/* * Internal header for libusb * Copyright © 2007-2009 Daniel Drake * Copyright © 2001 Johannes Erdfelt * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #ifndef LIBUSBI_H #define LIBUSBI_H #include #include #include #include #include #include #include #ifdef HAVE_POLL_H #include #endif #ifdef HAVE_MISSING_H #include #endif #include "libusb.h" #include "version.h" /* Attribute to ensure that a structure member is aligned to a natural * pointer alignment. Used for os_priv member. */ #if defined(_MSC_VER) #if defined(_WIN64) #define PTR_ALIGNED __declspec(align(8)) #else #define PTR_ALIGNED __declspec(align(4)) #endif #elif defined(__GNUC__) && (__GNUC__ >= 3) #define PTR_ALIGNED __attribute__((aligned(sizeof(void *)))) #else #define PTR_ALIGNED #endif /* Inside the libusb code, mark all public functions as follows: * return_type API_EXPORTED function_name(params) { ... } * But if the function returns a pointer, mark it as follows: * DEFAULT_VISIBILITY return_type * LIBUSB_CALL function_name(params) { ... } * In the libusb public header, mark all declarations as: * return_type LIBUSB_CALL function_name(params); */ #define API_EXPORTED LIBUSB_CALL DEFAULT_VISIBILITY /* Macro to decorate printf-like functions, in order to get * compiler warnings about format string mistakes. */ #if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 2) #define USBI_PRINTFLIKE(formatarg, firstvararg) \ __attribute__((__format__ (__printf__, formatarg, firstvararg))) #else #define USBI_PRINTFLIKE(formatarg, firstvararg) #endif #ifdef __cplusplus extern "C" { #endif #define DEVICE_DESC_LENGTH 18 #define USB_MAXENDPOINTS 32 #define USB_MAXINTERFACES 32 #define USB_MAXCONFIG 8 /* Backend specific capabilities */ #define USBI_CAP_HAS_HID_ACCESS 0x00010000 #define USBI_CAP_SUPPORTS_DETACH_KERNEL_DRIVER 0x00020000 /* Maximum number of bytes in a log line */ #define USBI_MAX_LOG_LEN 1024 /* Terminator for log lines */ #define USBI_LOG_LINE_END "\n" /* The following is used to silence warnings for unused variables */ #define UNUSED(var) do { (void)(var); } while(0) #if !defined(ARRAYSIZE) #define ARRAYSIZE(array) (sizeof(array) / sizeof(array[0])) #endif struct list_head { struct list_head *prev, *next; }; /* Get an entry from the list * ptr - the address of this list_head element in "type" * type - the data type that contains "member" * member - the list_head element in "type" */ #define list_entry(ptr, type, member) \ ((type *)((uintptr_t)(ptr) - (uintptr_t)offsetof(type, member))) #define list_first_entry(ptr, type, member) \ list_entry((ptr)->next, type, member) /* Get each entry from a list * pos - A structure pointer has a "member" element * head - list head * member - the list_head element in "pos" * type - the type of the first parameter */ #define list_for_each_entry(pos, head, member, type) \ for (pos = list_entry((head)->next, type, member); \ &pos->member != (head); \ pos = list_entry(pos->member.next, type, member)) #define list_for_each_entry_safe(pos, n, head, member, type) \ for (pos = list_entry((head)->next, type, member), \ n = list_entry(pos->member.next, type, member); \ &pos->member != (head); \ pos = n, n = list_entry(n->member.next, type, member)) #define list_empty(entry) ((entry)->next == (entry)) static inline void list_init(struct list_head *entry) { entry->prev = entry->next = entry; } static inline void list_add(struct list_head *entry, struct list_head *head) { entry->next = head->next; entry->prev = head; head->next->prev = entry; head->next = entry; } static inline void list_add_tail(struct list_head *entry, struct list_head *head) { entry->next = head; entry->prev = head->prev; head->prev->next = entry; head->prev = entry; } static inline void list_del(struct list_head *entry) { entry->next->prev = entry->prev; entry->prev->next = entry->next; entry->next = entry->prev = NULL; } static inline void list_cut(struct list_head *list, struct list_head *head) { if (list_empty(head)) return; list->next = head->next; list->next->prev = list; list->prev = head->prev; list->prev->next = list; list_init(head); } static inline void *usbi_reallocf(void *ptr, size_t size) { void *ret = realloc(ptr, size); if (!ret) free(ptr); return ret; } #define container_of(ptr, type, member) ({ \ const typeof( ((type *)0)->member ) *mptr = (ptr); \ (type *)( (char *)mptr - offsetof(type,member) );}) #ifndef CLAMP #define CLAMP(val, min, max) ((val) < (min) ? (min) : ((val) > (max) ? (max) : (val))) #endif #ifndef MIN #define MIN(a, b) ((a) < (b) ? (a) : (b)) #endif #ifndef MAX #define MAX(a, b) ((a) > (b) ? (a) : (b)) #endif #define TIMESPEC_IS_SET(ts) ((ts)->tv_sec != 0 || (ts)->tv_nsec != 0) #if defined(_WIN32) || defined(__CYGWIN__) || defined(_WIN32_WCE) #define TIMEVAL_TV_SEC_TYPE long #else #define TIMEVAL_TV_SEC_TYPE time_t #endif /* Some platforms don't have this define */ #ifndef TIMESPEC_TO_TIMEVAL #define TIMESPEC_TO_TIMEVAL(tv, ts) \ do { \ (tv)->tv_sec = (TIMEVAL_TV_SEC_TYPE) (ts)->tv_sec; \ (tv)->tv_usec = (ts)->tv_nsec / 1000; \ } while (0) #endif #ifdef ENABLE_LOGGING #if defined(_MSC_VER) && (_MSC_VER < 1900) #define snprintf usbi_snprintf #define vsnprintf usbi_vsnprintf int usbi_snprintf(char *dst, size_t size, const char *format, ...); int usbi_vsnprintf(char *dst, size_t size, const char *format, va_list ap); #define LIBUSB_PRINTF_WIN32 #endif /* defined(_MSC_VER) && (_MSC_VER < 1900) */ void usbi_log(struct libusb_context *ctx, enum libusb_log_level level, const char *function, const char *format, ...) USBI_PRINTFLIKE(4, 5); void usbi_log_v(struct libusb_context *ctx, enum libusb_log_level level, const char *function, const char *format, va_list args) USBI_PRINTFLIKE(4, 0); #if !defined(_MSC_VER) || (_MSC_VER >= 1400) #define _usbi_log(ctx, level, ...) usbi_log(ctx, level, __FUNCTION__, __VA_ARGS__) #define usbi_err(ctx, ...) _usbi_log(ctx, LIBUSB_LOG_LEVEL_ERROR, __VA_ARGS__) #define usbi_warn(ctx, ...) _usbi_log(ctx, LIBUSB_LOG_LEVEL_WARNING, __VA_ARGS__) #define usbi_info(ctx, ...) _usbi_log(ctx, LIBUSB_LOG_LEVEL_INFO, __VA_ARGS__) #define usbi_dbg(...) _usbi_log(NULL, LIBUSB_LOG_LEVEL_DEBUG, __VA_ARGS__) #else /* !defined(_MSC_VER) || (_MSC_VER >= 1400) */ #define LOG_BODY(ctxt, level) \ { \ va_list args; \ va_start(args, format); \ usbi_log_v(ctxt, level, "", format, args); \ va_end(args); \ } static inline void usbi_err(struct libusb_context *ctx, const char *format, ...) LOG_BODY(ctx, LIBUSB_LOG_LEVEL_ERROR) static inline void usbi_warn(struct libusb_context *ctx, const char *format, ...) LOG_BODY(ctx, LIBUSB_LOG_LEVEL_WARNING) static inline void usbi_info(struct libusb_context *ctx, const char *format, ...) LOG_BODY(ctx, LIBUSB_LOG_LEVEL_INFO) static inline void usbi_dbg(const char *format, ...) LOG_BODY(NULL, LIBUSB_LOG_LEVEL_DEBUG) #endif /* !defined(_MSC_VER) || (_MSC_VER >= 1400) */ #else /* ENABLE_LOGGING */ #define usbi_err(ctx, ...) do { (void)ctx; } while (0) #define usbi_warn(ctx, ...) do { (void)ctx; } while (0) #define usbi_info(ctx, ...) do { (void)ctx; } while (0) #define usbi_dbg(...) do {} while (0) #endif /* ENABLE_LOGGING */ #define USBI_GET_CONTEXT(ctx) \ do { \ if (!(ctx)) \ (ctx) = usbi_default_context; \ } while(0) #define DEVICE_CTX(dev) ((dev)->ctx) #define HANDLE_CTX(handle) (DEVICE_CTX((handle)->dev)) #define TRANSFER_CTX(transfer) (HANDLE_CTX((transfer)->dev_handle)) #define ITRANSFER_CTX(transfer) \ (TRANSFER_CTX(USBI_TRANSFER_TO_LIBUSB_TRANSFER(transfer))) #define IS_EPIN(ep) (0 != ((ep) & LIBUSB_ENDPOINT_IN)) #define IS_EPOUT(ep) (!IS_EPIN(ep)) #define IS_XFERIN(xfer) (0 != ((xfer)->endpoint & LIBUSB_ENDPOINT_IN)) #define IS_XFEROUT(xfer) (!IS_XFERIN(xfer)) /* Internal abstraction for thread synchronization */ #if defined(THREADS_POSIX) #include "os/threads_posix.h" #elif defined(OS_WINDOWS) || defined(OS_WINCE) #include "os/threads_windows.h" #endif extern struct libusb_context *usbi_default_context; /* Forward declaration for use in context (fully defined inside poll abstraction) */ struct pollfd; struct libusb_context { #if defined(ENABLE_LOGGING) && !defined(ENABLE_DEBUG_LOGGING) enum libusb_log_level debug; int debug_fixed; libusb_log_cb log_handler; #endif /* internal event pipe, used for signalling occurrence of an internal event. */ int event_pipe[2]; struct list_head usb_devs; usbi_mutex_t usb_devs_lock; /* A list of open handles. Backends are free to traverse this if required. */ struct list_head open_devs; usbi_mutex_t open_devs_lock; /* A list of registered hotplug callbacks */ struct list_head hotplug_cbs; libusb_hotplug_callback_handle next_hotplug_cb_handle; usbi_mutex_t hotplug_cbs_lock; /* this is a list of in-flight transfer handles, sorted by timeout * expiration. URBs to timeout the soonest are placed at the beginning of * the list, URBs that will time out later are placed after, and urbs with * infinite timeout are always placed at the very end. */ struct list_head flying_transfers; /* Note paths taking both this and usbi_transfer->lock must always * take this lock first */ usbi_mutex_t flying_transfers_lock; /* user callbacks for pollfd changes */ libusb_pollfd_added_cb fd_added_cb; libusb_pollfd_removed_cb fd_removed_cb; void *fd_cb_user_data; /* ensures that only one thread is handling events at any one time */ usbi_mutex_t events_lock; /* used to see if there is an active thread doing event handling */ int event_handler_active; /* A thread-local storage key to track which thread is performing event * handling */ usbi_tls_key_t event_handling_key; /* used to wait for event completion in threads other than the one that is * event handling */ usbi_mutex_t event_waiters_lock; usbi_cond_t event_waiters_cond; /* A lock to protect internal context event data. */ usbi_mutex_t event_data_lock; /* A bitmask of flags that are set to indicate specific events that need to * be handled. Protected by event_data_lock. */ unsigned int event_flags; /* A counter that is set when we want to interrupt and prevent event handling, * in order to safely close a device. Protected by event_data_lock. */ unsigned int device_close; /* list and count of poll fds and an array of poll fd structures that is * (re)allocated as necessary prior to polling. Protected by event_data_lock. */ struct list_head ipollfds; struct pollfd *pollfds; POLL_NFDS_TYPE pollfds_cnt; /* A list of pending hotplug messages. Protected by event_data_lock. */ struct list_head hotplug_msgs; /* A list of pending completed transfers. Protected by event_data_lock. */ struct list_head completed_transfers; #ifdef USBI_TIMERFD_AVAILABLE /* used for timeout handling, if supported by OS. * this timerfd is maintained to trigger on the next pending timeout */ int timerfd; #endif struct list_head list; PTR_ALIGNED unsigned char os_priv[ZERO_SIZED_ARRAY]; }; enum usbi_event_flags { /* The list of pollfds has been modified */ USBI_EVENT_POLLFDS_MODIFIED = 1U << 0, /* The user has interrupted the event handler */ USBI_EVENT_USER_INTERRUPT = 1U << 1, /* A hotplug callback deregistration is pending */ USBI_EVENT_HOTPLUG_CB_DEREGISTERED = 1U << 2, }; /* Macros for managing event handling state */ #define usbi_handling_events(ctx) \ (usbi_tls_key_get((ctx)->event_handling_key) != NULL) #define usbi_start_event_handling(ctx) \ usbi_tls_key_set((ctx)->event_handling_key, ctx) #define usbi_end_event_handling(ctx) \ usbi_tls_key_set((ctx)->event_handling_key, NULL) /* Update the following macro if new event sources are added */ #define usbi_pending_events(ctx) \ ((ctx)->event_flags || (ctx)->device_close \ || !list_empty(&(ctx)->hotplug_msgs) || !list_empty(&(ctx)->completed_transfers)) #ifdef USBI_TIMERFD_AVAILABLE #define usbi_using_timerfd(ctx) ((ctx)->timerfd >= 0) #else #define usbi_using_timerfd(ctx) (0) #endif struct libusb_device { /* lock protects refcnt, everything else is finalized at initialization * time */ usbi_mutex_t lock; int refcnt; struct libusb_context *ctx; uint8_t bus_number; uint8_t port_number; struct libusb_device* parent_dev; uint8_t device_address; uint8_t num_configurations; enum libusb_speed speed; struct list_head list; unsigned long session_data; struct libusb_device_descriptor device_descriptor; int attached; PTR_ALIGNED unsigned char os_priv[ZERO_SIZED_ARRAY]; }; struct libusb_device_handle { /* lock protects claimed_interfaces */ usbi_mutex_t lock; unsigned long claimed_interfaces; struct list_head list; struct libusb_device *dev; int auto_detach_kernel_driver; PTR_ALIGNED unsigned char os_priv[ZERO_SIZED_ARRAY]; }; enum { USBI_CLOCK_MONOTONIC, USBI_CLOCK_REALTIME }; /* in-memory transfer layout: * * 1. struct usbi_transfer * 2. struct libusb_transfer (which includes iso packets) [variable size] * 3. os private data [variable size] * * from a libusb_transfer, you can get the usbi_transfer by rewinding the * appropriate number of bytes. * the usbi_transfer includes the number of allocated packets, so you can * determine the size of the transfer and hence the start and length of the * OS-private data. */ struct usbi_transfer { int num_iso_packets; struct list_head list; struct list_head completed_list; struct timeval timeout; int transferred; uint32_t stream_id; uint8_t state_flags; /* Protected by usbi_transfer->lock */ uint8_t timeout_flags; /* Protected by the flying_stransfers_lock */ /* this lock is held during libusb_submit_transfer() and * libusb_cancel_transfer() (allowing the OS backend to prevent duplicate * cancellation, submission-during-cancellation, etc). the OS backend * should also take this lock in the handle_events path, to prevent the user * cancelling the transfer from another thread while you are processing * its completion (presumably there would be races within your OS backend * if this were possible). * Note paths taking both this and the flying_transfers_lock must * always take the flying_transfers_lock first */ usbi_mutex_t lock; }; enum usbi_transfer_state_flags { /* Transfer successfully submitted by backend */ USBI_TRANSFER_IN_FLIGHT = 1U << 0, /* Cancellation was requested via libusb_cancel_transfer() */ USBI_TRANSFER_CANCELLING = 1U << 1, /* Operation on the transfer failed because the device disappeared */ USBI_TRANSFER_DEVICE_DISAPPEARED = 1U << 2, }; enum usbi_transfer_timeout_flags { /* Set by backend submit_transfer() if the OS handles timeout */ USBI_TRANSFER_OS_HANDLES_TIMEOUT = 1U << 0, /* The transfer timeout has been handled */ USBI_TRANSFER_TIMEOUT_HANDLED = 1U << 1, /* The transfer timeout was successfully processed */ USBI_TRANSFER_TIMED_OUT = 1U << 2, }; #define USBI_TRANSFER_TO_LIBUSB_TRANSFER(transfer) \ ((struct libusb_transfer *)(((unsigned char *)(transfer)) \ + sizeof(struct usbi_transfer))) #define LIBUSB_TRANSFER_TO_USBI_TRANSFER(transfer) \ ((struct usbi_transfer *)(((unsigned char *)(transfer)) \ - sizeof(struct usbi_transfer))) static inline void *usbi_transfer_get_os_priv(struct usbi_transfer *transfer) { assert(transfer->num_iso_packets >= 0); return ((unsigned char *)transfer) + sizeof(struct usbi_transfer) + sizeof(struct libusb_transfer) + ((size_t)transfer->num_iso_packets * sizeof(struct libusb_iso_packet_descriptor)); } /* bus structures */ /* All standard descriptors have these 2 fields in common */ struct usb_descriptor_header { uint8_t bLength; uint8_t bDescriptorType; }; /* shared data and functions */ int usbi_io_init(struct libusb_context *ctx); void usbi_io_exit(struct libusb_context *ctx); struct libusb_device *usbi_alloc_device(struct libusb_context *ctx, unsigned long session_id); struct libusb_device *usbi_get_device_by_session_id(struct libusb_context *ctx, unsigned long session_id); int usbi_sanitize_device(struct libusb_device *dev); void usbi_handle_disconnect(struct libusb_device_handle *dev_handle); int usbi_handle_transfer_completion(struct usbi_transfer *itransfer, enum libusb_transfer_status status); int usbi_handle_transfer_cancellation(struct usbi_transfer *transfer); void usbi_signal_transfer_completion(struct usbi_transfer *transfer); int usbi_parse_descriptor(const unsigned char *source, const char *descriptor, void *dest, int host_endian); int usbi_device_cache_descriptor(libusb_device *dev); int usbi_get_config_index_by_value(struct libusb_device *dev, uint8_t bConfigurationValue, int *idx); void usbi_connect_device (struct libusb_device *dev); void usbi_disconnect_device (struct libusb_device *dev); int usbi_signal_event(struct libusb_context *ctx); int usbi_clear_event(struct libusb_context *ctx); /* Internal abstraction for poll (needs struct usbi_transfer on Windows) */ #if defined(OS_LINUX) || defined(OS_DARWIN) || defined(OS_OPENBSD) || defined(OS_NETBSD) ||\ defined(OS_HAIKU) || defined(OS_SUNOS) #include #include "os/poll_posix.h" #elif defined(OS_WINDOWS) || defined(OS_WINCE) #include "os/poll_windows.h" #endif struct usbi_pollfd { /* must come first */ struct libusb_pollfd pollfd; struct list_head list; }; int usbi_add_pollfd(struct libusb_context *ctx, int fd, short events); void usbi_remove_pollfd(struct libusb_context *ctx, int fd); /* device discovery */ /* we traverse usbfs without knowing how many devices we are going to find. * so we create this discovered_devs model which is similar to a linked-list * which grows when required. it can be freed once discovery has completed, * eliminating the need for a list node in the libusb_device structure * itself. */ struct discovered_devs { size_t len; size_t capacity; struct libusb_device *devices[ZERO_SIZED_ARRAY]; }; struct discovered_devs *discovered_devs_append( struct discovered_devs *discdevs, struct libusb_device *dev); /* OS abstraction */ /* This is the interface that OS backends need to implement. * All fields are mandatory, except ones explicitly noted as optional. */ struct usbi_os_backend { /* A human-readable name for your backend, e.g. "Linux usbfs" */ const char *name; /* Binary mask for backend specific capabilities */ uint32_t caps; /* Perform initialization of your backend. You might use this function * to determine specific capabilities of the system, allocate required * data structures for later, etc. * * This function is called when a libusb user initializes the library * prior to use. * * Return 0 on success, or a LIBUSB_ERROR code on failure. */ int (*init)(struct libusb_context *ctx); /* Deinitialization. Optional. This function should destroy anything * that was set up by init. * * This function is called when the user deinitializes the library. */ void (*exit)(struct libusb_context *ctx); /* Set a backend-specific option. Optional. * * This function is called when the user calls libusb_set_option() and * the option is not handled by the core library. * * Return 0 on success, or a LIBUSB_ERROR code on failure. */ int (*set_option)(struct libusb_context *ctx, enum libusb_option option, va_list args); /* Enumerate all the USB devices on the system, returning them in a list * of discovered devices. * * Your implementation should enumerate all devices on the system, * regardless of whether they have been seen before or not. * * When you have found a device, compute a session ID for it. The session * ID should uniquely represent that particular device for that particular * connection session since boot (i.e. if you disconnect and reconnect a * device immediately after, it should be assigned a different session ID). * If your OS cannot provide a unique session ID as described above, * presenting a session ID of (bus_number << 8 | device_address) should * be sufficient. Bus numbers and device addresses wrap and get reused, * but that is an unlikely case. * * After computing a session ID for a device, call * usbi_get_device_by_session_id(). This function checks if libusb already * knows about the device, and if so, it provides you with a reference * to a libusb_device structure for it. * * If usbi_get_device_by_session_id() returns NULL, it is time to allocate * a new device structure for the device. Call usbi_alloc_device() to * obtain a new libusb_device structure with reference count 1. Populate * the bus_number and device_address attributes of the new device, and * perform any other internal backend initialization you need to do. At * this point, you should be ready to provide device descriptors and so * on through the get_*_descriptor functions. Finally, call * usbi_sanitize_device() to perform some final sanity checks on the * device. Assuming all of the above succeeded, we can now continue. * If any of the above failed, remember to unreference the device that * was returned by usbi_alloc_device(). * * At this stage we have a populated libusb_device structure (either one * that was found earlier, or one that we have just allocated and * populated). This can now be added to the discovered devices list * using discovered_devs_append(). Note that discovered_devs_append() * may reallocate the list, returning a new location for it, and also * note that reallocation can fail. Your backend should handle these * error conditions appropriately. * * This function should not generate any bus I/O and should not block. * If I/O is required (e.g. reading the active configuration value), it is * OK to ignore these suggestions :) * * This function is executed when the user wishes to retrieve a list * of USB devices connected to the system. * * If the backend has hotplug support, this function is not used! * * Return 0 on success, or a LIBUSB_ERROR code on failure. */ int (*get_device_list)(struct libusb_context *ctx, struct discovered_devs **discdevs); /* Apps which were written before hotplug support, may listen for * hotplug events on their own and call libusb_get_device_list on * device addition. In this case libusb_get_device_list will likely * return a list without the new device in there, as the hotplug * event thread will still be busy enumerating the device, which may * take a while, or may not even have seen the event yet. * * To avoid this libusb_get_device_list will call this optional * function for backends with hotplug support before copying * ctx->usb_devs to the user. In this function the backend should * ensure any pending hotplug events are fully processed before * returning. * * Optional, should be implemented by backends with hotplug support. */ void (*hotplug_poll)(void); /* Wrap a platform-specific device handle for I/O and other USB * operations. The device handle is preallocated for you. * * Your backend should allocate any internal resources required for I/O * and other operations so that those operations can happen (hopefully) * without hiccup. This is also a good place to inform libusb that it * should monitor certain file descriptors related to this device - * see the usbi_add_pollfd() function. * * Your backend should also initialize the device structure * (dev_handle->dev), which is NULL at the beginning of the call. * * This function should not generate any bus I/O and should not block. * * This function is called when the user attempts to wrap an existing * platform-specific device handle for a device. * * Return: * - 0 on success * - LIBUSB_ERROR_ACCESS if the user has insufficient permissions * - another LIBUSB_ERROR code on other failure * * Do not worry about freeing the handle on failed open, the upper layers * do this for you. */ int (*wrap_sys_device)(struct libusb_context *ctx, struct libusb_device_handle *dev_handle, intptr_t sys_dev); /* Open a device for I/O and other USB operations. The device handle * is preallocated for you, you can retrieve the device in question * through handle->dev. * * Your backend should allocate any internal resources required for I/O * and other operations so that those operations can happen (hopefully) * without hiccup. This is also a good place to inform libusb that it * should monitor certain file descriptors related to this device - * see the usbi_add_pollfd() function. * * This function should not generate any bus I/O and should not block. * * This function is called when the user attempts to obtain a device * handle for a device. * * Return: * - 0 on success * - LIBUSB_ERROR_ACCESS if the user has insufficient permissions * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since * discovery * - another LIBUSB_ERROR code on other failure * * Do not worry about freeing the handle on failed open, the upper layers * do this for you. */ int (*open)(struct libusb_device_handle *dev_handle); /* Close a device such that the handle cannot be used again. Your backend * should destroy any resources that were allocated in the open path. * This may also be a good place to call usbi_remove_pollfd() to inform * libusb of any file descriptors associated with this device that should * no longer be monitored. * * This function is called when the user closes a device handle. */ void (*close)(struct libusb_device_handle *dev_handle); /* Retrieve the device descriptor from a device. * * The descriptor should be retrieved from memory, NOT via bus I/O to the * device. This means that you may have to cache it in a private structure * during get_device_list enumeration. Alternatively, you may be able * to retrieve it from a kernel interface (some Linux setups can do this) * still without generating bus I/O. * * This function is expected to write DEVICE_DESC_LENGTH (18) bytes into * buffer, which is guaranteed to be big enough. * * This function is called when sanity-checking a device before adding * it to the list of discovered devices, and also when the user requests * to read the device descriptor. * * This function is expected to return the descriptor in bus-endian format * (LE). If it returns the multi-byte values in host-endian format, * set the host_endian output parameter to "1". * * Return 0 on success or a LIBUSB_ERROR code on failure. */ int (*get_device_descriptor)(struct libusb_device *device, unsigned char *buffer, int *host_endian); /* Get the ACTIVE configuration descriptor for a device. * * The descriptor should be retrieved from memory, NOT via bus I/O to the * device. This means that you may have to cache it in a private structure * during get_device_list enumeration. You may also have to keep track * of which configuration is active when the user changes it. * * This function is expected to write len bytes of data into buffer, which * is guaranteed to be big enough. If you can only do a partial write, * return an error code. * * This function is expected to return the descriptor in bus-endian format * (LE). If it returns the multi-byte values in host-endian format, * set the host_endian output parameter to "1". * * Return: * - 0 on success * - LIBUSB_ERROR_NOT_FOUND if the device is in unconfigured state * - another LIBUSB_ERROR code on other failure */ int (*get_active_config_descriptor)(struct libusb_device *device, unsigned char *buffer, size_t len, int *host_endian); /* Get a specific configuration descriptor for a device. * * The descriptor should be retrieved from memory, NOT via bus I/O to the * device. This means that you may have to cache it in a private structure * during get_device_list enumeration. * * The requested descriptor is expressed as a zero-based index (i.e. 0 * indicates that we are requesting the first descriptor). The index does * not (necessarily) equal the bConfigurationValue of the configuration * being requested. * * This function is expected to write len bytes of data into buffer, which * is guaranteed to be big enough. If you can only do a partial write, * return an error code. * * This function is expected to return the descriptor in bus-endian format * (LE). If it returns the multi-byte values in host-endian format, * set the host_endian output parameter to "1". * * Return the length read on success or a LIBUSB_ERROR code on failure. */ int (*get_config_descriptor)(struct libusb_device *device, uint8_t config_index, unsigned char *buffer, size_t len, int *host_endian); /* Like get_config_descriptor but then by bConfigurationValue instead * of by index. * * Optional, if not present the core will call get_config_descriptor * for all configs until it finds the desired bConfigurationValue. * * Returns a pointer to the raw-descriptor in *buffer, this memory * is valid as long as device is valid. * * Returns the length of the returned raw-descriptor on success, * or a LIBUSB_ERROR code on failure. */ int (*get_config_descriptor_by_value)(struct libusb_device *device, uint8_t bConfigurationValue, unsigned char **buffer, int *host_endian); /* Get the bConfigurationValue for the active configuration for a device. * Optional. This should only be implemented if you can retrieve it from * cache (don't generate I/O). * * If you cannot retrieve this from cache, either do not implement this * function, or return LIBUSB_ERROR_NOT_SUPPORTED. This will cause * libusb to retrieve the information through a standard control transfer. * * This function must be non-blocking. * Return: * - 0 on success * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it * was opened * - LIBUSB_ERROR_NOT_SUPPORTED if the value cannot be retrieved without * blocking * - another LIBUSB_ERROR code on other failure. */ int (*get_configuration)(struct libusb_device_handle *dev_handle, int *config); /* Set the active configuration for a device. * * A configuration value of -1 should put the device in unconfigured state. * * This function can block. * * Return: * - 0 on success * - LIBUSB_ERROR_NOT_FOUND if the configuration does not exist * - LIBUSB_ERROR_BUSY if interfaces are currently claimed (and hence * configuration cannot be changed) * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it * was opened * - another LIBUSB_ERROR code on other failure. */ int (*set_configuration)(struct libusb_device_handle *dev_handle, int config); /* Claim an interface. When claimed, the application can then perform * I/O to an interface's endpoints. * * This function should not generate any bus I/O and should not block. * Interface claiming is a logical operation that simply ensures that * no other drivers/applications are using the interface, and after * claiming, no other drivers/applications can use the interface because * we now "own" it. * * Return: * - 0 on success * - LIBUSB_ERROR_NOT_FOUND if the interface does not exist * - LIBUSB_ERROR_BUSY if the interface is in use by another driver/app * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it * was opened * - another LIBUSB_ERROR code on other failure */ int (*claim_interface)(struct libusb_device_handle *dev_handle, int interface_number); /* Release a previously claimed interface. * * This function should also generate a SET_INTERFACE control request, * resetting the alternate setting of that interface to 0. It's OK for * this function to block as a result. * * You will only ever be asked to release an interface which was * successfully claimed earlier. * * Return: * - 0 on success * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it * was opened * - another LIBUSB_ERROR code on other failure */ int (*release_interface)(struct libusb_device_handle *dev_handle, int interface_number); /* Set the alternate setting for an interface. * * You will only ever be asked to set the alternate setting for an * interface which was successfully claimed earlier. * * It's OK for this function to block. * * Return: * - 0 on success * - LIBUSB_ERROR_NOT_FOUND if the alternate setting does not exist * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it * was opened * - another LIBUSB_ERROR code on other failure */ int (*set_interface_altsetting)(struct libusb_device_handle *dev_handle, int interface_number, int altsetting); /* Clear a halt/stall condition on an endpoint. * * It's OK for this function to block. * * Return: * - 0 on success * - LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it * was opened * - another LIBUSB_ERROR code on other failure */ int (*clear_halt)(struct libusb_device_handle *dev_handle, unsigned char endpoint); /* Perform a USB port reset to reinitialize a device. * * If possible, the device handle should still be usable after the reset * completes, assuming that the device descriptors did not change during * reset and all previous interface state can be restored. * * If something changes, or you cannot easily locate/verify the resetted * device, return LIBUSB_ERROR_NOT_FOUND. This prompts the application * to close the old handle and re-enumerate the device. * * Return: * - 0 on success * - LIBUSB_ERROR_NOT_FOUND if re-enumeration is required, or if the device * has been disconnected since it was opened * - another LIBUSB_ERROR code on other failure */ int (*reset_device)(struct libusb_device_handle *dev_handle); /* Alloc num_streams usb3 bulk streams on the passed in endpoints */ int (*alloc_streams)(struct libusb_device_handle *dev_handle, uint32_t num_streams, unsigned char *endpoints, int num_endpoints); /* Free usb3 bulk streams allocated with alloc_streams */ int (*free_streams)(struct libusb_device_handle *dev_handle, unsigned char *endpoints, int num_endpoints); /* Allocate persistent DMA memory for the given device, suitable for * zerocopy. May return NULL on failure. Optional to implement. */ unsigned char *(*dev_mem_alloc)(struct libusb_device_handle *handle, size_t len); /* Free memory allocated by dev_mem_alloc. */ int (*dev_mem_free)(struct libusb_device_handle *handle, unsigned char *buffer, size_t len); /* Determine if a kernel driver is active on an interface. Optional. * * The presence of a kernel driver on an interface indicates that any * calls to claim_interface would fail with the LIBUSB_ERROR_BUSY code. * * Return: * - 0 if no driver is active * - 1 if a driver is active * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it * was opened * - another LIBUSB_ERROR code on other failure */ int (*kernel_driver_active)(struct libusb_device_handle *dev_handle, int interface_number); /* Detach a kernel driver from an interface. Optional. * * After detaching a kernel driver, the interface should be available * for claim. * * Return: * - 0 on success * - LIBUSB_ERROR_NOT_FOUND if no kernel driver was active * - LIBUSB_ERROR_INVALID_PARAM if the interface does not exist * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it * was opened * - another LIBUSB_ERROR code on other failure */ int (*detach_kernel_driver)(struct libusb_device_handle *dev_handle, int interface_number); /* Attach a kernel driver to an interface. Optional. * * Reattach a kernel driver to the device. * * Return: * - 0 on success * - LIBUSB_ERROR_NOT_FOUND if no kernel driver was active * - LIBUSB_ERROR_INVALID_PARAM if the interface does not exist * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it * was opened * - LIBUSB_ERROR_BUSY if a program or driver has claimed the interface, * preventing reattachment * - another LIBUSB_ERROR code on other failure */ int (*attach_kernel_driver)(struct libusb_device_handle *dev_handle, int interface_number); /* Destroy a device. Optional. * * This function is called when the last reference to a device is * destroyed. It should free any resources allocated in the get_device_list * path. */ void (*destroy_device)(struct libusb_device *dev); /* Submit a transfer. Your implementation should take the transfer, * morph it into whatever form your platform requires, and submit it * asynchronously. * * This function must not block. * * This function gets called with the flying_transfers_lock locked! * * Return: * - 0 on success * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected * - another LIBUSB_ERROR code on other failure */ int (*submit_transfer)(struct usbi_transfer *itransfer); /* Cancel a previously submitted transfer. * * This function must not block. The transfer cancellation must complete * later, resulting in a call to usbi_handle_transfer_cancellation() * from the context of handle_events. */ int (*cancel_transfer)(struct usbi_transfer *itransfer); /* Clear a transfer as if it has completed or cancelled, but do not * report any completion/cancellation to the library. You should free * all private data from the transfer as if you were just about to report * completion or cancellation. * * This function might seem a bit out of place. It is used when libusb * detects a disconnected device - it calls this function for all pending * transfers before reporting completion (with the disconnect code) to * the user. Maybe we can improve upon this internal interface in future. */ void (*clear_transfer_priv)(struct usbi_transfer *itransfer); /* Handle any pending events on file descriptors. Optional. * * Provide this function when file descriptors directly indicate device * or transfer activity. If your backend does not have such file descriptors, * implement the handle_transfer_completion function below. * * This involves monitoring any active transfers and processing their * completion or cancellation. * * The function is passed an array of pollfd structures (size nfds) * as a result of the poll() system call. The num_ready parameter * indicates the number of file descriptors that have reported events * (i.e. the poll() return value). This should be enough information * for you to determine which actions need to be taken on the currently * active transfers. * * For any cancelled transfers, call usbi_handle_transfer_cancellation(). * For completed transfers, call usbi_handle_transfer_completion(). * For control/bulk/interrupt transfers, populate the "transferred" * element of the appropriate usbi_transfer structure before calling the * above functions. For isochronous transfers, populate the status and * transferred fields of the iso packet descriptors of the transfer. * * This function should also be able to detect disconnection of the * device, reporting that situation with usbi_handle_disconnect(). * * When processing an event related to a transfer, you probably want to * take usbi_transfer.lock to prevent races. See the documentation for * the usbi_transfer structure. * * Return 0 on success, or a LIBUSB_ERROR code on failure. */ int (*handle_events)(struct libusb_context *ctx, struct pollfd *fds, POLL_NFDS_TYPE nfds, int num_ready); /* Handle transfer completion. Optional. * * Provide this function when there are no file descriptors available * that directly indicate device or transfer activity. If your backend does * have such file descriptors, implement the handle_events function above. * * Your backend must tell the library when a transfer has completed by * calling usbi_signal_transfer_completion(). You should store any private * information about the transfer and its completion status in the transfer's * private backend data. * * During event handling, this function will be called on each transfer for * which usbi_signal_transfer_completion() was called. * * For any cancelled transfers, call usbi_handle_transfer_cancellation(). * For completed transfers, call usbi_handle_transfer_completion(). * For control/bulk/interrupt transfers, populate the "transferred" * element of the appropriate usbi_transfer structure before calling the * above functions. For isochronous transfers, populate the status and * transferred fields of the iso packet descriptors of the transfer. * * Return 0 on success, or a LIBUSB_ERROR code on failure. */ int (*handle_transfer_completion)(struct usbi_transfer *itransfer); /* Get time from specified clock. At least two clocks must be implemented by the backend: USBI_CLOCK_REALTIME, and USBI_CLOCK_MONOTONIC. Description of clocks: USBI_CLOCK_REALTIME : clock returns time since system epoch. USBI_CLOCK_MONOTONIC: clock returns time since unspecified start time (usually boot). */ int (*clock_gettime)(int clkid, struct timespec *tp); #ifdef USBI_TIMERFD_AVAILABLE /* clock ID of the clock that should be used for timerfd */ clockid_t (*get_timerfd_clockid)(void); #endif /* Number of bytes to reserve for per-context private backend data. * This private data area is accessible through the "os_priv" field of * struct libusb_context. */ size_t context_priv_size; /* Number of bytes to reserve for per-device private backend data. * This private data area is accessible through the "os_priv" field of * struct libusb_device. */ size_t device_priv_size; /* Number of bytes to reserve for per-handle private backend data. * This private data area is accessible through the "os_priv" field of * struct libusb_device. */ size_t device_handle_priv_size; /* Number of bytes to reserve for per-transfer private backend data. * This private data area is accessible by calling * usbi_transfer_get_os_priv() on the appropriate usbi_transfer instance. */ size_t transfer_priv_size; }; extern const struct usbi_os_backend usbi_backend; extern struct list_head active_contexts_list; extern usbi_mutex_static_t active_contexts_lock; #ifdef __cplusplus } #endif #endif