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_transfer *transfer)
 210 {
 211         struct usbi_transfer *itransfer = TRANSFER_TO_PRIV(transfer);
 212         int r;
 213
 214         usbi_dbg("");
 215         r = ioctl(transfer->dev_handle->fd, IOCTL_USB_DISCARDURB, &itransfer->urb);
 216         if (r < 0)
 217                 usbi_err("cancel transfer failed error %d", r);
 218         return r;
 219 }
 220
 221 API_EXPORTED int libusb_cancel_transfer_sync(struct libusb_transfer *transfer)
 222 {
 223         struct usbi_transfer *itransfer = TRANSFER_TO_PRIV(transfer);
 224         int r;
 225
 226         usbi_dbg("");
 227         r = ioctl(transfer->dev_handle->fd, IOCTL_USB_DISCARDURB, &itransfer->urb);
 228         if (r < 0) {
 229                 usbi_err("cancel transfer failed error %d", r);
 230                 return r;
 231         }
 232
 233         itransfer->flags |= USBI_TRANSFER_SYNC_CANCELLED;
 234         while (itransfer->flags & USBI_TRANSFER_SYNC_CANCELLED) {
 235                 r = libusb_poll();
 236                 if (r < 0)
 237                         return r;
 238         }
 239
 240         return 0;
 241 }
 242
 243 static void handle_transfer_completion(struct usbi_transfer *itransfer,
 244         enum libusb_transfer_status status)
 245 {
 246         struct libusb_transfer *transfer = &itransfer->pub;
 247
 248         if (status == LIBUSB_TRANSFER_SILENT_COMPLETION)
 249                 return;
 250
 251         transfer->status = status;
 252         transfer->actual_length = itransfer->transferred;
 253         if (transfer->callback)
 254                 transfer->callback(transfer);
 255 }
 256
 257 static void handle_transfer_cancellation(struct usbi_transfer *transfer)
 258 {
 259         /* if the URB is being cancelled synchronously, raise cancellation
 260          * completion event by unsetting flag, and ensure that user callback does
 261          * not get called.
 262          */
 263         if (transfer->flags & USBI_TRANSFER_SYNC_CANCELLED) {
 264                 transfer->flags &= ~USBI_TRANSFER_SYNC_CANCELLED;
 265                 usbi_dbg("detected sync. cancel");
 266                 handle_transfer_completion(transfer, LIBUSB_TRANSFER_SILENT_COMPLETION);
 267                 return;
 268         }
 269
 270         /* if the URB was cancelled due to timeout, report timeout to the user */
 271         if (transfer->flags & USBI_TRANSFER_TIMED_OUT) {
 272                 usbi_dbg("detected timeout cancellation");
 273                 handle_transfer_completion(transfer, LIBUSB_TRANSFER_TIMED_OUT);
 274                 return;
 275         }
 276
 277         /* otherwise its a normal async cancel */
 278         handle_transfer_completion(transfer, LIBUSB_TRANSFER_CANCELLED);
 279 }
 280
 281 static int reap_for_devh(struct libusb_device_handle *devh)
 282 {
 283         int r;
 284         struct usb_urb *urb;
 285         struct usbi_transfer *itransfer;
 286         struct libusb_transfer *transfer;
 287         int trf_requested;
 288         int length;
 289
 290         r = ioctl(devh->fd, IOCTL_USB_REAPURBNDELAY, &urb);
 291         if (r == -1 && errno == EAGAIN)
 292                 return r;
 293         if (r < 0) {
 294                 usbi_err("reap failed error %d errno=%d", r, errno);
 295                 return r;
 296         }
 297
 298         itransfer = container_of(urb, struct usbi_transfer, urb);
 299         transfer = &itransfer->pub;
 300
 301         usbi_dbg("urb type=%d status=%d transferred=%d", urb->type, urb->status,
 302                 urb->actual_length);
 303         list_del(&itransfer->list);
 304
 305         if (urb->status == -2) {
 306                 handle_transfer_cancellation(itransfer);
 307                 return 0;
 308         }
 309
 310         /* FIXME: research what other status codes may exist */
 311         if (urb->status != 0)
 312                 usbi_warn("unrecognised urb status %d", urb->status);
 313
 314         /* determine how much data was asked for */
 315         length = transfer->length;
 316         if (transfer->endpoint_type == LIBUSB_ENDPOINT_TYPE_CONTROL)
 317                 length -= LIBUSB_CONTROL_SETUP_SIZE;
 318         trf_requested = MIN(length - itransfer->transferred,
 319                 MAX_URB_BUFFER_LENGTH);
 320
 321         itransfer->transferred += urb->actual_length;
 322
 323         /* if we were provided less data than requested, then our transfer is
 324          * done */
 325         if (urb->actual_length < trf_requested) {
 326                 usbi_dbg("less data than requested (%d/%d) --> all done",
 327                         urb->actual_length, trf_requested);
 328                 handle_transfer_completion(itransfer, LIBUSB_TRANSFER_COMPLETED);
 329                 return 0;
 330         }
 331
 332         /* if we've transferred all data, we're done */
 333         if (itransfer->transferred == length) {
 334                 usbi_dbg("transfer complete --> all done");
 335                 handle_transfer_completion(itransfer, LIBUSB_TRANSFER_COMPLETED);
 336                 return 0;
 337         }
 338
 339         /* otherwise, we have more data to transfer */
 340         usbi_dbg("more data to transfer...");
 341         memset(urb, 0, sizeof(*urb));
 342         return submit_transfer(itransfer);
 343 }
 344
 345 static void handle_timeout(struct usbi_transfer *itransfer)
 346 {
 347         /* handling timeouts is tricky, as we may race with the kernel: we may
 348          * detect a timeout racing with the condition that the urb has actually
 349          * completed. we asynchronously cancel the URB and report timeout
 350          * to the user when the URB cancellation completes (or not at all if the
 351          * URB actually gets delivered as per this race) */
 352         struct libusb_transfer *transfer = &itransfer->pub;
 353         int r;
 354
 355         itransfer->flags |= USBI_TRANSFER_TIMED_OUT;
 356         r = libusb_cancel_transfer(transfer);
 357         if (r < 0)
 358                 usbi_warn("async cancel failed %d errno=%d", r, errno);
 359 }
 360
 361 static int handle_timeouts(void)
 362 {
 363         struct timespec systime_ts;
 364         struct timeval systime;
 365         struct usbi_transfer *transfer;
 366         int r;
 367
 368         if (list_empty(&flying_transfers))
 369                 return 0;
 370
 371         /* get current time */
 372         r = clock_gettime(CLOCK_MONOTONIC, &systime_ts);
 373         if (r < 0)
 374                 return r;
 375
 376         TIMESPEC_TO_TIMEVAL(&systime, &systime_ts);
 377
 378         /* iterate through flying transfers list, finding all transfers that
 379          * have expired timeouts */
 380         list_for_each_entry(transfer, &flying_transfers, list) {
 381                 struct timeval *cur_tv = &transfer->timeout;
 382
 383                 /* if we've reached transfers of infinite timeout, we're all done */
 384                 if (!timerisset(cur_tv))
 385                         return 0;
 386
 387                 /* ignore timeouts we've already handled */
 388                 if (transfer->flags & USBI_TRANSFER_TIMED_OUT)
 389                         continue;
 390
 391                 /* if transfer has non-expired timeout, nothing more to do */
 392                 if ((cur_tv->tv_sec > systime.tv_sec) ||
 393                                 (cur_tv->tv_sec == systime.tv_sec &&
 394                                         cur_tv->tv_usec > systime.tv_usec))
 395                         return 0;
 396
 397                 /* otherwise, we've got an expired timeout to handle */
 398                 handle_timeout(transfer);
 399         }
 400
 401         return 0;
 402 }
 403
 404 static int poll_io(struct timeval *tv)
 405 {
 406         struct libusb_device_handle *devh;
 407         int r;
 408         int maxfd = 0;
 409         fd_set writefds;
 410         struct timeval select_timeout;
 411         struct timeval timeout;
 412
 413         r = libusb_get_next_timeout(&timeout);
 414         if (r) {
 415                 /* timeout already expired? */
 416                 if (!timerisset(&timeout))
 417                         return handle_timeouts();
 418
 419                 /* choose the smallest of next URB timeout or user specified timeout */
 420                 if (timercmp(&timeout, tv, <))
 421                         select_timeout = timeout;
 422                 else
 423                         select_timeout = *tv;
 424         } else {
 425                 select_timeout = *tv;
 426         }
 427
 428         FD_ZERO(&writefds);
 429         list_for_each_entry(devh, &open_devs, list) {
 430                 int fd = devh->fd;
 431                 FD_SET(fd, &writefds);
 432                 if (fd > maxfd)
 433                         maxfd = fd;
 434         }
 435
 436         usbi_dbg("select() with timeout in %d.%06ds", select_timeout.tv_sec,
 437                 select_timeout.tv_usec);
 438         r = select(maxfd + 1, NULL, &writefds, NULL, &select_timeout);
 439         usbi_dbg("select() returned %d with %d.%06ds remaining", r, select_timeout.tv_sec,
 440                 select_timeout.tv_usec);
 441         if (r == 0) {
 442                 *tv = select_timeout;
 443                 return handle_timeouts();
 444         } else if (r == -1 && errno == EINTR) {
 445                 return 0;
 446         } else if (r < 0) {
 447                 usbi_err("select failed %d err=%d\n", r, errno);
 448                 return r;
 449         }
 450
 451         list_for_each_entry(devh, &open_devs, list) {
 452                 if (!FD_ISSET(devh->fd, &writefds))
 453                         continue;
 454                 r = reap_for_devh(devh);
 455                 if (r == -1 && errno == EAGAIN)
 456                         continue;
 457                 if (r < 0)
 458                         return r;
 459         }
 460
 461         /* FIXME check return value? */
 462         return handle_timeouts();
 463 }
 464
 465 API_EXPORTED int libusb_poll_timeout(struct timeval *tv)
 466 {
 467         return poll_io(tv);
 468 }
 469
 470 API_EXPORTED int libusb_poll(void)
 471 {
 472         struct timeval tv;
 473         tv.tv_sec = 2;
 474         tv.tv_usec = 0;
 475         return poll_io(&tv);
 476 }
 477
 478 API_EXPORTED int libusb_get_next_timeout(struct timeval *tv)
 479 {
 480         struct usbi_transfer *transfer;
 481         struct timespec cur_ts;
 482         struct timeval cur_tv;
 483         struct timeval *next_timeout;
 484         int r;
 485         int found = 0;
 486
 487         if (list_empty(&flying_transfers)) {
 488                 usbi_dbg("no URBs, no timeout!");
 489                 return 0;
 490         }
 491
 492         /* find next transfer which hasn't already been processed as timed out */
 493         list_for_each_entry(transfer, &flying_transfers, list) {
 494                 if (!(transfer->flags & USBI_TRANSFER_TIMED_OUT)) {
 495                         found = 1;
 496                         break;
 497                 }
 498         }
 499
 500         if (!found) {
 501                 usbi_dbg("all URBs have already been processed for timeouts");
 502                 return 0;
 503         }
 504
 505         next_timeout = &transfer->timeout;
 506
 507         /* no timeout for next transfer */
 508         if (!timerisset(next_timeout)) {
 509                 usbi_dbg("no URBs with timeouts, no timeout!");
 510                 return 0;
 511         }
 512
 513         r = clock_gettime(CLOCK_MONOTONIC, &cur_ts);
 514         if (r < 0) {
 515                 usbi_err("failed to read monotonic clock, errno=%d", errno);
 516                 return r;
 517         }
 518         TIMESPEC_TO_TIMEVAL(&cur_tv, &cur_ts);
 519
 520         if (timercmp(&cur_tv, next_timeout, >=)) {
 521                 usbi_dbg("first timeout already expired");
 522                 timerclear(tv);
 523         } else {
 524                 timersub(next_timeout, &cur_tv, tv);
 525                 usbi_dbg("next timeout in %d.%06ds", tv->tv_sec, tv->tv_usec);
 526         }
 527
 528         return 1;
 529 }
 530
 531 API_EXPORTED void libusb_free_transfer(struct libusb_transfer *transfer)
 532 {
 533         struct usbi_transfer *itransfer;
 534         if (!transfer)
 535                 return;
 536
 537         itransfer = TRANSFER_TO_PRIV(transfer);
 538         free(itransfer);
 539 }
 540
 541 API_EXPORTED void libusb_set_pollfd_notifiers(libusb_pollfd_added_cb added_cb,
 542         libusb_pollfd_removed_cb removed_cb)
 543 {
 544         fd_added_cb = added_cb;
 545         fd_removed_cb = removed_cb;
 546 }
 547
 548 void usbi_add_pollfd(int fd, short events)
 549 {
 550         usbi_dbg("add fd %d events %d", fd, events);
 551         if (fd_added_cb)
 552                 fd_added_cb(fd, events);
 553 }
 554
 555 void usbi_remove_pollfd(int fd)
 556 {
 557         usbi_dbg("remove fd %d", fd);
 558         if (fd_removed_cb)
 559                 fd_removed_cb(fd);
 560 }
 561