(&ctx->usb_devs_lock);
721 list_del(&dev->list);
722 usbi_mutex_unlock(&ctx->usb_devs_lock);
724 /* Signal that an event has occurred for this device if we support hotplug AND
725 * the hotplug message list is ready. This prevents an event from getting raised
726 * during initial enumeration. libusb_handle_events will take care of dereferencing
728 if (libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG) && dev->ctx->hotplug_msgs.next) {
729 usbi_hotplug_notification(ctx, dev, LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT);
733 /* Perform some final sanity checks on a newly discovered device. If this
734 * function fails (negative return code), the device should not be added
735 * to the discovered device list. */
736 int usbi_sanitize_device(struct libusb_device *dev)
739 uint8_t num_configurations;
741 r = usbi_device_cache_descriptor(dev);
745 num_configurations = dev->device_descriptor.bNumConfigurations;
746 if (num_configurations > USB_MAXCONFIG) {
747 usbi_err(DEVICE_CTX(dev), "too many configurations");
748 return LIBUSB_ERROR_IO;
749 } else if (0 == num_configurations)
750 usbi_dbg("zero configurations, maybe an unauthorized device");
752 dev->num_configurations = num_configurations;
756 /* Examine libusb's internal list of known devices, looking for one with
757 * a specific session ID. Returns the matching device if it was found, and
759 struct libusb_device *usbi_get_device_by_session_id(struct libusb_context *ctx,
760 unsigned long session_id)
762 struct libusb_device *dev;
763 struct libusb_device *ret = NULL;
765 usbi_mutex_lock(&ctx->usb_devs_lock);
766 list_for_each_entry(dev, &ctx->usb_devs, list, struct libusb_device)
767 if (dev->session_data == session_id) {
768 ret = libusb_ref_device(dev);
771 usbi_mutex_unlock(&ctx->usb_devs_lock);
776 /** @ingroup libusb_dev
777 * Returns a list of USB devices currently attached to the system. This is
778 * your entry point into finding a USB device to operate.
780 * You are expected to unreference all the devices when you are done with
781 * them, and then free the list with libusb_free_device_list(). Note that
782 * libusb_free_device_list() can unref all the devices for you. Be careful
783 * not to unreference a device you are about to open until after you have
786 * This return value of this function indicates the number of devices in
787 * the resultant list. The list is actually one element larger, as it is
790 * \param ctx the context to operate on, or NULL for the default context
791 * \param list output location for a list of devices. Must be later freed with
792 * libusb_free_device_list().
793 * \returns the number of devices in the outputted list, or any
794 * \ref libusb_error according to errors encountered by the backend.
796 ssize_t API_EXPORTED libusb_get_device_list(libusb_context *ctx,
797 libusb_device ***list)
799 struct discovered_devs *discdevs = discovered_devs_alloc();
800 struct libusb_device **ret;
803 USBI_GET_CONTEXT(ctx);
807 return LIBUSB_ERROR_NO_MEM;
809 if (libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG)) {
810 /* backend provides hotplug support */
811 struct libusb_device *dev;
813 if (usbi_backend.hotplug_poll)
814 usbi_backend.hotplug_poll();
816 usbi_mutex_lock(&ctx->usb_devs_lock);
817 list_for_each_entry(dev, &ctx->usb_devs, list, struct libusb_device) {
818 discdevs = discovered_devs_append(discdevs, dev);
821 r = LIBUSB_ERROR_NO_MEM;
825 usbi_mutex_unlock(&ctx->usb_devs_lock);
827 /* backend does not provide hotplug support */
828 r = usbi_backend.get_device_list(ctx, &discdevs);
836 /* convert discovered_devs into a list */
837 len = (ssize_t)discdevs->len;
838 ret = calloc((size_t)len + 1, sizeof(struct libusb_device *));
840 len = LIBUSB_ERROR_NO_MEM;
845 for (i = 0; i < len; i++) {
846 struct libusb_device *dev = discdevs->devices[i];
847 ret[i] = libusb_ref_device(dev);
853 discovered_devs_free(discdevs);
857 /** \ingroup libusb_dev
858 * Frees a list of devices previously discovered using
859 * libusb_get_device_list(). If the unref_devices parameter is set, the
860 * reference count of each device in the list is decremented by 1.
861 * \param list the list to free
862 * \param unref_devices whether to unref the devices in the list
864 void API_EXPORTED libusb_free_device_list(libusb_device **list,
872 struct libusb_device *dev;
874 while ((dev = list[i++]) != NULL)
875 libusb_unref_device(dev);
880 /** \ingroup libusb_dev
881 * Get the number of the bus that a device is connected to.
882 * \param dev a device
883 * \returns the bus number
885 uint8_t API_EXPORTED libusb_get_bus_number(libusb_device *dev)
887 return dev->bus_number;
890 /** \ingroup libusb_dev
891 * Get the number of the port that a device is connected to.
892 * Unless the OS does something funky, or you are hot-plugging USB extension cards,
893 * the port number returned by this call is usually guaranteed to be uniquely tied
894 * to a physical port, meaning that different devices plugged on the same physical
895 * port should return the same port number.
897 * But outside of this, there is no guarantee that the port number returned by this
898 * call will remain the same, or even match the order in which ports have been
899 * numbered by the HUB/HCD manufacturer.
901 * \param dev a device
902 * \returns the port number (0 if not available)
904 uint8_t API_EXPORTED libusb_get_port_number(libusb_device *dev)
906 return dev->port_number;
909 /** \ingroup libusb_dev
910 * Get the list of all port numbers from root for the specified device
912 * Since version 1.0.16, \ref LIBUSB_API_VERSION >= 0x01000102
913 * \param dev a device
914 * \param port_numbers the array that should contain the port numbers
915 * \param port_numbers_len the maximum length of the array. As per the USB 3.0
916 * specs, the current maximum limit for the depth is 7.
917 * \returns the number of elements filled
918 * \returns LIBUSB_ERROR_OVERFLOW if the array is too small
920 int API_EXPORTED libusb_get_port_numbers(libusb_device *dev,
921 uint8_t* port_numbers, int port_numbers_len)
923 int i = port_numbers_len;
924 struct libusb_context *ctx = DEVICE_CTX(dev);
926 if (port_numbers_len <= 0)
927 return LIBUSB_ERROR_INVALID_PARAM;
929 // HCDs can be listed as devices with port #0
930 while((dev) && (dev->port_number != 0)) {
932 usbi_warn(ctx, "port numbers array is too small");
933 return LIBUSB_ERROR_OVERFLOW;
935 port_numbers[i] = dev->port_number;
936 dev = dev->parent_dev;
938 if (i < port_numbers_len)
939 memmove(port_numbers, &port_numbers[i], port_numbers_len - i);
940 return port_numbers_len - i;
943 /** \ingroup libusb_dev
944 * Deprecated please use libusb_get_port_numbers instead.
946 int API_EXPORTED libusb_get_port_path(libusb_context *ctx, libusb_device *dev,
947 uint8_t* port_numbers, uint8_t port_numbers_len)
951 return libusb_get_port_numbers(dev, port_numbers, port_numbers_len);
954 /** \ingroup libusb_dev
955 * Get the the parent from the specified device.
956 * \param dev a device
957 * \returns the device parent or NULL if not available
958 * You should issue a \ref libusb_get_device_list() before calling this
959 * function and make sure that you only access the parent before issuing
960 * \ref libusb_free_device_list(). The reason is that libusb currently does
961 * not maintain a permanent list of device instances, and therefore can
962 * only guarantee that parents are fully instantiated within a
963 * libusb_get_device_list() - libusb_free_device_list() block.
966 libusb_device * LIBUSB_CALL libusb_get_parent(libusb_device *dev)
968 return dev->parent_dev;
971 /** \ingroup libusb_dev
972 * Get the address of the device on the bus it is connected to.
973 * \param dev a device
974 * \returns the device address
976 uint8_t API_EXPORTED libusb_get_device_address(libusb_device *dev)
978 return dev->device_address;
981 /** \ingroup libusb_dev
982 * Get the negotiated connection speed for a device.
983 * \param dev a device
984 * \returns a \ref libusb_speed code, where LIBUSB_SPEED_UNKNOWN means that
985 * the OS doesn't know or doesn't support returning the negotiated speed.
987 int API_EXPORTED libusb_get_device_speed(libusb_device *dev)
992 static const struct libusb_endpoint_descriptor *find_endpoint(
993 struct libusb_config_descriptor *config, unsigned char endpoint)
996 for (iface_idx = 0; iface_idx < config->bNumInterfaces; iface_idx++) {
997 const struct libusb_interface *iface = &config->interface[iface_idx];
1000 for (altsetting_idx = 0; altsetting_idx < iface->num_altsetting;
1002 const struct libusb_interface_descriptor *altsetting
1003 = &iface->altsetting[altsetting_idx];
1006 for (ep_idx = 0; ep_idx < altsetting->bNumEndpoints; ep_idx++) {
1007 const struct libusb_endpoint_descriptor *ep =
1008 &altsetting->endpoint[ep_idx];
1009 if (ep->bEndpointAddress == endpoint)
1017 /** \ingroup libusb_dev
1018 * Convenience function to retrieve the wMaxPacketSize value for a particular
1019 * endpoint in the active device configuration.
1021 * This function was originally intended to be of assistance when setting up
1022 * isochronous transfers, but a design mistake resulted in this function
1023 * instead. It simply returns the wMaxPacketSize value without considering
1024 * its contents. If you're dealing with isochronous transfers, you probably
1025 * want libusb_get_max_iso_packet_size() instead.
1027 * \param dev a device
1028 * \param endpoint address of the endpoint in question
1029 * \returns the wMaxPacketSize value
1030 * \returns LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist
1031 * \returns LIBUSB_ERROR_OTHER on other failure
1033 int API_EXPORTED libusb_get_max_packet_size(libusb_device *dev,
1034 unsigned char endpoint)
1036 struct libusb_config_descriptor *config;
1037 const struct libusb_endpoint_descriptor *ep;
1040 r = libusb_get_active_config_descriptor(dev, &config);
1042 usbi_err(DEVICE_CTX(dev),
1043 "could not retrieve active config descriptor");
1044 return LIBUSB_ERROR_OTHER;
1047 ep = find_endpoint(config, endpoint);
1049 r = LIBUSB_ERROR_NOT_FOUND;
1053 r = ep->wMaxPacketSize;
1056 libusb_free_config_descriptor(config);
1060 /** \ingroup libusb_dev
1061 * Calculate the maximum packet size which a specific endpoint is capable is
1062 * sending or receiving in the duration of 1 microframe
1064 * Only the active configuration is examined. The calculation is based on the
1065 * wMaxPacketSize field in the endpoint descriptor as described in section
1066 * 9.6.6 in the USB 2.0 specifications.
1068 * If acting on an isochronous or interrupt endpoint, this function will
1069 * multiply the value found in bits 0:10 by the number of transactions per
1070 * microframe (determined by bits 11:12). Otherwise, this function just
1071 * returns the numeric value found in bits 0:10. For USB 3.0 device, it
1072 * will attempts to retrieve the Endpoint Companion Descriptor to return
1073 * wBytesPerInterval.
1075 * This function is useful for setting up isochronous transfers, for example
1076 * you might pass the return value from this function to
1077 * libusb_set_iso_packet_lengths() in order to set the length field of every
1078 * isochronous packet in a transfer.
1082 * \param dev a device
1083 * \param endpoint address of the endpoint in question
1084 * \returns the maximum packet size which can be sent/received on this endpoint
1085 * \returns LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist
1086 * \returns LIBUSB_ERROR_OTHER on other failure
1088 int API_EXPORTED libusb_get_max_iso_packet_size(libusb_device *dev,
1089 unsigned char endpoint)
1091 struct libusb_config_descriptor *config;
1092 const struct libusb_endpoint_descriptor *ep;
1093 struct libusb_ss_endpoint_companion_descriptor *ss_ep_cmp;
1094 enum libusb_transfer_type ep_type;
1099 r = libusb_get_active_config_descriptor(dev, &config);
1101 usbi_err(DEVICE_CTX(dev),
1102 "could not retrieve active config descriptor");
1103 return LIBUSB_ERROR_OTHER;
1106 ep = find_endpoint(config, endpoint);
1108 r = LIBUSB_ERROR_NOT_FOUND;
1112 speed = libusb_get_device_speed(dev);
1113 if (speed >= LIBUSB_SPEED_SUPER) {
1114 r = libusb_get_ss_endpoint_companion_descriptor(dev->ctx, ep, &ss_ep_cmp);
1115 if (r == LIBUSB_SUCCESS) {
1116 r = ss_ep_cmp->wBytesPerInterval;
1117 libusb_free_ss_endpoint_companion_descriptor(ss_ep_cmp);
1121 /* If the device isn't a SuperSpeed device or retrieving the SS endpoint didn't worked. */
1122 if (speed < LIBUSB_SPEED_SUPER || r < 0) {
1123 val = ep->wMaxPacketSize;
1124 ep_type = (enum libusb_transfer_type) (ep->bmAttributes & 0x3);
1127 if (ep_type == LIBUSB_TRANSFER_TYPE_ISOCHRONOUS
1128 || ep_type == LIBUSB_TRANSFER_TYPE_INTERRUPT)
1129 r *= (1 + ((val >> 11) & 3));
1133 libusb_free_config_descriptor(config);
1137 /** \ingroup libusb_dev
1138 * Increment the reference count of a device.
1139 * \param dev the device to reference
1140 * \returns the same device
1143 libusb_device * LIBUSB_CALL libusb_ref_device(libusb_device *dev)
1145 usbi_mutex_lock(&dev->lock);
1147 usbi_mutex_unlock(&dev->lock);
1151 /** \ingroup libusb_dev
1152 * Decrement the reference count of a device. If the decrement operation
1153 * causes the reference count to reach zero, the device shall be destroyed.
1154 * \param dev the device to unreference
1156 void API_EXPORTED libusb_unref_device(libusb_device *dev)
1163 usbi_mutex_lock(&dev->lock);
1164 refcnt = --dev->refcnt;
1165 usbi_mutex_unlock(&dev->lock);
1168 usbi_dbg("destroy device %d.%d", dev->bus_number, dev->device_address);
1170 libusb_unref_device(dev->parent_dev);
1172 if (usbi_backend.destroy_device)
1173 usbi_backend.destroy_device(dev);
1175 if (!libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG)) {
1176 /* backend does not support hotplug */
1177 usbi_disconnect_device(dev);
1180 usbi_mutex_destroy(&dev->lock);
1186 * Signal the event pipe so that the event handling thread will be
1187 * interrupted to process an internal event.
1189 int usbi_signal_event(struct libusb_context *ctx)
1191 unsigned char dummy = 1;
1194 /* write some data on event pipe to interrupt event handlers */
1195 r = usbi_write(ctx->event_pipe[1], &dummy, sizeof(dummy));
1196 if (r != sizeof(dummy)) {
1197 usbi_warn(ctx, "internal signalling write failed");
1198 return LIBUSB_ERROR_IO;
1205 * Clear the event pipe so that the event handling will no longer be
1208 int usbi_clear_event(struct libusb_context *ctx)
1210 unsigned char dummy;
1213 /* read some data on event pipe to clear it */
1214 r = usbi_read(ctx->event_pipe[0], &dummy, sizeof(dummy));
1215 if (r != sizeof(dummy)) {
1216 usbi_warn(ctx, "internal signalling read failed");
1217 return LIBUSB_ERROR_IO;
1223 /** \ingroup libusb_dev
1224 * Wrap a platform-specific system device handle and obtain a libusb device
1225 * handle for the underlying device. The handle allows you to use libusb to
1226 * perform I/O on the device in question.
1228 * On Linux, the system device handle must be a valid file descriptor opened
1229 * on the device node.
1231 * The system device handle must remain open until libusb_close() is called.
1232 * The system device handle will not be closed by libusb_close().
1234 * Internally, this function creates a temporary device and makes it
1235 * available to you through libusb_get_device(). This device is destroyed
1236 * during libusb_close(). The device shall not be opened through libusb_open().
1238 * This is a non-blocking function; no requests are sent over the bus.
1240 * \param ctx the context to operate on, or NULL for the default context
1241 * \param sys_dev the platform-specific system device handle
1242 * \param dev_handle output location for the returned device handle pointer. Only
1243 * populated when the return code is 0.
1244 * \returns 0 on success
1245 * \returns LIBUSB_ERROR_NO_MEM on memory allocation failure
1246 * \returns LIBUSB_ERROR_ACCESS if the user has insufficient permissions
1247 * \returns LIBUSB_ERROR_NOT_SUPPORTED if the operation is not supported on this
1249 * \returns another LIBUSB_ERROR code on other failure
1251 int API_EXPORTED libusb_wrap_sys_device(libusb_context *ctx, intptr_t sys_dev,
1252 libusb_device_handle **dev_handle)
1254 struct libusb_device_handle *_dev_handle;
1255 size_t priv_size = usbi_backend.device_handle_priv_size;
1257 usbi_dbg("wrap_sys_device %p", (void *)sys_dev);
1259 USBI_GET_CONTEXT(ctx);
1261 if (!usbi_backend.wrap_sys_device)
1262 return LIBUSB_ERROR_NOT_SUPPORTED;
1264 _dev_handle = malloc(sizeof(*_dev_handle) + priv_size);
1266 return LIBUSB_ERROR_NO_MEM;
1268 r = usbi_mutex_init(&_dev_handle->lock);
1271 return LIBUSB_ERROR_OTHER;
1274 _dev_handle->dev = NULL;
1275 _dev_handle->auto_detach_kernel_driver = 0;
1276 _dev_handle->claimed_interfaces = 0;
1277 memset(&_dev_handle->os_priv, 0, priv_size);
1279 r = usbi_backend.wrap_sys_device(ctx, _dev_handle, sys_dev);
1281 usbi_dbg("wrap_sys_device %p returns %d", (void *)sys_dev, r);
1282 usbi_mutex_destroy(&_dev_handle->lock);
1287 usbi_mutex_lock(&ctx->open_devs_lock);
1288 list_add(&_dev_handle->list, &ctx->open_devs);
1289 usbi_mutex_unlock(&ctx->open_devs_lock);
1290 *dev_handle = _dev_handle;
1295 /** \ingroup libusb_dev
1296 * Open a device and obtain a device handle. A handle allows you to perform
1297 * I/O on the device in question.
1299 * Internally, this function adds a reference to the device and makes it
1300 * available to you through libusb_get_device(). This reference is removed
1301 * during libusb_close().
1303 * This is a non-blocking function; no requests are sent over the bus.
1305 * \param dev the device to open
1306 * \param dev_handle output location for the returned device handle pointer. Only
1307 * populated when the return code is 0.
1308 * \returns 0 on success
1309 * \returns LIBUSB_ERROR_NO_MEM on memory allocation failure
1310 * \returns LIBUSB_ERROR_ACCESS if the user has insufficient permissions
1311 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1312 * \returns another LIBUSB_ERROR code on other failure
1314 int API_EXPORTED libusb_open(libusb_device *dev,
1315 libusb_device_handle **dev_handle)
1317 struct libusb_context *ctx = DEVICE_CTX(dev);
1318 struct libusb_device_handle *_dev_handle;
1319 size_t priv_size = usbi_backend.device_handle_priv_size;
1321 usbi_dbg("open %d.%d", dev->bus_number, dev->device_address);
1323 if (!dev->attached) {
1324 return LIBUSB_ERROR_NO_DEVICE;
1327 _dev_handle = malloc(sizeof(*_dev_handle) + priv_size);
1329 return LIBUSB_ERROR_NO_MEM;
1331 r = usbi_mutex_init(&_dev_handle->lock);
1334 return LIBUSB_ERROR_OTHER;
1337 _dev_handle->dev = libusb_ref_device(dev);
1338 _dev_handle->auto_detach_kernel_driver = 0;
1339 _dev_handle->claimed_interfaces = 0;
1340 memset(&_dev_handle->os_priv, 0, priv_size);
1342 r = usbi_backend.open(_dev_handle);
1344 usbi_dbg("open %d.%d returns %d", dev->bus_number, dev->device_address, r);
1345 libusb_unref_device(dev);
1346 usbi_mutex_destroy(&_dev_handle->lock);
1351 usbi_mutex_lock(&ctx->open_devs_lock);
1352 list_add(&_dev_handle->list, &ctx->open_devs);
1353 usbi_mutex_unlock(&ctx->open_devs_lock);
1354 *dev_handle = _dev_handle;
1359 /** \ingroup libusb_dev
1360 * Convenience function for finding a device with a particular
1361 * <tt>idVendor</tt>/<tt>idProduct</tt> combination. This function is intended
1362 * for those scenarios where you are using libusb to knock up a quick test
1363 * application - it allows you to avoid calling libusb_get_device_list() and
1364 * worrying about traversing/freeing the list.
1366 * This function has limitations and is hence not intended for use in real
1367 * applications: if multiple devices have the same IDs it will only
1368 * give you the first one, etc.
1370 * \param ctx the context to operate on, or NULL for the default context
1371 * \param vendor_id the idVendor value to search for
1372 * \param product_id the idProduct value to search for
1373 * \returns a device handle for the first found device, or NULL on error
1374 * or if the device could not be found. */
1376 libusb_device_handle * LIBUSB_CALL libusb_open_device_with_vid_pid(
1377 libusb_context *ctx, uint16_t vendor_id, uint16_t product_id)
1379 struct libusb_device **devs;
1380 struct libusb_device *found = NULL;
1381 struct libusb_device *dev;
1382 struct libusb_device_handle *dev_handle = NULL;
1386 if (libusb_get_device_list(ctx, &devs) < 0)
1389 while ((dev = devs[i++]) != NULL) {
1390 struct libusb_device_descriptor desc;
1391 r = libusb_get_device_descriptor(dev, &desc);
1394 if (desc.idVendor == vendor_id && desc.idProduct == product_id) {
1401 r = libusb_open(found, &dev_handle);
1407 libusb_free_device_list(devs, 1);
1411 static void do_close(struct libusb_context *ctx,
1412 struct libusb_device_handle *dev_handle)
1414 struct usbi_transfer *itransfer;
1415 struct usbi_transfer *tmp;
1417 /* remove any transfers in flight that are for this device */
1418 usbi_mutex_lock(&ctx->flying_transfers_lock);
1420 /* safe iteration because transfers may be being deleted */
1421 list_for_each_entry_safe(itransfer, tmp, &ctx->flying_transfers, list, struct usbi_transfer) {
1422 struct libusb_transfer *transfer =
1423 USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
1425 if (transfer->dev_handle != dev_handle)
1428 usbi_mutex_lock(&itransfer->lock);
1429 if (!(itransfer->state_flags & USBI_TRANSFER_DEVICE_DISAPPEARED)) {
1430 usbi_err(ctx, "Device handle closed while transfer was still being processed, but the device is still connected as far as we know");
1432 if (itransfer->state_flags & USBI_TRANSFER_CANCELLING)
1433 usbi_warn(ctx, "A cancellation for an in-flight transfer hasn't completed but closing the device handle");
1435 usbi_err(ctx, "A cancellation hasn't even been scheduled on the transfer for which the device is closing");
1437 usbi_mutex_unlock(&itransfer->lock);
1439 /* remove from the list of in-flight transfers and make sure
1440 * we don't accidentally use the device handle in the future
1441 * (or that such accesses will be easily caught and identified as a crash)
1443 list_del(&itransfer->list);
1444 transfer->dev_handle = NULL;
1446 /* it is up to the user to free up the actual transfer struct. this is
1447 * just making sure that we don't attempt to process the transfer after
1448 * the device handle is invalid
1450 usbi_dbg("Removed transfer %p from the in-flight list because device handle %p closed",
1451 transfer, dev_handle);
1453 usbi_mutex_unlock(&ctx->flying_transfers_lock);
1455 usbi_mutex_lock(&ctx->open_devs_lock);
1456 list_del(&dev_handle->list);
1457 usbi_mutex_unlock(&ctx->open_devs_lock);
1459 usbi_backend.close(dev_handle);
1460 libusb_unref_device(dev_handle->dev);
1461 usbi_mutex_destroy(&dev_handle->lock);
1465 /** \ingroup libusb_dev
1466 * Close a device handle. Should be called on all open handles before your
1467 * application exits.
1469 * Internally, this function destroys the reference that was added by
1470 * libusb_open() on the given device.
1472 * This is a non-blocking function; no requests are sent over the bus.
1474 * \param dev_handle the device handle to close
1476 void API_EXPORTED libusb_close(libusb_device_handle *dev_handle)
1478 struct libusb_context *ctx;
1479 int handling_events;
1486 ctx = HANDLE_CTX(dev_handle);
1487 handling_events = usbi_handling_events(ctx);
1489 /* Similarly to libusb_open(), we want to interrupt all event handlers
1490 * at this point. More importantly, we want to perform the actual close of
1491 * the device while holding the event handling lock (preventing any other
1492 * thread from doing event handling) because we will be removing a file
1493 * descriptor from the polling loop. If this is being called by the current
1494 * event handler, we can bypass the interruption code because we already
1495 * hold the event handling lock. */
1497 if (!handling_events) {
1498 /* Record that we are closing a device.
1499 * Only signal an event if there are no prior pending events. */
1500 usbi_mutex_lock(&ctx->event_data_lock);
1501 pending_events = usbi_pending_events(ctx);
1502 ctx->device_close++;
1503 if (!pending_events)
1504 usbi_signal_event(ctx);
1505 usbi_mutex_unlock(&ctx->event_data_lock);
1507 /* take event handling lock */
1508 libusb_lock_events(ctx);
1511 /* Close the device */
1512 do_close(ctx, dev_handle);
1514 if (!handling_events) {
1515 /* We're done with closing this device.
1516 * Clear the event pipe if there are no further pending events. */
1517 usbi_mutex_lock(&ctx->event_data_lock);
1518 ctx->device_close--;
1519 pending_events = usbi_pending_events(ctx);
1520 if (!pending_events)
1521 usbi_clear_event(ctx);
1522 usbi_mutex_unlock(&ctx->event_data_lock);
1524 /* Release event handling lock and wake up event waiters */
1525 libusb_unlock_events(ctx);
1529 /** \ingroup libusb_dev
1530 * Get the underlying device for a device handle. This function does not modify
1531 * the reference count of the returned device, so do not feel compelled to
1532 * unreference it when you are done.
1533 * \param dev_handle a device handle
1534 * \returns the underlying device
1537 libusb_device * LIBUSB_CALL libusb_get_device(libusb_device_handle *dev_handle)
1539 return dev_handle->dev;
1542 /** \ingroup libusb_dev
1543 * Determine the bConfigurationValue of the currently active configuration.
1545 * You could formulate your own control request to obtain this information,
1546 * but this function has the advantage that it may be able to retrieve the
1547 * information from operating system caches (no I/O involved).
1549 * If the OS does not cache this information, then this function will block
1550 * while a control transfer is submitted to retrieve the information.
1552 * This function will return a value of 0 in the <tt>config</tt> output
1553 * parameter if the device is in unconfigured state.
1555 * \param dev_handle a device handle
1556 * \param config output location for the bConfigurationValue of the active
1557 * configuration (only valid for return code 0)
1558 * \returns 0 on success
1559 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1560 * \returns another LIBUSB_ERROR code on other failure
1562 int API_EXPORTED libusb_get_configuration(libusb_device_handle *dev_handle,
1565 int r = LIBUSB_ERROR_NOT_SUPPORTED;
1568 if (usbi_backend.get_configuration)
1569 r = usbi_backend.get_configuration(dev_handle, config);
1571 if (r == LIBUSB_ERROR_NOT_SUPPORTED) {
1573 usbi_dbg("falling back to control message");
1574 r = libusb_control_transfer(dev_handle, LIBUSB_ENDPOINT_IN,
1575 LIBUSB_REQUEST_GET_CONFIGURATION, 0, 0, &tmp, 1, 1000);
1577 usbi_err(HANDLE_CTX(dev_handle), "zero bytes returned in ctrl transfer?");
1578 r = LIBUSB_ERROR_IO;
1579 } else if (r == 1) {
1583 usbi_dbg("control failed, error %d", r);
1588 usbi_dbg("active config %d", *config);
1593 /** \ingroup libusb_dev
1594 * Set the active configuration for a device.
1596 * The operating system may or may not have already set an active
1597 * configuration on the device. It is up to your application to ensure the
1598 * correct configuration is selected before you attempt to claim interfaces
1599 * and perform other operations.
1601 * If you call this function on a device already configured with the selected
1602 * configuration, then this function will act as a lightweight device reset:
1603 * it will issue a SET_CONFIGURATION request using the current configuration,
1604 * causing most USB-related device state to be reset (altsetting reset to zero,
1605 * endpoint halts cleared, toggles reset).
1607 * You cannot change/reset configuration if your application has claimed
1608 * interfaces. It is advised to set the desired configuration before claiming
1611 * Alternatively you can call libusb_release_interface() first. Note if you
1612 * do things this way you must ensure that auto_detach_kernel_driver for
1613 * <tt>dev</tt> is 0, otherwise the kernel driver will be re-attached when you
1614 * release the interface(s).
1616 * You cannot change/reset configuration if other applications or drivers have
1617 * claimed interfaces.
1619 * A configuration value of -1 will put the device in unconfigured state.
1620 * The USB specifications state that a configuration value of 0 does this,
1621 * however buggy devices exist which actually have a configuration 0.
1623 * You should always use this function rather than formulating your own
1624 * SET_CONFIGURATION control request. This is because the underlying operating
1625 * system needs to know when such changes happen.
1627 * This is a blocking function.
1629 * \param dev_handle a device handle
1630 * \param configuration the bConfigurationValue of the configuration you
1631 * wish to activate, or -1 if you wish to put the device in an unconfigured
1633 * \returns 0 on success
1634 * \returns LIBUSB_ERROR_NOT_FOUND if the requested configuration does not exist
1635 * \returns LIBUSB_ERROR_BUSY if interfaces are currently claimed
1636 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1637 * \returns another LIBUSB_ERROR code on other failure
1638 * \see libusb_set_auto_detach_kernel_driver()
1640 int API_EXPORTED libusb_set_configuration(libusb_device_handle *dev_handle,
1643 usbi_dbg("configuration %d", configuration);
1644 return usbi_backend.set_configuration(dev_handle, configuration);
1647 /** \ingroup libusb_dev
1648 * Claim an interface on a given device handle. You must claim the interface
1649 * you wish to use before you can perform I/O on any of its endpoints.
1651 * It is legal to attempt to claim an already-claimed interface, in which
1652 * case libusb just returns 0 without doing anything.
1654 * If auto_detach_kernel_driver is set to 1 for <tt>dev</tt>, the kernel driver
1655 * will be detached if necessary, on failure the detach error is returned.
1657 * Claiming of interfaces is a purely logical operation; it does not cause
1658 * any requests to be sent over the bus. Interface claiming is used to
1659 * instruct the underlying operating system that your application wishes
1660 * to take ownership of the interface.
1662 * This is a non-blocking function.
1664 * \param dev_handle a device handle
1665 * \param interface_number the <tt>bInterfaceNumber</tt> of the interface you
1667 * \returns 0 on success
1668 * \returns LIBUSB_ERROR_NOT_FOUND if the requested interface does not exist
1669 * \returns LIBUSB_ERROR_BUSY if another program or driver has claimed the
1671 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1672 * \returns a LIBUSB_ERROR code on other failure
1673 * \see libusb_set_auto_detach_kernel_driver()
1675 int API_EXPORTED libusb_claim_interface(libusb_device_handle *dev_handle,
1676 int interface_number)
1680 usbi_dbg("interface %d", interface_number);
1681 if (interface_number >= USB_MAXINTERFACES)
1682 return LIBUSB_ERROR_INVALID_PARAM;
1684 if (!dev_handle->dev->attached)
1685 return LIBUSB_ERROR_NO_DEVICE;
1687 usbi_mutex_lock(&dev_handle->lock);
1688 if (dev_handle->claimed_interfaces & (1U << interface_number))
1691 r = usbi_backend.claim_interface(dev_handle, interface_number);
1693 dev_handle->claimed_interfaces |= 1U << interface_number;
1696 usbi_mutex_unlock(&dev_handle->lock);
1700 /** \ingroup libusb_dev
1701 * Release an interface previously claimed with libusb_claim_interface(). You
1702 * should release all claimed interfaces before closing a device handle.
1704 * This is a blocking function. A SET_INTERFACE control request will be sent
1705 * to the device, resetting interface state to the first alternate setting.
1707 * If auto_detach_kernel_driver is set to 1 for <tt>dev</tt>, the kernel
1708 * driver will be re-attached after releasing the interface.
1710 * \param dev_handle a device handle
1711 * \param interface_number the <tt>bInterfaceNumber</tt> of the
1712 * previously-claimed interface
1713 * \returns 0 on success
1714 * \returns LIBUSB_ERROR_NOT_FOUND if the interface was not claimed
1715 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1716 * \returns another LIBUSB_ERROR code on other failure
1717 * \see libusb_set_auto_detach_kernel_driver()
1719 int API_EXPORTED libusb_release_interface(libusb_device_handle *dev_handle,
1720 int interface_number)
1724 usbi_dbg("interface %d", interface_number);
1725 if (interface_number >= USB_MAXINTERFACES)
1726 return LIBUSB_ERROR_INVALID_PARAM;
1728 usbi_mutex_lock(&dev_handle->lock);
1729 if (!(dev_handle->claimed_interfaces & (1U << interface_number))) {
1730 r = LIBUSB_ERROR_NOT_FOUND;
1734 r = usbi_backend.release_interface(dev_handle, interface_number);
1736 dev_handle->claimed_interfaces &= ~(1U << interface_number);
1739 usbi_mutex_unlock(&dev_handle->lock);
1743 /** \ingroup libusb_dev
1744 * Activate an alternate setting for an interface. The interface must have
1745 * been previously claimed with libusb_claim_interface().
1747 * You should always use this function rather than formulating your own
1748 * SET_INTERFACE control request. This is because the underlying operating
1749 * system needs to know when such changes happen.
1751 * This is a blocking function.
1753 * \param dev_handle a device handle
1754 * \param interface_number the <tt>bInterfaceNumber</tt> of the
1755 * previously-claimed interface
1756 * \param alternate_setting the <tt>bAlternateSetting</tt> of the alternate
1757 * setting to activate
1758 * \returns 0 on success
1759 * \returns LIBUSB_ERROR_NOT_FOUND if the interface was not claimed, or the
1760 * requested alternate setting does not exist
1761 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1762 * \returns another LIBUSB_ERROR code on other failure
1764 int API_EXPORTED libusb_set_interface_alt_setting(libusb_device_handle *dev_handle,
1765 int interface_number, int alternate_setting)
1767 usbi_dbg("interface %d altsetting %d",
1768 interface_number, alternate_setting);
1769 if (interface_number >= USB_MAXINTERFACES)
1770 return LIBUSB_ERROR_INVALID_PARAM;
1772 usbi_mutex_lock(&dev_handle->lock);
1773 if (!dev_handle->dev->attached) {
1774 usbi_mutex_unlock(&dev_handle->lock);
1775 return LIBUSB_ERROR_NO_DEVICE;
1778 if (!(dev_handle->claimed_interfaces & (1U << interface_number))) {
1779 usbi_mutex_unlock(&dev_handle->lock);
1780 return LIBUSB_ERROR_NOT_FOUND;
1782 usbi_mutex_unlock(&dev_handle->lock);
1784 return usbi_backend.set_interface_altsetting(dev_handle, interface_number,
1788 /** \ingroup libusb_dev
1789 * Clear the halt/stall condition for an endpoint. Endpoints with halt status
1790 * are unable to receive or transmit data until the halt condition is stalled.
1792 * You should cancel all pending transfers before attempting to clear the halt
1795 * This is a blocking function.
1797 * \param dev_handle a device handle
1798 * \param endpoint the endpoint to clear halt status
1799 * \returns 0 on success
1800 * \returns LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist
1801 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1802 * \returns another LIBUSB_ERROR code on other failure
1804 int API_EXPORTED libusb_clear_halt(libusb_device_handle *dev_handle,
1805 unsigned char endpoint)
1807 usbi_dbg("endpoint %x", endpoint);
1808 if (!dev_handle->dev->attached)
1809 return LIBUSB_ERROR_NO_DEVICE;
1811 return usbi_backend.clear_halt(dev_handle, endpoint);
1814 /** \ingroup libusb_dev
1815 * Perform a USB port reset to reinitialize a device. The system will attempt
1816 * to restore the previous configuration and alternate settings after the
1817 * reset has completed.
1819 * If the reset fails, the descriptors change, or the previous state cannot be
1820 * restored, the device will appear to be disconnected and reconnected. This
1821 * means that the device handle is no longer valid (you should close it) and
1822 * rediscover the device. A return code of LIBUSB_ERROR_NOT_FOUND indicates
1823 * when this is the case.
1825 * This is a blocking function which usually incurs a noticeable delay.
1827 * \param dev_handle a handle of the device to reset
1828 * \returns 0 on success
1829 * \returns LIBUSB_ERROR_NOT_FOUND if re-enumeration is required, or if the
1830 * device has been disconnected
1831 * \returns another LIBUSB_ERROR code on other failure
1833 int API_EXPORTED libusb_reset_device(libusb_device_handle *dev_handle)
1836 if (!dev_handle->dev->attached)
1837 return LIBUSB_ERROR_NO_DEVICE;
1839 return usbi_backend.reset_device(dev_handle);
1842 /** \ingroup libusb_asyncio
1843 * Allocate up to num_streams usb bulk streams on the specified endpoints. This
1844 * function takes an array of endpoints rather then a single endpoint because
1845 * some protocols require that endpoints are setup with similar stream ids.
1846 * All endpoints passed in must belong to the same interface.
1848 * Note this function may return less streams then requested. Also note that the
1849 * same number of streams are allocated for each endpoint in the endpoint array.
1851 * Stream id 0 is reserved, and should not be used to communicate with devices.
1852 * If libusb_alloc_streams() returns with a value of N, you may use stream ids
1855 * Since version 1.0.19, \ref LIBUSB_API_VERSION >= 0x01000103
1857 * \param dev_handle a device handle
1858 * \param num_streams number of streams to try to allocate
1859 * \param endpoints array of endpoints to allocate streams on
1860 * \param num_endpoints length of the endpoints array
1861 * \returns number of streams allocated, or a LIBUSB_ERROR code on failure
1863 int API_EXPORTED libusb_alloc_streams(libusb_device_handle *dev_handle,
1864 uint32_t num_streams, unsigned char *endpoints, int num_endpoints)
1866 usbi_dbg("streams %u eps %d", (unsigned) num_streams, num_endpoints);
1868 if (!dev_handle->dev->attached)
1869 return LIBUSB_ERROR_NO_DEVICE;
1871 if (usbi_backend.alloc_streams)
1872 return usbi_backend.alloc_streams(dev_handle, num_streams, endpoints,
1875 return LIBUSB_ERROR_NOT_SUPPORTED;
1878 /** \ingroup libusb_asyncio
1879 * Free usb bulk streams allocated with libusb_alloc_streams().
1881 * Note streams are automatically free-ed when releasing an interface.
1883 * Since version 1.0.19, \ref LIBUSB_API_VERSION >= 0x01000103
1885 * \param dev_handle a device handle
1886 * \param endpoints array of endpoints to free streams on
1887 * \param num_endpoints length of the endpoints array
1888 * \returns LIBUSB_SUCCESS, or a LIBUSB_ERROR code on failure
1890 int API_EXPORTED libusb_free_streams(libusb_device_handle *dev_handle,
1891 unsigned char *endpoints, int num_endpoints)
1893 usbi_dbg("eps %d", num_endpoints);
1895 if (!dev_handle->dev->attached)
1896 return LIBUSB_ERROR_NO_DEVICE;
1898 if (usbi_backend.free_streams)
1899 return usbi_backend.free_streams(dev_handle, endpoints,
1902 return LIBUSB_ERROR_NOT_SUPPORTED;
1905 /** \ingroup libusb_asyncio
1906 * Attempts to allocate a block of persistent DMA memory suitable for transfers
1907 * against the given device. If successful, will return a block of memory
1908 * that is suitable for use as "buffer" in \ref libusb_transfer against this
1909 * device. Using this memory instead of regular memory means that the host
1910 * controller can use DMA directly into the buffer to increase performance, and
1911 * also that transfers can no longer fail due to kernel memory fragmentation.
1913 * Note that this means you should not modify this memory (or even data on
1914 * the same cache lines) when a transfer is in progress, although it is legal
1915 * to have several transfers going on within the same memory block.
1917 * Will return NULL on failure. Many systems do not support such zerocopy
1918 * and will always return NULL. Memory allocated with this function must be
1919 * freed with \ref libusb_dev_mem_free. Specifically, this means that the
1920 * flag \ref LIBUSB_TRANSFER_FREE_BUFFER cannot be used to free memory allocated
1921 * with this function.
1923 * Since version 1.0.21, \ref LIBUSB_API_VERSION >= 0x01000105
1925 * \param dev_handle a device handle
1926 * \param length size of desired data buffer
1927 * \returns a pointer to the newly allocated memory, or NULL on failure
1930 unsigned char * LIBUSB_CALL libusb_dev_mem_alloc(libusb_device_handle *dev_handle,
1933 if (!dev_handle->dev->attached)
1936 if (usbi_backend.dev_mem_alloc)
1937 return usbi_backend.dev_mem_alloc(dev_handle, length);
1942 /** \ingroup libusb_asyncio
1943 * Free device memory allocated with libusb_dev_mem_alloc().
1945 * \param dev_handle a device handle
1946 * \param buffer pointer to the previously allocated memory
1947 * \param length size of previously allocated memory
1948 * \returns LIBUSB_SUCCESS, or a LIBUSB_ERROR code on failure
1950 int API_EXPORTED libusb_dev_mem_free(libusb_device_handle *dev_handle,
1951 unsigned char *buffer, size_t length)
1953 if (usbi_backend.dev_mem_free)
1954 return usbi_backend.dev_mem_free(dev_handle, buffer, length);
1956 return LIBUSB_ERROR_NOT_SUPPORTED;
1959 /** \ingroup libusb_dev
1960 * Determine if a kernel driver is active on an interface. If a kernel driver
1961 * is active, you cannot claim the interface, and libusb will be unable to
1964 * This functionality is not available on Windows.
1966 * \param dev_handle a device handle
1967 * \param interface_number the interface to check
1968 * \returns 0 if no kernel driver is active
1969 * \returns 1 if a kernel driver is active
1970 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1971 * \returns LIBUSB_ERROR_NOT_SUPPORTED on platforms where the functionality
1973 * \returns another LIBUSB_ERROR code on other failure
1974 * \see libusb_detach_kernel_driver()
1976 int API_EXPORTED libusb_kernel_driver_active(libusb_device_handle *dev_handle,
1977 int interface_number)
1979 usbi_dbg("interface %d", interface_number);
1981 if (!dev_handle->dev->attached)
1982 return LIBUSB_ERROR_NO_DEVICE;
1984 if (usbi_backend.kernel_driver_active)
1985 return usbi_backend.kernel_driver_active(dev_handle, interface_number);
1987 return LIBUSB_ERROR_NOT_SUPPORTED;
1990 /** \ingroup libusb_dev
1991 * Detach a kernel driver from an interface. If successful, you will then be
1992 * able to claim the interface and perform I/O.
1994 * This functionality is not available on Darwin or Windows.
1996 * Note that libusb itself also talks to the device through a special kernel
1997 * driver, if this driver is already attached to the device, this call will
1998 * not detach it and return LIBUSB_ERROR_NOT_FOUND.
2000 * \param dev_handle a device handle
2001 * \param interface_number the interface to detach the driver from
2002 * \returns 0 on success
2003 * \returns LIBUSB_ERROR_NOT_FOUND if no kernel driver was active
2004 * \returns LIBUSB_ERROR_INVALID_PARAM if the interface does not exist
2005 * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
2006 * \returns LIBUSB_ERROR_NOT_SUPPORTED on platforms where the functionality
2008 * \returns another LIBUSB_ERROR code on other failure
2009 * \see libusb_kernel_driver_active()
2011 int API_EXPORTED libusb_detach_kernel_driver(libusb_device_handle *dev_handle,
2012 int interface_number)
2014 usbi_dbg("interface %d", interface_number);
2016 if (!dev_handle->dev->attached)
2017 return LIBUSB_ERROR_NO_DEVICE;
2019 if (usbi_backend.detach_kernel_driver)
2020 return usbi_backend.detach_kernel_driver(dev_handle, interface_number);
2022 return LIBUSB_ERROR_NOT_SUPPORTED;
2025 /** \ingroup libusb_dev
2026 * Re-attach an interface's kernel driver, which was previously detached
2027 * using libusb_detach_kernel_driver(). This call is only effective on
2028 * Linux and returns LIBUSB_ERROR_NOT_SUPPORTED on all other platforms.
2030 * This functionality is not available on Darwin or 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("interface %d", interface_number);
2050 if (!dev_handle->dev->attached)
2051 return LIBUSB_ERROR_NO_DEVICE;
2053 if (usbi_backend.attach_kernel_driver)
2054 return usbi_backend.attach_kernel_driver(dev_handle, interface_number);
2056 return LIBUSB_ERROR_NOT_SUPPORTED;
2059 /** \ingroup libusb_dev
2060 * Enable/disable libusb's automatic kernel driver detachment. When this is
2061 * enabled libusb will automatically detach the kernel driver on an interface
2062 * when claiming the interface, and attach it when releasing the interface.
2064 * Automatic kernel driver detachment is disabled on newly opened device
2065 * handles by default.
2067 * On platforms which do not have LIBUSB_CAP_SUPPORTS_DETACH_KERNEL_DRIVER
2068 * this function will return LIBUSB_ERROR_NOT_SUPPORTED, and libusb will
2069 * continue as if this function was never called.
2071 * \param dev_handle a device handle
2072 * \param enable whether to enable or disable auto kernel driver detachment
2074 * \returns LIBUSB_SUCCESS on success
2075 * \returns LIBUSB_ERROR_NOT_SUPPORTED on platforms where the functionality
2077 * \see libusb_claim_interface()
2078 * \see libusb_release_interface()
2079 * \see libusb_set_configuration()
2081 int API_EXPORTED libusb_set_auto_detach_kernel_driver(
2082 libusb_device_handle *dev_handle, int enable)
2084 if (!(usbi_backend.caps & USBI_CAP_SUPPORTS_DETACH_KERNEL_DRIVER))
2085 return LIBUSB_ERROR_NOT_SUPPORTED;
2087 dev_handle->auto_detach_kernel_driver = enable;
2088 return LIBUSB_SUCCESS;
2091 /** \ingroup libusb_lib
2092 * \deprecated Use libusb_set_option() instead using the
2093 * \ref LIBUSB_OPTION_LOG_LEVEL option.
2095 void API_EXPORTED libusb_set_debug(libusb_context *ctx, int level)
2097 #if defined(ENABLE_LOGGING) && !defined(ENABLE_DEBUG_LOGGING)
2098 USBI_GET_CONTEXT(ctx);
2099 if (!ctx->debug_fixed) {
2100 level = CLAMP(level, LIBUSB_LOG_LEVEL_NONE, LIBUSB_LOG_LEVEL_DEBUG);
2101 ctx->debug = (enum libusb_log_level)level;
2109 /** \ingroup libusb_lib
2112 * libusb will redirect its log messages to the provided callback function.
2113 * libusb supports redirection of per context and global log messages.
2114 * Log messages sent to the context will be sent to the global log handler too.
2116 * If libusb is compiled without message logging or USE_SYSTEM_LOGGING_FACILITY
2117 * is defined then global callback function will never be called.
2118 * If ENABLE_DEBUG_LOGGING is defined then per context callback function will
2121 * \param ctx context on which to assign log handler, or NULL for the default
2122 * context. Parameter ignored if only LIBUSB_LOG_CB_GLOBAL mode is requested.
2123 * \param cb pointer to the callback function, or NULL to stop log
2124 * messages redirection
2125 * \param mode mode of callback function operation. Several modes can be
2126 * selected for a single callback function, see \ref libusb_log_cb_mode for
2128 * \see libusb_log_cb, libusb_log_cb_mode
2130 void API_EXPORTED libusb_set_log_cb(libusb_context *ctx, libusb_log_cb cb,
2133 #if !defined(USE_SYSTEM_LOGGING_FACILITY)
2134 if (mode & LIBUSB_LOG_CB_GLOBAL) {
2138 #if defined(ENABLE_LOGGING) && !defined(ENABLE_DEBUG_LOGGING)
2139 if (mode & LIBUSB_LOG_CB_CONTEXT) {
2140 USBI_GET_CONTEXT(ctx);
2141 ctx->log_handler = cb;
2145 #if defined(USE_SYSTEM_LOGGING_FACILITY)
2152 /** \ingroup libusb_lib
2153 * Set an option in the library.
2155 * Use this function to configure a specific option within the library.
2157 * Some options require one or more arguments to be provided. Consult each
2158 * option's documentation for specific requirements.
2160 * Since version 1.0.22, \ref LIBUSB_API_VERSION >= 0x01000106
2162 * \param ctx context on which to operate
2163 * \param option which option to set
2164 * \param ... any required arguments for the specified option
2166 * \returns LIBUSB_SUCCESS on success
2167 * \returns LIBUSB_ERROR_INVALID_PARAM if the option or arguments are invalid
2168 * \returns LIBUSB_ERROR_NOT_SUPPORTED if the option is valid but not supported
2171 int API_EXPORTED libusb_set_option(libusb_context *ctx,
2172 enum libusb_option option, ...)
2174 int arg, r = LIBUSB_SUCCESS;
2177 USBI_GET_CONTEXT(ctx);
2179 va_start(ap, option);
2181 case LIBUSB_OPTION_LOG_LEVEL:
2182 arg = va_arg(ap, int);
2183 if (arg < LIBUSB_LOG_LEVEL_NONE || arg > LIBUSB_LOG_LEVEL_DEBUG) {
2184 r = LIBUSB_ERROR_INVALID_PARAM;
2187 #if defined(ENABLE_LOGGING) && !defined(ENABLE_DEBUG_LOGGING)
2188 if (!ctx->debug_fixed)
2189 ctx->debug = (enum libusb_log_level)arg;
2193 /* Handle all backend-specific options here */
2194 case LIBUSB_OPTION_USE_USBDK:
2195 if (usbi_backend.set_option)
2196 r = usbi_backend.set_option(ctx, option, ap);
2198 r = LIBUSB_ERROR_NOT_SUPPORTED;
2202 r = LIBUSB_ERROR_INVALID_PARAM;
2209 #if defined(ENABLE_LOGGING) && !defined(ENABLE_DEBUG_LOGGING)
2210 /* returns the log level as defined in the LIBUSB_DEBUG environment variable.
2211 * if LIBUSB_DEBUG is not present or not a number, returns LIBUSB_LOG_LEVEL_NONE.
2212 * value is clamped to ensure it is within the valid range of possibilities.
2214 static enum libusb_log_level get_env_debug_level(void)
2216 const char *dbg = getenv("LIBUSB_DEBUG");
2217 enum libusb_log_level level;
2219 int dbg_level = atoi(dbg);
2220 dbg_level = CLAMP(dbg_level, LIBUSB_LOG_LEVEL_NONE, LIBUSB_LOG_LEVEL_DEBUG);
2221 level = (enum libusb_log_level)dbg_level;
2223 level = LIBUSB_LOG_LEVEL_NONE;
2229 /** \ingroup libusb_lib
2230 * Initialize libusb. This function must be called before calling any other
2233 * If you do not provide an output location for a context pointer, a default
2234 * context will be created. If there was already a default context, it will
2235 * be reused (and nothing will be initialized/reinitialized).
2237 * \param context Optional output location for context pointer.
2238 * Only valid on return code 0.
2239 * \returns 0 on success, or a LIBUSB_ERROR code on failure
2240 * \see libusb_contexts
2242 int API_EXPORTED libusb_init(libusb_context **context)
2244 struct libusb_device *dev, *next;
2245 size_t priv_size = usbi_backend.context_priv_size;
2246 struct libusb_context *ctx;
2247 static int first_init = 1;
2250 usbi_mutex_static_lock(&default_context_lock);
2252 if (!timestamp_origin.tv_sec) {
2253 usbi_backend.clock_gettime(USBI_CLOCK_REALTIME, ×tamp_origin);
2256 if (!context && usbi_default_context) {
2257 usbi_dbg("reusing default context");
2258 default_context_refcnt++;
2259 usbi_mutex_static_unlock(&default_context_lock);
2263 ctx = calloc(1, sizeof(*ctx) + priv_size);
2265 r = LIBUSB_ERROR_NO_MEM;
2269 #if defined(ENABLE_LOGGING) && !defined(ENABLE_DEBUG_LOGGING)
2270 ctx->debug = get_env_debug_level();
2271 if (ctx->debug != LIBUSB_LOG_LEVEL_NONE)
2272 ctx->debug_fixed = 1;
2275 /* default context should be initialized before calling usbi_dbg */
2276 if (!usbi_default_context) {
2277 usbi_default_context = ctx;
2278 default_context_refcnt++;
2279 usbi_dbg("created default context");
2282 usbi_dbg("libusb v%u.%u.%u.%u%s", libusb_version_internal.major, libusb_version_internal.minor,
2283 libusb_version_internal.micro, libusb_version_internal.nano, libusb_version_internal.rc);
2285 usbi_mutex_init(&ctx->usb_devs_lock);
2286 usbi_mutex_init(&ctx->open_devs_lock);
2287 usbi_mutex_init(&ctx->hotplug_cbs_lock);
2288 list_init(&ctx->usb_devs);
2289 list_init(&ctx->open_devs);
2290 list_init(&ctx->hotplug_cbs);
2291 ctx->next_hotplug_cb_handle = 1;
2293 usbi_mutex_static_lock(&active_contexts_lock);
2296 list_init(&active_contexts_list);
2298 list_add (&ctx->list, &active_contexts_list);
2299 usbi_mutex_static_unlock(&active_contexts_lock);
2301 if (usbi_backend.init) {
2302 r = usbi_backend.init(ctx);
2307 r = usbi_io_init(ctx);
2309 goto err_backend_exit;
2311 usbi_mutex_static_unlock(&default_context_lock);
2319 if (usbi_backend.exit)
2320 usbi_backend.exit(ctx);
2322 if (ctx == usbi_default_context) {
2323 usbi_default_context = NULL;
2324 default_context_refcnt--;
2327 usbi_mutex_static_lock(&active_contexts_lock);
2328 list_del(&ctx->list);
2329 usbi_mutex_static_unlock(&active_contexts_lock);
2331 usbi_mutex_lock(&ctx->usb_devs_lock);
2332 list_for_each_entry_safe(dev, next, &ctx->usb_devs, list, struct libusb_device) {
2333 list_del(&dev->list);
2334 libusb_unref_device(dev);
2336 usbi_mutex_unlock(&ctx->usb_devs_lock);
2338 usbi_mutex_destroy(&ctx->open_devs_lock);
2339 usbi_mutex_destroy(&ctx->usb_devs_lock);
2340 usbi_mutex_destroy(&ctx->hotplug_cbs_lock);
2344 usbi_mutex_static_unlock(&default_context_lock);
2348 /** \ingroup libusb_lib
2349 * Deinitialize libusb. Should be called after closing all open devices and
2350 * before your application terminates.
2351 * \param ctx the context to deinitialize, or NULL for the default context
2353 void API_EXPORTED libusb_exit(struct libusb_context *ctx)
2355 struct libusb_device *dev, *next;
2356 struct timeval tv = { 0, 0 };
2357 int destroying_default_context = 0;
2360 USBI_GET_CONTEXT(ctx);
2362 /* if working with default context, only actually do the deinitialization
2363 * if we're the last user */
2364 usbi_mutex_static_lock(&default_context_lock);
2365 if (ctx == usbi_default_context) {
2366 if (!usbi_default_context) {
2367 usbi_dbg("no default context, not initialized?");
2368 usbi_mutex_static_unlock(&default_context_lock);
2372 if (--default_context_refcnt > 0) {
2373 usbi_dbg("not destroying default context");
2374 usbi_mutex_static_unlock(&default_context_lock);
2377 usbi_dbg("destroying default context");
2380 * Setting this flag without unlocking the default context, as
2381 * we are actually destroying the default context.
2382 * usbi_default_context is not set to NULL yet, as all activities
2383 * would only stop after usbi_backend->exit() returns.
2385 destroying_default_context = 1;
2387 /* Unlock default context, as we're not modifying it. */
2388 usbi_mutex_static_unlock(&default_context_lock);
2391 usbi_mutex_static_lock(&active_contexts_lock);
2392 list_del(&ctx->list);
2393 usbi_mutex_static_unlock(&active_contexts_lock);
2395 if (libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG)) {
2396 usbi_hotplug_deregister(ctx, 1);
2399 * Ensure any pending unplug events are read from the hotplug
2400 * pipe. The usb_device-s hold in the events are no longer part
2401 * of usb_devs, but the events still hold a reference!
2403 * Note we don't do this if the application has left devices
2404 * open (which implies a buggy app) to avoid packet completion
2405 * handlers running when the app does not expect them to run.
2407 if (list_empty(&ctx->open_devs))
2408 libusb_handle_events_timeout(ctx, &tv);
2410 usbi_mutex_lock(&ctx->usb_devs_lock);
2411 list_for_each_entry_safe(dev, next, &ctx->usb_devs, list, struct libusb_device) {
2412 list_del(&dev->list);
2413 libusb_unref_device(dev);
2415 usbi_mutex_unlock(&ctx->usb_devs_lock);
2418 /* a few sanity checks. don't bother with locking because unless
2419 * there is an application bug, nobody will be accessing these. */
2420 if (!list_empty(&ctx->usb_devs))
2421 usbi_warn(ctx, "some libusb_devices were leaked");
2422 if (!list_empty(&ctx->open_devs))
2423 usbi_warn(ctx, "application left some devices open");
2426 if (usbi_backend.exit)
2427 usbi_backend.exit(ctx);
2429 usbi_mutex_destroy(&ctx->open_devs_lock);
2430 usbi_mutex_destroy(&ctx->usb_devs_lock);
2431 usbi_mutex_destroy(&ctx->hotplug_cbs_lock);
2434 if (destroying_default_context) {
2435 usbi_default_context = NULL;
2436 usbi_mutex_static_unlock(&default_context_lock);
2440 /** \ingroup libusb_misc
2441 * Check at runtime if the loaded library has a given capability.
2442 * This call should be performed after \ref libusb_init(), to ensure the
2443 * backend has updated its capability set.
2445 * \param capability the \ref libusb_capability to check for
2446 * \returns nonzero if the running library has the capability, 0 otherwise
2448 int API_EXPORTED libusb_has_capability(uint32_t capability)
2450 switch (capability) {
2451 case LIBUSB_CAP_HAS_CAPABILITY:
2453 case LIBUSB_CAP_HAS_HOTPLUG:
2454 return !(usbi_backend.get_device_list);
2455 case LIBUSB_CAP_HAS_HID_ACCESS:
2456 return (usbi_backend.caps & USBI_CAP_HAS_HID_ACCESS);
2457 case LIBUSB_CAP_SUPPORTS_DETACH_KERNEL_DRIVER:
2458 return (usbi_backend.caps & USBI_CAP_SUPPORTS_DETACH_KERNEL_DRIVER);
2463 #ifdef ENABLE_LOGGING
2465 /* this is defined in libusbi.h if needed */
2466 #ifdef LIBUSB_PRINTF_WIN32
2468 * Prior to VS2015, Microsoft did not provide the snprintf() function and
2469 * provided a vsnprintf() that did not guarantee NULL-terminated output.
2470 * Microsoft did provide a _snprintf() function, but again it did not
2471 * guarantee NULL-terminated output.
2473 * The below implementations guarantee NULL-terminated output and are
2477 int usbi_snprintf(char *str, size_t size, const char *format, ...)
2482 va_start(ap, format);
2483 ret = usbi_vsnprintf(str, size, format, ap);
2489 int usbi_vsnprintf(char *str, size_t size, const char *format, va_list ap)
2493 ret = _vsnprintf(str, size, format, ap);
2494 if (ret < 0 || ret == (int)size) {
2495 /* Output is truncated, ensure buffer is NULL-terminated and
2496 * determine how many characters would have been written. */
2497 str[size - 1] = '\0';
2499 ret = _vsnprintf(NULL, 0, format, ap);
2504 #endif /* LIBUSB_PRINTF_WIN32 */
2506 static void usbi_log_str(enum libusb_log_level level, const char *str)
2508 #if defined(USE_SYSTEM_LOGGING_FACILITY)
2509 #if defined(OS_WINDOWS) || defined(OS_WINCE)
2510 #if !defined(UNICODE)
2511 OutputDebugStringA(str);
2513 WCHAR wbuf[USBI_MAX_LOG_LEN];
2514 if (MultiByteToWideChar(CP_UTF8, 0, str, -1, wbuf, sizeof(wbuf)) != 0)
2515 OutputDebugStringW(wbuf);
2517 #elif defined(__ANDROID__)
2518 int priority = ANDROID_LOG_UNKNOWN;
2520 case LIBUSB_LOG_LEVEL_NONE: return;
2521 case LIBUSB_LOG_LEVEL_ERROR: priority = ANDROID_LOG_ERROR; break;
2522 case LIBUSB_LOG_LEVEL_WARNING: priority = ANDROID_LOG_WARN; break;
2523 case LIBUSB_LOG_LEVEL_INFO: priority = ANDROID_LOG_INFO; break;
2524 case LIBUSB_LOG_LEVEL_DEBUG: priority = ANDROID_LOG_DEBUG; break;
2526 __android_log_write(priority, "libusb", str);
2527 #elif defined(HAVE_SYSLOG_FUNC)
2528 int syslog_level = LOG_INFO;
2530 case LIBUSB_LOG_LEVEL_NONE: return;
2531 case LIBUSB_LOG_LEVEL_ERROR: syslog_level = LOG_ERR; break;
2532 case LIBUSB_LOG_LEVEL_WARNING: syslog_level = LOG_WARNING; break;
2533 case LIBUSB_LOG_LEVEL_INFO: syslog_level = LOG_INFO; break;
2534 case LIBUSB_LOG_LEVEL_DEBUG: syslog_level = LOG_DEBUG; break;
2536 syslog(syslog_level, "%s", str);
2537 #else /* All of gcc, Clang, Xcode seem to use #warning */
2538 #warning System logging is not supported on this platform. Logging to stderr will be used instead.
2542 /* Global log handler */
2543 if (log_handler != NULL)
2544 log_handler(NULL, level, str);
2547 #endif /* USE_SYSTEM_LOGGING_FACILITY */
2551 void usbi_log_v(struct libusb_context *ctx, enum libusb_log_level level,
2552 const char *function, const char *format, va_list args)
2555 char buf[USBI_MAX_LOG_LEN];
2556 struct timespec now;
2557 int global_debug, header_len, text_len;
2558 static int has_debug_header_been_displayed = 0;
2560 #ifdef ENABLE_DEBUG_LOGGING
2564 enum libusb_log_level ctx_level = LIBUSB_LOG_LEVEL_NONE;
2566 USBI_GET_CONTEXT(ctx);
2568 ctx_level = ctx->debug;
2570 ctx_level = get_env_debug_level();
2572 if (ctx_level == LIBUSB_LOG_LEVEL_NONE)
2574 if (level == LIBUSB_LOG_LEVEL_WARNING && ctx_level < LIBUSB_LOG_LEVEL_WARNING)
2576 if (level == LIBUSB_LOG_LEVEL_INFO && ctx_level < LIBUSB_LOG_LEVEL_INFO)
2578 if (level == LIBUSB_LOG_LEVEL_DEBUG && ctx_level < LIBUSB_LOG_LEVEL_DEBUG)
2581 global_debug = (ctx_level == LIBUSB_LOG_LEVEL_DEBUG);
2584 usbi_backend.clock_gettime(USBI_CLOCK_REALTIME, &now);
2585 if ((global_debug) && (!has_debug_header_been_displayed)) {
2586 has_debug_header_been_displayed = 1;
2587 usbi_log_str(LIBUSB_LOG_LEVEL_DEBUG, "[timestamp] [threadID] facility level [function call] <message>" USBI_LOG_LINE_END);
2588 usbi_log_str(LIBUSB_LOG_LEVEL_DEBUG, "--------------------------------------------------------------------------------" USBI_LOG_LINE_END);
2590 if (now.tv_nsec < timestamp_origin.tv_nsec) {
2592 now.tv_nsec += 1000000000L;
2594 now.tv_sec -= timestamp_origin.tv_sec;
2595 now.tv_nsec -= timestamp_origin.tv_nsec;
2598 case LIBUSB_LOG_LEVEL_NONE:
2600 case LIBUSB_LOG_LEVEL_ERROR:
2603 case LIBUSB_LOG_LEVEL_WARNING:
2606 case LIBUSB_LOG_LEVEL_INFO:
2609 case LIBUSB_LOG_LEVEL_DEBUG:
2618 header_len = snprintf(buf, sizeof(buf),
2619 "[%2ld.%06ld] [%08x] libusb: %s [%s] ",
2620 (long)now.tv_sec, (long)(now.tv_nsec / 1000L), usbi_get_tid(), prefix, function);
2622 header_len = snprintf(buf, sizeof(buf),
2623 "libusb: %s [%s] ", prefix, function);
2626 if (header_len < 0 || header_len >= (int)sizeof(buf)) {
2627 /* Somehow snprintf failed to write to the buffer,
2628 * remove the header so something useful is output. */
2631 /* Make sure buffer is NUL terminated */
2632 buf[header_len] = '\0';
2633 text_len = vsnprintf(buf + header_len, sizeof(buf) - (size_t)header_len,
2635 if (text_len < 0 || text_len + header_len >= (int)sizeof(buf)) {
2636 /* Truncated log output. On some platforms a -1 return value means
2637 * that the output was truncated. */
2638 text_len = (int)sizeof(buf) - header_len;
2640 if (header_len + text_len + (int)sizeof(USBI_LOG_LINE_END) >= (int)sizeof(buf)) {
2641 /* Need to truncate the text slightly to fit on the terminator. */
2642 text_len -= (header_len + text_len + (int)sizeof(USBI_LOG_LINE_END)) - (int)sizeof(buf);
2644 strcpy(buf + header_len + text_len, USBI_LOG_LINE_END);
2646 usbi_log_str(level, buf);
2648 /* Per context log handler */
2649 #ifndef ENABLE_DEBUG_LOGGING
2650 if (ctx && ctx->log_handler)
2651 ctx->log_handler(ctx, level, buf);
2655 void usbi_log(struct libusb_context *ctx, enum libusb_log_level level,
2656 const char *function, const char *format, ...)
2660 va_start (args, format);
2661 usbi_log_v(ctx, level, function, format, args);
2665 #endif /* ENABLE_LOGGING */
2667 /** \ingroup libusb_misc
2668 * Returns a constant NULL-terminated string with the ASCII name of a libusb
2669 * error or transfer status code. The caller must not free() the returned
2672 * \param error_code The \ref libusb_error or libusb_transfer_status code to
2673 * return the name of.
2674 * \returns The error name, or the string **UNKNOWN** if the value of
2675 * error_code is not a known error / status code.
2677 DEFAULT_VISIBILITY const char * LIBUSB_CALL libusb_error_name(int error_code)
2679 switch (error_code) {
2680 case LIBUSB_ERROR_IO:
2681 return "LIBUSB_ERROR_IO";
2682 case LIBUSB_ERROR_INVALID_PARAM:
2683 return "LIBUSB_ERROR_INVALID_PARAM";
2684 case LIBUSB_ERROR_ACCESS:
2685 return "LIBUSB_ERROR_ACCESS";
2686 case LIBUSB_ERROR_NO_DEVICE:
2687 return "LIBUSB_ERROR_NO_DEVICE";
2688 case LIBUSB_ERROR_NOT_FOUND:
2689 return "LIBUSB_ERROR_NOT_FOUND";
2690 case LIBUSB_ERROR_BUSY:
2691 return "LIBUSB_ERROR_BUSY";
2692 case LIBUSB_ERROR_TIMEOUT:
2693 return "LIBUSB_ERROR_TIMEOUT";
2694 case LIBUSB_ERROR_OVERFLOW:
2695 return "LIBUSB_ERROR_OVERFLOW";
2696 case LIBUSB_ERROR_PIPE:
2697 return "LIBUSB_ERROR_PIPE";
2698 case LIBUSB_ERROR_INTERRUPTED:
2699 return "LIBUSB_ERROR_INTERRUPTED";
2700 case LIBUSB_ERROR_NO_MEM:
2701 return "LIBUSB_ERROR_NO_MEM";
2702 case LIBUSB_ERROR_NOT_SUPPORTED:
2703 return "LIBUSB_ERROR_NOT_SUPPORTED";
2704 case LIBUSB_ERROR_OTHER:
2705 return "LIBUSB_ERROR_OTHER";
2707 case LIBUSB_TRANSFER_ERROR:
2708 return "LIBUSB_TRANSFER_ERROR";
2709 case LIBUSB_TRANSFER_TIMED_OUT:
2710 return "LIBUSB_TRANSFER_TIMED_OUT";
2711 case LIBUSB_TRANSFER_CANCELLED:
2712 return "LIBUSB_TRANSFER_CANCELLED";
2713 case LIBUSB_TRANSFER_STALL:
2714 return "LIBUSB_TRANSFER_STALL";
2715 case LIBUSB_TRANSFER_NO_DEVICE:
2716 return "LIBUSB_TRANSFER_NO_DEVICE";
2717 case LIBUSB_TRANSFER_OVERFLOW:
2718 return "LIBUSB_TRANSFER_OVERFLOW";
2721 return "LIBUSB_SUCCESS / LIBUSB_TRANSFER_COMPLETED";
2723 return "**UNKNOWN**";
2727 /** \ingroup libusb_misc
2728 * Returns a pointer to const struct libusb_version with the version
2729 * (major, minor, micro, nano and rc) of the running library.
2732 const struct libusb_version * LIBUSB_CALL libusb_get_version(void)
2734 return &libusb_version_internal;