2 * Internal header for libusb
3 * Copyright © 2007-2009 Daniel Drake <dsd@gentoo.org>
4 * Copyright © 2001 Johannes Erdfelt <johannes@erdfelt.com>
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with this library; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
42 /* Inside the libusb code, mark all public functions as follows:
43 * return_type API_EXPORTED function_name(params) { ... }
44 * But if the function returns a pointer, mark it as follows:
45 * DEFAULT_VISIBILITY return_type * LIBUSB_CALL function_name(params) { ... }
46 * In the libusb public header, mark all declarations as:
47 * return_type LIBUSB_CALL function_name(params);
49 #define API_EXPORTED LIBUSB_CALL DEFAULT_VISIBILITY
55 #define DEVICE_DESC_LENGTH 18
57 #define USB_MAXENDPOINTS 32
58 #define USB_MAXINTERFACES 32
59 #define USB_MAXCONFIG 8
61 /* Backend specific capabilities */
62 #define USBI_CAP_HAS_HID_ACCESS 0x00010000
63 #define USBI_CAP_SUPPORTS_DETACH_KERNEL_DRIVER 0x00020000
65 /* Maximum number of bytes in a log line */
66 #define USBI_MAX_LOG_LEN 1024
67 /* Terminator for log lines */
68 #define USBI_LOG_LINE_END "\n"
70 /* The following is used to silence warnings for unused variables */
71 #define UNUSED(var) do { (void)(var); } while(0)
73 #if !defined(ARRAYSIZE)
74 #define ARRAYSIZE(array) (sizeof(array)/sizeof(array[0]))
78 struct list_head *prev, *next;
81 /* Get an entry from the list
82 * ptr - the address of this list_head element in "type"
83 * type - the data type that contains "member"
84 * member - the list_head element in "type"
86 #define list_entry(ptr, type, member) \
87 ((type *)((uintptr_t)(ptr) - (uintptr_t)offsetof(type, member)))
89 #define list_first_entry(ptr, type, member) \
90 list_entry((ptr)->next, type, member)
92 /* Get each entry from a list
93 * pos - A structure pointer has a "member" element
95 * member - the list_head element in "pos"
96 * type - the type of the first parameter
98 #define list_for_each_entry(pos, head, member, type) \
99 for (pos = list_entry((head)->next, type, member); \
100 &pos->member != (head); \
101 pos = list_entry(pos->member.next, type, member))
103 #define list_for_each_entry_safe(pos, n, head, member, type) \
104 for (pos = list_entry((head)->next, type, member), \
105 n = list_entry(pos->member.next, type, member); \
106 &pos->member != (head); \
107 pos = n, n = list_entry(n->member.next, type, member))
109 #define list_empty(entry) ((entry)->next == (entry))
111 static inline void list_init(struct list_head *entry)
113 entry->prev = entry->next = entry;
116 static inline void list_add(struct list_head *entry, struct list_head *head)
118 entry->next = head->next;
121 head->next->prev = entry;
125 static inline void list_add_tail(struct list_head *entry,
126 struct list_head *head)
129 entry->prev = head->prev;
131 head->prev->next = entry;
135 static inline void list_del(struct list_head *entry)
137 entry->next->prev = entry->prev;
138 entry->prev->next = entry->next;
139 entry->next = entry->prev = NULL;
142 static inline void *usbi_reallocf(void *ptr, size_t size)
144 void *ret = realloc(ptr, size);
150 #define container_of(ptr, type, member) ({ \
151 const typeof( ((type *)0)->member ) *mptr = (ptr); \
152 (type *)( (char *)mptr - offsetof(type,member) );})
155 #define MIN(a, b) ((a) < (b) ? (a) : (b))
158 #define MAX(a, b) ((a) > (b) ? (a) : (b))
161 #define TIMESPEC_IS_SET(ts) ((ts)->tv_sec != 0 || (ts)->tv_nsec != 0)
163 /* Some platforms don't have this define */
164 #ifndef TIMESPEC_TO_TIMEVAL
165 #define TIMESPEC_TO_TIMEVAL(tv, ts) \
167 (tv)->tv_sec = (ts)->tv_sec; \
168 (tv)->tv_usec = (ts)->tv_nsec / 1000; \
172 void usbi_log(struct libusb_context *ctx, enum libusb_log_level level,
173 const char *function, const char *format, ...);
175 void usbi_log_v(struct libusb_context *ctx, enum libusb_log_level level,
176 const char *function, const char *format, va_list args);
178 #if !defined(_MSC_VER) || _MSC_VER >= 1400
180 #ifdef ENABLE_LOGGING
181 #define _usbi_log(ctx, level, ...) usbi_log(ctx, level, __FUNCTION__, __VA_ARGS__)
182 #define usbi_dbg(...) _usbi_log(NULL, LIBUSB_LOG_LEVEL_DEBUG, __VA_ARGS__)
184 #define _usbi_log(ctx, level, ...) do { (void)(ctx); } while(0)
185 #define usbi_dbg(...) do {} while(0)
188 #define usbi_info(ctx, ...) _usbi_log(ctx, LIBUSB_LOG_LEVEL_INFO, __VA_ARGS__)
189 #define usbi_warn(ctx, ...) _usbi_log(ctx, LIBUSB_LOG_LEVEL_WARNING, __VA_ARGS__)
190 #define usbi_err(ctx, ...) _usbi_log(ctx, LIBUSB_LOG_LEVEL_ERROR, __VA_ARGS__)
192 #else /* !defined(_MSC_VER) || _MSC_VER >= 1400 */
194 #ifdef ENABLE_LOGGING
195 #define LOG_BODY(ctxt, level) \
198 va_start (args, format); \
199 usbi_log_v(ctxt, level, "", format, args); \
203 #define LOG_BODY(ctxt, level) do { (void)(ctxt); } while(0)
206 static inline void usbi_info(struct libusb_context *ctx, const char *format,
208 LOG_BODY(ctx,LIBUSB_LOG_LEVEL_INFO)
209 static inline void usbi_warn(struct libusb_context *ctx, const char *format,
211 LOG_BODY(ctx,LIBUSB_LOG_LEVEL_WARNING)
212 static inline void usbi_err( struct libusb_context *ctx, const char *format,
214 LOG_BODY(ctx,LIBUSB_LOG_LEVEL_ERROR)
216 static inline void usbi_dbg(const char *format, ...)
217 LOG_BODY(NULL,LIBUSB_LOG_LEVEL_DEBUG)
219 #endif /* !defined(_MSC_VER) || _MSC_VER >= 1400 */
221 #define USBI_GET_CONTEXT(ctx) if (!(ctx)) (ctx) = usbi_default_context
222 #define DEVICE_CTX(dev) ((dev)->ctx)
223 #define HANDLE_CTX(handle) (DEVICE_CTX((handle)->dev))
224 #define TRANSFER_CTX(transfer) (HANDLE_CTX((transfer)->dev_handle))
225 #define ITRANSFER_CTX(transfer) \
226 (TRANSFER_CTX(USBI_TRANSFER_TO_LIBUSB_TRANSFER(transfer)))
228 #define IS_EPIN(ep) (0 != ((ep) & LIBUSB_ENDPOINT_IN))
229 #define IS_EPOUT(ep) (!IS_EPIN(ep))
230 #define IS_XFERIN(xfer) (0 != ((xfer)->endpoint & LIBUSB_ENDPOINT_IN))
231 #define IS_XFEROUT(xfer) (!IS_XFERIN(xfer))
233 /* Internal abstraction for thread synchronization */
234 #if defined(THREADS_POSIX)
235 #include "os/threads_posix.h"
236 #elif defined(OS_WINDOWS) || defined(OS_WINCE)
237 #include <os/threads_windows.h>
240 extern struct libusb_context *usbi_default_context;
242 /* Forward declaration for use in context (fully defined inside poll abstraction) */
245 struct libusb_context {
249 /* internal event pipe, used for signalling occurrence of an internal event. */
252 struct list_head usb_devs;
253 usbi_mutex_t usb_devs_lock;
255 /* A list of open handles. Backends are free to traverse this if required.
257 struct list_head open_devs;
258 usbi_mutex_t open_devs_lock;
260 /* A list of registered hotplug callbacks */
261 struct list_head hotplug_cbs;
262 usbi_mutex_t hotplug_cbs_lock;
264 /* this is a list of in-flight transfer handles, sorted by timeout
265 * expiration. URBs to timeout the soonest are placed at the beginning of
266 * the list, URBs that will time out later are placed after, and urbs with
267 * infinite timeout are always placed at the very end. */
268 struct list_head flying_transfers;
269 usbi_mutex_t flying_transfers_lock;
271 /* user callbacks for pollfd changes */
272 libusb_pollfd_added_cb fd_added_cb;
273 libusb_pollfd_removed_cb fd_removed_cb;
274 void *fd_cb_user_data;
276 /* ensures that only one thread is handling events at any one time */
277 usbi_mutex_t events_lock;
279 /* used to see if there is an active thread doing event handling */
280 int event_handler_active;
282 /* used to wait for event completion in threads other than the one that is
284 usbi_mutex_t event_waiters_lock;
285 usbi_cond_t event_waiters_cond;
287 /* A lock to protect internal context event data. */
288 usbi_mutex_t event_data_lock;
290 /* A counter that is set when we want to interrupt and prevent event handling,
291 * in order to safely close a device. Protected by event_data_lock. */
292 unsigned int device_close;
294 /* list and count of poll fds and an array of poll fd structures that is
295 * (re)allocated as necessary prior to polling, and a flag to indicate
296 * when the list of poll fds has changed since the last poll.
297 * Protected by event_data_lock. */
298 struct list_head ipollfds;
299 struct pollfd *pollfds;
300 POLL_NFDS_TYPE pollfds_cnt;
301 unsigned int pollfds_modified;
303 /* A list of pending hotplug messages. Protected by event_data_lock. */
304 struct list_head hotplug_msgs;
306 #ifdef USBI_TIMERFD_AVAILABLE
307 /* used for timeout handling, if supported by OS.
308 * this timerfd is maintained to trigger on the next pending timeout */
312 struct list_head list;
315 /* Update the following macro if new event sources are added */
316 #define usbi_pending_events(ctx) \
317 ((ctx)->device_close || (ctx)->pollfds_modified || !list_empty(&(ctx)->hotplug_msgs))
319 #ifdef USBI_TIMERFD_AVAILABLE
320 #define usbi_using_timerfd(ctx) ((ctx)->timerfd >= 0)
322 #define usbi_using_timerfd(ctx) (0)
325 struct libusb_device {
326 /* lock protects refcnt, everything else is finalized at initialization
331 struct libusb_context *ctx;
335 struct libusb_device* parent_dev;
336 uint8_t device_address;
337 uint8_t num_configurations;
338 enum libusb_speed speed;
340 struct list_head list;
341 unsigned long session_data;
343 struct libusb_device_descriptor device_descriptor;
346 unsigned char os_priv
347 #if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
348 [] /* valid C99 code */
350 [0] /* non-standard, but usually working code */
355 struct libusb_device_handle {
356 /* lock protects claimed_interfaces */
358 unsigned long claimed_interfaces;
360 struct list_head list;
361 struct libusb_device *dev;
362 int auto_detach_kernel_driver;
363 unsigned char os_priv
364 #if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
365 [] /* valid C99 code */
367 [0] /* non-standard, but usually working code */
373 USBI_CLOCK_MONOTONIC,
377 /* in-memory transfer layout:
379 * 1. struct usbi_transfer
380 * 2. struct libusb_transfer (which includes iso packets) [variable size]
381 * 3. os private data [variable size]
383 * from a libusb_transfer, you can get the usbi_transfer by rewinding the
384 * appropriate number of bytes.
385 * the usbi_transfer includes the number of allocated packets, so you can
386 * determine the size of the transfer and hence the start and length of the
390 struct usbi_transfer {
392 struct list_head list;
393 struct timeval timeout;
398 /* this lock is held during libusb_submit_transfer() and
399 * libusb_cancel_transfer() (allowing the OS backend to prevent duplicate
400 * cancellation, submission-during-cancellation, etc). the OS backend
401 * should also take this lock in the handle_events path, to prevent the user
402 * cancelling the transfer from another thread while you are processing
403 * its completion (presumably there would be races within your OS backend
404 * if this were possible). */
408 enum usbi_transfer_flags {
409 /* The transfer has timed out */
410 USBI_TRANSFER_TIMED_OUT = 1 << 0,
412 /* Set by backend submit_transfer() if the OS handles timeout */
413 USBI_TRANSFER_OS_HANDLES_TIMEOUT = 1 << 1,
415 /* Cancellation was requested via libusb_cancel_transfer() */
416 USBI_TRANSFER_CANCELLING = 1 << 2,
418 /* Operation on the transfer failed because the device disappeared */
419 USBI_TRANSFER_DEVICE_DISAPPEARED = 1 << 3,
421 /* Transfer is currently active */
422 USBI_TRANSFER_IN_FLIGHT = 1 << 4,
425 #define USBI_TRANSFER_TO_LIBUSB_TRANSFER(transfer) \
426 ((struct libusb_transfer *)(((unsigned char *)(transfer)) \
427 + sizeof(struct usbi_transfer)))
428 #define LIBUSB_TRANSFER_TO_USBI_TRANSFER(transfer) \
429 ((struct usbi_transfer *)(((unsigned char *)(transfer)) \
430 - sizeof(struct usbi_transfer)))
432 static inline void *usbi_transfer_get_os_priv(struct usbi_transfer *transfer)
434 return ((unsigned char *)transfer) + sizeof(struct usbi_transfer)
435 + sizeof(struct libusb_transfer)
436 + (transfer->num_iso_packets
437 * sizeof(struct libusb_iso_packet_descriptor));
442 /* All standard descriptors have these 2 fields in common */
443 struct usb_descriptor_header {
445 uint8_t bDescriptorType;
448 /* shared data and functions */
450 int usbi_io_init(struct libusb_context *ctx);
451 void usbi_io_exit(struct libusb_context *ctx);
453 struct libusb_device *usbi_alloc_device(struct libusb_context *ctx,
454 unsigned long session_id);
455 struct libusb_device *usbi_get_device_by_session_id(struct libusb_context *ctx,
456 unsigned long session_id);
457 int usbi_sanitize_device(struct libusb_device *dev);
458 void usbi_handle_disconnect(struct libusb_device_handle *handle);
460 int usbi_handle_transfer_completion(struct usbi_transfer *itransfer,
461 enum libusb_transfer_status status);
462 int usbi_handle_transfer_cancellation(struct usbi_transfer *transfer);
464 int usbi_parse_descriptor(const unsigned char *source, const char *descriptor,
465 void *dest, int host_endian);
466 int usbi_device_cache_descriptor(libusb_device *dev);
467 int usbi_get_config_index_by_value(struct libusb_device *dev,
468 uint8_t bConfigurationValue, int *idx);
470 void usbi_connect_device (struct libusb_device *dev);
471 void usbi_disconnect_device (struct libusb_device *dev);
473 int usbi_signal_event(struct libusb_context *ctx);
474 int usbi_clear_event(struct libusb_context *ctx);
476 /* Internal abstraction for poll (needs struct usbi_transfer on Windows) */
477 #if defined(OS_LINUX) || defined(OS_DARWIN) || defined(OS_OPENBSD) || defined(OS_NETBSD) || defined(OS_HAIKU)
479 #include "os/poll_posix.h"
480 #elif defined(OS_WINDOWS) || defined(OS_WINCE)
481 #include "os/poll_windows.h"
484 #if (defined(OS_WINDOWS) || defined(OS_WINCE)) && !defined(__GNUC__)
485 #define snprintf _snprintf
486 #define vsnprintf _vsnprintf
487 int usbi_gettimeofday(struct timeval *tp, void *tzp);
488 #define LIBUSB_GETTIMEOFDAY_WIN32
489 #define HAVE_USBI_GETTIMEOFDAY
491 #ifdef HAVE_GETTIMEOFDAY
492 #define usbi_gettimeofday(tv, tz) gettimeofday((tv), (tz))
493 #define HAVE_USBI_GETTIMEOFDAY
498 /* must come first */
499 struct libusb_pollfd pollfd;
501 struct list_head list;
504 int usbi_add_pollfd(struct libusb_context *ctx, int fd, short events);
505 void usbi_remove_pollfd(struct libusb_context *ctx, int fd);
507 /* device discovery */
509 /* we traverse usbfs without knowing how many devices we are going to find.
510 * so we create this discovered_devs model which is similar to a linked-list
511 * which grows when required. it can be freed once discovery has completed,
512 * eliminating the need for a list node in the libusb_device structure
514 struct discovered_devs {
517 struct libusb_device *devices
518 #if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
519 [] /* valid C99 code */
521 [0] /* non-standard, but usually working code */
526 struct discovered_devs *discovered_devs_append(
527 struct discovered_devs *discdevs, struct libusb_device *dev);
531 /* This is the interface that OS backends need to implement.
532 * All fields are mandatory, except ones explicitly noted as optional. */
533 struct usbi_os_backend {
534 /* A human-readable name for your backend, e.g. "Linux usbfs" */
537 /* Binary mask for backend specific capabilities */
540 /* Perform initialization of your backend. You might use this function
541 * to determine specific capabilities of the system, allocate required
542 * data structures for later, etc.
544 * This function is called when a libusb user initializes the library
547 * Return 0 on success, or a LIBUSB_ERROR code on failure.
549 int (*init)(struct libusb_context *ctx);
551 /* Deinitialization. Optional. This function should destroy anything
552 * that was set up by init.
554 * This function is called when the user deinitializes the library.
558 /* Enumerate all the USB devices on the system, returning them in a list
559 * of discovered devices.
561 * Your implementation should enumerate all devices on the system,
562 * regardless of whether they have been seen before or not.
564 * When you have found a device, compute a session ID for it. The session
565 * ID should uniquely represent that particular device for that particular
566 * connection session since boot (i.e. if you disconnect and reconnect a
567 * device immediately after, it should be assigned a different session ID).
568 * If your OS cannot provide a unique session ID as described above,
569 * presenting a session ID of (bus_number << 8 | device_address) should
570 * be sufficient. Bus numbers and device addresses wrap and get reused,
571 * but that is an unlikely case.
573 * After computing a session ID for a device, call
574 * usbi_get_device_by_session_id(). This function checks if libusb already
575 * knows about the device, and if so, it provides you with a reference
576 * to a libusb_device structure for it.
578 * If usbi_get_device_by_session_id() returns NULL, it is time to allocate
579 * a new device structure for the device. Call usbi_alloc_device() to
580 * obtain a new libusb_device structure with reference count 1. Populate
581 * the bus_number and device_address attributes of the new device, and
582 * perform any other internal backend initialization you need to do. At
583 * this point, you should be ready to provide device descriptors and so
584 * on through the get_*_descriptor functions. Finally, call
585 * usbi_sanitize_device() to perform some final sanity checks on the
586 * device. Assuming all of the above succeeded, we can now continue.
587 * If any of the above failed, remember to unreference the device that
588 * was returned by usbi_alloc_device().
590 * At this stage we have a populated libusb_device structure (either one
591 * that was found earlier, or one that we have just allocated and
592 * populated). This can now be added to the discovered devices list
593 * using discovered_devs_append(). Note that discovered_devs_append()
594 * may reallocate the list, returning a new location for it, and also
595 * note that reallocation can fail. Your backend should handle these
596 * error conditions appropriately.
598 * This function should not generate any bus I/O and should not block.
599 * If I/O is required (e.g. reading the active configuration value), it is
600 * OK to ignore these suggestions :)
602 * This function is executed when the user wishes to retrieve a list
603 * of USB devices connected to the system.
605 * If the backend has hotplug support, this function is not used!
607 * Return 0 on success, or a LIBUSB_ERROR code on failure.
609 int (*get_device_list)(struct libusb_context *ctx,
610 struct discovered_devs **discdevs);
612 /* Apps which were written before hotplug support, may listen for
613 * hotplug events on their own and call libusb_get_device_list on
614 * device addition. In this case libusb_get_device_list will likely
615 * return a list without the new device in there, as the hotplug
616 * event thread will still be busy enumerating the device, which may
617 * take a while, or may not even have seen the event yet.
619 * To avoid this libusb_get_device_list will call this optional
620 * function for backends with hotplug support before copying
621 * ctx->usb_devs to the user. In this function the backend should
622 * ensure any pending hotplug events are fully processed before
625 * Optional, should be implemented by backends with hotplug support.
627 void (*hotplug_poll)(void);
629 /* Open a device for I/O and other USB operations. The device handle
630 * is preallocated for you, you can retrieve the device in question
631 * through handle->dev.
633 * Your backend should allocate any internal resources required for I/O
634 * and other operations so that those operations can happen (hopefully)
635 * without hiccup. This is also a good place to inform libusb that it
636 * should monitor certain file descriptors related to this device -
637 * see the usbi_add_pollfd() function.
639 * This function should not generate any bus I/O and should not block.
641 * This function is called when the user attempts to obtain a device
642 * handle for a device.
646 * - LIBUSB_ERROR_ACCESS if the user has insufficient permissions
647 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since
649 * - another LIBUSB_ERROR code on other failure
651 * Do not worry about freeing the handle on failed open, the upper layers
654 int (*open)(struct libusb_device_handle *handle);
656 /* Close a device such that the handle cannot be used again. Your backend
657 * should destroy any resources that were allocated in the open path.
658 * This may also be a good place to call usbi_remove_pollfd() to inform
659 * libusb of any file descriptors associated with this device that should
660 * no longer be monitored.
662 * This function is called when the user closes a device handle.
664 void (*close)(struct libusb_device_handle *handle);
666 /* Retrieve the device descriptor from a device.
668 * The descriptor should be retrieved from memory, NOT via bus I/O to the
669 * device. This means that you may have to cache it in a private structure
670 * during get_device_list enumeration. Alternatively, you may be able
671 * to retrieve it from a kernel interface (some Linux setups can do this)
672 * still without generating bus I/O.
674 * This function is expected to write DEVICE_DESC_LENGTH (18) bytes into
675 * buffer, which is guaranteed to be big enough.
677 * This function is called when sanity-checking a device before adding
678 * it to the list of discovered devices, and also when the user requests
679 * to read the device descriptor.
681 * This function is expected to return the descriptor in bus-endian format
682 * (LE). If it returns the multi-byte values in host-endian format,
683 * set the host_endian output parameter to "1".
685 * Return 0 on success or a LIBUSB_ERROR code on failure.
687 int (*get_device_descriptor)(struct libusb_device *device,
688 unsigned char *buffer, int *host_endian);
690 /* Get the ACTIVE configuration descriptor for a device.
692 * The descriptor should be retrieved from memory, NOT via bus I/O to the
693 * device. This means that you may have to cache it in a private structure
694 * during get_device_list enumeration. You may also have to keep track
695 * of which configuration is active when the user changes it.
697 * This function is expected to write len bytes of data into buffer, which
698 * is guaranteed to be big enough. If you can only do a partial write,
699 * return an error code.
701 * This function is expected to return the descriptor in bus-endian format
702 * (LE). If it returns the multi-byte values in host-endian format,
703 * set the host_endian output parameter to "1".
707 * - LIBUSB_ERROR_NOT_FOUND if the device is in unconfigured state
708 * - another LIBUSB_ERROR code on other failure
710 int (*get_active_config_descriptor)(struct libusb_device *device,
711 unsigned char *buffer, size_t len, int *host_endian);
713 /* Get a specific configuration descriptor for a device.
715 * The descriptor should be retrieved from memory, NOT via bus I/O to the
716 * device. This means that you may have to cache it in a private structure
717 * during get_device_list enumeration.
719 * The requested descriptor is expressed as a zero-based index (i.e. 0
720 * indicates that we are requesting the first descriptor). The index does
721 * not (necessarily) equal the bConfigurationValue of the configuration
724 * This function is expected to write len bytes of data into buffer, which
725 * is guaranteed to be big enough. If you can only do a partial write,
726 * return an error code.
728 * This function is expected to return the descriptor in bus-endian format
729 * (LE). If it returns the multi-byte values in host-endian format,
730 * set the host_endian output parameter to "1".
732 * Return the length read on success or a LIBUSB_ERROR code on failure.
734 int (*get_config_descriptor)(struct libusb_device *device,
735 uint8_t config_index, unsigned char *buffer, size_t len,
738 /* Like get_config_descriptor but then by bConfigurationValue instead
741 * Optional, if not present the core will call get_config_descriptor
742 * for all configs until it finds the desired bConfigurationValue.
744 * Returns a pointer to the raw-descriptor in *buffer, this memory
745 * is valid as long as device is valid.
747 * Returns the length of the returned raw-descriptor on success,
748 * or a LIBUSB_ERROR code on failure.
750 int (*get_config_descriptor_by_value)(struct libusb_device *device,
751 uint8_t bConfigurationValue, unsigned char **buffer,
754 /* Get the bConfigurationValue for the active configuration for a device.
755 * Optional. This should only be implemented if you can retrieve it from
756 * cache (don't generate I/O).
758 * If you cannot retrieve this from cache, either do not implement this
759 * function, or return LIBUSB_ERROR_NOT_SUPPORTED. This will cause
760 * libusb to retrieve the information through a standard control transfer.
762 * This function must be non-blocking.
765 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
767 * - LIBUSB_ERROR_NOT_SUPPORTED if the value cannot be retrieved without
769 * - another LIBUSB_ERROR code on other failure.
771 int (*get_configuration)(struct libusb_device_handle *handle, int *config);
773 /* Set the active configuration for a device.
775 * A configuration value of -1 should put the device in unconfigured state.
777 * This function can block.
781 * - LIBUSB_ERROR_NOT_FOUND if the configuration does not exist
782 * - LIBUSB_ERROR_BUSY if interfaces are currently claimed (and hence
783 * configuration cannot be changed)
784 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
786 * - another LIBUSB_ERROR code on other failure.
788 int (*set_configuration)(struct libusb_device_handle *handle, int config);
790 /* Claim an interface. When claimed, the application can then perform
791 * I/O to an interface's endpoints.
793 * This function should not generate any bus I/O and should not block.
794 * Interface claiming is a logical operation that simply ensures that
795 * no other drivers/applications are using the interface, and after
796 * claiming, no other drivers/applicatiosn can use the interface because
801 * - LIBUSB_ERROR_NOT_FOUND if the interface does not exist
802 * - LIBUSB_ERROR_BUSY if the interface is in use by another driver/app
803 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
805 * - another LIBUSB_ERROR code on other failure
807 int (*claim_interface)(struct libusb_device_handle *handle, int interface_number);
809 /* Release a previously claimed interface.
811 * This function should also generate a SET_INTERFACE control request,
812 * resetting the alternate setting of that interface to 0. It's OK for
813 * this function to block as a result.
815 * You will only ever be asked to release an interface which was
816 * successfully claimed earlier.
820 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
822 * - another LIBUSB_ERROR code on other failure
824 int (*release_interface)(struct libusb_device_handle *handle, int interface_number);
826 /* Set the alternate setting for an interface.
828 * You will only ever be asked to set the alternate setting for an
829 * interface which was successfully claimed earlier.
831 * It's OK for this function to block.
835 * - LIBUSB_ERROR_NOT_FOUND if the alternate setting does not exist
836 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
838 * - another LIBUSB_ERROR code on other failure
840 int (*set_interface_altsetting)(struct libusb_device_handle *handle,
841 int interface_number, int altsetting);
843 /* Clear a halt/stall condition on an endpoint.
845 * It's OK for this function to block.
849 * - LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist
850 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
852 * - another LIBUSB_ERROR code on other failure
854 int (*clear_halt)(struct libusb_device_handle *handle,
855 unsigned char endpoint);
857 /* Perform a USB port reset to reinitialize a device.
859 * If possible, the handle should still be usable after the reset
860 * completes, assuming that the device descriptors did not change during
861 * reset and all previous interface state can be restored.
863 * If something changes, or you cannot easily locate/verify the resetted
864 * device, return LIBUSB_ERROR_NOT_FOUND. This prompts the application
865 * to close the old handle and re-enumerate the device.
869 * - LIBUSB_ERROR_NOT_FOUND if re-enumeration is required, or if the device
870 * has been disconnected since it was opened
871 * - another LIBUSB_ERROR code on other failure
873 int (*reset_device)(struct libusb_device_handle *handle);
875 /* Alloc num_streams usb3 bulk streams on the passed in endpoints */
876 int (*alloc_streams)(struct libusb_device_handle *handle,
877 uint32_t num_streams, unsigned char *endpoints, int num_endpoints);
879 /* Free usb3 bulk streams allocated with alloc_streams */
880 int (*free_streams)(struct libusb_device_handle *handle,
881 unsigned char *endpoints, int num_endpoints);
883 /* Determine if a kernel driver is active on an interface. Optional.
885 * The presence of a kernel driver on an interface indicates that any
886 * calls to claim_interface would fail with the LIBUSB_ERROR_BUSY code.
889 * - 0 if no driver is active
890 * - 1 if a driver is active
891 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
893 * - another LIBUSB_ERROR code on other failure
895 int (*kernel_driver_active)(struct libusb_device_handle *handle,
896 int interface_number);
898 /* Detach a kernel driver from an interface. Optional.
900 * After detaching a kernel driver, the interface should be available
905 * - LIBUSB_ERROR_NOT_FOUND if no kernel driver was active
906 * - LIBUSB_ERROR_INVALID_PARAM if the interface does not exist
907 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
909 * - another LIBUSB_ERROR code on other failure
911 int (*detach_kernel_driver)(struct libusb_device_handle *handle,
912 int interface_number);
914 /* Attach a kernel driver to an interface. Optional.
916 * Reattach a kernel driver to the device.
920 * - LIBUSB_ERROR_NOT_FOUND if no kernel driver was active
921 * - LIBUSB_ERROR_INVALID_PARAM if the interface does not exist
922 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
924 * - LIBUSB_ERROR_BUSY if a program or driver has claimed the interface,
925 * preventing reattachment
926 * - another LIBUSB_ERROR code on other failure
928 int (*attach_kernel_driver)(struct libusb_device_handle *handle,
929 int interface_number);
931 /* Destroy a device. Optional.
933 * This function is called when the last reference to a device is
934 * destroyed. It should free any resources allocated in the get_device_list
937 void (*destroy_device)(struct libusb_device *dev);
939 /* Submit a transfer. Your implementation should take the transfer,
940 * morph it into whatever form your platform requires, and submit it
943 * This function must not block.
945 * This function gets called with the flying_transfers_lock locked!
949 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
950 * - another LIBUSB_ERROR code on other failure
952 int (*submit_transfer)(struct usbi_transfer *itransfer);
954 /* Cancel a previously submitted transfer.
956 * This function must not block. The transfer cancellation must complete
957 * later, resulting in a call to usbi_handle_transfer_cancellation()
958 * from the context of handle_events.
960 int (*cancel_transfer)(struct usbi_transfer *itransfer);
962 /* Clear a transfer as if it has completed or cancelled, but do not
963 * report any completion/cancellation to the library. You should free
964 * all private data from the transfer as if you were just about to report
965 * completion or cancellation.
967 * This function might seem a bit out of place. It is used when libusb
968 * detects a disconnected device - it calls this function for all pending
969 * transfers before reporting completion (with the disconnect code) to
970 * the user. Maybe we can improve upon this internal interface in future.
972 void (*clear_transfer_priv)(struct usbi_transfer *itransfer);
974 /* Handle any pending events. This involves monitoring any active
975 * transfers and processing their completion or cancellation.
977 * The function is passed an array of pollfd structures (size nfds)
978 * as a result of the poll() system call. The num_ready parameter
979 * indicates the number of file descriptors that have reported events
980 * (i.e. the poll() return value). This should be enough information
981 * for you to determine which actions need to be taken on the currently
984 * For any cancelled transfers, call usbi_handle_transfer_cancellation().
985 * For completed transfers, call usbi_handle_transfer_completion().
986 * For control/bulk/interrupt transfers, populate the "transferred"
987 * element of the appropriate usbi_transfer structure before calling the
988 * above functions. For isochronous transfers, populate the status and
989 * transferred fields of the iso packet descriptors of the transfer.
991 * This function should also be able to detect disconnection of the
992 * device, reporting that situation with usbi_handle_disconnect().
994 * When processing an event related to a transfer, you probably want to
995 * take usbi_transfer.lock to prevent races. See the documentation for
996 * the usbi_transfer structure.
998 * Return 0 on success, or a LIBUSB_ERROR code on failure.
1000 int (*handle_events)(struct libusb_context *ctx,
1001 struct pollfd *fds, POLL_NFDS_TYPE nfds, int num_ready);
1003 /* Get time from specified clock. At least two clocks must be implemented
1004 by the backend: USBI_CLOCK_REALTIME, and USBI_CLOCK_MONOTONIC.
1006 Description of clocks:
1007 USBI_CLOCK_REALTIME : clock returns time since system epoch.
1008 USBI_CLOCK_MONOTONIC: clock returns time since unspecified start
1009 time (usually boot).
1011 int (*clock_gettime)(int clkid, struct timespec *tp);
1013 #ifdef USBI_TIMERFD_AVAILABLE
1014 /* clock ID of the clock that should be used for timerfd */
1015 clockid_t (*get_timerfd_clockid)(void);
1018 /* Number of bytes to reserve for per-device private backend data.
1019 * This private data area is accessible through the "os_priv" field of
1020 * struct libusb_device. */
1021 size_t device_priv_size;
1023 /* Number of bytes to reserve for per-handle private backend data.
1024 * This private data area is accessible through the "os_priv" field of
1025 * struct libusb_device. */
1026 size_t device_handle_priv_size;
1028 /* Number of bytes to reserve for per-transfer private backend data.
1029 * This private data area is accessible by calling
1030 * usbi_transfer_get_os_priv() on the appropriate usbi_transfer instance.
1032 size_t transfer_priv_size;
1034 /* Mumber of additional bytes for os_priv for each iso packet.
1035 * Can your backend use this? */
1036 /* FIXME: linux can't use this any more. if other OS's cannot either,
1037 * then remove this */
1038 size_t add_iso_packet_size;
1041 extern const struct usbi_os_backend * const usbi_backend;
1043 extern const struct usbi_os_backend linux_usbfs_backend;
1044 extern const struct usbi_os_backend darwin_backend;
1045 extern const struct usbi_os_backend openbsd_backend;
1046 extern const struct usbi_os_backend netbsd_backend;
1047 extern const struct usbi_os_backend windows_backend;
1048 extern const struct usbi_os_backend wince_backend;
1049 extern const struct usbi_os_backend haiku_usb_raw_backend;
1051 extern struct list_head active_contexts_list;
1052 extern usbi_mutex_static_t active_contexts_lock;