libusb/sync.c

   1 /*
   2  * Synchronous I/O functions for libusbx
   3  * Copyright © 2007-2008 Daniel Drake <dsd@gentoo.org>
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2.1 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  18  */
  19
  20 #include <config.h>
  21 #include <errno.h>
  22 #include <stdint.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25
  26 #include "libusbi.h"
  27
  28 /**
  29  * @defgroup syncio Synchronous device I/O
  30  *
  31  * This page documents libusbx's synchronous (blocking) API for USB device I/O.
  32  * This interface is easy to use but has some limitations. More advanced users
  33  * may wish to consider using the \ref asyncio "asynchronous I/O API" instead.
  34  */
  35
  36 static void LIBUSB_CALL ctrl_transfer_cb(struct libusb_transfer *transfer)
  37 {
  38         int *completed = transfer->user_data;
  39         *completed = 1;
  40         usbi_dbg("actual_length=%d", transfer->actual_length);
  41         /* caller interprets result and frees transfer */
  42 }
  43
  44 /** \ingroup syncio
  45  * Perform a USB control transfer.
  46  *
  47  * The direction of the transfer is inferred from the bmRequestType field of
  48  * the setup packet.
  49  *
  50  * The wValue, wIndex and wLength fields values should be given in host-endian
  51  * byte order.
  52  *
  53  * \param dev_handle a handle for the device to communicate with
  54  * \param bmRequestType the request type field for the setup packet
  55  * \param bRequest the request field for the setup packet
  56  * \param wValue the value field for the setup packet
  57  * \param wIndex the index field for the setup packet
  58  * \param data a suitably-sized data buffer for either input or output
  59  * (depending on direction bits within bmRequestType)
  60  * \param wLength the length field for the setup packet. The data buffer should
  61  * be at least this size.
  62  * \param timeout timeout (in millseconds) that this function should wait
  63  * before giving up due to no response being received. For an unlimited
  64  * timeout, use value 0.
  65  * \returns on success, the number of bytes actually transferred
  66  * \returns LIBUSB_ERROR_TIMEOUT if the transfer timed out
  67  * \returns LIBUSB_ERROR_PIPE if the control request was not supported by the
  68  * device
  69  * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
  70  * \returns another LIBUSB_ERROR code on other failures
  71  */
  72 int API_EXPORTED libusb_control_transfer(libusb_device_handle *dev_handle,
  73         uint8_t bmRequestType, uint8_t bRequest, uint16_t wValue, uint16_t wIndex,
  74         unsigned char *data, uint16_t wLength, unsigned int timeout)
  75 {
  76         struct libusb_transfer *transfer = libusb_alloc_transfer(0);
  77         unsigned char *buffer;
  78         int completed = 0;
  79         int r;
  80
  81         if (!transfer)
  82                 return LIBUSB_ERROR_NO_MEM;
  83
  84         buffer = (unsigned char*) malloc(LIBUSB_CONTROL_SETUP_SIZE + wLength);
  85         if (!buffer) {
  86                 libusb_free_transfer(transfer);
  87                 return LIBUSB_ERROR_NO_MEM;
  88         }
  89
  90         libusb_fill_control_setup(buffer, bmRequestType, bRequest, wValue, wIndex,
  91                 wLength);
  92         if ((bmRequestType & LIBUSB_ENDPOINT_DIR_MASK) == LIBUSB_ENDPOINT_OUT)
  93                 memcpy(buffer + LIBUSB_CONTROL_SETUP_SIZE, data, wLength);
  94
  95         libusb_fill_control_transfer(transfer, dev_handle, buffer,
  96                 ctrl_transfer_cb, &completed, timeout);
  97         transfer->flags = LIBUSB_TRANSFER_FREE_BUFFER;
  98         r = libusb_submit_transfer(transfer);
  99         if (r < 0) {
 100                 libusb_free_transfer(transfer);
 101                 return r;
 102         }
 103
 104         while (!completed) {
 105                 r = libusb_handle_events_completed(HANDLE_CTX(dev_handle), &completed);
 106                 if (r < 0) {
 107                         if (r == LIBUSB_ERROR_INTERRUPTED)
 108                                 continue;
 109                         libusb_cancel_transfer(transfer);
 110                         while (!completed)
 111                                 if (libusb_handle_events_completed(HANDLE_CTX(dev_handle), &completed) < 0)
 112                                         break;
 113                         libusb_free_transfer(transfer);
 114                         return r;
 115                 }
 116         }
 117
 118         if ((bmRequestType & LIBUSB_ENDPOINT_DIR_MASK) == LIBUSB_ENDPOINT_IN)
 119                 memcpy(data, libusb_control_transfer_get_data(transfer),
 120                         transfer->actual_length);
 121
 122         switch (transfer->status) {
 123         case LIBUSB_TRANSFER_COMPLETED:
 124                 r = transfer->actual_length;
 125                 break;
 126         case LIBUSB_TRANSFER_TIMED_OUT:
 127                 r = LIBUSB_ERROR_TIMEOUT;
 128                 break;
 129         case LIBUSB_TRANSFER_STALL:
 130                 r = LIBUSB_ERROR_PIPE;
 131                 break;
 132         case LIBUSB_TRANSFER_NO_DEVICE:
 133                 r = LIBUSB_ERROR_NO_DEVICE;
 134                 break;
 135         case LIBUSB_TRANSFER_OVERFLOW:
 136                 r = LIBUSB_ERROR_OVERFLOW;
 137                 break;
 138         case LIBUSB_TRANSFER_ERROR:
 139         case LIBUSB_TRANSFER_CANCELLED:
 140                 r = LIBUSB_ERROR_IO;
 141                 break;
 142         default:
 143                 usbi_warn(HANDLE_CTX(dev_handle),
 144                         "unrecognised status code %d", transfer->status);
 145                 r = LIBUSB_ERROR_OTHER;
 146         }
 147
 148         libusb_free_transfer(transfer);
 149         return r;
 150 }
 151
 152 static void LIBUSB_CALL bulk_transfer_cb(struct libusb_transfer *transfer)
 153 {
 154         int *completed = transfer->user_data;
 155         *completed = 1;
 156         usbi_dbg("actual_length=%d", transfer->actual_length);
 157         /* caller interprets results and frees transfer */
 158 }
 159
 160 static int do_sync_bulk_transfer(struct libusb_device_handle *dev_handle,
 161         unsigned char endpoint, unsigned char *buffer, int length,
 162         int *transferred, unsigned int timeout, unsigned char type)
 163 {
 164         struct libusb_transfer *transfer = libusb_alloc_transfer(0);
 165         int completed = 0;
 166         int r;
 167
 168         if (!transfer)
 169                 return LIBUSB_ERROR_NO_MEM;
 170
 171         libusb_fill_bulk_transfer(transfer, dev_handle, endpoint, buffer, length,
 172                 bulk_transfer_cb, &completed, timeout);
 173         transfer->type = type;
 174
 175         r = libusb_submit_transfer(transfer);
 176         if (r < 0) {
 177                 libusb_free_transfer(transfer);
 178                 return r;
 179         }
 180
 181         while (!completed) {
 182                 r = libusb_handle_events_completed(HANDLE_CTX(dev_handle), &completed);
 183                 if (r < 0) {
 184                         if (r == LIBUSB_ERROR_INTERRUPTED)
 185                                 continue;
 186                         libusb_cancel_transfer(transfer);
 187                         while (!completed)
 188                                 if (libusb_handle_events_completed(HANDLE_CTX(dev_handle), &completed) < 0)
 189                                         break;
 190                         libusb_free_transfer(transfer);
 191                         return r;
 192                 }
 193         }
 194
 195         *transferred = transfer->actual_length;
 196         switch (transfer->status) {
 197         case LIBUSB_TRANSFER_COMPLETED:
 198                 r = 0;
 199                 break;
 200         case LIBUSB_TRANSFER_TIMED_OUT:
 201                 r = LIBUSB_ERROR_TIMEOUT;
 202                 break;
 203         case LIBUSB_TRANSFER_STALL:
 204                 r = LIBUSB_ERROR_PIPE;
 205                 break;
 206         case LIBUSB_TRANSFER_OVERFLOW:
 207                 r = LIBUSB_ERROR_OVERFLOW;
 208                 break;
 209         case LIBUSB_TRANSFER_NO_DEVICE:
 210                 r = LIBUSB_ERROR_NO_DEVICE;
 211                 break;
 212         case LIBUSB_TRANSFER_ERROR:
 213         case LIBUSB_TRANSFER_CANCELLED:
 214                 r = LIBUSB_ERROR_IO;
 215                 break;
 216         default:
 217                 usbi_warn(HANDLE_CTX(dev_handle),
 218                         "unrecognised status code %d", transfer->status);
 219                 r = LIBUSB_ERROR_OTHER;
 220         }
 221
 222         libusb_free_transfer(transfer);
 223         return r;
 224 }
 225
 226 /** \ingroup syncio
 227  * Perform a USB bulk transfer. The direction of the transfer is inferred from
 228  * the direction bits of the endpoint address.
 229  *
 230  * For bulk reads, the <tt>length</tt> field indicates the maximum length of
 231  * data you are expecting to receive. If less data arrives than expected,
 232  * this function will return that data, so be sure to check the
 233  * <tt>transferred</tt> output parameter.
 234  *
 235  * You should also check the <tt>transferred</tt> parameter for bulk writes.
 236  * Not all of the data may have been written.
 237  *
 238  * Also check <tt>transferred</tt> when dealing with a timeout error code.
 239  * libusbx may have to split your transfer into a number of chunks to satisfy
 240  * underlying O/S requirements, meaning that the timeout may expire after
 241  * the first few chunks have completed. libusbx is careful not to lose any data
 242  * that may have been transferred; do not assume that timeout conditions
 243  * indicate a complete lack of I/O.
 244  *
 245  * \param dev_handle a handle for the device to communicate with
 246  * \param endpoint the address of a valid endpoint to communicate with
 247  * \param data a suitably-sized data buffer for either input or output
 248  * (depending on endpoint)
 249  * \param length for bulk writes, the number of bytes from data to be sent. for
 250  * bulk reads, the maximum number of bytes to receive into the data buffer.
 251  * \param transferred output location for the number of bytes actually
 252  * transferred.
 253  * \param timeout timeout (in millseconds) that this function should wait
 254  * before giving up due to no response being received. For an unlimited
 255  * timeout, use value 0.
 256  *
 257  * \returns 0 on success (and populates <tt>transferred</tt>)
 258  * \returns LIBUSB_ERROR_TIMEOUT if the transfer timed out (and populates
 259  * <tt>transferred</tt>)
 260  * \returns LIBUSB_ERROR_PIPE if the endpoint halted
 261  * \returns LIBUSB_ERROR_OVERFLOW if the device offered more data, see
 262  * \ref packetoverflow
 263  * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
 264  * \returns another LIBUSB_ERROR code on other failures
 265  */
 266 int API_EXPORTED libusb_bulk_transfer(struct libusb_device_handle *dev_handle,
 267         unsigned char endpoint, unsigned char *data, int length, int *transferred,
 268         unsigned int timeout)
 269 {
 270         return do_sync_bulk_transfer(dev_handle, endpoint, data, length,
 271                 transferred, timeout, LIBUSB_TRANSFER_TYPE_BULK);
 272 }
 273
 274 /** \ingroup syncio
 275  * Perform a USB interrupt transfer. The direction of the transfer is inferred
 276  * from the direction bits of the endpoint address.
 277  *
 278  * For interrupt reads, the <tt>length</tt> field indicates the maximum length
 279  * of data you are expecting to receive. If less data arrives than expected,
 280  * this function will return that data, so be sure to check the
 281  * <tt>transferred</tt> output parameter.
 282  *
 283  * You should also check the <tt>transferred</tt> parameter for interrupt
 284  * writes. Not all of the data may have been written.
 285  *
 286  * Also check <tt>transferred</tt> when dealing with a timeout error code.
 287  * libusbx may have to split your transfer into a number of chunks to satisfy
 288  * underlying O/S requirements, meaning that the timeout may expire after
 289  * the first few chunks have completed. libusbx is careful not to lose any data
 290  * that may have been transferred; do not assume that timeout conditions
 291  * indicate a complete lack of I/O.
 292  *
 293  * The default endpoint bInterval value is used as the polling interval.
 294  *
 295  * \param dev_handle a handle for the device to communicate with
 296  * \param endpoint the address of a valid endpoint to communicate with
 297  * \param data a suitably-sized data buffer for either input or output
 298  * (depending on endpoint)
 299  * \param length for bulk writes, the number of bytes from data to be sent. for
 300  * bulk reads, the maximum number of bytes to receive into the data buffer.
 301  * \param transferred output location for the number of bytes actually
 302  * transferred.
 303  * \param timeout timeout (in millseconds) that this function should wait
 304  * before giving up due to no response being received. For an unlimited
 305  * timeout, use value 0.
 306  *
 307  * \returns 0 on success (and populates <tt>transferred</tt>)
 308  * \returns LIBUSB_ERROR_TIMEOUT if the transfer timed out
 309  * \returns LIBUSB_ERROR_PIPE if the endpoint halted
 310  * \returns LIBUSB_ERROR_OVERFLOW if the device offered more data, see
 311  * \ref packetoverflow
 312  * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
 313  * \returns another LIBUSB_ERROR code on other error
 314  */
 315 int API_EXPORTED libusb_interrupt_transfer(
 316         struct libusb_device_handle *dev_handle, unsigned char endpoint,
 317         unsigned char *data, int length, int *transferred, unsigned int timeout)
 318 {
 319         return do_sync_bulk_transfer(dev_handle, endpoint, data, length,
 320                 transferred, timeout, LIBUSB_TRANSFER_TYPE_INTERRUPT);
 321 }