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
43 /* Inside the libusb code, mark all public functions as follows:
44 * return_type API_EXPORTED function_name(params) { ... }
45 * But if the function returns a pointer, mark it as follows:
46 * DEFAULT_VISIBILITY return_type * LIBUSB_CALL function_name(params) { ... }
47 * In the libusb public header, mark all declarations as:
48 * return_type LIBUSB_CALL function_name(params);
50 #define API_EXPORTED LIBUSB_CALL DEFAULT_VISIBILITY
52 #define DEVICE_DESC_LENGTH 18
54 #define USB_MAXENDPOINTS 32
55 #define USB_MAXINTERFACES 32
56 #define USB_MAXCONFIG 8
58 /* Backend specific capabilities */
59 #define USBI_CAP_HAS_HID_ACCESS 0x00010000
60 #define USBI_CAP_SUPPORTS_DETACH_KERNEL_DRIVER 0x00020000
62 /* Maximum number of bytes in a log line */
63 #define USBI_MAX_LOG_LEN 1024
64 /* Terminator for log lines */
65 #define USBI_LOG_LINE_END "\n"
67 /* The following is used to silence warnings for unused variables */
68 #define UNUSED(var) do { (void)(var); } while(0)
70 #if !defined(ARRAYSIZE)
71 #define ARRAYSIZE(array) (sizeof(array)/sizeof(array[0]))
75 struct list_head *prev, *next;
78 /* Get an entry from the list
79 * ptr - the address of this list_head element in "type"
80 * type - the data type that contains "member"
81 * member - the list_head element in "type"
83 #define list_entry(ptr, type, member) \
84 ((type *)((uintptr_t)(ptr) - (uintptr_t)offsetof(type, member)))
86 /* Get each entry from a list
87 * pos - A structure pointer has a "member" element
89 * member - the list_head element in "pos"
90 * type - the type of the first parameter
92 #define list_for_each_entry(pos, head, member, type) \
93 for (pos = list_entry((head)->next, type, member); \
94 &pos->member != (head); \
95 pos = list_entry(pos->member.next, type, member))
97 #define list_for_each_entry_safe(pos, n, head, member, type) \
98 for (pos = list_entry((head)->next, type, member), \
99 n = list_entry(pos->member.next, type, member); \
100 &pos->member != (head); \
101 pos = n, n = list_entry(n->member.next, type, member))
103 #define list_empty(entry) ((entry)->next == (entry))
105 static inline void list_init(struct list_head *entry) {
106 entry->prev = entry->next = entry;
109 static inline void list_add(struct list_head *entry, struct list_head *head) {
110 entry->next = head->next;
113 head->next->prev = entry;
117 static inline void list_add_tail(struct list_head *entry, struct list_head *head) {
119 entry->prev = head->prev;
121 head->prev->next = entry;
125 static inline void list_del(struct list_head *entry) {
126 if (!list_empty(entry)) { // XXX add saki@serenegiant because sometimes crash
127 entry->next->prev = entry->prev;
128 entry->prev->next = entry->next;
129 entry->next = entry->prev = NULL;
133 static inline void *usbi_reallocf(void *ptr, size_t size) {
134 void *ret = realloc(ptr, size);
140 #define container_of(ptr, type, member) ({ \
141 const typeof( ((type *)0)->member ) *mptr = (ptr); \
142 (type *)( (char *)mptr - offsetof(type,member) );})
144 #define MIN(a, b) ((a) < (b) ? (a) : (b))
145 #define MAX(a, b) ((a) > (b) ? (a) : (b))
147 #define TIMESPEC_IS_SET(ts) ((ts)->tv_sec != 0 || (ts)->tv_nsec != 0)
149 /* Some platforms don't have this define */
150 #ifndef TIMESPEC_TO_TIMEVAL
151 #define TIMESPEC_TO_TIMEVAL(tv, ts) \
153 (tv)->tv_sec = (ts)->tv_sec; \
154 (tv)->tv_usec = (ts)->tv_nsec / 1000; \
158 void usbi_log(struct libusb_context *ctx, enum libusb_log_level level,
159 const char *function, const char *format, ...);
161 void usbi_log_v(struct libusb_context *ctx, enum libusb_log_level level,
162 const char *function, const char *format, va_list args);
164 #if !defined(_MSC_VER) || _MSC_VER >= 1400
166 #ifdef ENABLE_LOGGING
167 #define _usbi_log(ctx, level, ...) usbi_log(ctx, level, __FUNCTION__, __VA_ARGS__)
168 #define usbi_dbg(...) _usbi_log(NULL, LIBUSB_LOG_LEVEL_DEBUG, __VA_ARGS__)
170 #define _usbi_log(ctx, level, ...) do { (void)(ctx); } while(0)
171 #define usbi_dbg(...) do {} while(0)
174 #define usbi_info(ctx, ...) _usbi_log(ctx, LIBUSB_LOG_LEVEL_INFO, __VA_ARGS__)
175 #define usbi_warn(ctx, ...) _usbi_log(ctx, LIBUSB_LOG_LEVEL_WARNING, __VA_ARGS__)
176 #define usbi_err(ctx, ...) _usbi_log(ctx, LIBUSB_LOG_LEVEL_ERROR, __VA_ARGS__)
178 #else /* !defined(_MSC_VER) || _MSC_VER >= 1400 */
180 #ifdef ENABLE_LOGGING
181 #define LOG_BODY(ctxt, level) \
184 va_start (args, format); \
185 usbi_log_v(ctxt, level, "", format, args); \
189 #define LOG_BODY(ctxt, level) do { (void)(ctxt); } while(0)
192 static inline void usbi_info(struct libusb_context *ctx, const char *format,
194 LOG_BODY(ctx,LIBUSB_LOG_LEVEL_INFO)
195 static inline void usbi_warn(struct libusb_context *ctx, const char *format,
197 LOG_BODY(ctx,LIBUSB_LOG_LEVEL_WARNING)
198 static inline void usbi_err( struct libusb_context *ctx, const char *format,
200 LOG_BODY(ctx,LIBUSB_LOG_LEVEL_ERROR)
202 static inline void usbi_dbg(const char *format, ...)
203 LOG_BODY(NULL,LIBUSB_LOG_LEVEL_DEBUG)
205 #endif /* !defined(_MSC_VER) || _MSC_VER >= 1400 */
207 #define USBI_GET_CONTEXT(ctx) if (!(ctx)) (ctx) = usbi_default_context
208 #define DEVICE_CTX(dev) ((dev)->ctx)
209 #define HANDLE_CTX(handle) (DEVICE_CTX((handle)->dev))
210 #define TRANSFER_CTX(transfer) (HANDLE_CTX((transfer)->dev_handle))
211 #define ITRANSFER_CTX(transfer) \
212 (TRANSFER_CTX(USBI_TRANSFER_TO_LIBUSB_TRANSFER(transfer)))
214 #define IS_EPIN(ep) (0 != ((ep) & LIBUSB_ENDPOINT_IN))
215 #define IS_EPOUT(ep) (!IS_EPIN(ep))
216 #define IS_XFERIN(xfer) (0 != ((xfer)->endpoint & LIBUSB_ENDPOINT_IN))
217 #define IS_XFEROUT(xfer) (!IS_XFERIN(xfer))
219 /* Internal abstraction for thread synchronization */
220 #if defined(THREADS_POSIX)
221 #include "os/threads_posix.h"
222 #elif defined(OS_WINDOWS) || defined(OS_WINCE)
223 #include <os/threads_windows.h>
226 extern struct libusb_context *usbi_default_context;
228 struct libusb_context {
232 /* internal control pipe, used for interrupting event handling when
233 * something needs to modify poll fds. */
236 struct list_head usb_devs;
237 usbi_mutex_t usb_devs_lock;
239 /* A list of open handles. Backends are free to traverse this if required.
241 struct list_head open_devs;
242 usbi_mutex_t open_devs_lock;
244 /* A list of registered hotplug callbacks */
245 struct list_head hotplug_cbs;
246 usbi_mutex_t hotplug_cbs_lock;
249 /* this is a list of in-flight transfer handles, sorted by timeout
250 * expiration. URBs to timeout the soonest are placed at the beginning of
251 * the list, URBs that will time out later are placed after, and urbs with
252 * infinite timeout are always placed at the very end. */
253 struct list_head flying_transfers;
254 usbi_mutex_t flying_transfers_lock;
256 /* list of poll fds */
257 struct list_head pollfds;
258 usbi_mutex_t pollfds_lock;
260 /* a counter that is set when we want to interrupt event handling, in order
261 * to modify the poll fd set. and a lock to protect it. */
262 unsigned int pollfd_modify;
263 usbi_mutex_t pollfd_modify_lock;
265 /* user callbacks for pollfd changes */
266 libusb_pollfd_added_cb fd_added_cb;
267 libusb_pollfd_removed_cb fd_removed_cb;
268 void *fd_cb_user_data;
270 /* ensures that only one thread is handling events at any one time */
271 usbi_mutex_t events_lock;
273 /* used to see if there is an active thread doing event handling */
274 int event_handler_active;
276 /* used to wait for event completion in threads other than the one that is
278 usbi_mutex_t event_waiters_lock;
279 usbi_cond_t event_waiters_cond;
281 #ifdef USBI_TIMERFD_AVAILABLE
282 /* used for timeout handling, if supported by OS.
283 * this timerfd is maintained to trigger on the next pending timeout */
287 struct list_head list;
290 #ifdef USBI_TIMERFD_AVAILABLE
291 #define usbi_using_timerfd(ctx) ((ctx)->timerfd >= 0)
293 #define usbi_using_timerfd(ctx) (0)
296 struct libusb_device {
297 /* lock protects refcnt, everything else is finalized at initialization
302 struct libusb_context *ctx;
306 struct libusb_device* parent_dev;
307 uint8_t device_address;
308 uint8_t num_configurations;
309 enum libusb_speed speed;
311 struct list_head list;
312 unsigned long session_data;
314 struct libusb_device_descriptor device_descriptor;
317 unsigned char os_priv
318 #if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
319 [] /* valid C99 code */
321 [0] /* non-standard, but usually working code */
326 struct libusb_device_handle {
327 /* lock protects claimed_interfaces */
329 unsigned long claimed_interfaces;
331 struct list_head list;
332 struct libusb_device *dev;
333 int auto_detach_kernel_driver;
334 unsigned char os_priv
335 #if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
336 [] /* valid C99 code */
338 [0] /* non-standard, but usually working code */
344 USBI_CLOCK_MONOTONIC,
348 /* in-memory transfer layout:
350 * 1. struct usbi_transfer
351 * 2. struct libusb_transfer (which includes iso packets) [variable size]
352 * 3. os private data [variable size]
354 * from a libusb_transfer, you can get the usbi_transfer by rewinding the
355 * appropriate number of bytes.
356 * the usbi_transfer includes the number of allocated packets, so you can
357 * determine the size of the transfer and hence the start and length of the
361 struct usbi_transfer {
363 struct list_head list;
364 struct timeval timeout;
369 /* this lock is held during libusb_submit_transfer() and
370 * libusb_cancel_transfer() (allowing the OS backend to prevent duplicate
371 * cancellation, submission-during-cancellation, etc). the OS backend
372 * should also take this lock in the handle_events path, to prevent the user
373 * cancelling the transfer from another thread while you are processing
374 * its completion (presumably there would be races within your OS backend
375 * if this were possible). */
379 enum usbi_transfer_flags {
380 /* The transfer has timed out */
381 USBI_TRANSFER_TIMED_OUT = 1 << 0,
383 /* Set by backend submit_transfer() if the OS handles timeout */
384 USBI_TRANSFER_OS_HANDLES_TIMEOUT = 1 << 1,
386 /* Cancellation was requested via libusb_cancel_transfer() */
387 USBI_TRANSFER_CANCELLING = 1 << 2,
389 /* Operation on the transfer failed because the device disappeared */
390 USBI_TRANSFER_DEVICE_DISAPPEARED = 1 << 3,
392 /* Set by backend submit_transfer() if the fds in use have been updated */
393 USBI_TRANSFER_UPDATED_FDS = 1 << 4,
396 #define USBI_TRANSFER_TO_LIBUSB_TRANSFER(transfer) \
397 ((struct libusb_transfer *)(((unsigned char *)(transfer)) \
398 + sizeof(struct usbi_transfer)))
399 #define LIBUSB_TRANSFER_TO_USBI_TRANSFER(transfer) \
400 ((struct usbi_transfer *)(((unsigned char *)(transfer)) \
401 - sizeof(struct usbi_transfer)))
403 static inline void *usbi_transfer_get_os_priv(struct usbi_transfer *transfer) {
404 return ((unsigned char *) transfer) + sizeof(struct usbi_transfer)
405 + sizeof(struct libusb_transfer)
406 + (transfer->num_iso_packets
407 * sizeof(struct libusb_iso_packet_descriptor));
412 /* All standard descriptors have these 2 fields in common */
413 struct usb_descriptor_header {
415 uint8_t bDescriptorType;
418 /* shared data and functions */
420 int usbi_io_init(struct libusb_context *ctx);
421 void usbi_io_exit(struct libusb_context *ctx);
423 struct libusb_device *usbi_alloc_device(struct libusb_context *ctx,
424 unsigned long session_id);
425 struct libusb_device *usbi_get_device_by_session_id(struct libusb_context *ctx,
426 unsigned long session_id);
427 int usbi_sanitize_device(struct libusb_device *dev);
428 void usbi_handle_disconnect(struct libusb_device_handle *handle);
430 int usbi_handle_transfer_completion(struct usbi_transfer *itransfer,
431 enum libusb_transfer_status status);
432 int usbi_handle_transfer_cancellation(struct usbi_transfer *transfer);
434 int usbi_parse_descriptor(const unsigned char *source, const char *descriptor,
435 void *dest, int host_endian);
436 int usbi_device_cache_descriptor(libusb_device *dev);
437 int usbi_get_config_index_by_value(struct libusb_device *dev,
438 uint8_t bConfigurationValue, int *idx);
440 void usbi_connect_device(struct libusb_device *dev);
441 void usbi_disconnect_device(struct libusb_device *dev);
443 /* Internal abstraction for poll (needs struct usbi_transfer on Windows) */
444 #if defined(OS_ANDROID) || defined(OS_LINUX) || defined(OS_DARWIN) || defined(OS_OPENBSD) || defined(OS_NETBSD) // XXX
446 #include "os/poll_posix.h"
447 #elif defined(OS_WINDOWS) || defined(OS_WINCE)
448 #include "os/poll_windows.h"
451 #if (defined(OS_WINDOWS) || defined(OS_WINCE)) && !defined(__GNUC__)
452 #define snprintf _snprintf
453 #define vsnprintf _vsnprintf
454 int usbi_gettimeofday(struct timeval *tp, void *tzp);
455 #define LIBUSB_GETTIMEOFDAY_WIN32
456 #define HAVE_USBI_GETTIMEOFDAY
458 #ifdef HAVE_GETTIMEOFDAY
459 #define usbi_gettimeofday(tv, tz) gettimeofday((tv), (tz))
460 #define HAVE_USBI_GETTIMEOFDAY
465 /* must come first */
466 struct libusb_pollfd pollfd;
468 struct list_head list;
471 int usbi_add_pollfd(struct libusb_context *ctx, int fd, short events);
472 void usbi_remove_pollfd(struct libusb_context *ctx, int fd);
473 void usbi_fd_notification(struct libusb_context *ctx);
475 /* device discovery */
477 /* we traverse usbfs without knowing how many devices we are going to find.
478 * so we create this discovered_devs model which is similar to a linked-list
479 * which grows when required. it can be freed once discovery has completed,
480 * eliminating the need for a list node in the libusb_device structure
482 struct discovered_devs {
485 struct libusb_device *devices
486 #if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
487 [] /* valid C99 code */
489 [0] /* non-standard, but usually working code */
494 struct discovered_devs *discovered_devs_append(struct discovered_devs *discdevs,
495 struct libusb_device *dev);
499 /* This is the interface that OS backends need to implement.
500 * All fields are mandatory, except ones explicitly noted as optional. */
501 struct usbi_os_backend {
502 /* A human-readable name for your backend, e.g. "Linux usbfs" */
505 /* Binary mask for backend specific capabilities */
508 /* Perform initialization of your backend. You might use this function
509 * to determine specific capabilities of the system, allocate required
510 * data structures for later, etc.
512 * This function is called when a libusb user initializes the library
515 * Return 0 on success, or a LIBUSB_ERROR code on failure.
517 int (*init)(struct libusb_context *ctx);
518 int (*init2)(struct libusb_context *ctx, const char *usbfs);
520 /* Deinitialization. Optional. This function should destroy anything
521 * that was set up by init.
523 * This function is called when the user deinitializes the library.
527 /* Enumerate all the USB devices on the system, returning them in a list
528 * of discovered devices.
530 * Your implementation should enumerate all devices on the system,
531 * regardless of whether they have been seen before or not.
533 * When you have found a device, compute a session ID for it. The session
534 * ID should uniquely represent that particular device for that particular
535 * connection session since boot (i.e. if you disconnect and reconnect a
536 * device immediately after, it should be assigned a different session ID).
537 * If your OS cannot provide a unique session ID as described above,
538 * presenting a session ID of (bus_number << 8 | device_address) should
539 * be sufficient. Bus numbers and device addresses wrap and get reused,
540 * but that is an unlikely case.
542 * After computing a session ID for a device, call
543 * usbi_get_device_by_session_id(). This function checks if libusb already
544 * knows about the device, and if so, it provides you with a reference
545 * to a libusb_device structure for it.
547 * If usbi_get_device_by_session_id() returns NULL, it is time to allocate
548 * a new device structure for the device. Call usbi_alloc_device() to
549 * obtain a new libusb_device structure with reference count 1. Populate
550 * the bus_number and device_address attributes of the new device, and
551 * perform any other internal backend initialization you need to do. At
552 * this point, you should be ready to provide device descriptors and so
553 * on through the get_*_descriptor functions. Finally, call
554 * usbi_sanitize_device() to perform some final sanity checks on the
555 * device. Assuming all of the above succeeded, we can now continue.
556 * If any of the above failed, remember to unreference the device that
557 * was returned by usbi_alloc_device().
559 * At this stage we have a populated libusb_device structure (either one
560 * that was found earlier, or one that we have just allocated and
561 * populated). This can now be added to the discovered devices list
562 * using discovered_devs_append(). Note that discovered_devs_append()
563 * may reallocate the list, returning a new location for it, and also
564 * note that reallocation can fail. Your backend should handle these
565 * error conditions appropriately.
567 * This function should not generate any bus I/O and should not block.
568 * If I/O is required (e.g. reading the active configuration value), it is
569 * OK to ignore these suggestions :)
571 * This function is executed when the user wishes to retrieve a list
572 * of USB devices connected to the system.
574 * If the backend has hotplug support, this function is not used!
576 * Return 0 on success, or a LIBUSB_ERROR code on failure.
578 int (*get_device_list)(struct libusb_context *ctx,
579 struct discovered_devs **discdevs);
581 /* Apps which were written before hotplug support, may listen for
582 * hotplug events on their own and call libusb_get_device_list on
583 * device addition. In this case libusb_get_device_list will likely
584 * return a list without the new device in there, as the hotplug
585 * event thread will still be busy enumerating the device, which may
586 * take a while, or may not even have seen the event yet.
588 * To avoid this libusb_get_device_list will call this optional
589 * function for backends with hotplug support before copying
590 * ctx->usb_devs to the user. In this function the backend should
591 * ensure any pending hotplug events are fully processed before
594 * Optional, should be implemented by backends with hotplug support.
596 void (*hotplug_poll)(void);
598 /* Open a device for I/O and other USB operations. The device handle
599 * is preallocated for you, you can retrieve the device in question
600 * through handle->dev.
602 * Your backend should allocate any internal resources required for I/O
603 * and other operations so that those operations can happen (hopefully)
604 * without hiccup. This is also a good place to inform libusb that it
605 * should monitor certain file descriptors related to this device -
606 * see the usbi_add_pollfd() function.
608 * This function should not generate any bus I/O and should not block.
610 * This function is called when the user attempts to obtain a device
611 * handle for a device.
615 * - LIBUSB_ERROR_ACCESS if the user has insufficient permissions
616 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since
618 * - another LIBUSB_ERROR code on other failure
620 * Do not worry about freeing the handle on failed open, the upper layers
623 int (*open)(struct libusb_device_handle *handle);
626 * XXX function to set file descriptor, added for mainly non-rooted Android
628 int (*set_device_fd)(struct libusb_device *device, int fd);
629 /* Close a device such that the handle cannot be used again. Your backend
630 * should destroy any resources that were allocated in the open path.
631 * This may also be a good place to call usbi_remove_pollfd() to inform
632 * libusb of any file descriptors associated with this device that should
633 * no longer be monitored.
635 * This function is called when the user closes a device handle.
637 void (*close)(struct libusb_device_handle *handle);
639 #ifdef ACCESS_RAW_DESCRIPTORS
640 int (*get_raw_descriptor)(struct libusb_device *device,
641 unsigned char *buffer, int *descriptors_len, int *host_endian); // XXX
643 /* Retrieve the device descriptor from a device.
645 * The descriptor should be retrieved from memory, NOT via bus I/O to the
646 * device. This means that you may have to cache it in a private structure
647 * during get_device_list enumeration. Alternatively, you may be able
648 * to retrieve it from a kernel interface (some Linux setups can do this)
649 * still without generating bus I/O.
651 * This function is expected to write DEVICE_DESC_LENGTH (18) bytes into
652 * buffer, which is guaranteed to be big enough.
654 * This function is called when sanity-checking a device before adding
655 * it to the list of discovered devices, and also when the user requests
656 * to read the device descriptor.
658 * This function is expected to return the descriptor in bus-endian format
659 * (LE). If it returns the multi-byte values in host-endian format,
660 * set the host_endian output parameter to "1".
662 * Return 0 on success or a LIBUSB_ERROR code on failure.
664 int (*get_device_descriptor)(struct libusb_device *device,
665 unsigned char *buffer, int *host_endian);
667 /* Get the ACTIVE configuration descriptor for a device.
669 * The descriptor should be retrieved from memory, NOT via bus I/O to the
670 * device. This means that you may have to cache it in a private structure
671 * during get_device_list enumeration. You may also have to keep track
672 * of which configuration is active when the user changes it.
674 * This function is expected to write len bytes of data into buffer, which
675 * is guaranteed to be big enough. If you can only do a partial write,
676 * return an error code.
678 * This function is expected to return the descriptor in bus-endian format
679 * (LE). If it returns the multi-byte values in host-endian format,
680 * set the host_endian output parameter to "1".
684 * - LIBUSB_ERROR_NOT_FOUND if the device is in unconfigured state
685 * - another LIBUSB_ERROR code on other failure
687 int (*get_active_config_descriptor)(struct libusb_device *device,
688 unsigned char *buffer, size_t len, int *host_endian);
690 /* Get a specific 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.
696 * The requested descriptor is expressed as a zero-based index (i.e. 0
697 * indicates that we are requesting the first descriptor). The index does
698 * not (necessarily) equal the bConfigurationValue of the configuration
701 * This function is expected to write len bytes of data into buffer, which
702 * is guaranteed to be big enough. If you can only do a partial write,
703 * return an error code.
705 * This function is expected to return the descriptor in bus-endian format
706 * (LE). If it returns the multi-byte values in host-endian format,
707 * set the host_endian output parameter to "1".
709 * Return the length read on success or a LIBUSB_ERROR code on failure.
711 int (*get_config_descriptor)(struct libusb_device *device,
712 uint8_t config_index, unsigned char *buffer, size_t len,
715 /* Like get_config_descriptor but then by bConfigurationValue instead
718 * Optional, if not present the core will call get_config_descriptor
719 * for all configs until it finds the desired bConfigurationValue.
721 * Returns a pointer to the raw-descriptor in *buffer, this memory
722 * is valid as long as device is valid.
724 * Returns the length of the returned raw-descriptor on success,
725 * or a LIBUSB_ERROR code on failure.
727 int (*get_config_descriptor_by_value)(struct libusb_device *device,
728 uint8_t bConfigurationValue, unsigned char **buffer,
731 /* Get the bConfigurationValue for the active configuration for a device.
732 * Optional. This should only be implemented if you can retrieve it from
733 * cache (don't generate I/O).
735 * If you cannot retrieve this from cache, either do not implement this
736 * function, or return LIBUSB_ERROR_NOT_SUPPORTED. This will cause
737 * libusb to retrieve the information through a standard control transfer.
739 * This function must be non-blocking.
742 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
744 * - LIBUSB_ERROR_NOT_SUPPORTED if the value cannot be retrieved without
746 * - another LIBUSB_ERROR code on other failure.
748 int (*get_configuration)(struct libusb_device_handle *handle, int *config);
750 /* Set the active configuration for a device.
752 * A configuration value of -1 should put the device in unconfigured state.
754 * This function can block.
758 * - LIBUSB_ERROR_NOT_FOUND if the configuration does not exist
759 * - LIBUSB_ERROR_BUSY if interfaces are currently claimed (and hence
760 * configuration cannot be changed)
761 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
763 * - another LIBUSB_ERROR code on other failure.
765 int (*set_configuration)(struct libusb_device_handle *handle, int config);
767 /* Claim an interface. When claimed, the application can then perform
768 * I/O to an interface's endpoints.
770 * This function should not generate any bus I/O and should not block.
771 * Interface claiming is a logical operation that simply ensures that
772 * no other drivers/applications are using the interface, and after
773 * claiming, no other drivers/applicatiosn can use the interface because
778 * - LIBUSB_ERROR_NOT_FOUND if the interface does not exist
779 * - LIBUSB_ERROR_BUSY if the interface is in use by another driver/app
780 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
782 * - another LIBUSB_ERROR code on other failure
784 int (*claim_interface)(struct libusb_device_handle *handle, int interface_number);
786 /* Release a previously claimed interface.
788 * This function should also generate a SET_INTERFACE control request,
789 * resetting the alternate setting of that interface to 0. It's OK for
790 * this function to block as a result.
792 * You will only ever be asked to release an interface which was
793 * successfully claimed earlier.
797 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
799 * - another LIBUSB_ERROR code on other failure
801 int (*release_interface)(struct libusb_device_handle *handle, int interface_number);
803 /* Set the alternate setting for an interface.
805 * You will only ever be asked to set the alternate setting for an
806 * interface which was successfully claimed earlier.
808 * It's OK for this function to block.
812 * - LIBUSB_ERROR_NOT_FOUND if the alternate setting does not exist
813 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
815 * - another LIBUSB_ERROR code on other failure
817 int (*set_interface_altsetting)(struct libusb_device_handle *handle,
818 int interface_number, int altsetting);
820 /* Clear a halt/stall condition on an endpoint.
822 * It's OK for this function to block.
826 * - LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist
827 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
829 * - another LIBUSB_ERROR code on other failure
831 int (*clear_halt)(struct libusb_device_handle *handle,
832 unsigned char endpoint);
834 /* Perform a USB port reset to reinitialize a device.
836 * If possible, the handle should still be usable after the reset
837 * completes, assuming that the device descriptors did not change during
838 * reset and all previous interface state can be restored.
840 * If something changes, or you cannot easily locate/verify the resetted
841 * device, return LIBUSB_ERROR_NOT_FOUND. This prompts the application
842 * to close the old handle and re-enumerate the device.
846 * - LIBUSB_ERROR_NOT_FOUND if re-enumeration is required, or if the device
847 * has been disconnected since it was opened
848 * - another LIBUSB_ERROR code on other failure
850 int (*reset_device)(struct libusb_device_handle *handle);
852 /* Alloc num_streams usb3 bulk streams on the passed in endpoints */
853 int (*alloc_streams)(struct libusb_device_handle *handle,
854 uint32_t num_streams, unsigned char *endpoints, int num_endpoints);
856 /* Free usb3 bulk streams allocated with alloc_streams */
857 int (*free_streams)(struct libusb_device_handle *handle,
858 unsigned char *endpoints, int num_endpoints);
860 /* Determine if a kernel driver is active on an interface. Optional.
862 * The presence of a kernel driver on an interface indicates that any
863 * calls to claim_interface would fail with the LIBUSB_ERROR_BUSY code.
866 * - 0 if no driver is active
867 * - 1 if a driver is active
868 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
870 * - another LIBUSB_ERROR code on other failure
872 int (*kernel_driver_active)(struct libusb_device_handle *handle,
873 int interface_number);
875 /* Detach a kernel driver from an interface. Optional.
877 * After detaching a kernel driver, the interface should be available
882 * - LIBUSB_ERROR_NOT_FOUND if no kernel driver was active
883 * - LIBUSB_ERROR_INVALID_PARAM if the interface does not exist
884 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
886 * - another LIBUSB_ERROR code on other failure
888 int (*detach_kernel_driver)(struct libusb_device_handle *handle,
889 int interface_number);
891 /* Attach a kernel driver to an interface. Optional.
893 * Reattach a kernel driver to the device.
897 * - LIBUSB_ERROR_NOT_FOUND if no kernel driver was active
898 * - LIBUSB_ERROR_INVALID_PARAM if the interface does not exist
899 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
901 * - LIBUSB_ERROR_BUSY if a program or driver has claimed the interface,
902 * preventing reattachment
903 * - another LIBUSB_ERROR code on other failure
905 int (*attach_kernel_driver)(struct libusb_device_handle *handle,
906 int interface_number);
908 /* Destroy a device. Optional.
910 * This function is called when the last reference to a device is
911 * destroyed. It should free any resources allocated in the get_device_list
914 void (*destroy_device)(struct libusb_device *dev);
916 /* Submit a transfer. Your implementation should take the transfer,
917 * morph it into whatever form your platform requires, and submit it
920 * This function must not block.
922 * This function gets called with the flying_transfers_lock locked!
926 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
927 * - another LIBUSB_ERROR code on other failure
929 int (*submit_transfer)(struct usbi_transfer *itransfer);
931 /* Cancel a previously submitted transfer.
933 * This function must not block. The transfer cancellation must complete
934 * later, resulting in a call to usbi_handle_transfer_cancellation()
935 * from the context of handle_events.
937 int (*cancel_transfer)(struct usbi_transfer *itransfer);
939 /* Clear a transfer as if it has completed or cancelled, but do not
940 * report any completion/cancellation to the library. You should free
941 * all private data from the transfer as if you were just about to report
942 * completion or cancellation.
944 * This function might seem a bit out of place. It is used when libusb
945 * detects a disconnected device - it calls this function for all pending
946 * transfers before reporting completion (with the disconnect code) to
947 * the user. Maybe we can improve upon this internal interface in future.
949 void (*clear_transfer_priv)(struct usbi_transfer *itransfer);
951 /* Handle any pending events. This involves monitoring any active
952 * transfers and processing their completion or cancellation.
954 * The function is passed an array of pollfd structures (size nfds)
955 * as a result of the poll() system call. The num_ready parameter
956 * indicates the number of file descriptors that have reported events
957 * (i.e. the poll() return value). This should be enough information
958 * for you to determine which actions need to be taken on the currently
961 * For any cancelled transfers, call usbi_handle_transfer_cancellation().
962 * For completed transfers, call usbi_handle_transfer_completion().
963 * For control/bulk/interrupt transfers, populate the "transferred"
964 * element of the appropriate usbi_transfer structure before calling the
965 * above functions. For isochronous transfers, populate the status and
966 * transferred fields of the iso packet descriptors of the transfer.
968 * This function should also be able to detect disconnection of the
969 * device, reporting that situation with usbi_handle_disconnect().
971 * When processing an event related to a transfer, you probably want to
972 * take usbi_transfer.lock to prevent races. See the documentation for
973 * the usbi_transfer structure.
975 * Return 0 on success, or a LIBUSB_ERROR code on failure.
977 int (*handle_events)(struct libusb_context *ctx, struct pollfd *fds,
978 POLL_NFDS_TYPE nfds, int num_ready);
980 /* Get time from specified clock. At least two clocks must be implemented
981 by the backend: USBI_CLOCK_REALTIME, and USBI_CLOCK_MONOTONIC.
983 Description of clocks:
984 USBI_CLOCK_REALTIME : clock returns time since system epoch.
985 USBI_CLOCK_MONOTONIC: clock returns time since unspecified start
988 int (*clock_gettime)(int clkid, struct timespec *tp);
990 #ifdef USBI_TIMERFD_AVAILABLE
991 /* clock ID of the clock that should be used for timerfd */
992 clockid_t (*get_timerfd_clockid)(void);
995 /* Number of bytes to reserve for per-device private backend data.
996 * This private data area is accessible through the "os_priv" field of
997 * struct libusb_device. */
998 size_t device_priv_size;
1000 /* Number of bytes to reserve for per-handle private backend data.
1001 * This private data area is accessible through the "os_priv" field of
1002 * struct libusb_device. */
1003 size_t device_handle_priv_size;
1005 /* Number of bytes to reserve for per-transfer private backend data.
1006 * This private data area is accessible by calling
1007 * usbi_transfer_get_os_priv() on the appropriate usbi_transfer instance.
1009 size_t transfer_priv_size;
1011 /* Mumber of additional bytes for os_priv for each iso packet.
1012 * Can your backend use this? */
1013 /* FIXME: linux can't use this any more. if other OS's cannot either,
1014 * then remove this */
1015 size_t add_iso_packet_size;
1018 extern const struct usbi_os_backend * const usbi_backend;
1020 extern const struct usbi_os_backend android_usbfs_backend; // XXX added for mainly non-rooted Android
1021 extern const struct usbi_os_backend linux_usbfs_backend;
1022 extern const struct usbi_os_backend darwin_backend;
1023 extern const struct usbi_os_backend openbsd_backend;
1024 extern const struct usbi_os_backend netbsd_backend;
1025 extern const struct usbi_os_backend windows_backend;
1026 extern const struct usbi_os_backend wince_backend;
1028 extern struct list_head active_contexts_list;
1029 extern usbi_mutex_static_t active_contexts_lock;