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 sync_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 static void sync_transfer_wait_for_completion(struct libusb_transfer *transfer)
  45 {
  46         int r, *completed = transfer->user_data;
  47         struct libusb_context *ctx = HANDLE_CTX(transfer->dev_handle);
  48
  49         while (!*completed) {
  50                 r = libusb_handle_events_completed(ctx, completed);
  51                 if (r < 0) {
  52                         if (r == LIBUSB_ERROR_INTERRUPTED)
  53                                 continue;
  54                         usbi_err(ctx, "libusb_handle_events failed: %s, cancelling transfer and retrying",
  55                                  libusb_error_name(r));
  56                         libusb_cancel_transfer(transfer);
  57                         continue;
  58                 }
  59         }
  60 }
  61
  62 /** \ingroup syncio
  63  * Perform a USB control transfer.
  64  *
  65  * The direction of the transfer is inferred from the bmRequestType field of
  66  * the setup packet.
  67  *
  68  * The wValue, wIndex and wLength fields values should be given in host-endian
  69  * byte order.
  70  *
  71  * \param dev_handle a handle for the device to communicate with
  72  * \param bmRequestType the request type field for the setup packet
  73  * \param bRequest the request field for the setup packet
  74  * \param wValue the value field for the setup packet
  75  * \param wIndex the index field for the setup packet
  76  * \param data a suitably-sized data buffer for either input or output
  77  * (depending on direction bits within bmRequestType)
  78  * \param wLength the length field for the setup packet. The data buffer should
  79  * be at least this size.
  80  * \param timeout timeout (in millseconds) that this function should wait
  81  * before giving up due to no response being received. For an unlimited
  82  * timeout, use value 0.
  83  * \returns on success, the number of bytes actually transferred
  84  * \returns LIBUSB_ERROR_TIMEOUT if the transfer timed out
  85  * \returns LIBUSB_ERROR_PIPE if the control request was not supported by the
  86  * device
  87  * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
  88  * \returns another LIBUSB_ERROR code on other failures
  89  */
  90 int API_EXPORTED libusb_control_transfer(libusb_device_handle *dev_handle,
  91         uint8_t bmRequestType, uint8_t bRequest, uint16_t wValue, uint16_t wIndex,
  92         unsigned char *data, uint16_t wLength, unsigned int timeout)
  93 {
  94         struct libusb_transfer *transfer = libusb_alloc_transfer(0);
  95         unsigned char *buffer;
  96         int completed = 0;
  97         int r;
  98
  99         if (!transfer)
 100                 return LIBUSB_ERROR_NO_MEM;
 101
 102         buffer = (unsigned char*) malloc(LIBUSB_CONTROL_SETUP_SIZE + wLength);
 103         if (!buffer) {
 104                 libusb_free_transfer(transfer);
 105                 return LIBUSB_ERROR_NO_MEM;
 106         }
 107
 108         libusb_fill_control_setup(buffer, bmRequestType, bRequest, wValue, wIndex,
 109                 wLength);
 110         if ((bmRequestType & LIBUSB_ENDPOINT_DIR_MASK) == LIBUSB_ENDPOINT_OUT)
 111                 memcpy(buffer + LIBUSB_CONTROL_SETUP_SIZE, data, wLength);
 112
 113         libusb_fill_control_transfer(transfer, dev_handle, buffer,
 114                 sync_transfer_cb, &completed, timeout);
 115         transfer->flags = LIBUSB_TRANSFER_FREE_BUFFER;
 116         r = libusb_submit_transfer(transfer);
 117         if (r < 0) {
 118                 libusb_free_transfer(transfer);
 119                 return r;
 120         }
 121
 122         sync_transfer_wait_for_completion(transfer);
 123
 124         if ((bmRequestType & LIBUSB_ENDPOINT_DIR_MASK) == LIBUSB_ENDPOINT_IN)
 125                 memcpy(data, libusb_control_transfer_get_data(transfer),
 126                         transfer->actual_length);
 127
 128         switch (transfer->status) {
 129         case LIBUSB_TRANSFER_COMPLETED:
 130                 r = transfer->actual_length;
 131                 break;
 132         case LIBUSB_TRANSFER_TIMED_OUT:
 133                 r = LIBUSB_ERROR_TIMEOUT;
 134                 break;
 135         case LIBUSB_TRANSFER_STALL:
 136                 r = LIBUSB_ERROR_PIPE;
 137                 break;
 138         case LIBUSB_TRANSFER_NO_DEVICE:
 139                 r = LIBUSB_ERROR_NO_DEVICE;
 140                 break;
 141         case LIBUSB_TRANSFER_OVERFLOW:
 142                 r = LIBUSB_ERROR_OVERFLOW;
 143                 break;
 144         case LIBUSB_TRANSFER_ERROR:
 145         case LIBUSB_TRANSFER_CANCELLED:
 146                 r = LIBUSB_ERROR_IO;
 147                 break;
 148         default:
 149                 usbi_warn(HANDLE_CTX(dev_handle),
 150                         "unrecognised status code %d", transfer->status);
 151                 r = LIBUSB_ERROR_OTHER;
 152         }
 153
 154         libusb_free_transfer(transfer);
 155         return r;
 156 }
 157
 158 static int do_sync_bulk_transfer(struct libusb_device_handle *dev_handle,
 159         unsigned char endpoint, unsigned char *buffer, int length,
 160         int *transferred, unsigned int timeout, unsigned char type)
 161 {
 162         struct libusb_transfer *transfer = libusb_alloc_transfer(0);
 163         int completed = 0;
 164         int r;
 165
 166         if (!transfer)
 167                 return LIBUSB_ERROR_NO_MEM;
 168
 169         libusb_fill_bulk_transfer(transfer, dev_handle, endpoint, buffer, length,
 170                 sync_transfer_cb, &completed, timeout);
 171         transfer->type = type;
 172
 173         r = libusb_submit_transfer(transfer);
 174         if (r < 0) {
 175                 libusb_free_transfer(transfer);
 176                 return r;
 177         }
 178
 179         sync_transfer_wait_for_completion(transfer);
 180
 181         *transferred = transfer->actual_length;
 182         switch (transfer->status) {
 183         case LIBUSB_TRANSFER_COMPLETED:
 184                 r = 0;
 185                 break;
 186         case LIBUSB_TRANSFER_TIMED_OUT:
 187                 r = LIBUSB_ERROR_TIMEOUT;
 188                 break;
 189         case LIBUSB_TRANSFER_STALL:
 190                 r = LIBUSB_ERROR_PIPE;
 191                 break;
 192         case LIBUSB_TRANSFER_OVERFLOW:
 193                 r = LIBUSB_ERROR_OVERFLOW;
 194                 break;
 195         case LIBUSB_TRANSFER_NO_DEVICE:
 196                 r = LIBUSB_ERROR_NO_DEVICE;
 197                 break;
 198         case LIBUSB_TRANSFER_ERROR:
 199         case LIBUSB_TRANSFER_CANCELLED:
 200                 r = LIBUSB_ERROR_IO;
 201                 break;
 202         default:
 203                 usbi_warn(HANDLE_CTX(dev_handle),
 204                         "unrecognised status code %d", transfer->status);
 205                 r = LIBUSB_ERROR_OTHER;
 206         }
 207
 208         libusb_free_transfer(transfer);
 209         return r;
 210 }
 211
 212 /** \ingroup syncio
 213  * Perform a USB bulk transfer. The direction of the transfer is inferred from
 214  * the direction bits of the endpoint address.
 215  *
 216  * For bulk reads, the <tt>length</tt> field indicates the maximum length of
 217  * data you are expecting to receive. If less data arrives than expected,
 218  * this function will return that data, so be sure to check the
 219  * <tt>transferred</tt> output parameter.
 220  *
 221  * You should also check the <tt>transferred</tt> parameter for bulk writes.
 222  * Not all of the data may have been written.
 223  *
 224  * Also check <tt>transferred</tt> when dealing with a timeout error code.
 225  * libusbx may have to split your transfer into a number of chunks to satisfy
 226  * underlying O/S requirements, meaning that the timeout may expire after
 227  * the first few chunks have completed. libusbx is careful not to lose any data
 228  * that may have been transferred; do not assume that timeout conditions
 229  * indicate a complete lack of I/O.
 230  *
 231  * \param dev_handle a handle for the device to communicate with
 232  * \param endpoint the address of a valid endpoint to communicate with
 233  * \param data a suitably-sized data buffer for either input or output
 234  * (depending on endpoint)
 235  * \param length for bulk writes, the number of bytes from data to be sent. for
 236  * bulk reads, the maximum number of bytes to receive into the data buffer.
 237  * \param transferred output location for the number of bytes actually
 238  * transferred.
 239  * \param timeout timeout (in millseconds) that this function should wait
 240  * before giving up due to no response being received. For an unlimited
 241  * timeout, use value 0.
 242  *
 243  * \returns 0 on success (and populates <tt>transferred</tt>)
 244  * \returns LIBUSB_ERROR_TIMEOUT if the transfer timed out (and populates
 245  * <tt>transferred</tt>)
 246  * \returns LIBUSB_ERROR_PIPE if the endpoint halted
 247  * \returns LIBUSB_ERROR_OVERFLOW if the device offered more data, see
 248  * \ref packetoverflow
 249  * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
 250  * \returns another LIBUSB_ERROR code on other failures
 251  */
 252 int API_EXPORTED libusb_bulk_transfer(struct libusb_device_handle *dev_handle,
 253         unsigned char endpoint, unsigned char *data, int length, int *transferred,
 254         unsigned int timeout)
 255 {
 256         return do_sync_bulk_transfer(dev_handle, endpoint, data, length,
 257                 transferred, timeout, LIBUSB_TRANSFER_TYPE_BULK);
 258 }
 259
 260 /** \ingroup syncio
 261  * Perform a USB interrupt transfer. The direction of the transfer is inferred
 262  * from the direction bits of the endpoint address.
 263  *
 264  * For interrupt reads, the <tt>length</tt> field indicates the maximum length
 265  * of data you are expecting to receive. If less data arrives than expected,
 266  * this function will return that data, so be sure to check the
 267  * <tt>transferred</tt> output parameter.
 268  *
 269  * You should also check the <tt>transferred</tt> parameter for interrupt
 270  * writes. Not all of the data may have been written.
 271  *
 272  * Also check <tt>transferred</tt> when dealing with a timeout error code.
 273  * libusbx may have to split your transfer into a number of chunks to satisfy
 274  * underlying O/S requirements, meaning that the timeout may expire after
 275  * the first few chunks have completed. libusbx is careful not to lose any data
 276  * that may have been transferred; do not assume that timeout conditions
 277  * indicate a complete lack of I/O.
 278  *
 279  * The default endpoint bInterval value is used as the polling interval.
 280  *
 281  * \param dev_handle a handle for the device to communicate with
 282  * \param endpoint the address of a valid endpoint to communicate with
 283  * \param data a suitably-sized data buffer for either input or output
 284  * (depending on endpoint)
 285  * \param length for bulk writes, the number of bytes from data to be sent. for
 286  * bulk reads, the maximum number of bytes to receive into the data buffer.
 287  * \param transferred output location for the number of bytes actually
 288  * transferred.
 289  * \param timeout timeout (in millseconds) that this function should wait
 290  * before giving up due to no response being received. For an unlimited
 291  * timeout, use value 0.
 292  *
 293  * \returns 0 on success (and populates <tt>transferred</tt>)
 294  * \returns LIBUSB_ERROR_TIMEOUT if the transfer timed out
 295  * \returns LIBUSB_ERROR_PIPE if the endpoint halted
 296  * \returns LIBUSB_ERROR_OVERFLOW if the device offered more data, see
 297  * \ref packetoverflow
 298  * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
 299  * \returns another LIBUSB_ERROR code on other error
 300  */
 301 int API_EXPORTED libusb_interrupt_transfer(
 302         struct libusb_device_handle *dev_handle, unsigned char endpoint,
 303         unsigned char *data, int length, int *transferred, unsigned int timeout)
 304 {
 305         return do_sync_bulk_transfer(dev_handle, endpoint, data, length,
 306                 transferred, timeout, LIBUSB_TRANSFER_TYPE_INTERRUPT);
 307 }