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 /* A thread-local storage key to track which thread is performing event
284 usbi_tls_key_t event_handling_key;
286 /* used to wait for event completion in threads other than the one that is
288 usbi_mutex_t event_waiters_lock;
289 usbi_cond_t event_waiters_cond;
291 /* A lock to protect internal context event data. */
292 usbi_mutex_t event_data_lock;
294 /* A bitmask of flags that are set to indicate specific events that need to
295 * be handled. Protected by event_data_lock. */
296 unsigned int event_flags;
298 /* A counter that is set when we want to interrupt and prevent event handling,
299 * in order to safely close a device. Protected by event_data_lock. */
300 unsigned int device_close;
302 /* list and count of poll fds and an array of poll fd structures that is
303 * (re)allocated as necessary prior to polling. Protected by event_data_lock. */
304 struct list_head ipollfds;
305 struct pollfd *pollfds;
306 POLL_NFDS_TYPE pollfds_cnt;
308 /* A list of pending hotplug messages. Protected by event_data_lock. */
309 struct list_head hotplug_msgs;
311 /* A list of pending completed transfers. Protected by event_data_lock. */
312 struct list_head completed_transfers;
314 #ifdef USBI_TIMERFD_AVAILABLE
315 /* used for timeout handling, if supported by OS.
316 * this timerfd is maintained to trigger on the next pending timeout */
320 struct list_head list;
323 enum usbi_event_flags {
324 /* The list of pollfds has been modified */
325 USBI_EVENT_POLLFDS_MODIFIED = 1 << 0,
327 /* The user has interrupted the event handler */
328 USBI_EVENT_USER_INTERRUPT = 1 << 1,
331 /* Macros for managing event handling state */
332 #define usbi_handling_events(ctx) \
333 (usbi_tls_key_get((ctx)->event_handling_key) != NULL)
335 #define usbi_start_event_handling(ctx) \
336 usbi_tls_key_set((ctx)->event_handling_key, ctx)
338 #define usbi_end_event_handling(ctx) \
339 usbi_tls_key_set((ctx)->event_handling_key, NULL)
341 /* Update the following macro if new event sources are added */
342 #define usbi_pending_events(ctx) \
343 ((ctx)->event_flags || (ctx)->device_close \
344 || !list_empty(&(ctx)->hotplug_msgs) || !list_empty(&(ctx)->completed_transfers))
346 #ifdef USBI_TIMERFD_AVAILABLE
347 #define usbi_using_timerfd(ctx) ((ctx)->timerfd >= 0)
349 #define usbi_using_timerfd(ctx) (0)
352 struct libusb_device {
353 /* lock protects refcnt, everything else is finalized at initialization
358 struct libusb_context *ctx;
362 struct libusb_device* parent_dev;
363 uint8_t device_address;
364 uint8_t num_configurations;
365 enum libusb_speed speed;
367 struct list_head list;
368 unsigned long session_data;
370 struct libusb_device_descriptor device_descriptor;
373 unsigned char os_priv
374 #if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
375 [] /* valid C99 code */
377 [0] /* non-standard, but usually working code */
382 struct libusb_device_handle {
383 /* lock protects claimed_interfaces */
385 unsigned long claimed_interfaces;
387 struct list_head list;
388 struct libusb_device *dev;
389 int auto_detach_kernel_driver;
390 unsigned char os_priv
391 #if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
392 [] /* valid C99 code */
394 [0] /* non-standard, but usually working code */
400 USBI_CLOCK_MONOTONIC,
404 /* in-memory transfer layout:
406 * 1. struct usbi_transfer
407 * 2. struct libusb_transfer (which includes iso packets) [variable size]
408 * 3. os private data [variable size]
410 * from a libusb_transfer, you can get the usbi_transfer by rewinding the
411 * appropriate number of bytes.
412 * the usbi_transfer includes the number of allocated packets, so you can
413 * determine the size of the transfer and hence the start and length of the
417 struct usbi_transfer {
419 struct list_head list;
420 struct list_head completed_list;
421 struct timeval timeout;
426 /* this lock is held during libusb_submit_transfer() and
427 * libusb_cancel_transfer() (allowing the OS backend to prevent duplicate
428 * cancellation, submission-during-cancellation, etc). the OS backend
429 * should also take this lock in the handle_events path, to prevent the user
430 * cancelling the transfer from another thread while you are processing
431 * its completion (presumably there would be races within your OS backend
432 * if this were possible). */
435 /* this lock should be held whenever viewing or modifying flags
436 * relating to the transfer state */
437 usbi_mutex_t flags_lock;
440 enum usbi_transfer_flags {
441 /* The transfer has timed out */
442 USBI_TRANSFER_TIMED_OUT = 1 << 0,
444 /* Set by backend submit_transfer() if the OS handles timeout */
445 USBI_TRANSFER_OS_HANDLES_TIMEOUT = 1 << 1,
447 /* Cancellation was requested via libusb_cancel_transfer() */
448 USBI_TRANSFER_CANCELLING = 1 << 2,
450 /* Operation on the transfer failed because the device disappeared */
451 USBI_TRANSFER_DEVICE_DISAPPEARED = 1 << 3,
453 /* Transfer is currently being submitted */
454 USBI_TRANSFER_SUBMITTING = 1 << 4,
456 /* Transfer successfully submitted by backend */
457 USBI_TRANSFER_IN_FLIGHT = 1 << 5,
459 /* Completion handler has run */
460 USBI_TRANSFER_COMPLETED = 1 << 6,
462 /* The transfer timeout has been handled */
463 USBI_TRANSFER_TIMEOUT_HANDLED = 1 << 7,
466 #define USBI_TRANSFER_TO_LIBUSB_TRANSFER(transfer) \
467 ((struct libusb_transfer *)(((unsigned char *)(transfer)) \
468 + sizeof(struct usbi_transfer)))
469 #define LIBUSB_TRANSFER_TO_USBI_TRANSFER(transfer) \
470 ((struct usbi_transfer *)(((unsigned char *)(transfer)) \
471 - sizeof(struct usbi_transfer)))
473 static inline void *usbi_transfer_get_os_priv(struct usbi_transfer *transfer)
475 return ((unsigned char *)transfer) + sizeof(struct usbi_transfer)
476 + sizeof(struct libusb_transfer)
477 + (transfer->num_iso_packets
478 * sizeof(struct libusb_iso_packet_descriptor));
483 /* All standard descriptors have these 2 fields in common */
484 struct usb_descriptor_header {
486 uint8_t bDescriptorType;
489 /* shared data and functions */
491 int usbi_io_init(struct libusb_context *ctx);
492 void usbi_io_exit(struct libusb_context *ctx);
494 struct libusb_device *usbi_alloc_device(struct libusb_context *ctx,
495 unsigned long session_id);
496 struct libusb_device *usbi_get_device_by_session_id(struct libusb_context *ctx,
497 unsigned long session_id);
498 int usbi_sanitize_device(struct libusb_device *dev);
499 void usbi_handle_disconnect(struct libusb_device_handle *handle);
501 int usbi_handle_transfer_completion(struct usbi_transfer *itransfer,
502 enum libusb_transfer_status status);
503 int usbi_handle_transfer_cancellation(struct usbi_transfer *transfer);
504 void usbi_signal_transfer_completion(struct usbi_transfer *transfer);
506 int usbi_parse_descriptor(const unsigned char *source, const char *descriptor,
507 void *dest, int host_endian);
508 int usbi_device_cache_descriptor(libusb_device *dev);
509 int usbi_get_config_index_by_value(struct libusb_device *dev,
510 uint8_t bConfigurationValue, int *idx);
512 void usbi_connect_device (struct libusb_device *dev);
513 void usbi_disconnect_device (struct libusb_device *dev);
515 int usbi_signal_event(struct libusb_context *ctx);
516 int usbi_clear_event(struct libusb_context *ctx);
518 /* Internal abstraction for poll (needs struct usbi_transfer on Windows) */
519 #if defined(OS_LINUX) || defined(OS_DARWIN) || defined(OS_OPENBSD) || defined(OS_NETBSD) || defined(OS_HAIKU)
521 #include "os/poll_posix.h"
522 #elif defined(OS_WINDOWS) || defined(OS_WINCE)
523 #include "os/poll_windows.h"
526 #if (defined(OS_WINDOWS) || defined(OS_WINCE)) && !defined(__GNUC__)
527 #define snprintf _snprintf
528 #define vsnprintf _vsnprintf
529 int usbi_gettimeofday(struct timeval *tp, void *tzp);
530 #define LIBUSB_GETTIMEOFDAY_WIN32
531 #define HAVE_USBI_GETTIMEOFDAY
533 #ifdef HAVE_GETTIMEOFDAY
534 #define usbi_gettimeofday(tv, tz) gettimeofday((tv), (tz))
535 #define HAVE_USBI_GETTIMEOFDAY
540 /* must come first */
541 struct libusb_pollfd pollfd;
543 struct list_head list;
546 int usbi_add_pollfd(struct libusb_context *ctx, int fd, short events);
547 void usbi_remove_pollfd(struct libusb_context *ctx, int fd);
549 /* device discovery */
551 /* we traverse usbfs without knowing how many devices we are going to find.
552 * so we create this discovered_devs model which is similar to a linked-list
553 * which grows when required. it can be freed once discovery has completed,
554 * eliminating the need for a list node in the libusb_device structure
556 struct discovered_devs {
559 struct libusb_device *devices
560 #if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
561 [] /* valid C99 code */
563 [0] /* non-standard, but usually working code */
568 struct discovered_devs *discovered_devs_append(
569 struct discovered_devs *discdevs, struct libusb_device *dev);
573 /* This is the interface that OS backends need to implement.
574 * All fields are mandatory, except ones explicitly noted as optional. */
575 struct usbi_os_backend {
576 /* A human-readable name for your backend, e.g. "Linux usbfs" */
579 /* Binary mask for backend specific capabilities */
582 /* Perform initialization of your backend. You might use this function
583 * to determine specific capabilities of the system, allocate required
584 * data structures for later, etc.
586 * This function is called when a libusb user initializes the library
589 * Return 0 on success, or a LIBUSB_ERROR code on failure.
591 int (*init)(struct libusb_context *ctx);
593 /* Deinitialization. Optional. This function should destroy anything
594 * that was set up by init.
596 * This function is called when the user deinitializes the library.
600 /* Enumerate all the USB devices on the system, returning them in a list
601 * of discovered devices.
603 * Your implementation should enumerate all devices on the system,
604 * regardless of whether they have been seen before or not.
606 * When you have found a device, compute a session ID for it. The session
607 * ID should uniquely represent that particular device for that particular
608 * connection session since boot (i.e. if you disconnect and reconnect a
609 * device immediately after, it should be assigned a different session ID).
610 * If your OS cannot provide a unique session ID as described above,
611 * presenting a session ID of (bus_number << 8 | device_address) should
612 * be sufficient. Bus numbers and device addresses wrap and get reused,
613 * but that is an unlikely case.
615 * After computing a session ID for a device, call
616 * usbi_get_device_by_session_id(). This function checks if libusb already
617 * knows about the device, and if so, it provides you with a reference
618 * to a libusb_device structure for it.
620 * If usbi_get_device_by_session_id() returns NULL, it is time to allocate
621 * a new device structure for the device. Call usbi_alloc_device() to
622 * obtain a new libusb_device structure with reference count 1. Populate
623 * the bus_number and device_address attributes of the new device, and
624 * perform any other internal backend initialization you need to do. At
625 * this point, you should be ready to provide device descriptors and so
626 * on through the get_*_descriptor functions. Finally, call
627 * usbi_sanitize_device() to perform some final sanity checks on the
628 * device. Assuming all of the above succeeded, we can now continue.
629 * If any of the above failed, remember to unreference the device that
630 * was returned by usbi_alloc_device().
632 * At this stage we have a populated libusb_device structure (either one
633 * that was found earlier, or one that we have just allocated and
634 * populated). This can now be added to the discovered devices list
635 * using discovered_devs_append(). Note that discovered_devs_append()
636 * may reallocate the list, returning a new location for it, and also
637 * note that reallocation can fail. Your backend should handle these
638 * error conditions appropriately.
640 * This function should not generate any bus I/O and should not block.
641 * If I/O is required (e.g. reading the active configuration value), it is
642 * OK to ignore these suggestions :)
644 * This function is executed when the user wishes to retrieve a list
645 * of USB devices connected to the system.
647 * If the backend has hotplug support, this function is not used!
649 * Return 0 on success, or a LIBUSB_ERROR code on failure.
651 int (*get_device_list)(struct libusb_context *ctx,
652 struct discovered_devs **discdevs);
654 /* Apps which were written before hotplug support, may listen for
655 * hotplug events on their own and call libusb_get_device_list on
656 * device addition. In this case libusb_get_device_list will likely
657 * return a list without the new device in there, as the hotplug
658 * event thread will still be busy enumerating the device, which may
659 * take a while, or may not even have seen the event yet.
661 * To avoid this libusb_get_device_list will call this optional
662 * function for backends with hotplug support before copying
663 * ctx->usb_devs to the user. In this function the backend should
664 * ensure any pending hotplug events are fully processed before
667 * Optional, should be implemented by backends with hotplug support.
669 void (*hotplug_poll)(void);
671 /* Open a device for I/O and other USB operations. The device handle
672 * is preallocated for you, you can retrieve the device in question
673 * through handle->dev.
675 * Your backend should allocate any internal resources required for I/O
676 * and other operations so that those operations can happen (hopefully)
677 * without hiccup. This is also a good place to inform libusb that it
678 * should monitor certain file descriptors related to this device -
679 * see the usbi_add_pollfd() function.
681 * This function should not generate any bus I/O and should not block.
683 * This function is called when the user attempts to obtain a device
684 * handle for a device.
688 * - LIBUSB_ERROR_ACCESS if the user has insufficient permissions
689 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since
691 * - another LIBUSB_ERROR code on other failure
693 * Do not worry about freeing the handle on failed open, the upper layers
696 int (*open)(struct libusb_device_handle *handle);
698 /* Close a device such that the handle cannot be used again. Your backend
699 * should destroy any resources that were allocated in the open path.
700 * This may also be a good place to call usbi_remove_pollfd() to inform
701 * libusb of any file descriptors associated with this device that should
702 * no longer be monitored.
704 * This function is called when the user closes a device handle.
706 void (*close)(struct libusb_device_handle *handle);
708 /* Retrieve the device descriptor from a device.
710 * The descriptor should be retrieved from memory, NOT via bus I/O to the
711 * device. This means that you may have to cache it in a private structure
712 * during get_device_list enumeration. Alternatively, you may be able
713 * to retrieve it from a kernel interface (some Linux setups can do this)
714 * still without generating bus I/O.
716 * This function is expected to write DEVICE_DESC_LENGTH (18) bytes into
717 * buffer, which is guaranteed to be big enough.
719 * This function is called when sanity-checking a device before adding
720 * it to the list of discovered devices, and also when the user requests
721 * to read the device descriptor.
723 * This function is expected to return the descriptor in bus-endian format
724 * (LE). If it returns the multi-byte values in host-endian format,
725 * set the host_endian output parameter to "1".
727 * Return 0 on success or a LIBUSB_ERROR code on failure.
729 int (*get_device_descriptor)(struct libusb_device *device,
730 unsigned char *buffer, int *host_endian);
732 /* Get the ACTIVE configuration descriptor for a device.
734 * The descriptor should be retrieved from memory, NOT via bus I/O to the
735 * device. This means that you may have to cache it in a private structure
736 * during get_device_list enumeration. You may also have to keep track
737 * of which configuration is active when the user changes it.
739 * This function is expected to write len bytes of data into buffer, which
740 * is guaranteed to be big enough. If you can only do a partial write,
741 * return an error code.
743 * This function is expected to return the descriptor in bus-endian format
744 * (LE). If it returns the multi-byte values in host-endian format,
745 * set the host_endian output parameter to "1".
749 * - LIBUSB_ERROR_NOT_FOUND if the device is in unconfigured state
750 * - another LIBUSB_ERROR code on other failure
752 int (*get_active_config_descriptor)(struct libusb_device *device,
753 unsigned char *buffer, size_t len, int *host_endian);
755 /* Get a specific configuration descriptor for a device.
757 * The descriptor should be retrieved from memory, NOT via bus I/O to the
758 * device. This means that you may have to cache it in a private structure
759 * during get_device_list enumeration.
761 * The requested descriptor is expressed as a zero-based index (i.e. 0
762 * indicates that we are requesting the first descriptor). The index does
763 * not (necessarily) equal the bConfigurationValue of the configuration
766 * This function is expected to write len bytes of data into buffer, which
767 * is guaranteed to be big enough. If you can only do a partial write,
768 * return an error code.
770 * This function is expected to return the descriptor in bus-endian format
771 * (LE). If it returns the multi-byte values in host-endian format,
772 * set the host_endian output parameter to "1".
774 * Return the length read on success or a LIBUSB_ERROR code on failure.
776 int (*get_config_descriptor)(struct libusb_device *device,
777 uint8_t config_index, unsigned char *buffer, size_t len,
780 /* Like get_config_descriptor but then by bConfigurationValue instead
783 * Optional, if not present the core will call get_config_descriptor
784 * for all configs until it finds the desired bConfigurationValue.
786 * Returns a pointer to the raw-descriptor in *buffer, this memory
787 * is valid as long as device is valid.
789 * Returns the length of the returned raw-descriptor on success,
790 * or a LIBUSB_ERROR code on failure.
792 int (*get_config_descriptor_by_value)(struct libusb_device *device,
793 uint8_t bConfigurationValue, unsigned char **buffer,
796 /* Get the bConfigurationValue for the active configuration for a device.
797 * Optional. This should only be implemented if you can retrieve it from
798 * cache (don't generate I/O).
800 * If you cannot retrieve this from cache, either do not implement this
801 * function, or return LIBUSB_ERROR_NOT_SUPPORTED. This will cause
802 * libusb to retrieve the information through a standard control transfer.
804 * This function must be non-blocking.
807 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
809 * - LIBUSB_ERROR_NOT_SUPPORTED if the value cannot be retrieved without
811 * - another LIBUSB_ERROR code on other failure.
813 int (*get_configuration)(struct libusb_device_handle *handle, int *config);
815 /* Set the active configuration for a device.
817 * A configuration value of -1 should put the device in unconfigured state.
819 * This function can block.
823 * - LIBUSB_ERROR_NOT_FOUND if the configuration does not exist
824 * - LIBUSB_ERROR_BUSY if interfaces are currently claimed (and hence
825 * configuration cannot be changed)
826 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
828 * - another LIBUSB_ERROR code on other failure.
830 int (*set_configuration)(struct libusb_device_handle *handle, int config);
832 /* Claim an interface. When claimed, the application can then perform
833 * I/O to an interface's endpoints.
835 * This function should not generate any bus I/O and should not block.
836 * Interface claiming is a logical operation that simply ensures that
837 * no other drivers/applications are using the interface, and after
838 * claiming, no other drivers/applications can use the interface because
843 * - LIBUSB_ERROR_NOT_FOUND if the interface does not exist
844 * - LIBUSB_ERROR_BUSY if the interface is in use by another driver/app
845 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
847 * - another LIBUSB_ERROR code on other failure
849 int (*claim_interface)(struct libusb_device_handle *handle, int interface_number);
851 /* Release a previously claimed interface.
853 * This function should also generate a SET_INTERFACE control request,
854 * resetting the alternate setting of that interface to 0. It's OK for
855 * this function to block as a result.
857 * You will only ever be asked to release an interface which was
858 * successfully claimed earlier.
862 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
864 * - another LIBUSB_ERROR code on other failure
866 int (*release_interface)(struct libusb_device_handle *handle, int interface_number);
868 /* Set the alternate setting for an interface.
870 * You will only ever be asked to set the alternate setting for an
871 * interface which was successfully claimed earlier.
873 * It's OK for this function to block.
877 * - LIBUSB_ERROR_NOT_FOUND if the alternate setting does not exist
878 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
880 * - another LIBUSB_ERROR code on other failure
882 int (*set_interface_altsetting)(struct libusb_device_handle *handle,
883 int interface_number, int altsetting);
885 /* Clear a halt/stall condition on an endpoint.
887 * It's OK for this function to block.
891 * - LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist
892 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
894 * - another LIBUSB_ERROR code on other failure
896 int (*clear_halt)(struct libusb_device_handle *handle,
897 unsigned char endpoint);
899 /* Perform a USB port reset to reinitialize a device.
901 * If possible, the handle should still be usable after the reset
902 * completes, assuming that the device descriptors did not change during
903 * reset and all previous interface state can be restored.
905 * If something changes, or you cannot easily locate/verify the resetted
906 * device, return LIBUSB_ERROR_NOT_FOUND. This prompts the application
907 * to close the old handle and re-enumerate the device.
911 * - LIBUSB_ERROR_NOT_FOUND if re-enumeration is required, or if the device
912 * has been disconnected since it was opened
913 * - another LIBUSB_ERROR code on other failure
915 int (*reset_device)(struct libusb_device_handle *handle);
917 /* Alloc num_streams usb3 bulk streams on the passed in endpoints */
918 int (*alloc_streams)(struct libusb_device_handle *handle,
919 uint32_t num_streams, unsigned char *endpoints, int num_endpoints);
921 /* Free usb3 bulk streams allocated with alloc_streams */
922 int (*free_streams)(struct libusb_device_handle *handle,
923 unsigned char *endpoints, int num_endpoints);
925 /* Determine if a kernel driver is active on an interface. Optional.
927 * The presence of a kernel driver on an interface indicates that any
928 * calls to claim_interface would fail with the LIBUSB_ERROR_BUSY code.
931 * - 0 if no driver is active
932 * - 1 if a driver is active
933 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
935 * - another LIBUSB_ERROR code on other failure
937 int (*kernel_driver_active)(struct libusb_device_handle *handle,
938 int interface_number);
940 /* Detach a kernel driver from an interface. Optional.
942 * After detaching a kernel driver, the interface should be available
947 * - LIBUSB_ERROR_NOT_FOUND if no kernel driver was active
948 * - LIBUSB_ERROR_INVALID_PARAM if the interface does not exist
949 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
951 * - another LIBUSB_ERROR code on other failure
953 int (*detach_kernel_driver)(struct libusb_device_handle *handle,
954 int interface_number);
956 /* Attach a kernel driver to an interface. Optional.
958 * Reattach a kernel driver to the device.
962 * - LIBUSB_ERROR_NOT_FOUND if no kernel driver was active
963 * - LIBUSB_ERROR_INVALID_PARAM if the interface does not exist
964 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
966 * - LIBUSB_ERROR_BUSY if a program or driver has claimed the interface,
967 * preventing reattachment
968 * - another LIBUSB_ERROR code on other failure
970 int (*attach_kernel_driver)(struct libusb_device_handle *handle,
971 int interface_number);
973 /* Destroy a device. Optional.
975 * This function is called when the last reference to a device is
976 * destroyed. It should free any resources allocated in the get_device_list
979 void (*destroy_device)(struct libusb_device *dev);
981 /* Submit a transfer. Your implementation should take the transfer,
982 * morph it into whatever form your platform requires, and submit it
985 * This function must not block.
987 * This function gets called with the flying_transfers_lock locked!
991 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
992 * - another LIBUSB_ERROR code on other failure
994 int (*submit_transfer)(struct usbi_transfer *itransfer);
996 /* Cancel a previously submitted transfer.
998 * This function must not block. The transfer cancellation must complete
999 * later, resulting in a call to usbi_handle_transfer_cancellation()
1000 * from the context of handle_events.
1002 int (*cancel_transfer)(struct usbi_transfer *itransfer);
1004 /* Clear a transfer as if it has completed or cancelled, but do not
1005 * report any completion/cancellation to the library. You should free
1006 * all private data from the transfer as if you were just about to report
1007 * completion or cancellation.
1009 * This function might seem a bit out of place. It is used when libusb
1010 * detects a disconnected device - it calls this function for all pending
1011 * transfers before reporting completion (with the disconnect code) to
1012 * the user. Maybe we can improve upon this internal interface in future.
1014 void (*clear_transfer_priv)(struct usbi_transfer *itransfer);
1016 /* Handle any pending events on file descriptors. Optional.
1018 * Provide this function when file descriptors directly indicate device
1019 * or transfer activity. If your backend does not have such file descriptors,
1020 * implement the handle_transfer_completion function below.
1022 * This involves monitoring any active transfers and processing their
1023 * completion or cancellation.
1025 * The function is passed an array of pollfd structures (size nfds)
1026 * as a result of the poll() system call. The num_ready parameter
1027 * indicates the number of file descriptors that have reported events
1028 * (i.e. the poll() return value). This should be enough information
1029 * for you to determine which actions need to be taken on the currently
1032 * For any cancelled transfers, call usbi_handle_transfer_cancellation().
1033 * For completed transfers, call usbi_handle_transfer_completion().
1034 * For control/bulk/interrupt transfers, populate the "transferred"
1035 * element of the appropriate usbi_transfer structure before calling the
1036 * above functions. For isochronous transfers, populate the status and
1037 * transferred fields of the iso packet descriptors of the transfer.
1039 * This function should also be able to detect disconnection of the
1040 * device, reporting that situation with usbi_handle_disconnect().
1042 * When processing an event related to a transfer, you probably want to
1043 * take usbi_transfer.lock to prevent races. See the documentation for
1044 * the usbi_transfer structure.
1046 * Return 0 on success, or a LIBUSB_ERROR code on failure.
1048 int (*handle_events)(struct libusb_context *ctx,
1049 struct pollfd *fds, POLL_NFDS_TYPE nfds, int num_ready);
1051 /* Handle transfer completion. Optional.
1053 * Provide this function when there are no file descriptors available
1054 * that directly indicate device or transfer activity. If your backend does
1055 * have such file descriptors, implement the handle_events function above.
1057 * Your backend must tell the library when a transfer has completed by
1058 * calling usbi_signal_transfer_completion(). You should store any private
1059 * information about the transfer and its completion status in the transfer's
1060 * private backend data.
1062 * During event handling, this function will be called on each transfer for
1063 * which usbi_signal_transfer_completion() was called.
1065 * For any cancelled transfers, call usbi_handle_transfer_cancellation().
1066 * For completed transfers, call usbi_handle_transfer_completion().
1067 * For control/bulk/interrupt transfers, populate the "transferred"
1068 * element of the appropriate usbi_transfer structure before calling the
1069 * above functions. For isochronous transfers, populate the status and
1070 * transferred fields of the iso packet descriptors of the transfer.
1072 * Return 0 on success, or a LIBUSB_ERROR code on failure.
1074 int (*handle_transfer_completion)(struct usbi_transfer *itransfer);
1076 /* Get time from specified clock. At least two clocks must be implemented
1077 by the backend: USBI_CLOCK_REALTIME, and USBI_CLOCK_MONOTONIC.
1079 Description of clocks:
1080 USBI_CLOCK_REALTIME : clock returns time since system epoch.
1081 USBI_CLOCK_MONOTONIC: clock returns time since unspecified start
1082 time (usually boot).
1084 int (*clock_gettime)(int clkid, struct timespec *tp);
1086 #ifdef USBI_TIMERFD_AVAILABLE
1087 /* clock ID of the clock that should be used for timerfd */
1088 clockid_t (*get_timerfd_clockid)(void);
1091 /* Number of bytes to reserve for per-device private backend data.
1092 * This private data area is accessible through the "os_priv" field of
1093 * struct libusb_device. */
1094 size_t device_priv_size;
1096 /* Number of bytes to reserve for per-handle private backend data.
1097 * This private data area is accessible through the "os_priv" field of
1098 * struct libusb_device. */
1099 size_t device_handle_priv_size;
1101 /* Number of bytes to reserve for per-transfer private backend data.
1102 * This private data area is accessible by calling
1103 * usbi_transfer_get_os_priv() on the appropriate usbi_transfer instance.
1105 size_t transfer_priv_size;
1108 extern const struct usbi_os_backend * const usbi_backend;
1110 extern const struct usbi_os_backend linux_usbfs_backend;
1111 extern const struct usbi_os_backend darwin_backend;
1112 extern const struct usbi_os_backend openbsd_backend;
1113 extern const struct usbi_os_backend netbsd_backend;
1114 extern const struct usbi_os_backend windows_backend;
1115 extern const struct usbi_os_backend wince_backend;
1116 extern const struct usbi_os_backend haiku_usb_raw_backend;
1118 extern struct list_head active_contexts_list;
1119 extern usbi_mutex_static_t active_contexts_lock;