/*
* Synchronous I/O functions for libusb
* Copyright (C) 2007-2008 Daniel Drake <dsd@gentoo.org>
*
* 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
*/
#include <config.h>
#include <errno.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include "libusbi.h"
/**
* @defgroup syncio Synchronous device I/O
*
* This page documents libusb's synchronous (blocking) API for USB device I/O.
* This interface is easy to use but has some limitations. More advanced users
* may wish to consider using the \ref asyncio "asynchronous I/O API" instead.
*/
static void LIBUSB_CALL ctrl_transfer_cb(struct libusb_transfer *transfer)
{
int *completed = transfer->user_data;
*completed = 1;
usbi_dbg("actual_length=%d", transfer->actual_length);
/* caller interprets result and frees transfer */
}
/** \ingroup syncio
* Perform a USB control transfer.
*
* The direction of the transfer is inferred from the bmRequestType field of
* the setup packet.
*
* The wValue, wIndex and wLength fields values should be given in host-endian
* byte order.
*
* \param dev_handle a handle for the device to communicate with
* \param bmRequestType the request type field for the setup packet
* \param bRequest the request field for the setup packet
* \param wValue the value field for the setup packet
* \param wIndex the index field for the setup packet
* \param data a suitably-sized data buffer for either input or output
* (depending on direction bits within bmRequestType)
* \param wLength the length field for the setup packet. The data buffer should
* be at least this size.
* \param timeout timeout (in millseconds) that this function should wait
* before giving up due to no response being received. For an unlimited
* timeout, use value 0.
* \returns on success, the number of bytes actually transferred
* \returns LIBUSB_ERROR_TIMEOUT if the transfer timed out
* \returns LIBUSB_ERROR_PIPE if the control request was not supported by the
* device
* \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
* \returns another LIBUSB_ERROR code on other failures
*/
int API_EXPORTED libusb_control_transfer(libusb_device_handle *dev_handle,
uint8_t bmRequestType, uint8_t bRequest, uint16_t wValue, uint16_t wIndex,
unsigned char *data, uint16_t wLength, unsigned int timeout)
{
struct libusb_transfer *transfer = libusb_alloc_transfer(0);
unsigned char *buffer;
int completed = 0;
int r;
if (!transfer)
return LIBUSB_ERROR_NO_MEM;
buffer = malloc(LIBUSB_CONTROL_SETUP_SIZE + wLength);
if (!buffer) {
libusb_free_transfer(transfer);
return LIBUSB_ERROR_NO_MEM;
}
libusb_fill_control_setup(buffer, bmRequestType, bRequest, wValue, wIndex,
wLength);
if ((bmRequestType & LIBUSB_ENDPOINT_DIR_MASK) == LIBUSB_ENDPOINT_OUT)
memcpy(buffer + LIBUSB_CONTROL_SETUP_SIZE, data, wLength);
libusb_fill_control_transfer(transfer, dev_handle, buffer,
ctrl_transfer_cb, &completed, timeout);
transfer->flags = LIBUSB_TRANSFER_FREE_BUFFER;
r = libusb_submit_transfer(transfer);
if (r < 0) {
libusb_free_transfer(transfer);
return r;
}
while (!completed) {
r = libusb_handle_events_check(HANDLE_CTX(dev_handle), &completed);
if (r < 0) {
if (r == LIBUSB_ERROR_INTERRUPTED)
continue;
libusb_cancel_transfer(transfer);
while (!completed)
if (libusb_handle_events_check(HANDLE_CTX(dev_handle), &completed) < 0)
break;
libusb_free_transfer(transfer);
return r;
}
}
if ((bmRequestType & LIBUSB_ENDPOINT_DIR_MASK) == LIBUSB_ENDPOINT_IN)
memcpy(data, libusb_control_transfer_get_data(transfer),
transfer->actual_length);
switch (transfer->status) {
case LIBUSB_TRANSFER_COMPLETED:
r = transfer->actual_length;
break;
case LIBUSB_TRANSFER_TIMED_OUT:
r = LIBUSB_ERROR_TIMEOUT;
break;
case LIBUSB_TRANSFER_STALL:
r = LIBUSB_ERROR_PIPE;
break;
case LIBUSB_TRANSFER_NO_DEVICE:
r = LIBUSB_ERROR_NO_DEVICE;
break;
default:
usbi_warn(HANDLE_CTX(dev_handle),
"unrecognised status code %d", transfer->status);
r = LIBUSB_ERROR_OTHER;
}
libusb_free_transfer(transfer);
return r;
}
static void LIBUSB_CALL bulk_transfer_cb(struct libusb_transfer *transfer)
{
int *completed = transfer->user_data;
*completed = 1;
usbi_dbg("actual_length=%d", transfer->actual_length);
/* caller interprets results and frees transfer */
}
static int do_sync_bulk_transfer(struct libusb_device_handle *dev_handle,
unsigned char endpoint, unsigned char *buffer, int length,
int *transferred, unsigned int timeout, unsigned char type)
{
struct libusb_transfer *transfer = libusb_alloc_transfer(0);
int completed = 0;
int r;
if (!transfer)
return LIBUSB_ERROR_NO_MEM;
libusb_fill_bulk_transfer(transfer, dev_handle, endpoint, buffer, length,
bulk_transfer_cb, &completed, timeout);
transfer->type = type;
r = libusb_submit_transfer(transfer);
if (r < 0) {
libusb_free_transfer(transfer);
return r;
}
while (!completed) {
r = libusb_handle_events_check(HANDLE_CTX(dev_handle), &completed);
if (r < 0) {
if (r == LIBUSB_ERROR_INTERRUPTED)
continue;
libusb_cancel_transfer(transfer);
while (!completed)
if (libusb_handle_events_check(HANDLE_CTX(dev_handle), &completed) < 0)
break;
libusb_free_transfer(transfer);
return r;
}
}
*transferred = transfer->actual_length;
switch (transfer->status) {
case LIBUSB_TRANSFER_COMPLETED:
r = 0;
break;
case LIBUSB_TRANSFER_TIMED_OUT:
r = LIBUSB_ERROR_TIMEOUT;
break;
case LIBUSB_TRANSFER_STALL:
r = LIBUSB_ERROR_PIPE;
break;
case LIBUSB_TRANSFER_OVERFLOW:
r = LIBUSB_ERROR_OVERFLOW;
break;
case LIBUSB_TRANSFER_NO_DEVICE:
r = LIBUSB_ERROR_NO_DEVICE;
break;
default:
usbi_warn(HANDLE_CTX(dev_handle),
"unrecognised status code %d", transfer->status);
r = LIBUSB_ERROR_OTHER;
}
libusb_free_transfer(transfer);
return r;
}
/** \ingroup syncio
* Perform a USB bulk transfer. The direction of the transfer is inferred from
* the direction bits of the endpoint address.
*
* For bulk reads, the <tt>length</tt> field indicates the maximum length of
* data you are expecting to receive. If less data arrives than expected,
* this function will return that data, so be sure to check the
* <tt>transferred</tt> output parameter.
*
* You should also check the <tt>transferred</tt> parameter for bulk writes.
* Not all of the data may have been written.
*
* Also check <tt>transferred</tt> when dealing with a timeout error code.
* libusb may have to split your transfer into a number of chunks to satisfy
* underlying O/S requirements, meaning that the timeout may expire after
* the first few chunks have completed. libusb is careful not to lose any data
* that may have been transferred; do not assume that timeout conditions
* indicate a complete lack of I/O.
*
* \param dev_handle a handle for the device to communicate with
* \param endpoint the address of a valid endpoint to communicate with
* \param data a suitably-sized data buffer for either input or output
* (depending on endpoint)
* \param length for bulk writes, the number of bytes from data to be sent. for
* bulk reads, the maximum number of bytes to receive into the data buffer.
* \param transferred output location for the number of bytes actually
* transferred.
* \param timeout timeout (in millseconds) that this function should wait
* before giving up due to no response being received. For an unlimited
* timeout, use value 0.
*
* \returns 0 on success (and populates <tt>transferred</tt>)
* \returns LIBUSB_ERROR_TIMEOUT if the transfer timed out (and populates
* <tt>transferred</tt>)
* \returns LIBUSB_ERROR_PIPE if the endpoint halted
* \returns LIBUSB_ERROR_OVERFLOW if the device offered more data, see
* \ref packetoverflow
* \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
* \returns another LIBUSB_ERROR code on other failures
*/
int API_EXPORTED libusb_bulk_transfer(struct libusb_device_handle *dev_handle,
unsigned char endpoint, unsigned char *data, int length, int *transferred,
unsigned int timeout)
{
return do_sync_bulk_transfer(dev_handle, endpoint, data, length,
transferred, timeout, LIBUSB_TRANSFER_TYPE_BULK);
}
/** \ingroup syncio
* Perform a USB interrupt transfer. The direction of the transfer is inferred
* from the direction bits of the endpoint address.
*
* For interrupt reads, the <tt>length</tt> field indicates the maximum length
* of data you are expecting to receive. If less data arrives than expected,
* this function will return that data, so be sure to check the
* <tt>transferred</tt> output parameter.
*
* You should also check the <tt>transferred</tt> parameter for interrupt
* writes. Not all of the data may have been written.
*
* Also check <tt>transferred</tt> when dealing with a timeout error code.
* libusb may have to split your transfer into a number of chunks to satisfy
* underlying O/S requirements, meaning that the timeout may expire after
* the first few chunks have completed. libusb is careful not to lose any data
* that may have been transferred; do not assume that timeout conditions
* indicate a complete lack of I/O.
*
* The default endpoint bInterval value is used as the polling interval.
*
* \param dev_handle a handle for the device to communicate with
* \param endpoint the address of a valid endpoint to communicate with
* \param data a suitably-sized data buffer for either input or output
* (depending on endpoint)
* \param length for bulk writes, the number of bytes from data to be sent. for
* bulk reads, the maximum number of bytes to receive into the data buffer.
* \param transferred output location for the number of bytes actually
* transferred.
* \param timeout timeout (in millseconds) that this function should wait
* before giving up due to no response being received. For an unlimited
* timeout, use value 0.
*
* \returns 0 on success (and populates <tt>transferred</tt>)
* \returns LIBUSB_ERROR_TIMEOUT if the transfer timed out
* \returns LIBUSB_ERROR_PIPE if the endpoint halted
* \returns LIBUSB_ERROR_OVERFLOW if the device offered more data, see
* \ref packetoverflow
* \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
* \returns another LIBUSB_ERROR code on other error
*/
int API_EXPORTED libusb_interrupt_transfer(
struct libusb_device_handle *dev_handle, unsigned char endpoint,
unsigned char *data, int length, int *transferred, unsigned int timeout)
{
return do_sync_bulk_transfer(dev_handle, endpoint, data, length,
transferred, timeout, LIBUSB_TRANSFER_TYPE_INTERRUPT);
}
