libusb/os/netbsd_usb.c

   1 /*
   2  * Copyright © 2011 Martin Pieuchot <mpi@openbsd.org>
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2.1 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  17  */
  18
  19 #include <config.h>
  20
  21 #include <sys/time.h>
  22 #include <sys/types.h>
  23
  24 #include <errno.h>
  25 #include <fcntl.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <unistd.h>
  30
  31 #include <dev/usb/usb.h>
  32
  33 #include "libusbi.h"
  34
  35 struct device_priv {
  36         char devnode[16];
  37         int fd;
  38
  39         unsigned char *cdesc;                   /* active config descriptor */
  40         usb_device_descriptor_t ddesc;          /* usb device descriptor */
  41 };
  42
  43 struct handle_priv {
  44         int endpoints[USB_MAX_ENDPOINTS];
  45 };
  46
  47 /*
  48  * Backend functions
  49  */
  50 static int netbsd_get_device_list(struct libusb_context *,
  51     struct discovered_devs **);
  52 static int netbsd_open(struct libusb_device_handle *);
  53 static void netbsd_close(struct libusb_device_handle *);
  54
  55 static int netbsd_get_device_descriptor(struct libusb_device *, unsigned char *,
  56     int *);
  57 static int netbsd_get_active_config_descriptor(struct libusb_device *,
  58     unsigned char *, size_t, int *);
  59 static int netbsd_get_config_descriptor(struct libusb_device *, uint8_t,
  60     unsigned char *, size_t, int *);
  61
  62 static int netbsd_get_configuration(struct libusb_device_handle *, int *);
  63 static int netbsd_set_configuration(struct libusb_device_handle *, int);
  64
  65 static int netbsd_claim_interface(struct libusb_device_handle *, int);
  66 static int netbsd_release_interface(struct libusb_device_handle *, int);
  67
  68 static int netbsd_set_interface_altsetting(struct libusb_device_handle *, int,
  69     int);
  70 static int netbsd_clear_halt(struct libusb_device_handle *, unsigned char);
  71 static int netbsd_reset_device(struct libusb_device_handle *);
  72 static void netbsd_destroy_device(struct libusb_device *);
  73
  74 static int netbsd_submit_transfer(struct usbi_transfer *);
  75 static int netbsd_cancel_transfer(struct usbi_transfer *);
  76 static void netbsd_clear_transfer_priv(struct usbi_transfer *);
  77 static int netbsd_handle_transfer_completion(struct usbi_transfer *);
  78 static int netbsd_clock_gettime(int, struct timespec *);
  79
  80 /*
  81  * Private functions
  82  */
  83 static int _errno_to_libusb(int);
  84 static int _cache_active_config_descriptor(struct libusb_device *, int);
  85 static int _sync_control_transfer(struct usbi_transfer *);
  86 static int _sync_gen_transfer(struct usbi_transfer *);
  87 static int _access_endpoint(struct libusb_transfer *);
  88
  89 const struct usbi_os_backend netbsd_backend = {
  90         "Synchronous NetBSD backend",
  91         0,
  92         NULL,                           /* init() */
  93         NULL,                           /* exit() */
  94         netbsd_get_device_list,
  95         NULL,                           /* hotplug_poll */
  96         netbsd_open,
  97         netbsd_close,
  98
  99         netbsd_get_device_descriptor,
 100         netbsd_get_active_config_descriptor,
 101         netbsd_get_config_descriptor,
 102         NULL,                           /* get_config_descriptor_by_value() */
 103
 104         netbsd_get_configuration,
 105         netbsd_set_configuration,
 106
 107         netbsd_claim_interface,
 108         netbsd_release_interface,
 109
 110         netbsd_set_interface_altsetting,
 111         netbsd_clear_halt,
 112         netbsd_reset_device,
 113
 114         NULL,                           /* alloc_streams */
 115         NULL,                           /* free_streams */
 116
 117         NULL,                           /* dev_mem_alloc() */
 118         NULL,                           /* dev_mem_free() */
 119
 120         NULL,                           /* kernel_driver_active() */
 121         NULL,                           /* detach_kernel_driver() */
 122         NULL,                           /* attach_kernel_driver() */
 123
 124         netbsd_destroy_device,
 125
 126         netbsd_submit_transfer,
 127         netbsd_cancel_transfer,
 128         netbsd_clear_transfer_priv,
 129
 130         NULL,                           /* handle_events() */
 131         netbsd_handle_transfer_completion,
 132
 133         netbsd_clock_gettime,
 134         sizeof(struct device_priv),
 135         sizeof(struct handle_priv),
 136         0,                              /* transfer_priv_size */
 137 };
 138
 139 int
 140 netbsd_get_device_list(struct libusb_context * ctx,
 141         struct discovered_devs **discdevs)
 142 {
 143         struct libusb_device *dev;
 144         struct device_priv *dpriv;
 145         struct usb_device_info di;
 146         unsigned long session_id;
 147         char devnode[16];
 148         int fd, err, i;
 149
 150         usbi_dbg("");
 151
 152         /* Only ugen(4) is supported */
 153         for (i = 0; i < USB_MAX_DEVICES; i++) {
 154                 /* Control endpoint is always .00 */
 155                 snprintf(devnode, sizeof(devnode), "/dev/ugen%d.00", i);
 156
 157                 if ((fd = open(devnode, O_RDONLY)) < 0) {
 158                         if (errno != ENOENT && errno != ENXIO)
 159                                 usbi_err(ctx, "could not open %s", devnode);
 160                         continue;
 161                 }
 162
 163                 if (ioctl(fd, USB_GET_DEVICEINFO, &di) < 0)
 164                         continue;
 165
 166                 session_id = (di.udi_bus << 8 | di.udi_addr);
 167                 dev = usbi_get_device_by_session_id(ctx, session_id);
 168
 169                 if (dev == NULL) {
 170                         dev = usbi_alloc_device(ctx, session_id);
 171                         if (dev == NULL)
 172                                 return (LIBUSB_ERROR_NO_MEM);
 173
 174                         dev->bus_number = di.udi_bus;
 175                         dev->device_address = di.udi_addr;
 176                         dev->speed = di.udi_speed;
 177
 178                         dpriv = (struct device_priv *)dev->os_priv;
 179                         strlcpy(dpriv->devnode, devnode, sizeof(devnode));
 180                         dpriv->fd = -1;
 181
 182                         if (ioctl(fd, USB_GET_DEVICE_DESC, &dpriv->ddesc) < 0) {
 183                                 err = errno;
 184                                 goto error;
 185                         }
 186
 187                         dpriv->cdesc = NULL;
 188                         if (_cache_active_config_descriptor(dev, fd)) {
 189                                 err = errno;
 190                                 goto error;
 191                         }
 192
 193                         if ((err = usbi_sanitize_device(dev)))
 194                                 goto error;
 195                 }
 196                 close(fd);
 197
 198                 if (discovered_devs_append(*discdevs, dev) == NULL)
 199                         return (LIBUSB_ERROR_NO_MEM);
 200
 201                 libusb_unref_device(dev);
 202         }
 203
 204         return (LIBUSB_SUCCESS);
 205
 206 error:
 207         close(fd);
 208         libusb_unref_device(dev);
 209         return _errno_to_libusb(err);
 210 }
 211
 212 int
 213 netbsd_open(struct libusb_device_handle *handle)
 214 {
 215         struct handle_priv *hpriv = (struct handle_priv *)handle->os_priv;
 216         struct device_priv *dpriv = (struct device_priv *)handle->dev->os_priv;
 217
 218         dpriv->fd = open(dpriv->devnode, O_RDWR);
 219         if (dpriv->fd < 0) {
 220                 dpriv->fd = open(dpriv->devnode, O_RDONLY);
 221                 if (dpriv->fd < 0)
 222                         return _errno_to_libusb(errno);
 223         }
 224
 225         usbi_dbg("open %s: fd %d", dpriv->devnode, dpriv->fd);
 226
 227         return (LIBUSB_SUCCESS);
 228 }
 229
 230 void
 231 netbsd_close(struct libusb_device_handle *handle)
 232 {
 233         struct handle_priv *hpriv = (struct handle_priv *)handle->os_priv;
 234         struct device_priv *dpriv = (struct device_priv *)handle->dev->os_priv;
 235
 236         usbi_dbg("close: fd %d", dpriv->fd);
 237
 238         close(dpriv->fd);
 239         dpriv->fd = -1;
 240 }
 241
 242 int
 243 netbsd_get_device_descriptor(struct libusb_device *dev, unsigned char *buf,
 244     int *host_endian)
 245 {
 246         struct device_priv *dpriv = (struct device_priv *)dev->os_priv;
 247
 248         usbi_dbg("");
 249
 250         memcpy(buf, &dpriv->ddesc, DEVICE_DESC_LENGTH);
 251
 252         *host_endian = 0;
 253
 254         return (LIBUSB_SUCCESS);
 255 }
 256
 257 int
 258 netbsd_get_active_config_descriptor(struct libusb_device *dev,
 259     unsigned char *buf, size_t len, int *host_endian)
 260 {
 261         struct device_priv *dpriv = (struct device_priv *)dev->os_priv;
 262         usb_config_descriptor_t *ucd;
 263
 264         ucd = (usb_config_descriptor_t *) dpriv->cdesc;
 265         len = MIN(len, UGETW(ucd->wTotalLength));
 266
 267         usbi_dbg("len %d", len);
 268
 269         memcpy(buf, dpriv->cdesc, len);
 270
 271         *host_endian = 0;
 272
 273         return len;
 274 }
 275
 276 int
 277 netbsd_get_config_descriptor(struct libusb_device *dev, uint8_t idx,
 278     unsigned char *buf, size_t len, int *host_endian)
 279 {
 280         struct device_priv *dpriv = (struct device_priv *)dev->os_priv;
 281         struct usb_full_desc ufd;
 282         int fd, err;
 283
 284         usbi_dbg("index %d, len %d", idx, len);
 285
 286         /* A config descriptor may be requested before opening the device */
 287         if (dpriv->fd >= 0) {
 288                 fd = dpriv->fd;
 289         } else {
 290                 fd = open(dpriv->devnode, O_RDONLY);
 291                 if (fd < 0)
 292                         return _errno_to_libusb(errno);
 293         }
 294
 295         ufd.ufd_config_index = idx;
 296         ufd.ufd_size = len;
 297         ufd.ufd_data = buf;
 298
 299         if ((ioctl(fd, USB_GET_FULL_DESC, &ufd)) < 0) {
 300                 err = errno;
 301                 if (dpriv->fd < 0)
 302                         close(fd);
 303                 return _errno_to_libusb(err);
 304         }
 305
 306         if (dpriv->fd < 0)
 307                 close(fd);
 308
 309         *host_endian = 0;
 310
 311         return len;
 312 }
 313
 314 int
 315 netbsd_get_configuration(struct libusb_device_handle *handle, int *config)
 316 {
 317         struct device_priv *dpriv = (struct device_priv *)handle->dev->os_priv;
 318
 319         usbi_dbg("");
 320
 321         if (ioctl(dpriv->fd, USB_GET_CONFIG, config) < 0)
 322                 return _errno_to_libusb(errno);
 323
 324         usbi_dbg("configuration %d", *config);
 325
 326         return (LIBUSB_SUCCESS);
 327 }
 328
 329 int
 330 netbsd_set_configuration(struct libusb_device_handle *handle, int config)
 331 {
 332         struct device_priv *dpriv = (struct device_priv *)handle->dev->os_priv;
 333
 334         usbi_dbg("configuration %d", config);
 335
 336         if (ioctl(dpriv->fd, USB_SET_CONFIG, &config) < 0)
 337                 return _errno_to_libusb(errno);
 338
 339         return _cache_active_config_descriptor(handle->dev, dpriv->fd);
 340 }
 341
 342 int
 343 netbsd_claim_interface(struct libusb_device_handle *handle, int iface)
 344 {
 345         struct handle_priv *hpriv = (struct handle_priv *)handle->os_priv;
 346         int i;
 347
 348         for (i = 0; i < USB_MAX_ENDPOINTS; i++)
 349                 hpriv->endpoints[i] = -1;
 350
 351         return (LIBUSB_SUCCESS);
 352 }
 353
 354 int
 355 netbsd_release_interface(struct libusb_device_handle *handle, int iface)
 356 {
 357         struct handle_priv *hpriv = (struct handle_priv *)handle->os_priv;
 358         int i;
 359
 360         for (i = 0; i < USB_MAX_ENDPOINTS; i++)
 361                 if (hpriv->endpoints[i] >= 0)
 362                         close(hpriv->endpoints[i]);
 363
 364         return (LIBUSB_SUCCESS);
 365 }
 366
 367 int
 368 netbsd_set_interface_altsetting(struct libusb_device_handle *handle, int iface,
 369     int altsetting)
 370 {
 371         struct device_priv *dpriv = (struct device_priv *)handle->dev->os_priv;
 372         struct usb_alt_interface intf;
 373
 374         usbi_dbg("iface %d, setting %d", iface, altsetting);
 375
 376         memset(&intf, 0, sizeof(intf));
 377
 378         intf.uai_interface_index = iface;
 379         intf.uai_alt_no = altsetting;
 380
 381         if (ioctl(dpriv->fd, USB_SET_ALTINTERFACE, &intf) < 0)
 382                 return _errno_to_libusb(errno);
 383
 384         return (LIBUSB_SUCCESS);
 385 }
 386
 387 int
 388 netbsd_clear_halt(struct libusb_device_handle *handle, unsigned char endpoint)
 389 {
 390         struct device_priv *dpriv = (struct device_priv *)handle->dev->os_priv;
 391         struct usb_ctl_request req;
 392
 393         usbi_dbg("");
 394
 395         req.ucr_request.bmRequestType = UT_WRITE_ENDPOINT;
 396         req.ucr_request.bRequest = UR_CLEAR_FEATURE;
 397         USETW(req.ucr_request.wValue, UF_ENDPOINT_HALT);
 398         USETW(req.ucr_request.wIndex, endpoint);
 399         USETW(req.ucr_request.wLength, 0);
 400
 401         if (ioctl(dpriv->fd, USB_DO_REQUEST, &req) < 0)
 402                 return _errno_to_libusb(errno);
 403
 404         return (LIBUSB_SUCCESS);
 405 }
 406
 407 int
 408 netbsd_reset_device(struct libusb_device_handle *handle)
 409 {
 410         usbi_dbg("");
 411
 412         return (LIBUSB_ERROR_NOT_SUPPORTED);
 413 }
 414
 415 void
 416 netbsd_destroy_device(struct libusb_device *dev)
 417 {
 418         struct device_priv *dpriv = (struct device_priv *)dev->os_priv;
 419
 420         usbi_dbg("");
 421
 422         free(dpriv->cdesc);
 423 }
 424
 425 int
 426 netbsd_submit_transfer(struct usbi_transfer *itransfer)
 427 {
 428         struct libusb_transfer *transfer;
 429         struct handle_priv *hpriv;
 430         int err = 0;
 431
 432         usbi_dbg("");
 433
 434         transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
 435         hpriv = (struct handle_priv *)transfer->dev_handle->os_priv;
 436
 437         switch (transfer->type) {
 438         case LIBUSB_TRANSFER_TYPE_CONTROL:
 439                 err = _sync_control_transfer(itransfer);
 440                 break;
 441         case LIBUSB_TRANSFER_TYPE_ISOCHRONOUS:
 442                 if (IS_XFEROUT(transfer)) {
 443                         /* Isochronous write is not supported */
 444                         err = LIBUSB_ERROR_NOT_SUPPORTED;
 445                         break;
 446                 }
 447                 err = _sync_gen_transfer(itransfer);
 448                 break;
 449         case LIBUSB_TRANSFER_TYPE_BULK:
 450         case LIBUSB_TRANSFER_TYPE_INTERRUPT:
 451                 if (IS_XFEROUT(transfer) &&
 452                     transfer->flags & LIBUSB_TRANSFER_ADD_ZERO_PACKET) {
 453                         err = LIBUSB_ERROR_NOT_SUPPORTED;
 454                         break;
 455                 }
 456                 err = _sync_gen_transfer(itransfer);
 457                 break;
 458         case LIBUSB_TRANSFER_TYPE_BULK_STREAM:
 459                 err = LIBUSB_ERROR_NOT_SUPPORTED;
 460                 break;
 461         }
 462
 463         if (err)
 464                 return (err);
 465
 466         usbi_signal_transfer_completion(itransfer);
 467
 468         return (LIBUSB_SUCCESS);
 469 }
 470
 471 int
 472 netbsd_cancel_transfer(struct usbi_transfer *itransfer)
 473 {
 474         usbi_dbg("");
 475
 476         return (LIBUSB_ERROR_NOT_SUPPORTED);
 477 }
 478
 479 void
 480 netbsd_clear_transfer_priv(struct usbi_transfer *itransfer)
 481 {
 482         usbi_dbg("");
 483
 484         /* Nothing to do */
 485 }
 486
 487 int
 488 netbsd_handle_transfer_completion(struct usbi_transfer *itransfer)
 489 {
 490         return usbi_handle_transfer_completion(itransfer, LIBUSB_TRANSFER_COMPLETED);
 491 }
 492
 493 int
 494 netbsd_clock_gettime(int clkid, struct timespec *tp)
 495 {
 496         usbi_dbg("clock %d", clkid);
 497
 498         if (clkid == USBI_CLOCK_REALTIME)
 499                 return clock_gettime(CLOCK_REALTIME, tp);
 500
 501         if (clkid == USBI_CLOCK_MONOTONIC)
 502                 return clock_gettime(CLOCK_MONOTONIC, tp);
 503
 504         return (LIBUSB_ERROR_INVALID_PARAM);
 505 }
 506
 507 int
 508 _errno_to_libusb(int err)
 509 {
 510         switch (err) {
 511         case EIO:
 512                 return (LIBUSB_ERROR_IO);
 513         case EACCES:
 514                 return (LIBUSB_ERROR_ACCESS);
 515         case ENOENT:
 516                 return (LIBUSB_ERROR_NO_DEVICE);
 517         case ENOMEM:
 518                 return (LIBUSB_ERROR_NO_MEM);
 519         }
 520
 521         usbi_dbg("error: %s", strerror(err));
 522
 523         return (LIBUSB_ERROR_OTHER);
 524 }
 525
 526 int
 527 _cache_active_config_descriptor(struct libusb_device *dev, int fd)
 528 {
 529         struct device_priv *dpriv = (struct device_priv *)dev->os_priv;
 530         struct usb_config_desc ucd;
 531         struct usb_full_desc ufd;
 532         unsigned char* buf;
 533         int len;
 534
 535         usbi_dbg("fd %d", fd);
 536
 537         ucd.ucd_config_index = USB_CURRENT_CONFIG_INDEX;
 538
 539         if ((ioctl(fd, USB_GET_CONFIG_DESC, &ucd)) < 0)
 540                 return _errno_to_libusb(errno);
 541
 542         usbi_dbg("active bLength %d", ucd.ucd_desc.bLength);
 543
 544         len = UGETW(ucd.ucd_desc.wTotalLength);
 545         buf = malloc(len);
 546         if (buf == NULL)
 547                 return (LIBUSB_ERROR_NO_MEM);
 548
 549         ufd.ufd_config_index = ucd.ucd_config_index;
 550         ufd.ufd_size = len;
 551         ufd.ufd_data = buf;
 552
 553         usbi_dbg("index %d, len %d", ufd.ufd_config_index, len);
 554
 555         if ((ioctl(fd, USB_GET_FULL_DESC, &ufd)) < 0) {
 556                 free(buf);
 557                 return _errno_to_libusb(errno);
 558         }
 559
 560         if (dpriv->cdesc)
 561                 free(dpriv->cdesc);
 562         dpriv->cdesc = buf;
 563
 564         return (0);
 565 }
 566
 567 int
 568 _sync_control_transfer(struct usbi_transfer *itransfer)
 569 {
 570         struct libusb_transfer *transfer;
 571         struct libusb_control_setup *setup;
 572         struct device_priv *dpriv;
 573         struct usb_ctl_request req;
 574
 575         transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
 576         dpriv = (struct device_priv *)transfer->dev_handle->dev->os_priv;
 577         setup = (struct libusb_control_setup *)transfer->buffer;
 578
 579         usbi_dbg("type %d request %d value %d index %d length %d timeout %d",
 580             setup->bmRequestType, setup->bRequest,
 581             libusb_le16_to_cpu(setup->wValue),
 582             libusb_le16_to_cpu(setup->wIndex),
 583             libusb_le16_to_cpu(setup->wLength), transfer->timeout);
 584
 585         req.ucr_request.bmRequestType = setup->bmRequestType;
 586         req.ucr_request.bRequest = setup->bRequest;
 587         /* Don't use USETW, libusb already deals with the endianness */
 588         (*(uint16_t *)req.ucr_request.wValue) = setup->wValue;
 589         (*(uint16_t *)req.ucr_request.wIndex) = setup->wIndex;
 590         (*(uint16_t *)req.ucr_request.wLength) = setup->wLength;
 591         req.ucr_data = transfer->buffer + LIBUSB_CONTROL_SETUP_SIZE;
 592
 593         if ((transfer->flags & LIBUSB_TRANSFER_SHORT_NOT_OK) == 0)
 594                 req.ucr_flags = USBD_SHORT_XFER_OK;
 595
 596         if ((ioctl(dpriv->fd, USB_SET_TIMEOUT, &transfer->timeout)) < 0)
 597                 return _errno_to_libusb(errno);
 598
 599         if ((ioctl(dpriv->fd, USB_DO_REQUEST, &req)) < 0)
 600                 return _errno_to_libusb(errno);
 601
 602         itransfer->transferred = req.ucr_actlen;
 603
 604         usbi_dbg("transferred %d", itransfer->transferred);
 605
 606         return (0);
 607 }
 608
 609 int
 610 _access_endpoint(struct libusb_transfer *transfer)
 611 {
 612         struct handle_priv *hpriv;
 613         struct device_priv *dpriv;
 614         char *s, devnode[16];
 615         int fd, endpt;
 616         mode_t mode;
 617
 618         hpriv = (struct handle_priv *)transfer->dev_handle->os_priv;
 619         dpriv = (struct device_priv *)transfer->dev_handle->dev->os_priv;
 620
 621         endpt = UE_GET_ADDR(transfer->endpoint);
 622         mode = IS_XFERIN(transfer) ? O_RDONLY : O_WRONLY;
 623
 624         usbi_dbg("endpoint %d mode %d", endpt, mode);
 625
 626         if (hpriv->endpoints[endpt] < 0) {
 627                 /* Pick the right node given the control one */
 628                 strlcpy(devnode, dpriv->devnode, sizeof(devnode));
 629                 s = strchr(devnode, '.');
 630                 snprintf(s, 4, ".%02d", endpt);
 631
 632                 /* We may need to read/write to the same endpoint later. */
 633                 if (((fd = open(devnode, O_RDWR)) < 0) && (errno == ENXIO))
 634                         if ((fd = open(devnode, mode)) < 0)
 635                                 return (-1);
 636
 637                 hpriv->endpoints[endpt] = fd;
 638         }
 639
 640         return (hpriv->endpoints[endpt]);
 641 }
 642
 643 int
 644 _sync_gen_transfer(struct usbi_transfer *itransfer)
 645 {
 646         struct libusb_transfer *transfer;
 647         int fd, nr = 1;
 648
 649         transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
 650
 651         /*
 652          * Bulk, Interrupt or Isochronous transfer depends on the
 653          * endpoint and thus the node to open.
 654          */
 655         if ((fd = _access_endpoint(transfer)) < 0)
 656                 return _errno_to_libusb(errno);
 657
 658         if ((ioctl(fd, USB_SET_TIMEOUT, &transfer->timeout)) < 0)
 659                 return _errno_to_libusb(errno);
 660
 661         if (IS_XFERIN(transfer)) {
 662                 if ((transfer->flags & LIBUSB_TRANSFER_SHORT_NOT_OK) == 0)
 663                         if ((ioctl(fd, USB_SET_SHORT_XFER, &nr)) < 0)
 664                                 return _errno_to_libusb(errno);
 665
 666                 nr = read(fd, transfer->buffer, transfer->length);
 667         } else {
 668                 nr = write(fd, transfer->buffer, transfer->length);
 669         }
 670
 671         if (nr < 0)
 672                 return _errno_to_libusb(errno);
 673
 674         itransfer->transferred = nr;
 675
 676         return (0);
 677 }