drivers/input/evdev.c

   1 /*
   2  * Event char devices, giving access to raw input device events.
   3  *
   4  * Copyright (c) 1999-2002 Vojtech Pavlik
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 as published by
   8  * the Free Software Foundation.
   9  */
  10
  11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  12
  13 #define EVDEV_MINOR_BASE        64
  14 #define EVDEV_MINORS            32
  15 #define EVDEV_MIN_BUFFER_SIZE   64U
  16 #define EVDEV_BUF_PACKETS       8
  17
  18 #include <linux/poll.h>
  19 #include <linux/sched.h>
  20 #include <linux/slab.h>
  21 #include <linux/vmalloc.h>
  22 #include <linux/mm.h>
  23 #include <linux/module.h>
  24 #include <linux/init.h>
  25 #include <linux/input/mt.h>
  26 #include <linux/major.h>
  27 #include <linux/device.h>
  28 #include <linux/cdev.h>
  29 #include "input-compat.h"
  30
  31 enum evdev_clock_type {
  32         EV_CLK_REAL = 0,
  33         EV_CLK_MONO,
  34         EV_CLK_BOOT,
  35         EV_CLK_MAX
  36 };
  37
  38 struct evdev {
  39         int open;
  40         struct input_handle handle;
  41         wait_queue_head_t wait;
  42         struct evdev_client __rcu *grab;
  43         struct list_head client_list;
  44         spinlock_t client_lock; /* protects client_list */
  45         struct mutex mutex;
  46         struct device dev;
  47         struct cdev cdev;
  48         bool exist;
  49 };
  50
  51 struct evdev_client {
  52         unsigned int head;
  53         unsigned int tail;
  54         unsigned int packet_head; /* [future] position of the first element of next packet */
  55         spinlock_t buffer_lock; /* protects access to buffer, head and tail */
  56         struct fasync_struct *fasync;
  57         struct evdev *evdev;
  58         struct list_head node;
  59         int clk_type;
  60         bool revoked;
  61         unsigned int bufsize;
  62         struct input_event buffer[];
  63 };
  64
  65 /* flush queued events of type @type, caller must hold client->buffer_lock */
  66 static void __evdev_flush_queue(struct evdev_client *client, unsigned int type)
  67 {
  68         unsigned int i, head, num;
  69         unsigned int mask = client->bufsize - 1;
  70         bool is_report;
  71         struct input_event *ev;
  72
  73         BUG_ON(type == EV_SYN);
  74
  75         head = client->tail;
  76         client->packet_head = client->tail;
  77
  78         /* init to 1 so a leading SYN_REPORT will not be dropped */
  79         num = 1;
  80
  81         for (i = client->tail; i != client->head; i = (i + 1) & mask) {
  82                 ev = &client->buffer[i];
  83                 is_report = ev->type == EV_SYN && ev->code == SYN_REPORT;
  84
  85                 if (ev->type == type) {
  86                         /* drop matched entry */
  87                         continue;
  88                 } else if (is_report && !num) {
  89                         /* drop empty SYN_REPORT groups */
  90                         continue;
  91                 } else if (head != i) {
  92                         /* move entry to fill the gap */
  93                         client->buffer[head].time = ev->time;
  94                         client->buffer[head].type = ev->type;
  95                         client->buffer[head].code = ev->code;
  96                         client->buffer[head].value = ev->value;
  97                 }
  98
  99                 num++;
 100                 head = (head + 1) & mask;
 101
 102                 if (is_report) {
 103                         num = 0;
 104                         client->packet_head = head;
 105                 }
 106         }
 107
 108         client->head = head;
 109 }
 110
 111 static void __evdev_queue_syn_dropped(struct evdev_client *client)
 112 {
 113         struct input_event ev;
 114         ktime_t time;
 115
 116         time = client->clk_type == EV_CLK_REAL ?
 117                         ktime_get_real() :
 118                         client->clk_type == EV_CLK_MONO ?
 119                                 ktime_get() :
 120                                 ktime_get_boottime();
 121
 122         ev.time = ktime_to_timeval(time);
 123         ev.type = EV_SYN;
 124         ev.code = SYN_DROPPED;
 125         ev.value = 0;
 126
 127         client->buffer[client->head++] = ev;
 128         client->head &= client->bufsize - 1;
 129
 130         if (unlikely(client->head == client->tail)) {
 131                 /* drop queue but keep our SYN_DROPPED event */
 132                 client->tail = (client->head - 1) & (client->bufsize - 1);
 133                 client->packet_head = client->tail;
 134         }
 135 }
 136
 137 static void evdev_queue_syn_dropped(struct evdev_client *client)
 138 {
 139         unsigned long flags;
 140
 141         spin_lock_irqsave(&client->buffer_lock, flags);
 142         __evdev_queue_syn_dropped(client);
 143         spin_unlock_irqrestore(&client->buffer_lock, flags);
 144 }
 145
 146 static int evdev_set_clk_type(struct evdev_client *client, unsigned int clkid)
 147 {
 148         unsigned long flags;
 149
 150         if (client->clk_type == clkid)
 151                 return 0;
 152
 153         switch (clkid) {
 154
 155         case CLOCK_REALTIME:
 156                 client->clk_type = EV_CLK_REAL;
 157                 break;
 158         case CLOCK_MONOTONIC:
 159                 client->clk_type = EV_CLK_MONO;
 160                 break;
 161         case CLOCK_BOOTTIME:
 162                 client->clk_type = EV_CLK_BOOT;
 163                 break;
 164         default:
 165                 return -EINVAL;
 166         }
 167
 168         /*
 169          * Flush pending events and queue SYN_DROPPED event,
 170          * but only if the queue is not empty.
 171          */
 172         spin_lock_irqsave(&client->buffer_lock, flags);
 173
 174         if (client->head != client->tail) {
 175                 client->packet_head = client->head = client->tail;
 176                 __evdev_queue_syn_dropped(client);
 177         }
 178
 179         spin_unlock_irqrestore(&client->buffer_lock, flags);
 180
 181         return 0;
 182 }
 183
 184 static void __pass_event(struct evdev_client *client,
 185                          const struct input_event *event)
 186 {
 187         client->buffer[client->head++] = *event;
 188         client->head &= client->bufsize - 1;
 189
 190         if (unlikely(client->head == client->tail)) {
 191                 /*
 192                  * This effectively "drops" all unconsumed events, leaving
 193                  * EV_SYN/SYN_DROPPED plus the newest event in the queue.
 194                  */
 195                 client->tail = (client->head - 2) & (client->bufsize - 1);
 196
 197                 client->buffer[client->tail].time = event->time;
 198                 client->buffer[client->tail].type = EV_SYN;
 199                 client->buffer[client->tail].code = SYN_DROPPED;
 200                 client->buffer[client->tail].value = 0;
 201
 202                 client->packet_head = client->tail;
 203         }
 204
 205         if (event->type == EV_SYN && event->code == SYN_REPORT) {
 206                 client->packet_head = client->head;
 207                 kill_fasync(&client->fasync, SIGIO, POLL_IN);
 208         }
 209 }
 210
 211 static void evdev_pass_values(struct evdev_client *client,
 212                         const struct input_value *vals, unsigned int count,
 213                         ktime_t *ev_time)
 214 {
 215         struct evdev *evdev = client->evdev;
 216         const struct input_value *v;
 217         struct input_event event;
 218         bool wakeup = false;
 219
 220         if (client->revoked)
 221                 return;
 222
 223         event.time = ktime_to_timeval(ev_time[client->clk_type]);
 224
 225         /* Interrupts are disabled, just acquire the lock. */
 226         spin_lock(&client->buffer_lock);
 227
 228         for (v = vals; v != vals + count; v++) {
 229                 event.type = v->type;
 230                 event.code = v->code;
 231                 event.value = v->value;
 232                 __pass_event(client, &event);
 233                 if (v->type == EV_SYN && v->code == SYN_REPORT)
 234                         wakeup = true;
 235         }
 236
 237         spin_unlock(&client->buffer_lock);
 238
 239         if (wakeup)
 240                 wake_up_interruptible(&evdev->wait);
 241 }
 242
 243 /*
 244  * Pass incoming events to all connected clients.
 245  */
 246 static void evdev_events(struct input_handle *handle,
 247                          const struct input_value *vals, unsigned int count)
 248 {
 249         struct evdev *evdev = handle->private;
 250         struct evdev_client *client;
 251         ktime_t ev_time[EV_CLK_MAX];
 252
 253         ev_time[EV_CLK_MONO] = ktime_get();
 254         ev_time[EV_CLK_REAL] = ktime_mono_to_real(ev_time[EV_CLK_MONO]);
 255         ev_time[EV_CLK_BOOT] = ktime_mono_to_any(ev_time[EV_CLK_MONO],
 256                                                  TK_OFFS_BOOT);
 257
 258         rcu_read_lock();
 259
 260         client = rcu_dereference(evdev->grab);
 261
 262         if (client)
 263                 evdev_pass_values(client, vals, count, ev_time);
 264         else
 265                 list_for_each_entry_rcu(client, &evdev->client_list, node)
 266                         evdev_pass_values(client, vals, count, ev_time);
 267
 268         rcu_read_unlock();
 269 }
 270
 271 /*
 272  * Pass incoming event to all connected clients.
 273  */
 274 static void evdev_event(struct input_handle *handle,
 275                         unsigned int type, unsigned int code, int value)
 276 {
 277         struct input_value vals[] = { { type, code, value } };
 278
 279         evdev_events(handle, vals, 1);
 280 }
 281
 282 static int evdev_fasync(int fd, struct file *file, int on)
 283 {
 284         struct evdev_client *client = file->private_data;
 285
 286         return fasync_helper(fd, file, on, &client->fasync);
 287 }
 288
 289 static int evdev_flush(struct file *file, fl_owner_t id)
 290 {
 291         struct evdev_client *client = file->private_data;
 292         struct evdev *evdev = client->evdev;
 293
 294         mutex_lock(&evdev->mutex);
 295
 296         if (evdev->exist && !client->revoked)
 297                 input_flush_device(&evdev->handle, file);
 298
 299         mutex_unlock(&evdev->mutex);
 300         return 0;
 301 }
 302
 303 static void evdev_free(struct device *dev)
 304 {
 305         struct evdev *evdev = container_of(dev, struct evdev, dev);
 306
 307         input_put_device(evdev->handle.dev);
 308         kfree(evdev);
 309 }
 310
 311 /*
 312  * Grabs an event device (along with underlying input device).
 313  * This function is called with evdev->mutex taken.
 314  */
 315 static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
 316 {
 317         int error;
 318
 319         if (evdev->grab)
 320                 return -EBUSY;
 321
 322         error = input_grab_device(&evdev->handle);
 323         if (error)
 324                 return error;
 325
 326         rcu_assign_pointer(evdev->grab, client);
 327
 328         return 0;
 329 }
 330
 331 static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
 332 {
 333         struct evdev_client *grab = rcu_dereference_protected(evdev->grab,
 334                                         lockdep_is_held(&evdev->mutex));
 335
 336         if (grab != client)
 337                 return  -EINVAL;
 338
 339         rcu_assign_pointer(evdev->grab, NULL);
 340         synchronize_rcu();
 341         input_release_device(&evdev->handle);
 342
 343         return 0;
 344 }
 345
 346 static void evdev_attach_client(struct evdev *evdev,
 347                                 struct evdev_client *client)
 348 {
 349         spin_lock(&evdev->client_lock);
 350         list_add_tail_rcu(&client->node, &evdev->client_list);
 351         spin_unlock(&evdev->client_lock);
 352 }
 353
 354 static void evdev_detach_client(struct evdev *evdev,
 355                                 struct evdev_client *client)
 356 {
 357         spin_lock(&evdev->client_lock);
 358         list_del_rcu(&client->node);
 359         spin_unlock(&evdev->client_lock);
 360         synchronize_rcu();
 361 }
 362
 363 static int evdev_open_device(struct evdev *evdev)
 364 {
 365         int retval;
 366
 367         retval = mutex_lock_interruptible(&evdev->mutex);
 368         if (retval)
 369                 return retval;
 370
 371         if (!evdev->exist)
 372                 retval = -ENODEV;
 373         else if (!evdev->open++) {
 374                 retval = input_open_device(&evdev->handle);
 375                 if (retval)
 376                         evdev->open--;
 377         }
 378
 379         mutex_unlock(&evdev->mutex);
 380         return retval;
 381 }
 382
 383 static void evdev_close_device(struct evdev *evdev)
 384 {
 385         mutex_lock(&evdev->mutex);
 386
 387         if (evdev->exist && !--evdev->open)
 388                 input_close_device(&evdev->handle);
 389
 390         mutex_unlock(&evdev->mutex);
 391 }
 392
 393 /*
 394  * Wake up users waiting for IO so they can disconnect from
 395  * dead device.
 396  */
 397 static void evdev_hangup(struct evdev *evdev)
 398 {
 399         struct evdev_client *client;
 400
 401         spin_lock(&evdev->client_lock);
 402         list_for_each_entry(client, &evdev->client_list, node)
 403                 kill_fasync(&client->fasync, SIGIO, POLL_HUP);
 404         spin_unlock(&evdev->client_lock);
 405
 406         wake_up_interruptible(&evdev->wait);
 407 }
 408
 409 static int evdev_release(struct inode *inode, struct file *file)
 410 {
 411         struct evdev_client *client = file->private_data;
 412         struct evdev *evdev = client->evdev;
 413
 414         mutex_lock(&evdev->mutex);
 415         evdev_ungrab(evdev, client);
 416         mutex_unlock(&evdev->mutex);
 417
 418         evdev_detach_client(evdev, client);
 419
 420         kvfree(client);
 421
 422         evdev_close_device(evdev);
 423
 424         return 0;
 425 }
 426
 427 static unsigned int evdev_compute_buffer_size(struct input_dev *dev)
 428 {
 429         unsigned int n_events =
 430                 max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS,
 431                     EVDEV_MIN_BUFFER_SIZE);
 432
 433         return roundup_pow_of_two(n_events);
 434 }
 435
 436 static int evdev_open(struct inode *inode, struct file *file)
 437 {
 438         struct evdev *evdev = container_of(inode->i_cdev, struct evdev, cdev);
 439         unsigned int bufsize = evdev_compute_buffer_size(evdev->handle.dev);
 440         unsigned int size = sizeof(struct evdev_client) +
 441                                         bufsize * sizeof(struct input_event);
 442         struct evdev_client *client;
 443         int error;
 444
 445         client = kzalloc(size, GFP_KERNEL | __GFP_NOWARN);
 446         if (!client)
 447                 client = vzalloc(size);
 448         if (!client)
 449                 return -ENOMEM;
 450
 451         client->bufsize = bufsize;
 452         spin_lock_init(&client->buffer_lock);
 453         client->evdev = evdev;
 454         evdev_attach_client(evdev, client);
 455
 456         error = evdev_open_device(evdev);
 457         if (error)
 458                 goto err_free_client;
 459
 460         file->private_data = client;
 461         nonseekable_open(inode, file);
 462
 463         return 0;
 464
 465  err_free_client:
 466         evdev_detach_client(evdev, client);
 467         kvfree(client);
 468         return error;
 469 }
 470
 471 static ssize_t evdev_write(struct file *file, const char __user *buffer,
 472                            size_t count, loff_t *ppos)
 473 {
 474         struct evdev_client *client = file->private_data;
 475         struct evdev *evdev = client->evdev;
 476         struct input_event event;
 477         int retval = 0;
 478
 479         if (count != 0 && count < input_event_size())
 480                 return -EINVAL;
 481
 482         retval = mutex_lock_interruptible(&evdev->mutex);
 483         if (retval)
 484                 return retval;
 485
 486         if (!evdev->exist || client->revoked) {
 487                 retval = -ENODEV;
 488                 goto out;
 489         }
 490
 491         while (retval + input_event_size() <= count) {
 492
 493                 if (input_event_from_user(buffer + retval, &event)) {
 494                         retval = -EFAULT;
 495                         goto out;
 496                 }
 497                 retval += input_event_size();
 498
 499                 input_inject_event(&evdev->handle,
 500                                    event.type, event.code, event.value);
 501         }
 502
 503  out:
 504         mutex_unlock(&evdev->mutex);
 505         return retval;
 506 }
 507
 508 static int evdev_fetch_next_event(struct evdev_client *client,
 509                                   struct input_event *event)
 510 {
 511         int have_event;
 512
 513         spin_lock_irq(&client->buffer_lock);
 514
 515         have_event = client->packet_head != client->tail;
 516         if (have_event) {
 517                 *event = client->buffer[client->tail++];
 518                 client->tail &= client->bufsize - 1;
 519         }
 520
 521         spin_unlock_irq(&client->buffer_lock);
 522
 523         return have_event;
 524 }
 525
 526 static ssize_t evdev_read(struct file *file, char __user *buffer,
 527                           size_t count, loff_t *ppos)
 528 {
 529         struct evdev_client *client = file->private_data;
 530         struct evdev *evdev = client->evdev;
 531         struct input_event event;
 532         size_t read = 0;
 533         int error;
 534
 535         if (count != 0 && count < input_event_size())
 536                 return -EINVAL;
 537
 538         for (;;) {
 539                 if (!evdev->exist || client->revoked)
 540                         return -ENODEV;
 541
 542                 if (client->packet_head == client->tail &&
 543                     (file->f_flags & O_NONBLOCK))
 544                         return -EAGAIN;
 545
 546                 /*
 547                  * count == 0 is special - no IO is done but we check
 548                  * for error conditions (see above).
 549                  */
 550                 if (count == 0)
 551                         break;
 552
 553                 while (read + input_event_size() <= count &&
 554                        evdev_fetch_next_event(client, &event)) {
 555
 556                         if (input_event_to_user(buffer + read, &event))
 557                                 return -EFAULT;
 558
 559                         read += input_event_size();
 560                 }
 561
 562                 if (read)
 563                         break;
 564
 565                 if (!(file->f_flags & O_NONBLOCK)) {
 566                         error = wait_event_interruptible(evdev->wait,
 567                                         client->packet_head != client->tail ||
 568                                         !evdev->exist || client->revoked);
 569                         if (error)
 570                                 return error;
 571                 }
 572         }
 573
 574         return read;
 575 }
 576
 577 /* No kernel lock - fine */
 578 static unsigned int evdev_poll(struct file *file, poll_table *wait)
 579 {
 580         struct evdev_client *client = file->private_data;
 581         struct evdev *evdev = client->evdev;
 582         unsigned int mask;
 583
 584         poll_wait(file, &evdev->wait, wait);
 585
 586         if (evdev->exist && !client->revoked)
 587                 mask = POLLOUT | POLLWRNORM;
 588         else
 589                 mask = POLLHUP | POLLERR;
 590
 591         if (client->packet_head != client->tail)
 592                 mask |= POLLIN | POLLRDNORM;
 593
 594         return mask;
 595 }
 596
 597 #ifdef CONFIG_COMPAT
 598
 599 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
 600 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
 601
 602 #ifdef __BIG_ENDIAN
 603 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 604                         unsigned int maxlen, void __user *p, int compat)
 605 {
 606         int len, i;
 607
 608         if (compat) {
 609                 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
 610                 if (len > maxlen)
 611                         len = maxlen;
 612
 613                 for (i = 0; i < len / sizeof(compat_long_t); i++)
 614                         if (copy_to_user((compat_long_t __user *) p + i,
 615                                          (compat_long_t *) bits +
 616                                                 i + 1 - ((i % 2) << 1),
 617                                          sizeof(compat_long_t)))
 618                                 return -EFAULT;
 619         } else {
 620                 len = BITS_TO_LONGS(maxbit) * sizeof(long);
 621                 if (len > maxlen)
 622                         len = maxlen;
 623
 624                 if (copy_to_user(p, bits, len))
 625                         return -EFAULT;
 626         }
 627
 628         return len;
 629 }
 630 #else
 631 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 632                         unsigned int maxlen, void __user *p, int compat)
 633 {
 634         int len = compat ?
 635                         BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
 636                         BITS_TO_LONGS(maxbit) * sizeof(long);
 637
 638         if (len > maxlen)
 639                 len = maxlen;
 640
 641         return copy_to_user(p, bits, len) ? -EFAULT : len;
 642 }
 643 #endif /* __BIG_ENDIAN */
 644
 645 #else
 646
 647 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 648                         unsigned int maxlen, void __user *p, int compat)
 649 {
 650         int len = BITS_TO_LONGS(maxbit) * sizeof(long);
 651
 652         if (len > maxlen)
 653                 len = maxlen;
 654
 655         return copy_to_user(p, bits, len) ? -EFAULT : len;
 656 }
 657
 658 #endif /* CONFIG_COMPAT */
 659
 660 static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
 661 {
 662         int len;
 663
 664         if (!str)
 665                 return -ENOENT;
 666
 667         len = strlen(str) + 1;
 668         if (len > maxlen)
 669                 len = maxlen;
 670
 671         return copy_to_user(p, str, len) ? -EFAULT : len;
 672 }
 673
 674 static int handle_eviocgbit(struct input_dev *dev,
 675                             unsigned int type, unsigned int size,
 676                             void __user *p, int compat_mode)
 677 {
 678         unsigned long *bits;
 679         int len;
 680
 681         switch (type) {
 682
 683         case      0: bits = dev->evbit;  len = EV_MAX;  break;
 684         case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
 685         case EV_REL: bits = dev->relbit; len = REL_MAX; break;
 686         case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
 687         case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
 688         case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
 689         case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
 690         case EV_FF:  bits = dev->ffbit;  len = FF_MAX;  break;
 691         case EV_SW:  bits = dev->swbit;  len = SW_MAX;  break;
 692         default: return -EINVAL;
 693         }
 694
 695         return bits_to_user(bits, len, size, p, compat_mode);
 696 }
 697
 698 static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p)
 699 {
 700         struct input_keymap_entry ke = {
 701                 .len    = sizeof(unsigned int),
 702                 .flags  = 0,
 703         };
 704         int __user *ip = (int __user *)p;
 705         int error;
 706
 707         /* legacy case */
 708         if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
 709                 return -EFAULT;
 710
 711         error = input_get_keycode(dev, &ke);
 712         if (error)
 713                 return error;
 714
 715         if (put_user(ke.keycode, ip + 1))
 716                 return -EFAULT;
 717
 718         return 0;
 719 }
 720
 721 static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p)
 722 {
 723         struct input_keymap_entry ke;
 724         int error;
 725
 726         if (copy_from_user(&ke, p, sizeof(ke)))
 727                 return -EFAULT;
 728
 729         error = input_get_keycode(dev, &ke);
 730         if (error)
 731                 return error;
 732
 733         if (copy_to_user(p, &ke, sizeof(ke)))
 734                 return -EFAULT;
 735
 736         return 0;
 737 }
 738
 739 static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p)
 740 {
 741         struct input_keymap_entry ke = {
 742                 .len    = sizeof(unsigned int),
 743                 .flags  = 0,
 744         };
 745         int __user *ip = (int __user *)p;
 746
 747         if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
 748                 return -EFAULT;
 749
 750         if (get_user(ke.keycode, ip + 1))
 751                 return -EFAULT;
 752
 753         return input_set_keycode(dev, &ke);
 754 }
 755
 756 static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p)
 757 {
 758         struct input_keymap_entry ke;
 759
 760         if (copy_from_user(&ke, p, sizeof(ke)))
 761                 return -EFAULT;
 762
 763         if (ke.len > sizeof(ke.scancode))
 764                 return -EINVAL;
 765
 766         return input_set_keycode(dev, &ke);
 767 }
 768
 769 /*
 770  * If we transfer state to the user, we should flush all pending events
 771  * of the same type from the client's queue. Otherwise, they might end up
 772  * with duplicate events, which can screw up client's state tracking.
 773  * If bits_to_user fails after flushing the queue, we queue a SYN_DROPPED
 774  * event so user-space will notice missing events.
 775  *
 776  * LOCKING:
 777  * We need to take event_lock before buffer_lock to avoid dead-locks. But we
 778  * need the even_lock only to guarantee consistent state. We can safely release
 779  * it while flushing the queue. This allows input-core to handle filters while
 780  * we flush the queue.
 781  */
 782 static int evdev_handle_get_val(struct evdev_client *client,
 783                                 struct input_dev *dev, unsigned int type,
 784                                 unsigned long *bits, unsigned int maxbit,
 785                                 unsigned int maxlen, void __user *p,
 786                                 int compat)
 787 {
 788         int ret;
 789         unsigned long *mem;
 790         size_t len;
 791
 792         len = BITS_TO_LONGS(maxbit) * sizeof(unsigned long);
 793         mem = kmalloc(len, GFP_KERNEL);
 794         if (!mem)
 795                 return -ENOMEM;
 796
 797         spin_lock_irq(&dev->event_lock);
 798         spin_lock(&client->buffer_lock);
 799
 800         memcpy(mem, bits, len);
 801
 802         spin_unlock(&dev->event_lock);
 803
 804         __evdev_flush_queue(client, type);
 805
 806         spin_unlock_irq(&client->buffer_lock);
 807
 808         ret = bits_to_user(mem, maxbit, maxlen, p, compat);
 809         if (ret < 0)
 810                 evdev_queue_syn_dropped(client);
 811
 812         kfree(mem);
 813
 814         return ret;
 815 }
 816
 817 static int evdev_handle_mt_request(struct input_dev *dev,
 818                                    unsigned int size,
 819                                    int __user *ip)
 820 {
 821         const struct input_mt *mt = dev->mt;
 822         unsigned int code;
 823         int max_slots;
 824         int i;
 825
 826         if (get_user(code, &ip[0]))
 827                 return -EFAULT;
 828         if (!mt || !input_is_mt_value(code))
 829                 return -EINVAL;
 830
 831         max_slots = (size - sizeof(__u32)) / sizeof(__s32);
 832         for (i = 0; i < mt->num_slots && i < max_slots; i++) {
 833                 int value = input_mt_get_value(&mt->slots[i], code);
 834                 if (put_user(value, &ip[1 + i]))
 835                         return -EFAULT;
 836         }
 837
 838         return 0;
 839 }
 840
 841 static int evdev_revoke(struct evdev *evdev, struct evdev_client *client,
 842                         struct file *file)
 843 {
 844         client->revoked = true;
 845         evdev_ungrab(evdev, client);
 846         input_flush_device(&evdev->handle, file);
 847         wake_up_interruptible(&evdev->wait);
 848
 849         return 0;
 850 }
 851
 852 static long evdev_do_ioctl(struct file *file, unsigned int cmd,
 853                            void __user *p, int compat_mode)
 854 {
 855         struct evdev_client *client = file->private_data;
 856         struct evdev *evdev = client->evdev;
 857         struct input_dev *dev = evdev->handle.dev;
 858         struct input_absinfo abs;
 859         struct ff_effect effect;
 860         int __user *ip = (int __user *)p;
 861         unsigned int i, t, u, v;
 862         unsigned int size;
 863         int error;
 864
 865         /* First we check for fixed-length commands */
 866         switch (cmd) {
 867
 868         case EVIOCGVERSION:
 869                 return put_user(EV_VERSION, ip);
 870
 871         case EVIOCGID:
 872                 if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
 873                         return -EFAULT;
 874                 return 0;
 875
 876         case EVIOCGREP:
 877                 if (!test_bit(EV_REP, dev->evbit))
 878                         return -ENOSYS;
 879                 if (put_user(dev->rep[REP_DELAY], ip))
 880                         return -EFAULT;
 881                 if (put_user(dev->rep[REP_PERIOD], ip + 1))
 882                         return -EFAULT;
 883                 return 0;
 884
 885         case EVIOCSREP:
 886                 if (!test_bit(EV_REP, dev->evbit))
 887                         return -ENOSYS;
 888                 if (get_user(u, ip))
 889                         return -EFAULT;
 890                 if (get_user(v, ip + 1))
 891                         return -EFAULT;
 892
 893                 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
 894                 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
 895
 896                 return 0;
 897
 898         case EVIOCRMFF:
 899                 return input_ff_erase(dev, (int)(unsigned long) p, file);
 900
 901         case EVIOCGEFFECTS:
 902                 i = test_bit(EV_FF, dev->evbit) ?
 903                                 dev->ff->max_effects : 0;
 904                 if (put_user(i, ip))
 905                         return -EFAULT;
 906                 return 0;
 907
 908         case EVIOCGRAB:
 909                 if (p)
 910                         return evdev_grab(evdev, client);
 911                 else
 912                         return evdev_ungrab(evdev, client);
 913
 914         case EVIOCREVOKE:
 915                 if (p)
 916                         return -EINVAL;
 917                 else
 918                         return evdev_revoke(evdev, client, file);
 919
 920         case EVIOCSCLOCKID:
 921                 if (copy_from_user(&i, p, sizeof(unsigned int)))
 922                         return -EFAULT;
 923
 924                 return evdev_set_clk_type(client, i);
 925
 926         case EVIOCGKEYCODE:
 927                 return evdev_handle_get_keycode(dev, p);
 928
 929         case EVIOCSKEYCODE:
 930                 return evdev_handle_set_keycode(dev, p);
 931
 932         case EVIOCGKEYCODE_V2:
 933                 return evdev_handle_get_keycode_v2(dev, p);
 934
 935         case EVIOCSKEYCODE_V2:
 936                 return evdev_handle_set_keycode_v2(dev, p);
 937         }
 938
 939         size = _IOC_SIZE(cmd);
 940
 941         /* Now check variable-length commands */
 942 #define EVIOC_MASK_SIZE(nr)     ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
 943         switch (EVIOC_MASK_SIZE(cmd)) {
 944
 945         case EVIOCGPROP(0):
 946                 return bits_to_user(dev->propbit, INPUT_PROP_MAX,
 947                                     size, p, compat_mode);
 948
 949         case EVIOCGMTSLOTS(0):
 950                 return evdev_handle_mt_request(dev, size, ip);
 951
 952         case EVIOCGKEY(0):
 953                 return evdev_handle_get_val(client, dev, EV_KEY, dev->key,
 954                                             KEY_MAX, size, p, compat_mode);
 955
 956         case EVIOCGLED(0):
 957                 return evdev_handle_get_val(client, dev, EV_LED, dev->led,
 958                                             LED_MAX, size, p, compat_mode);
 959
 960         case EVIOCGSND(0):
 961                 return evdev_handle_get_val(client, dev, EV_SND, dev->snd,
 962                                             SND_MAX, size, p, compat_mode);
 963
 964         case EVIOCGSW(0):
 965                 return evdev_handle_get_val(client, dev, EV_SW, dev->sw,
 966                                             SW_MAX, size, p, compat_mode);
 967
 968         case EVIOCGNAME(0):
 969                 return str_to_user(dev->name, size, p);
 970
 971         case EVIOCGPHYS(0):
 972                 return str_to_user(dev->phys, size, p);
 973
 974         case EVIOCGUNIQ(0):
 975                 return str_to_user(dev->uniq, size, p);
 976
 977         case EVIOC_MASK_SIZE(EVIOCSFF):
 978                 if (input_ff_effect_from_user(p, size, &effect))
 979                         return -EFAULT;
 980
 981                 error = input_ff_upload(dev, &effect, file);
 982                 if (error)
 983                         return error;
 984
 985                 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
 986                         return -EFAULT;
 987
 988                 return 0;
 989         }
 990
 991         /* Multi-number variable-length handlers */
 992         if (_IOC_TYPE(cmd) != 'E')
 993                 return -EINVAL;
 994
 995         if (_IOC_DIR(cmd) == _IOC_READ) {
 996
 997                 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
 998                         return handle_eviocgbit(dev,
 999                                                 _IOC_NR(cmd) & EV_MAX, size,
1000                                                 p, compat_mode);
1001
1002                 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
1003
1004                         if (!dev->absinfo)
1005                                 return -EINVAL;
1006
1007                         t = _IOC_NR(cmd) & ABS_MAX;
1008                         abs = dev->absinfo[t];
1009
1010                         if (copy_to_user(p, &abs, min_t(size_t,
1011                                         size, sizeof(struct input_absinfo))))
1012                                 return -EFAULT;
1013
1014                         return 0;
1015                 }
1016         }
1017
1018         if (_IOC_DIR(cmd) == _IOC_WRITE) {
1019
1020                 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
1021
1022                         if (!dev->absinfo)
1023                                 return -EINVAL;
1024
1025                         t = _IOC_NR(cmd) & ABS_MAX;
1026
1027                         if (copy_from_user(&abs, p, min_t(size_t,
1028                                         size, sizeof(struct input_absinfo))))
1029                                 return -EFAULT;
1030
1031                         if (size < sizeof(struct input_absinfo))
1032                                 abs.resolution = 0;
1033
1034                         /* We can't change number of reserved MT slots */
1035                         if (t == ABS_MT_SLOT)
1036                                 return -EINVAL;
1037
1038                         /*
1039                          * Take event lock to ensure that we are not
1040                          * changing device parameters in the middle
1041                          * of event.
1042                          */
1043                         spin_lock_irq(&dev->event_lock);
1044                         dev->absinfo[t] = abs;
1045                         spin_unlock_irq(&dev->event_lock);
1046
1047                         return 0;
1048                 }
1049         }
1050
1051         return -EINVAL;
1052 }
1053
1054 static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
1055                                 void __user *p, int compat_mode)
1056 {
1057         struct evdev_client *client = file->private_data;
1058         struct evdev *evdev = client->evdev;
1059         int retval;
1060
1061         retval = mutex_lock_interruptible(&evdev->mutex);
1062         if (retval)
1063                 return retval;
1064
1065         if (!evdev->exist || client->revoked) {
1066                 retval = -ENODEV;
1067                 goto out;
1068         }
1069
1070         retval = evdev_do_ioctl(file, cmd, p, compat_mode);
1071
1072  out:
1073         mutex_unlock(&evdev->mutex);
1074         return retval;
1075 }
1076
1077 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1078 {
1079         return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
1080 }
1081
1082 #ifdef CONFIG_COMPAT
1083 static long evdev_ioctl_compat(struct file *file,
1084                                 unsigned int cmd, unsigned long arg)
1085 {
1086         return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
1087 }
1088 #endif
1089
1090 static const struct file_operations evdev_fops = {
1091         .owner          = THIS_MODULE,
1092         .read           = evdev_read,
1093         .write          = evdev_write,
1094         .poll           = evdev_poll,
1095         .open           = evdev_open,
1096         .release        = evdev_release,
1097         .unlocked_ioctl = evdev_ioctl,
1098 #ifdef CONFIG_COMPAT
1099         .compat_ioctl   = evdev_ioctl_compat,
1100 #endif
1101         .fasync         = evdev_fasync,
1102         .flush          = evdev_flush,
1103         .llseek         = no_llseek,
1104 };
1105
1106 /*
1107  * Mark device non-existent. This disables writes, ioctls and
1108  * prevents new users from opening the device. Already posted
1109  * blocking reads will stay, however new ones will fail.
1110  */
1111 static void evdev_mark_dead(struct evdev *evdev)
1112 {
1113         mutex_lock(&evdev->mutex);
1114         evdev->exist = false;
1115         mutex_unlock(&evdev->mutex);
1116 }
1117
1118 static void evdev_cleanup(struct evdev *evdev)
1119 {
1120         struct input_handle *handle = &evdev->handle;
1121
1122         evdev_mark_dead(evdev);
1123         evdev_hangup(evdev);
1124
1125         cdev_del(&evdev->cdev);
1126
1127         /* evdev is marked dead so no one else accesses evdev->open */
1128         if (evdev->open) {
1129                 input_flush_device(handle, NULL);
1130                 input_close_device(handle);
1131         }
1132 }
1133
1134 /*
1135  * Create new evdev device. Note that input core serializes calls
1136  * to connect and disconnect.
1137  */
1138 static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
1139                          const struct input_device_id *id)
1140 {
1141         struct evdev *evdev;
1142         int minor;
1143         int dev_no;
1144         int error;
1145
1146         minor = input_get_new_minor(EVDEV_MINOR_BASE, EVDEV_MINORS, true);
1147         if (minor < 0) {
1148                 error = minor;
1149                 pr_err("failed to reserve new minor: %d\n", error);
1150                 return error;
1151         }
1152
1153         evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
1154         if (!evdev) {
1155                 error = -ENOMEM;
1156                 goto err_free_minor;
1157         }
1158
1159         INIT_LIST_HEAD(&evdev->client_list);
1160         spin_lock_init(&evdev->client_lock);
1161         mutex_init(&evdev->mutex);
1162         init_waitqueue_head(&evdev->wait);
1163         evdev->exist = true;
1164
1165         dev_no = minor;
1166         /* Normalize device number if it falls into legacy range */
1167         if (dev_no < EVDEV_MINOR_BASE + EVDEV_MINORS)
1168                 dev_no -= EVDEV_MINOR_BASE;
1169         dev_set_name(&evdev->dev, "event%d", dev_no);
1170
1171         evdev->handle.dev = input_get_device(dev);
1172         evdev->handle.name = dev_name(&evdev->dev);
1173         evdev->handle.handler = handler;
1174         evdev->handle.private = evdev;
1175
1176         evdev->dev.devt = MKDEV(INPUT_MAJOR, minor);
1177         evdev->dev.class = &input_class;
1178         evdev->dev.parent = &dev->dev;
1179         evdev->dev.release = evdev_free;
1180         device_initialize(&evdev->dev);
1181
1182         error = input_register_handle(&evdev->handle);
1183         if (error)
1184                 goto err_free_evdev;
1185
1186         cdev_init(&evdev->cdev, &evdev_fops);
1187         evdev->cdev.kobj.parent = &evdev->dev.kobj;
1188         error = cdev_add(&evdev->cdev, evdev->dev.devt, 1);
1189         if (error)
1190                 goto err_unregister_handle;
1191
1192         error = device_add(&evdev->dev);
1193         if (error)
1194                 goto err_cleanup_evdev;
1195
1196         return 0;
1197
1198  err_cleanup_evdev:
1199         evdev_cleanup(evdev);
1200  err_unregister_handle:
1201         input_unregister_handle(&evdev->handle);
1202  err_free_evdev:
1203         put_device(&evdev->dev);
1204  err_free_minor:
1205         input_free_minor(minor);
1206         return error;
1207 }
1208
1209 static void evdev_disconnect(struct input_handle *handle)
1210 {
1211         struct evdev *evdev = handle->private;
1212
1213         device_del(&evdev->dev);
1214         evdev_cleanup(evdev);
1215         input_free_minor(MINOR(evdev->dev.devt));
1216         input_unregister_handle(handle);
1217         put_device(&evdev->dev);
1218 }
1219
1220 static const struct input_device_id evdev_ids[] = {
1221         { .driver_info = 1 },   /* Matches all devices */
1222         { },                    /* Terminating zero entry */
1223 };
1224
1225 MODULE_DEVICE_TABLE(input, evdev_ids);
1226
1227 static struct input_handler evdev_handler = {
1228         .event          = evdev_event,
1229         .events         = evdev_events,
1230         .connect        = evdev_connect,
1231         .disconnect     = evdev_disconnect,
1232         .legacy_minors  = true,
1233         .minor          = EVDEV_MINOR_BASE,
1234         .name           = "evdev",
1235         .id_table       = evdev_ids,
1236 };
1237
1238 static int __init evdev_init(void)
1239 {
1240         return input_register_handler(&evdev_handler);
1241 }
1242
1243 static void __exit evdev_exit(void)
1244 {
1245         input_unregister_handler(&evdev_handler);
1246 }
1247
1248 module_init(evdev_init);
1249 module_exit(evdev_exit);
1250
1251 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
1252 MODULE_DESCRIPTION("Input driver event char devices");
1253 MODULE_LICENSE("GPL");