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
netbsd_get_device_list(struct libusb_context * ctx,struct discovered_devs ** discdevs)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
netbsd_open(struct libusb_device_handle * handle)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
netbsd_close(struct libusb_device_handle * handle)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
netbsd_get_device_descriptor(struct libusb_device * dev,unsigned char * buf,int * host_endian)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
netbsd_get_active_config_descriptor(struct libusb_device * dev,unsigned char * buf,size_t len,int * host_endian)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
netbsd_get_config_descriptor(struct libusb_device * dev,uint8_t idx,unsigned char * buf,size_t len,int * host_endian)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
netbsd_get_configuration(struct libusb_device_handle * handle,int * config)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
netbsd_set_configuration(struct libusb_device_handle * handle,int config)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
netbsd_claim_interface(struct libusb_device_handle * handle,int iface)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
netbsd_release_interface(struct libusb_device_handle * handle,int iface)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
netbsd_set_interface_altsetting(struct libusb_device_handle * handle,int iface,int altsetting)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
netbsd_clear_halt(struct libusb_device_handle * handle,unsigned char endpoint)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
netbsd_reset_device(struct libusb_device_handle * handle)408 netbsd_reset_device(struct libusb_device_handle *handle)
409 {
410 usbi_dbg("");
411
412 return (LIBUSB_ERROR_NOT_SUPPORTED);
413 }
414
415 void
netbsd_destroy_device(struct libusb_device * dev)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
netbsd_submit_transfer(struct usbi_transfer * itransfer)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
netbsd_cancel_transfer(struct usbi_transfer * itransfer)472 netbsd_cancel_transfer(struct usbi_transfer *itransfer)
473 {
474 usbi_dbg("");
475
476 return (LIBUSB_ERROR_NOT_SUPPORTED);
477 }
478
479 void
netbsd_clear_transfer_priv(struct usbi_transfer * itransfer)480 netbsd_clear_transfer_priv(struct usbi_transfer *itransfer)
481 {
482 usbi_dbg("");
483
484 /* Nothing to do */
485 }
486
487 int
netbsd_handle_transfer_completion(struct usbi_transfer * itransfer)488 netbsd_handle_transfer_completion(struct usbi_transfer *itransfer)
489 {
490 return usbi_handle_transfer_completion(itransfer, LIBUSB_TRANSFER_COMPLETED);
491 }
492
493 int
netbsd_clock_gettime(int clkid,struct timespec * tp)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
_errno_to_libusb(int err)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
_cache_active_config_descriptor(struct libusb_device * dev,int fd)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
_sync_control_transfer(struct usbi_transfer * itransfer)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
_access_endpoint(struct libusb_transfer * transfer)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
_sync_gen_transfer(struct usbi_transfer * itransfer)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 }
678