/*
* Internal header for libusb
* Copyright (C) 2007-2009 Daniel Drake <dsd@gentoo.org>
* Copyright (c) 2001 Johannes Erdfelt <johannes@erdfelt.com>
*
* 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 <config.h>
#include <stddef.h>
#include <stdint.h>
#include <time.h>
#include <libusb.h>
#include "libusb_version.h"
/* 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
#define DEVICE_DESC_LENGTH 18
#define USB_MAXENDPOINTS 32
#define USB_MAXINTERFACES 32
#define USB_MAXCONFIG 8
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)(&((type *)0L)->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;
}
#define container_of(ptr, type, member) ({ \
const typeof( ((type *)0)->member ) *__mptr = (ptr); \
(type *)( (char *)__mptr - offsetof(type,member) );})
#define MIN(a, b) ((a) < (b) ? (a) : (b))
#define MAX(a, b) ((a) > (b) ? (a) : (b))
#define TIMESPEC_IS_SET(ts) ((ts)->tv_sec != 0 || (ts)->tv_nsec != 0)
enum usbi_log_level {
LOG_LEVEL_DEBUG,
LOG_LEVEL_INFO,
LOG_LEVEL_WARNING,
LOG_LEVEL_ERROR,
};
void usbi_log(struct libusb_context *ctx, enum usbi_log_level level,
const char *function, const char *format, ...);
#if !defined(_MSC_VER) || _MSC_VER > 1200
#ifdef ENABLE_LOGGING
#define _usbi_log(ctx, level, ...) usbi_log(ctx, level, __FUNCTION__, __VA_ARGS__)
#else
#define _usbi_log(ctx, level, ...)
#endif
#if defined(ENABLE_DEBUG_LOGGING) || defined(INCLUDE_DEBUG_LOGGING)
#define usbi_dbg(...) _usbi_log(NULL, LOG_LEVEL_DEBUG, __VA_ARGS__)
#else
#define usbi_dbg(...)
#endif
#define usbi_info(ctx, ...) _usbi_log(ctx, LOG_LEVEL_INFO, __VA_ARGS__)
#define usbi_warn(ctx, ...) _usbi_log(ctx, LOG_LEVEL_WARNING, __VA_ARGS__)
#define usbi_err(ctx, ...) _usbi_log(ctx, LOG_LEVEL_ERROR, __VA_ARGS__)
#else /* !defined(_MSC_VER) || _MSC_VER > 1200 */
void usbi_log_v(struct libusb_context *ctx, enum usbi_log_level level,
const char *function, const char *format, va_list args);
#ifdef ENABLE_LOGGING
#define LOG_BODY(ctxt, level) \
{ \
va_list args; \
va_start (args, format); \
usbi_log_v(ctxt, level, "", format, args); \
va_end(args); \
}
#else
#define LOG_BODY(ctxt, level) { }
#endif
static inline void usbi_info(struct libusb_context *ctx, const char *format,
...)
LOG_BODY(ctx,LOG_LEVEL_INFO)
static inline void usbi_warn(struct libusb_context *ctx, const char *format,
...)
LOG_BODY(ctx,LOG_LEVEL_WARNING)
static inline void usbi_err( struct libusb_context *ctx, const char *format,
...)
LOG_BODY(ctx,LOG_LEVEL_ERROR)
static inline void usbi_dbg(const char *format, ...)
#if defined(ENABLE_DEBUG_LOGGING) || defined(INCLUDE_DEBUG_LOGGING)
LOG_BODY(NULL,LOG_LEVEL_DEBUG)
#else
{ }
#endif
#endif /* !defined(_MSC_VER) || _MSC_VER > 1200 */
#define USBI_GET_CONTEXT(ctx) if (!(ctx)) (ctx) = usbi_default_context
#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)))
/* Internal abstractions for thread synchronization and poll */
#if defined(THREADS_POSIX)
#include <os/threads_posix.h>
#elif defined(OS_WINDOWS)
#include <os/threads_windows.h>
#endif
#if defined(OS_LINUX) || defined(OS_DARWIN)
#include <os/poll_posix.h>
#elif defined(OS_WINDOWS)
#include <os/poll_windows.h>
#endif
extern struct libusb_context *usbi_default_context;
struct libusb_context {
int debug;
int debug_fixed;
/* internal control pipe, used for interrupting event handling when
* something needs to modify poll fds. */
int ctrl_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;
/* 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;
usbi_mutex_t flying_transfers_lock;
/* list of poll fds */
struct list_head pollfds;
usbi_mutex_t pollfds_lock;
/* a counter that is set when we want to interrupt event handling, in order
* to modify the poll fd set. and a lock to protect it. */
unsigned int pollfd_modify;
usbi_mutex_t pollfd_modify_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;
/* 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;
#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
};
#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 device_address;
uint8_t num_configurations;
struct list_head list;
unsigned long session_data;
unsigned char os_priv[0];
};
struct libusb_device_handle {
/* lock protects claimed_interfaces */
usbi_mutex_t lock;
unsigned long claimed_interfaces;
struct list_head list;
struct libusb_device *dev;
unsigned char os_priv[0];
};
#define USBI_TRANSFER_TIMED_OUT (1<<0)
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 timeval timeout;
int transferred;
uint8_t flags;
/* 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). */
usbi_mutex_t lock;
};
#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)
{
return ((unsigned char *)transfer) + sizeof(struct usbi_transfer)
+ sizeof(struct libusb_transfer)
+ (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 *handle);
int usbi_handle_transfer_completion(struct usbi_transfer *itransfer,
enum libusb_transfer_status status);
int usbi_handle_transfer_cancellation(struct usbi_transfer *transfer);
int usbi_parse_descriptor(unsigned char *source, char *descriptor, void *dest,
int host_endian);
int usbi_get_config_index_by_value(struct libusb_device *dev,
uint8_t bConfigurationValue, int *idx);
/* polling */
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);
void usbi_fd_notification(struct libusb_context *ctx);
/* 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[0];
};
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;
/* 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)(void);
/* 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 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.
*
* Return 0 on success, or a LIBUSB_ERROR code on failure.
*/
int (*get_device_list)(struct libusb_context *ctx,
struct discovered_devs **discdevs);
/* 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 *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 *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 0 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);
/* 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 *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 *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/applicatiosn 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 *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 *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 *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 *handle,
unsigned char endpoint);
/* Perform a USB port reset to reinitialize a device.
*
* If possible, the 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 *handle);
/* 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 *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 *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 *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.
*
* 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. 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, nfds_t nfds, int num_ready);
/* 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-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;
/* Mumber of additional bytes for os_priv for each iso packet.
* Can your backend use this? */
/* FIXME: linux can't use this any more. if other OS's cannot either,
* then remove this */
size_t add_iso_packet_size;
};
extern const struct usbi_os_backend * const usbi_backend;
extern const struct usbi_os_backend linux_usbfs_backend;
extern const struct usbi_os_backend darwin_backend;
extern const struct usbi_os_backend windows_backend;
#endif
