libusb/io.c

   1 /*
   2  * I/O functions for libusb
   3  * Copyright (C) 2007-2008 Daniel Drake <dsd@gentoo.org>
   4  * Copyright (c) 2001 Johannes Erdfelt <johannes@erdfelt.com>
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 #include <config.h>
  22 #include <errno.h>
  23 #include <signal.h>
  24 #include <stdint.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <sys/select.h>
  28 #include <sys/time.h>
  29 #include <time.h>
  30 #include <unistd.h>
  31
  32 #include "libusbi.h"
  33
  34 #define TRANSFER_TO_PRIV(trf) (container_of((trf), struct usbi_transfer, pub))
  35
  36 /* this is a list of in-flight rb_handles, sorted by timeout expiration.
  37  * URBs to timeout the soonest are placed at the beginning of the list, URBs
  38  * that will time out later are placed after, and urbs with infinite timeout
  39  * are always placed at the very end. */
  40 static struct list_head flying_transfers;
  41
  42 /* user callbacks for pollfd changes */
  43 static libusb_pollfd_added_cb fd_added_cb = NULL;
  44 static libusb_pollfd_removed_cb fd_removed_cb = NULL;
  45
  46 void usbi_io_init()
  47 {
  48         list_init(&flying_transfers);
  49         fd_added_cb = NULL;
  50         fd_removed_cb = NULL;
  51 }
  52
  53 static int calculate_timeout(struct usbi_transfer *transfer)
  54 {
  55         int r;
  56         struct timespec current_time;
  57         unsigned int timeout = transfer->pub.timeout;
  58
  59         if (!timeout)
  60                 return 0;
  61
  62         r = clock_gettime(CLOCK_MONOTONIC, &current_time);
  63         if (r < 0) {
  64                 usbi_err("failed to read monotonic clock, errno=%d", errno);
  65                 return r;
  66         }
  67
  68         current_time.tv_sec += timeout / 1000;
  69         current_time.tv_nsec += (timeout % 1000) * 1000000;
  70
  71         if (current_time.tv_nsec > 1000000000) {
  72                 current_time.tv_nsec -= 1000000000;
  73                 current_time.tv_sec++;
  74         }
  75
  76         TIMESPEC_TO_TIMEVAL(&transfer->timeout, &current_time);
  77         return 0;
  78 }
  79
  80 static void add_to_flying_list(struct usbi_transfer *transfer)
  81 {
  82         struct usbi_transfer *cur;
  83         struct timeval *timeout = &transfer->timeout;
  84
  85         /* if we have no other flying transfers, start the list with this one */
  86         if (list_empty(&flying_transfers)) {
  87                 list_add(&transfer->list, &flying_transfers);
  88                 return;
  89         }
  90
  91         /* if we have infinite timeout, append to end of list */
  92         if (!timerisset(timeout)) {
  93                 list_add_tail(&transfer->list, &flying_transfers);
  94                 return;
  95         }
  96
  97         /* otherwise, find appropriate place in list */
  98         list_for_each_entry(cur, &flying_transfers, list) {
  99                 /* find first timeout that occurs after the transfer in question */
 100                 struct timeval *cur_tv = &cur->timeout;
 101
 102                 if (!timerisset(cur_tv) || (cur_tv->tv_sec > timeout->tv_sec) ||
 103                                 (cur_tv->tv_sec == timeout->tv_sec &&
 104                                         cur_tv->tv_usec > timeout->tv_usec)) {
 105                         list_add_tail(&transfer->list, &cur->list);
 106                         return;
 107                 }
 108         }
 109
 110         /* otherwise we need to be inserted at the end */
 111         list_add_tail(&transfer->list, &flying_transfers);
 112 }
 113
 114 static int submit_transfer(struct usbi_transfer *itransfer)
 115 {
 116         int r;
 117         struct usb_urb *urb = &itransfer->urb;
 118         struct libusb_transfer *transfer = &itransfer->pub;
 119         int to_be_transferred = transfer->length - itransfer->transferred;
 120
 121         switch (transfer->endpoint_type) {
 122         case LIBUSB_ENDPOINT_TYPE_CONTROL:
 123                 urb->type = USB_URB_TYPE_CONTROL;
 124                 break;
 125         case LIBUSB_ENDPOINT_TYPE_BULK:
 126                 urb->type = USB_URB_TYPE_BULK;
 127                 break;
 128         case LIBUSB_ENDPOINT_TYPE_INTERRUPT:
 129                 urb->type = USB_URB_TYPE_INTERRUPT;
 130                 break;
 131         default:
 132                 usbi_err("unknown endpoint type %d", transfer->endpoint_type);
 133                 return -EINVAL;
 134         }
 135
 136         urb->endpoint = transfer->endpoint;
 137         urb->buffer = transfer->buffer + itransfer->transferred;
 138         urb->buffer_length = MIN(to_be_transferred, MAX_URB_BUFFER_LENGTH);
 139
 140         /* FIXME: for requests that we have to split into multiple URBs, we should
 141          * submit all the URBs instantly: submit, submit, submit, reap, reap, reap
 142          * rather than: submit, reap, submit, reap, submit, reap
 143          * this will improve performance and fix bugs concerning behaviour when
 144          * the user submits two similar multiple-urb requests */
 145         usbi_dbg("transferring %d from %d bytes", urb->buffer_length,
 146                 to_be_transferred);
 147
 148         r = ioctl(transfer->dev_handle->fd, IOCTL_USB_SUBMITURB, urb);
 149         if (r < 0) {
 150                 usbi_err("submiturb failed error %d errno=%d", r, errno);
 151                 return r;
 152         }
 153
 154         add_to_flying_list(itransfer);
 155         return 0;
 156 }
 157
 158 API_EXPORTED size_t libusb_get_transfer_alloc_size(void)
 159 {
 160         return sizeof(struct usbi_transfer);
 161 }
 162
 163 void __init_transfer(struct usbi_transfer *transfer)
 164 {
 165         memset(transfer, 0, sizeof(*transfer));
 166 }
 167
 168 API_EXPORTED void libusb_init_transfer(struct libusb_transfer *transfer)
 169 {
 170         __init_transfer(TRANSFER_TO_PRIV(transfer));
 171 }
 172
 173 API_EXPORTED struct libusb_transfer *libusb_alloc_transfer(void)
 174 {
 175         struct usbi_transfer *transfer = malloc(sizeof(*transfer));
 176         if (!transfer)
 177                 return NULL;
 178
 179         __init_transfer(transfer);
 180         return &transfer->pub;
 181 }
 182
 183 API_EXPORTED int libusb_submit_transfer(struct libusb_transfer *transfer)
 184 {
 185         struct usbi_transfer *itransfer = TRANSFER_TO_PRIV(transfer);
 186         int r;
 187
 188         itransfer->transferred = 0;
 189         r = calculate_timeout(itransfer);
 190         if (r < 0)
 191                 return r;
 192
 193         if (transfer->endpoint_type == LIBUSB_ENDPOINT_TYPE_CONTROL) {
 194                 struct libusb_control_setup *setup =
 195                         (struct libusb_control_setup *) transfer->buffer;
 196
 197                 usbi_dbg("RQT=%02x RQ=%02x VAL=%04x IDX=%04x length=%d",
 198                         setup->bRequestType, setup->bRequest, setup->wValue, setup->wIndex,
 199                         setup->wLength);
 200
 201                 setup->wValue = cpu_to_le16(setup->wValue);
 202                 setup->wIndex = cpu_to_le16(setup->wIndex);
 203                 setup->wLength = cpu_to_le16(setup->wLength);
 204         }
 205
 206         return submit_transfer(itransfer);
 207 }
 208
 209 API_EXPORTED int libusb_cancel_transfer(struct libusb_device_handle *devh,
 210         struct libusb_transfer *transfer)
 211 {
 212         struct usbi_transfer *itransfer = TRANSFER_TO_PRIV(transfer);
 213         int r;
 214
 215         usbi_dbg("");
 216         r = ioctl(devh->fd, IOCTL_USB_DISCARDURB, &itransfer->urb);
 217         if (r < 0)
 218                 usbi_err("cancel transfer failed error %d", r);
 219         return r;
 220 }
 221
 222 API_EXPORTED int libusb_cancel_transfer_sync(struct libusb_device_handle *devh,
 223         struct libusb_transfer *transfer)
 224 {
 225         struct usbi_transfer *itransfer = TRANSFER_TO_PRIV(transfer);
 226         int r;
 227
 228         usbi_dbg("");
 229         r = ioctl(devh->fd, IOCTL_USB_DISCARDURB, &itransfer->urb);
 230         if (r < 0) {
 231                 usbi_err("cancel transfer failed error %d", r);
 232                 return r;
 233         }
 234
 235         itransfer->flags |= USBI_TRANSFER_SYNC_CANCELLED;
 236         while (itransfer->flags & USBI_TRANSFER_SYNC_CANCELLED) {
 237                 r = libusb_poll();
 238                 if (r < 0)
 239                         return r;
 240         }
 241
 242         return 0;
 243 }
 244
 245 static void handle_transfer_completion(struct usbi_transfer *itransfer,
 246         enum libusb_transfer_status status)
 247 {
 248         struct libusb_transfer *transfer = &itransfer->pub;
 249
 250         if (status == LIBUSB_TRANSFER_SILENT_COMPLETION)
 251                 return;
 252
 253         transfer->status = status;
 254         transfer->actual_length = itransfer->transferred;
 255         if (transfer->callback)
 256                 transfer->callback(transfer);
 257 }
 258
 259 static void handle_transfer_cancellation(struct libusb_device_handle *devh,
 260         struct usbi_transfer *transfer)
 261 {
 262         /* if the URB is being cancelled synchronously, raise cancellation
 263          * completion event by unsetting flag, and ensure that user callback does
 264          * not get called.
 265          */
 266         if (transfer->flags & USBI_TRANSFER_SYNC_CANCELLED) {
 267                 transfer->flags &= ~USBI_TRANSFER_SYNC_CANCELLED;
 268                 usbi_dbg("detected sync. cancel");
 269                 handle_transfer_completion(transfer, LIBUSB_TRANSFER_SILENT_COMPLETION);
 270                 return;
 271         }
 272
 273         /* if the URB was cancelled due to timeout, report timeout to the user */
 274         if (transfer->flags & USBI_TRANSFER_TIMED_OUT) {
 275                 usbi_dbg("detected timeout cancellation");
 276                 handle_transfer_completion(transfer, LIBUSB_TRANSFER_TIMED_OUT);
 277                 return;
 278         }
 279
 280         /* otherwise its a normal async cancel */
 281         handle_transfer_completion(transfer, LIBUSB_TRANSFER_CANCELLED);
 282 }
 283
 284 static int reap_for_devh(struct libusb_device_handle *devh)
 285 {
 286         int r;
 287         struct usb_urb *urb;
 288         struct usbi_transfer *itransfer;
 289         struct libusb_transfer *transfer;
 290         int trf_requested;
 291         int length;
 292
 293         r = ioctl(devh->fd, IOCTL_USB_REAPURBNDELAY, &urb);
 294         if (r == -1 && errno == EAGAIN)
 295                 return r;
 296         if (r < 0) {
 297                 usbi_err("reap failed error %d errno=%d", r, errno);
 298                 return r;
 299         }
 300
 301         itransfer = container_of(urb, struct usbi_transfer, urb);
 302         transfer = &itransfer->pub;
 303
 304         usbi_dbg("urb type=%d status=%d transferred=%d", urb->type, urb->status,
 305                 urb->actual_length);
 306         list_del(&itransfer->list);
 307
 308         if (urb->status == -2) {
 309                 handle_transfer_cancellation(devh, itransfer);
 310                 return 0;
 311         }
 312
 313         /* FIXME: research what other status codes may exist */
 314         if (urb->status != 0)
 315                 usbi_warn("unrecognised urb status %d", urb->status);
 316
 317         /* determine how much data was asked for */
 318         length = transfer->length;
 319         if (transfer->endpoint_type == LIBUSB_ENDPOINT_TYPE_CONTROL)
 320                 length -= LIBUSB_CONTROL_SETUP_SIZE;
 321         trf_requested = MIN(length - itransfer->transferred,
 322                 MAX_URB_BUFFER_LENGTH);
 323
 324         itransfer->transferred += urb->actual_length;
 325
 326         /* if we were provided less data than requested, then our transfer is
 327          * done */
 328         if (urb->actual_length < trf_requested) {
 329                 usbi_dbg("less data than requested (%d/%d) --> all done",
 330                         urb->actual_length, trf_requested);
 331                 handle_transfer_completion(itransfer, LIBUSB_TRANSFER_COMPLETED);
 332                 return 0;
 333         }
 334
 335         /* if we've transferred all data, we're done */
 336         if (itransfer->transferred == length) {
 337                 usbi_dbg("transfer complete --> all done");
 338                 handle_transfer_completion(itransfer, LIBUSB_TRANSFER_COMPLETED);
 339                 return 0;
 340         }
 341
 342         /* otherwise, we have more data to transfer */
 343         usbi_dbg("more data to transfer...");
 344         memset(urb, 0, sizeof(*urb));
 345         return submit_transfer(itransfer);
 346 }
 347
 348 static void handle_timeout(struct usbi_transfer *itransfer)
 349 {
 350         /* handling timeouts is tricky, as we may race with the kernel: we may
 351          * detect a timeout racing with the condition that the urb has actually
 352          * completed. we asynchronously cancel the URB and report timeout
 353          * to the user when the URB cancellation completes (or not at all if the
 354          * URB actually gets delivered as per this race) */
 355         struct libusb_transfer *transfer = &itransfer->pub;
 356         int r;
 357
 358         itransfer->flags |= USBI_TRANSFER_TIMED_OUT;
 359         r = libusb_cancel_transfer(transfer->dev_handle, transfer);
 360         if (r < 0)
 361                 usbi_warn("async cancel failed %d errno=%d", r, errno);
 362 }
 363
 364 static int handle_timeouts(void)
 365 {
 366         struct timespec systime_ts;
 367         struct timeval systime;
 368         struct usbi_transfer *transfer;
 369         int r;
 370
 371         if (list_empty(&flying_transfers))
 372                 return 0;
 373
 374         /* get current time */
 375         r = clock_gettime(CLOCK_MONOTONIC, &systime_ts);
 376         if (r < 0)
 377                 return r;
 378
 379         TIMESPEC_TO_TIMEVAL(&systime, &systime_ts);
 380
 381         /* iterate through flying transfers list, finding all transfers that
 382          * have expired timeouts */
 383         list_for_each_entry(transfer, &flying_transfers, list) {
 384                 struct timeval *cur_tv = &transfer->timeout;
 385
 386                 /* if we've reached transfers of infinite timeout, we're all done */
 387                 if (!timerisset(cur_tv))
 388                         return 0;
 389
 390                 /* ignore timeouts we've already handled */
 391                 if (transfer->flags & USBI_TRANSFER_TIMED_OUT)
 392                         continue;
 393
 394                 /* if transfer has non-expired timeout, nothing more to do */
 395                 if ((cur_tv->tv_sec > systime.tv_sec) ||
 396                                 (cur_tv->tv_sec == systime.tv_sec &&
 397                                         cur_tv->tv_usec > systime.tv_usec))
 398                         return 0;
 399
 400                 /* otherwise, we've got an expired timeout to handle */
 401                 handle_timeout(transfer);
 402         }
 403
 404         return 0;
 405 }
 406
 407 static int poll_io(struct timeval *tv)
 408 {
 409         struct libusb_device_handle *devh;
 410         int r;
 411         int maxfd = 0;
 412         fd_set writefds;
 413         struct timeval select_timeout;
 414         struct timeval timeout;
 415
 416         r = libusb_get_next_timeout(&timeout);
 417         if (r) {
 418                 /* timeout already expired? */
 419                 if (!timerisset(&timeout))
 420                         return handle_timeouts();
 421
 422                 /* choose the smallest of next URB timeout or user specified timeout */
 423                 if (timercmp(&timeout, tv, <))
 424                         select_timeout = timeout;
 425                 else
 426                         select_timeout = *tv;
 427         } else {
 428                 select_timeout = *tv;
 429         }
 430
 431         FD_ZERO(&writefds);
 432         list_for_each_entry(devh, &open_devs, list) {
 433                 int fd = devh->fd;
 434                 FD_SET(fd, &writefds);
 435                 if (fd > maxfd)
 436                         maxfd = fd;
 437         }
 438
 439         usbi_dbg("select() with timeout in %d.%06ds", select_timeout.tv_sec,
 440                 select_timeout.tv_usec);
 441         r = select(maxfd + 1, NULL, &writefds, NULL, &select_timeout);
 442         usbi_dbg("select() returned %d with %d.%06ds remaining", r, select_timeout.tv_sec,
 443                 select_timeout.tv_usec);
 444         if (r == 0) {
 445                 *tv = select_timeout;
 446                 return handle_timeouts();
 447         } else if (r == -1 && errno == EINTR) {
 448                 return 0;
 449         } else if (r < 0) {
 450                 usbi_err("select failed %d err=%d\n", r, errno);
 451                 return r;
 452         }
 453
 454         list_for_each_entry(devh, &open_devs, list) {
 455                 if (!FD_ISSET(devh->fd, &writefds))
 456                         continue;
 457                 r = reap_for_devh(devh);
 458                 if (r == -1 && errno == EAGAIN)
 459                         continue;
 460                 if (r < 0)
 461                         return r;
 462         }
 463
 464         /* FIXME check return value? */
 465         return handle_timeouts();
 466 }
 467
 468 API_EXPORTED int libusb_poll_timeout(struct timeval *tv)
 469 {
 470         return poll_io(tv);
 471 }
 472
 473 API_EXPORTED int libusb_poll(void)
 474 {
 475         struct timeval tv;
 476         tv.tv_sec = 2;
 477         tv.tv_usec = 0;
 478         return poll_io(&tv);
 479 }
 480
 481 API_EXPORTED int libusb_get_next_timeout(struct timeval *tv)
 482 {
 483         struct usbi_transfer *transfer;
 484         struct timespec cur_ts;
 485         struct timeval cur_tv;
 486         struct timeval *next_timeout;
 487         int r;
 488         int found = 0;
 489
 490         if (list_empty(&flying_transfers)) {
 491                 usbi_dbg("no URBs, no timeout!");
 492                 return 0;
 493         }
 494
 495         /* find next transfer which hasn't already been processed as timed out */
 496         list_for_each_entry(transfer, &flying_transfers, list) {
 497                 if (!(transfer->flags & USBI_TRANSFER_TIMED_OUT)) {
 498                         found = 1;
 499                         break;
 500                 }
 501         }
 502
 503         if (!found) {
 504                 usbi_dbg("all URBs have already been processed for timeouts");
 505                 return 0;
 506         }
 507
 508         next_timeout = &transfer->timeout;
 509
 510         /* no timeout for next transfer */
 511         if (!timerisset(next_timeout)) {
 512                 usbi_dbg("no URBs with timeouts, no timeout!");
 513                 return 0;
 514         }
 515
 516         r = clock_gettime(CLOCK_MONOTONIC, &cur_ts);
 517         if (r < 0) {
 518                 usbi_err("failed to read monotonic clock, errno=%d", errno);
 519                 return r;
 520         }
 521         TIMESPEC_TO_TIMEVAL(&cur_tv, &cur_ts);
 522
 523         if (timercmp(&cur_tv, next_timeout, >=)) {
 524                 usbi_dbg("first timeout already expired");
 525                 timerclear(tv);
 526         } else {
 527                 timersub(next_timeout, &cur_tv, tv);
 528                 usbi_dbg("next timeout in %d.%06ds", tv->tv_sec, tv->tv_usec);
 529         }
 530
 531         return 1;
 532 }
 533
 534 API_EXPORTED void libusb_free_transfer(struct libusb_transfer *transfer)
 535 {
 536         struct usbi_transfer *itransfer;
 537         if (!transfer)
 538                 return;
 539
 540         itransfer = TRANSFER_TO_PRIV(transfer);
 541         free(itransfer);
 542 }
 543
 544 API_EXPORTED void libusb_set_pollfd_notifiers(libusb_pollfd_added_cb added_cb,
 545         libusb_pollfd_removed_cb removed_cb)
 546 {
 547         fd_added_cb = added_cb;
 548         fd_removed_cb = removed_cb;
 549 }
 550
 551 void usbi_add_pollfd(int fd, short events)
 552 {
 553         usbi_dbg("add fd %d events %d", fd, events);
 554         if (fd_added_cb)
 555                 fd_added_cb(fd, events);
 556 }
 557
 558 void usbi_remove_pollfd(int fd)
 559 {
 560         usbi_dbg("remove fd %d", fd);
 561         if (fd_removed_cb)
 562                 fd_removed_cb(fd);
 563 }
 564