linux: Not finding a device on hotplug_disconnect is not an error
[libusbx.git] / libusb / libusbi.h
blob531e419feabcbb2fbeafcb8694c000d081a9ef59
1 /*
2 * Internal header for libusbx
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
21 #ifndef LIBUSBI_H
22 #define LIBUSBI_H
24 #include "config.h"
26 #include <stddef.h>
27 #include <stdint.h>
28 #include <time.h>
29 #include <stdarg.h>
30 #ifdef HAVE_POLL_H
31 #include <poll.h>
32 #endif
34 #ifdef HAVE_MISSING_H
35 #include "missing.h"
36 #endif
37 #include "libusb.h"
38 #include "version.h"
40 /* Inside the libusbx code, mark all public functions as follows:
41 * return_type API_EXPORTED function_name(params) { ... }
42 * But if the function returns a pointer, mark it as follows:
43 * DEFAULT_VISIBILITY return_type * LIBUSB_CALL function_name(params) { ... }
44 * In the libusbx public header, mark all declarations as:
45 * return_type LIBUSB_CALL function_name(params);
47 #define API_EXPORTED LIBUSB_CALL DEFAULT_VISIBILITY
49 #define DEVICE_DESC_LENGTH 18
51 #define USB_MAXENDPOINTS 32
52 #define USB_MAXINTERFACES 32
53 #define USB_MAXCONFIG 8
55 /* Backend specific capabilities */
56 #define USBI_CAP_HAS_HID_ACCESS 0x00010000
57 #define USBI_CAP_SUPPORTS_DETACH_KERNEL_DRIVER 0x00020000
59 /* The following is used to silence warnings for unused variables */
60 #define UNUSED(var) do { (void)(var); } while(0)
62 struct list_head {
63 struct list_head *prev, *next;
66 /* Get an entry from the list
67 * ptr - the address of this list_head element in "type"
68 * type - the data type that contains "member"
69 * member - the list_head element in "type"
71 #define list_entry(ptr, type, member) \
72 ((type *)((uintptr_t)(ptr) - (uintptr_t)offsetof(type, member)))
74 /* Get each entry from a list
75 * pos - A structure pointer has a "member" element
76 * head - list head
77 * member - the list_head element in "pos"
78 * type - the type of the first parameter
80 #define list_for_each_entry(pos, head, member, type) \
81 for (pos = list_entry((head)->next, type, member); \
82 &pos->member != (head); \
83 pos = list_entry(pos->member.next, type, member))
85 #define list_for_each_entry_safe(pos, n, head, member, type) \
86 for (pos = list_entry((head)->next, type, member), \
87 n = list_entry(pos->member.next, type, member); \
88 &pos->member != (head); \
89 pos = n, n = list_entry(n->member.next, type, member))
91 #define list_empty(entry) ((entry)->next == (entry))
93 static inline void list_init(struct list_head *entry)
95 entry->prev = entry->next = entry;
98 static inline void list_add(struct list_head *entry, struct list_head *head)
100 entry->next = head->next;
101 entry->prev = head;
103 head->next->prev = entry;
104 head->next = entry;
107 static inline void list_add_tail(struct list_head *entry,
108 struct list_head *head)
110 entry->next = head;
111 entry->prev = head->prev;
113 head->prev->next = entry;
114 head->prev = entry;
117 static inline void list_del(struct list_head *entry)
119 entry->next->prev = entry->prev;
120 entry->prev->next = entry->next;
121 entry->next = entry->prev = NULL;
124 static inline void *usbi_reallocf(void *ptr, size_t size)
126 void *ret = realloc(ptr, size);
127 if (!ret)
128 free(ptr);
129 return ret;
132 #define container_of(ptr, type, member) ({ \
133 const typeof( ((type *)0)->member ) *mptr = (ptr); \
134 (type *)( (char *)mptr - offsetof(type,member) );})
136 #define MIN(a, b) ((a) < (b) ? (a) : (b))
137 #define MAX(a, b) ((a) > (b) ? (a) : (b))
139 #define TIMESPEC_IS_SET(ts) ((ts)->tv_sec != 0 || (ts)->tv_nsec != 0)
141 void usbi_log(struct libusb_context *ctx, enum libusb_log_level level,
142 const char *function, const char *format, ...);
144 void usbi_log_v(struct libusb_context *ctx, enum libusb_log_level level,
145 const char *function, const char *format, va_list args);
147 #if !defined(_MSC_VER) || _MSC_VER >= 1400
149 #ifdef ENABLE_LOGGING
150 #define _usbi_log(ctx, level, ...) usbi_log(ctx, level, __FUNCTION__, __VA_ARGS__)
151 #define usbi_dbg(...) _usbi_log(NULL, LIBUSB_LOG_LEVEL_DEBUG, __VA_ARGS__)
152 #else
153 #define _usbi_log(ctx, level, ...) do { (void)(ctx); } while(0)
154 #define usbi_dbg(...) do {} while(0)
155 #endif
157 #define usbi_info(ctx, ...) _usbi_log(ctx, LIBUSB_LOG_LEVEL_INFO, __VA_ARGS__)
158 #define usbi_warn(ctx, ...) _usbi_log(ctx, LIBUSB_LOG_LEVEL_WARNING, __VA_ARGS__)
159 #define usbi_err(ctx, ...) _usbi_log(ctx, LIBUSB_LOG_LEVEL_ERROR, __VA_ARGS__)
161 #else /* !defined(_MSC_VER) || _MSC_VER >= 1400 */
163 #ifdef ENABLE_LOGGING
164 #define LOG_BODY(ctxt, level) \
166 va_list args; \
167 va_start (args, format); \
168 usbi_log_v(ctxt, level, "", format, args); \
169 va_end(args); \
171 #else
172 #define LOG_BODY(ctxt, level) do { (void)(ctxt); } while(0)
173 #endif
175 static inline void usbi_info(struct libusb_context *ctx, const char *format,
176 ...)
177 LOG_BODY(ctx,LIBUSB_LOG_LEVEL_INFO)
178 static inline void usbi_warn(struct libusb_context *ctx, const char *format,
179 ...)
180 LOG_BODY(ctx,LIBUSB_LOG_LEVEL_WARNING)
181 static inline void usbi_err( struct libusb_context *ctx, const char *format,
182 ...)
183 LOG_BODY(ctx,LIBUSB_LOG_LEVEL_ERROR)
185 static inline void usbi_dbg(const char *format, ...)
186 LOG_BODY(NULL,LIBUSB_LOG_LEVEL_DEBUG)
188 #endif /* !defined(_MSC_VER) || _MSC_VER >= 1400 */
190 #define USBI_GET_CONTEXT(ctx) if (!(ctx)) (ctx) = usbi_default_context
191 #define DEVICE_CTX(dev) ((dev)->ctx)
192 #define HANDLE_CTX(handle) (DEVICE_CTX((handle)->dev))
193 #define TRANSFER_CTX(transfer) (HANDLE_CTX((transfer)->dev_handle))
194 #define ITRANSFER_CTX(transfer) \
195 (TRANSFER_CTX(USBI_TRANSFER_TO_LIBUSB_TRANSFER(transfer)))
197 #define IS_EPIN(ep) (0 != ((ep) & LIBUSB_ENDPOINT_IN))
198 #define IS_EPOUT(ep) (!IS_EPIN(ep))
199 #define IS_XFERIN(xfer) (0 != ((xfer)->endpoint & LIBUSB_ENDPOINT_IN))
200 #define IS_XFEROUT(xfer) (!IS_XFERIN(xfer))
202 /* Internal abstraction for thread synchronization */
203 #if defined(THREADS_POSIX)
204 #include "os/threads_posix.h"
205 #elif defined(OS_WINDOWS) || defined(OS_WINCE)
206 #include <os/threads_windows.h>
207 #endif
209 extern struct libusb_context *usbi_default_context;
211 struct libusb_context {
212 int debug;
213 int debug_fixed;
215 /* internal control pipe, used for interrupting event handling when
216 * something needs to modify poll fds. */
217 int ctrl_pipe[2];
219 struct list_head usb_devs;
220 usbi_mutex_t usb_devs_lock;
222 /* A list of open handles. Backends are free to traverse this if required.
224 struct list_head open_devs;
225 usbi_mutex_t open_devs_lock;
227 /* A list of registered hotplug callbacks */
228 struct list_head hotplug_cbs;
229 usbi_mutex_t hotplug_cbs_lock;
230 int hotplug_pipe[2];
232 /* this is a list of in-flight transfer handles, sorted by timeout
233 * expiration. URBs to timeout the soonest are placed at the beginning of
234 * the list, URBs that will time out later are placed after, and urbs with
235 * infinite timeout are always placed at the very end. */
236 struct list_head flying_transfers;
237 usbi_mutex_t flying_transfers_lock;
239 /* list of poll fds */
240 struct list_head pollfds;
241 usbi_mutex_t pollfds_lock;
243 /* a counter that is set when we want to interrupt event handling, in order
244 * to modify the poll fd set. and a lock to protect it. */
245 unsigned int pollfd_modify;
246 usbi_mutex_t pollfd_modify_lock;
248 /* user callbacks for pollfd changes */
249 libusb_pollfd_added_cb fd_added_cb;
250 libusb_pollfd_removed_cb fd_removed_cb;
251 void *fd_cb_user_data;
253 /* ensures that only one thread is handling events at any one time */
254 usbi_mutex_t events_lock;
256 /* used to see if there is an active thread doing event handling */
257 int event_handler_active;
259 /* used to wait for event completion in threads other than the one that is
260 * event handling */
261 usbi_mutex_t event_waiters_lock;
262 usbi_cond_t event_waiters_cond;
264 #ifdef USBI_TIMERFD_AVAILABLE
265 /* used for timeout handling, if supported by OS.
266 * this timerfd is maintained to trigger on the next pending timeout */
267 int timerfd;
268 #endif
270 struct list_head list;
273 #ifdef USBI_TIMERFD_AVAILABLE
274 #define usbi_using_timerfd(ctx) ((ctx)->timerfd >= 0)
275 #else
276 #define usbi_using_timerfd(ctx) (0)
277 #endif
279 struct libusb_device {
280 /* lock protects refcnt, everything else is finalized at initialization
281 * time */
282 usbi_mutex_t lock;
283 int refcnt;
285 struct libusb_context *ctx;
287 uint8_t bus_number;
288 uint8_t port_number;
289 struct libusb_device* parent_dev;
290 uint8_t device_address;
291 uint8_t num_configurations;
292 enum libusb_speed speed;
294 struct list_head list;
295 unsigned long session_data;
297 struct libusb_device_descriptor device_descriptor;
298 int attached;
300 unsigned char os_priv
301 #if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
302 [] /* valid C99 code */
303 #else
304 [0] /* non-standard, but usually working code */
305 #endif
309 struct libusb_device_handle {
310 /* lock protects claimed_interfaces */
311 usbi_mutex_t lock;
312 unsigned long claimed_interfaces;
314 struct list_head list;
315 struct libusb_device *dev;
316 unsigned char os_priv
317 #if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
318 [] /* valid C99 code */
319 #else
320 [0] /* non-standard, but usually working code */
321 #endif
325 enum {
326 USBI_CLOCK_MONOTONIC,
327 USBI_CLOCK_REALTIME
330 /* in-memory transfer layout:
332 * 1. struct usbi_transfer
333 * 2. struct libusb_transfer (which includes iso packets) [variable size]
334 * 3. os private data [variable size]
336 * from a libusb_transfer, you can get the usbi_transfer by rewinding the
337 * appropriate number of bytes.
338 * the usbi_transfer includes the number of allocated packets, so you can
339 * determine the size of the transfer and hence the start and length of the
340 * OS-private data.
343 struct usbi_transfer {
344 int num_iso_packets;
345 struct list_head list;
346 struct timeval timeout;
347 int transferred;
348 uint8_t flags;
350 /* this lock is held during libusb_submit_transfer() and
351 * libusb_cancel_transfer() (allowing the OS backend to prevent duplicate
352 * cancellation, submission-during-cancellation, etc). the OS backend
353 * should also take this lock in the handle_events path, to prevent the user
354 * cancelling the transfer from another thread while you are processing
355 * its completion (presumably there would be races within your OS backend
356 * if this were possible). */
357 usbi_mutex_t lock;
360 enum usbi_transfer_flags {
361 /* The transfer has timed out */
362 USBI_TRANSFER_TIMED_OUT = 1 << 0,
364 /* Set by backend submit_transfer() if the OS handles timeout */
365 USBI_TRANSFER_OS_HANDLES_TIMEOUT = 1 << 1,
367 /* Cancellation was requested via libusb_cancel_transfer() */
368 USBI_TRANSFER_CANCELLING = 1 << 2,
370 /* Operation on the transfer failed because the device disappeared */
371 USBI_TRANSFER_DEVICE_DISAPPEARED = 1 << 3,
373 /* Set by backend submit_transfer() if the fds in use have been updated */
374 USBI_TRANSFER_UPDATED_FDS = 1 << 4,
377 #define USBI_TRANSFER_TO_LIBUSB_TRANSFER(transfer) \
378 ((struct libusb_transfer *)(((unsigned char *)(transfer)) \
379 + sizeof(struct usbi_transfer)))
380 #define LIBUSB_TRANSFER_TO_USBI_TRANSFER(transfer) \
381 ((struct usbi_transfer *)(((unsigned char *)(transfer)) \
382 - sizeof(struct usbi_transfer)))
384 static inline void *usbi_transfer_get_os_priv(struct usbi_transfer *transfer)
386 return ((unsigned char *)transfer) + sizeof(struct usbi_transfer)
387 + sizeof(struct libusb_transfer)
388 + (transfer->num_iso_packets
389 * sizeof(struct libusb_iso_packet_descriptor));
392 /* bus structures */
394 /* All standard descriptors have these 2 fields in common */
395 struct usb_descriptor_header {
396 uint8_t bLength;
397 uint8_t bDescriptorType;
400 /* shared data and functions */
402 int usbi_io_init(struct libusb_context *ctx);
403 void usbi_io_exit(struct libusb_context *ctx);
405 struct libusb_device *usbi_alloc_device(struct libusb_context *ctx,
406 unsigned long session_id);
407 struct libusb_device *usbi_get_device_by_session_id(struct libusb_context *ctx,
408 unsigned long session_id);
409 int usbi_sanitize_device(struct libusb_device *dev);
410 void usbi_handle_disconnect(struct libusb_device_handle *handle);
412 int usbi_handle_transfer_completion(struct usbi_transfer *itransfer,
413 enum libusb_transfer_status status);
414 int usbi_handle_transfer_cancellation(struct usbi_transfer *transfer);
416 int usbi_parse_descriptor(unsigned char *source, const char *descriptor,
417 void *dest, int host_endian);
418 int usbi_device_cache_descriptor(libusb_device *dev);
419 int usbi_get_config_index_by_value(struct libusb_device *dev,
420 uint8_t bConfigurationValue, int *idx);
422 void usbi_connect_device (struct libusb_device *dev);
423 void usbi_disconnect_device (struct libusb_device *dev);
425 /* Internal abstraction for poll (needs struct usbi_transfer on Windows) */
426 #if defined(OS_LINUX) || defined(OS_DARWIN) || defined(OS_OPENBSD)
427 #include <unistd.h>
428 #include "os/poll_posix.h"
429 #elif defined(OS_WINDOWS) || defined(OS_WINCE)
430 #include <os/poll_windows.h>
431 #endif
433 #if (defined(OS_WINDOWS) || defined(OS_WINCE)) && !defined(__GCC__)
434 #undef HAVE_GETTIMEOFDAY
435 int usbi_gettimeofday(struct timeval *tp, void *tzp);
436 #define LIBUSB_GETTIMEOFDAY_WIN32
437 #define HAVE_USBI_GETTIMEOFDAY
438 #else
439 #ifdef HAVE_GETTIMEOFDAY
440 #define usbi_gettimeofday(tv, tz) gettimeofday((tv), (tz))
441 #define HAVE_USBI_GETTIMEOFDAY
442 #endif
443 #endif
445 struct usbi_pollfd {
446 /* must come first */
447 struct libusb_pollfd pollfd;
449 struct list_head list;
452 int usbi_add_pollfd(struct libusb_context *ctx, int fd, short events);
453 void usbi_remove_pollfd(struct libusb_context *ctx, int fd);
454 void usbi_fd_notification(struct libusb_context *ctx);
456 /* device discovery */
458 /* we traverse usbfs without knowing how many devices we are going to find.
459 * so we create this discovered_devs model which is similar to a linked-list
460 * which grows when required. it can be freed once discovery has completed,
461 * eliminating the need for a list node in the libusb_device structure
462 * itself. */
463 struct discovered_devs {
464 size_t len;
465 size_t capacity;
466 struct libusb_device *devices
467 #if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
468 [] /* valid C99 code */
469 #else
470 [0] /* non-standard, but usually working code */
471 #endif
475 struct discovered_devs *discovered_devs_append(
476 struct discovered_devs *discdevs, struct libusb_device *dev);
478 /* OS abstraction */
480 /* This is the interface that OS backends need to implement.
481 * All fields are mandatory, except ones explicitly noted as optional. */
482 struct usbi_os_backend {
483 /* A human-readable name for your backend, e.g. "Linux usbfs" */
484 const char *name;
486 /* Binary mask for backend specific capabilities */
487 uint32_t caps;
489 /* Perform initialization of your backend. You might use this function
490 * to determine specific capabilities of the system, allocate required
491 * data structures for later, etc.
493 * This function is called when a libusbx user initializes the library
494 * prior to use.
496 * Return 0 on success, or a LIBUSB_ERROR code on failure.
498 int (*init)(struct libusb_context *ctx);
500 /* Deinitialization. Optional. This function should destroy anything
501 * that was set up by init.
503 * This function is called when the user deinitializes the library.
505 void (*exit)(void);
507 /* Enumerate all the USB devices on the system, returning them in a list
508 * of discovered devices.
510 * Your implementation should enumerate all devices on the system,
511 * regardless of whether they have been seen before or not.
513 * When you have found a device, compute a session ID for it. The session
514 * ID should uniquely represent that particular device for that particular
515 * connection session since boot (i.e. if you disconnect and reconnect a
516 * device immediately after, it should be assigned a different session ID).
517 * If your OS cannot provide a unique session ID as described above,
518 * presenting a session ID of (bus_number << 8 | device_address) should
519 * be sufficient. Bus numbers and device addresses wrap and get reused,
520 * but that is an unlikely case.
522 * After computing a session ID for a device, call
523 * usbi_get_device_by_session_id(). This function checks if libusbx already
524 * knows about the device, and if so, it provides you with a libusb_device
525 * structure for it.
527 * If usbi_get_device_by_session_id() returns NULL, it is time to allocate
528 * a new device structure for the device. Call usbi_alloc_device() to
529 * obtain a new libusb_device structure with reference count 1. Populate
530 * the bus_number and device_address attributes of the new device, and
531 * perform any other internal backend initialization you need to do. At
532 * this point, you should be ready to provide device descriptors and so
533 * on through the get_*_descriptor functions. Finally, call
534 * usbi_sanitize_device() to perform some final sanity checks on the
535 * device. Assuming all of the above succeeded, we can now continue.
536 * If any of the above failed, remember to unreference the device that
537 * was returned by usbi_alloc_device().
539 * At this stage we have a populated libusb_device structure (either one
540 * that was found earlier, or one that we have just allocated and
541 * populated). This can now be added to the discovered devices list
542 * using discovered_devs_append(). Note that discovered_devs_append()
543 * may reallocate the list, returning a new location for it, and also
544 * note that reallocation can fail. Your backend should handle these
545 * error conditions appropriately.
547 * This function should not generate any bus I/O and should not block.
548 * If I/O is required (e.g. reading the active configuration value), it is
549 * OK to ignore these suggestions :)
551 * This function is executed when the user wishes to retrieve a list
552 * of USB devices connected to the system.
554 * Return 0 on success, or a LIBUSB_ERROR code on failure.
556 int (*get_device_list)(struct libusb_context *ctx,
557 struct discovered_devs **discdevs);
559 /* Open a device for I/O and other USB operations. The device handle
560 * is preallocated for you, you can retrieve the device in question
561 * through handle->dev.
563 * Your backend should allocate any internal resources required for I/O
564 * and other operations so that those operations can happen (hopefully)
565 * without hiccup. This is also a good place to inform libusbx that it
566 * should monitor certain file descriptors related to this device -
567 * see the usbi_add_pollfd() function.
569 * This function should not generate any bus I/O and should not block.
571 * This function is called when the user attempts to obtain a device
572 * handle for a device.
574 * Return:
575 * - 0 on success
576 * - LIBUSB_ERROR_ACCESS if the user has insufficient permissions
577 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since
578 * discovery
579 * - another LIBUSB_ERROR code on other failure
581 * Do not worry about freeing the handle on failed open, the upper layers
582 * do this for you.
584 int (*open)(struct libusb_device_handle *handle);
586 /* Close a device such that the handle cannot be used again. Your backend
587 * should destroy any resources that were allocated in the open path.
588 * This may also be a good place to call usbi_remove_pollfd() to inform
589 * libusbx of any file descriptors associated with this device that should
590 * no longer be monitored.
592 * This function is called when the user closes a device handle.
594 void (*close)(struct libusb_device_handle *handle);
596 /* Retrieve the device descriptor from a device.
598 * The descriptor should be retrieved from memory, NOT via bus I/O to the
599 * device. This means that you may have to cache it in a private structure
600 * during get_device_list enumeration. Alternatively, you may be able
601 * to retrieve it from a kernel interface (some Linux setups can do this)
602 * still without generating bus I/O.
604 * This function is expected to write DEVICE_DESC_LENGTH (18) bytes into
605 * buffer, which is guaranteed to be big enough.
607 * This function is called when sanity-checking a device before adding
608 * it to the list of discovered devices, and also when the user requests
609 * to read the device descriptor.
611 * This function is expected to return the descriptor in bus-endian format
612 * (LE). If it returns the multi-byte values in host-endian format,
613 * set the host_endian output parameter to "1".
615 * Return 0 on success or a LIBUSB_ERROR code on failure.
617 int (*get_device_descriptor)(struct libusb_device *device,
618 unsigned char *buffer, int *host_endian);
620 /* Get the ACTIVE configuration descriptor for a device.
622 * The descriptor should be retrieved from memory, NOT via bus I/O to the
623 * device. This means that you may have to cache it in a private structure
624 * during get_device_list enumeration. You may also have to keep track
625 * of which configuration is active when the user changes it.
627 * This function is expected to write len bytes of data into buffer, which
628 * is guaranteed to be big enough. If you can only do a partial write,
629 * return an error code.
631 * This function is expected to return the descriptor in bus-endian format
632 * (LE). If it returns the multi-byte values in host-endian format,
633 * set the host_endian output parameter to "1".
635 * Return:
636 * - 0 on success
637 * - LIBUSB_ERROR_NOT_FOUND if the device is in unconfigured state
638 * - another LIBUSB_ERROR code on other failure
640 int (*get_active_config_descriptor)(struct libusb_device *device,
641 unsigned char *buffer, size_t len, int *host_endian);
643 /* Get a specific configuration descriptor for 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.
649 * The requested descriptor is expressed as a zero-based index (i.e. 0
650 * indicates that we are requesting the first descriptor). The index does
651 * not (necessarily) equal the bConfigurationValue of the configuration
652 * being requested.
654 * This function is expected to write len bytes of data into buffer, which
655 * is guaranteed to be big enough. If you can only do a partial write,
656 * return an error code.
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_config_descriptor)(struct libusb_device *device,
665 uint8_t config_index, unsigned char *buffer, size_t len,
666 int *host_endian);
668 /* Get the bConfigurationValue for the active configuration for a device.
669 * Optional. This should only be implemented if you can retrieve it from
670 * cache (don't generate I/O).
672 * If you cannot retrieve this from cache, either do not implement this
673 * function, or return LIBUSB_ERROR_NOT_SUPPORTED. This will cause
674 * libusbx to retrieve the information through a standard control transfer.
676 * This function must be non-blocking.
677 * Return:
678 * - 0 on success
679 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
680 * was opened
681 * - LIBUSB_ERROR_NOT_SUPPORTED if the value cannot be retrieved without
682 * blocking
683 * - another LIBUSB_ERROR code on other failure.
685 int (*get_configuration)(struct libusb_device_handle *handle, int *config);
687 /* Set the active configuration for a device.
689 * A configuration value of -1 should put the device in unconfigured state.
691 * This function can block.
693 * Return:
694 * - 0 on success
695 * - LIBUSB_ERROR_NOT_FOUND if the configuration does not exist
696 * - LIBUSB_ERROR_BUSY if interfaces are currently claimed (and hence
697 * configuration cannot be changed)
698 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
699 * was opened
700 * - another LIBUSB_ERROR code on other failure.
702 int (*set_configuration)(struct libusb_device_handle *handle, int config);
704 /* Claim an interface. When claimed, the application can then perform
705 * I/O to an interface's endpoints.
707 * This function should not generate any bus I/O and should not block.
708 * Interface claiming is a logical operation that simply ensures that
709 * no other drivers/applications are using the interface, and after
710 * claiming, no other drivers/applicatiosn can use the interface because
711 * we now "own" it.
713 * Return:
714 * - 0 on success
715 * - LIBUSB_ERROR_NOT_FOUND if the interface does not exist
716 * - LIBUSB_ERROR_BUSY if the interface is in use by another driver/app
717 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
718 * was opened
719 * - another LIBUSB_ERROR code on other failure
721 int (*claim_interface)(struct libusb_device_handle *handle, int interface_number);
723 /* Release a previously claimed interface.
725 * This function should also generate a SET_INTERFACE control request,
726 * resetting the alternate setting of that interface to 0. It's OK for
727 * this function to block as a result.
729 * You will only ever be asked to release an interface which was
730 * successfully claimed earlier.
732 * Return:
733 * - 0 on success
734 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
735 * was opened
736 * - another LIBUSB_ERROR code on other failure
738 int (*release_interface)(struct libusb_device_handle *handle, int interface_number);
740 /* Set the alternate setting for an interface.
742 * You will only ever be asked to set the alternate setting for an
743 * interface which was successfully claimed earlier.
745 * It's OK for this function to block.
747 * Return:
748 * - 0 on success
749 * - LIBUSB_ERROR_NOT_FOUND if the alternate setting does not exist
750 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
751 * was opened
752 * - another LIBUSB_ERROR code on other failure
754 int (*set_interface_altsetting)(struct libusb_device_handle *handle,
755 int interface_number, int altsetting);
757 /* Clear a halt/stall condition on an endpoint.
759 * It's OK for this function to block.
761 * Return:
762 * - 0 on success
763 * - LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist
764 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
765 * was opened
766 * - another LIBUSB_ERROR code on other failure
768 int (*clear_halt)(struct libusb_device_handle *handle,
769 unsigned char endpoint);
771 /* Perform a USB port reset to reinitialize a device.
773 * If possible, the handle should still be usable after the reset
774 * completes, assuming that the device descriptors did not change during
775 * reset and all previous interface state can be restored.
777 * If something changes, or you cannot easily locate/verify the resetted
778 * device, return LIBUSB_ERROR_NOT_FOUND. This prompts the application
779 * to close the old handle and re-enumerate the device.
781 * Return:
782 * - 0 on success
783 * - LIBUSB_ERROR_NOT_FOUND if re-enumeration is required, or if the device
784 * has been disconnected since it was opened
785 * - another LIBUSB_ERROR code on other failure
787 int (*reset_device)(struct libusb_device_handle *handle);
789 /* Determine if a kernel driver is active on an interface. Optional.
791 * The presence of a kernel driver on an interface indicates that any
792 * calls to claim_interface would fail with the LIBUSB_ERROR_BUSY code.
794 * Return:
795 * - 0 if no driver is active
796 * - 1 if a driver is active
797 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
798 * was opened
799 * - another LIBUSB_ERROR code on other failure
801 int (*kernel_driver_active)(struct libusb_device_handle *handle,
802 int interface_number);
804 /* Detach a kernel driver from an interface. Optional.
806 * After detaching a kernel driver, the interface should be available
807 * for claim.
809 * Return:
810 * - 0 on success
811 * - LIBUSB_ERROR_NOT_FOUND if no kernel driver was active
812 * - LIBUSB_ERROR_INVALID_PARAM if the interface does not exist
813 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
814 * was opened
815 * - another LIBUSB_ERROR code on other failure
817 int (*detach_kernel_driver)(struct libusb_device_handle *handle,
818 int interface_number);
820 /* Attach a kernel driver to an interface. Optional.
822 * Reattach a kernel driver to the device.
824 * Return:
825 * - 0 on success
826 * - LIBUSB_ERROR_NOT_FOUND if no kernel driver was active
827 * - LIBUSB_ERROR_INVALID_PARAM if the interface does not exist
828 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
829 * was opened
830 * - LIBUSB_ERROR_BUSY if a program or driver has claimed the interface,
831 * preventing reattachment
832 * - another LIBUSB_ERROR code on other failure
834 int (*attach_kernel_driver)(struct libusb_device_handle *handle,
835 int interface_number);
837 /* Destroy a device. Optional.
839 * This function is called when the last reference to a device is
840 * destroyed. It should free any resources allocated in the get_device_list
841 * path.
843 void (*destroy_device)(struct libusb_device *dev);
845 /* Submit a transfer. Your implementation should take the transfer,
846 * morph it into whatever form your platform requires, and submit it
847 * asynchronously.
849 * This function must not block.
851 * Return:
852 * - 0 on success
853 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
854 * - another LIBUSB_ERROR code on other failure
856 int (*submit_transfer)(struct usbi_transfer *itransfer);
858 /* Cancel a previously submitted transfer.
860 * This function must not block. The transfer cancellation must complete
861 * later, resulting in a call to usbi_handle_transfer_cancellation()
862 * from the context of handle_events.
864 int (*cancel_transfer)(struct usbi_transfer *itransfer);
866 /* Clear a transfer as if it has completed or cancelled, but do not
867 * report any completion/cancellation to the library. You should free
868 * all private data from the transfer as if you were just about to report
869 * completion or cancellation.
871 * This function might seem a bit out of place. It is used when libusbx
872 * detects a disconnected device - it calls this function for all pending
873 * transfers before reporting completion (with the disconnect code) to
874 * the user. Maybe we can improve upon this internal interface in future.
876 void (*clear_transfer_priv)(struct usbi_transfer *itransfer);
878 /* Handle any pending events. This involves monitoring any active
879 * transfers and processing their completion or cancellation.
881 * The function is passed an array of pollfd structures (size nfds)
882 * as a result of the poll() system call. The num_ready parameter
883 * indicates the number of file descriptors that have reported events
884 * (i.e. the poll() return value). This should be enough information
885 * for you to determine which actions need to be taken on the currently
886 * active transfers.
888 * For any cancelled transfers, call usbi_handle_transfer_cancellation().
889 * For completed transfers, call usbi_handle_transfer_completion().
890 * For control/bulk/interrupt transfers, populate the "transferred"
891 * element of the appropriate usbi_transfer structure before calling the
892 * above functions. For isochronous transfers, populate the status and
893 * transferred fields of the iso packet descriptors of the transfer.
895 * This function should also be able to detect disconnection of the
896 * device, reporting that situation with usbi_handle_disconnect().
898 * When processing an event related to a transfer, you probably want to
899 * take usbi_transfer.lock to prevent races. See the documentation for
900 * the usbi_transfer structure.
902 * Return 0 on success, or a LIBUSB_ERROR code on failure.
904 int (*handle_events)(struct libusb_context *ctx,
905 struct pollfd *fds, POLL_NFDS_TYPE nfds, int num_ready);
907 /* Get time from specified clock. At least two clocks must be implemented
908 by the backend: USBI_CLOCK_REALTIME, and USBI_CLOCK_MONOTONIC.
910 Description of clocks:
911 USBI_CLOCK_REALTIME : clock returns time since system epoch.
912 USBI_CLOCK_MONOTONIC: clock returns time since unspecified start
913 time (usually boot).
915 int (*clock_gettime)(int clkid, struct timespec *tp);
917 #ifdef USBI_TIMERFD_AVAILABLE
918 /* clock ID of the clock that should be used for timerfd */
919 clockid_t (*get_timerfd_clockid)(void);
920 #endif
922 /* Number of bytes to reserve for per-device private backend data.
923 * This private data area is accessible through the "os_priv" field of
924 * struct libusb_device. */
925 size_t device_priv_size;
927 /* Number of bytes to reserve for per-handle private backend data.
928 * This private data area is accessible through the "os_priv" field of
929 * struct libusb_device. */
930 size_t device_handle_priv_size;
932 /* Number of bytes to reserve for per-transfer private backend data.
933 * This private data area is accessible by calling
934 * usbi_transfer_get_os_priv() on the appropriate usbi_transfer instance.
936 size_t transfer_priv_size;
938 /* Mumber of additional bytes for os_priv for each iso packet.
939 * Can your backend use this? */
940 /* FIXME: linux can't use this any more. if other OS's cannot either,
941 * then remove this */
942 size_t add_iso_packet_size;
945 extern const struct usbi_os_backend * const usbi_backend;
947 extern const struct usbi_os_backend linux_usbfs_backend;
948 extern const struct usbi_os_backend darwin_backend;
949 extern const struct usbi_os_backend openbsd_backend;
950 extern const struct usbi_os_backend windows_backend;
951 extern const struct usbi_os_backend wince_backend;
953 extern struct list_head active_contexts_list;
954 extern usbi_mutex_static_t active_contexts_lock;
956 #endif