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         int retval;
 294
 295         retval = mutex_lock_interruptible(&evdev->mutex);
 296         if (retval)
 297                 return retval;
 298
 299         if (!evdev->exist || client->revoked)
 300                 retval = -ENODEV;
 301         else
 302                 retval = input_flush_device(&evdev->handle, file);
 303
 304         mutex_unlock(&evdev->mutex);
 305         return retval;
 306 }
 307
 308 static void evdev_free(struct device *dev)
 309 {
 310         struct evdev *evdev = container_of(dev, struct evdev, dev);
 311
 312         input_put_device(evdev->handle.dev);
 313         kfree(evdev);
 314 }
 315
 316 /*
 317  * Grabs an event device (along with underlying input device).
 318  * This function is called with evdev->mutex taken.
 319  */
 320 static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
 321 {
 322         int error;
 323
 324         if (evdev->grab)
 325                 return -EBUSY;
 326
 327         error = input_grab_device(&evdev->handle);
 328         if (error)
 329                 return error;
 330
 331         rcu_assign_pointer(evdev->grab, client);
 332
 333         return 0;
 334 }
 335
 336 static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
 337 {
 338         struct evdev_client *grab = rcu_dereference_protected(evdev->grab,
 339                                         lockdep_is_held(&evdev->mutex));
 340
 341         if (grab != client)
 342                 return  -EINVAL;
 343
 344         rcu_assign_pointer(evdev->grab, NULL);
 345         synchronize_rcu();
 346         input_release_device(&evdev->handle);
 347
 348         return 0;
 349 }
 350
 351 static void evdev_attach_client(struct evdev *evdev,
 352                                 struct evdev_client *client)
 353 {
 354         spin_lock(&evdev->client_lock);
 355         list_add_tail_rcu(&client->node, &evdev->client_list);
 356         spin_unlock(&evdev->client_lock);
 357 }
 358
 359 static void evdev_detach_client(struct evdev *evdev,
 360                                 struct evdev_client *client)
 361 {
 362         spin_lock(&evdev->client_lock);
 363         list_del_rcu(&client->node);
 364         spin_unlock(&evdev->client_lock);
 365         synchronize_rcu();
 366 }
 367
 368 static int evdev_open_device(struct evdev *evdev)
 369 {
 370         int retval;
 371
 372         retval = mutex_lock_interruptible(&evdev->mutex);
 373         if (retval)
 374                 return retval;
 375
 376         if (!evdev->exist)
 377                 retval = -ENODEV;
 378         else if (!evdev->open++) {
 379                 retval = input_open_device(&evdev->handle);
 380                 if (retval)
 381                         evdev->open--;
 382         }
 383
 384         mutex_unlock(&evdev->mutex);
 385         return retval;
 386 }
 387
 388 static void evdev_close_device(struct evdev *evdev)
 389 {
 390         mutex_lock(&evdev->mutex);
 391
 392         if (evdev->exist && !--evdev->open)
 393                 input_close_device(&evdev->handle);
 394
 395         mutex_unlock(&evdev->mutex);
 396 }
 397
 398 /*
 399  * Wake up users waiting for IO so they can disconnect from
 400  * dead device.
 401  */
 402 static void evdev_hangup(struct evdev *evdev)
 403 {
 404         struct evdev_client *client;
 405
 406         spin_lock(&evdev->client_lock);
 407         list_for_each_entry(client, &evdev->client_list, node)
 408                 kill_fasync(&client->fasync, SIGIO, POLL_HUP);
 409         spin_unlock(&evdev->client_lock);
 410
 411         wake_up_interruptible(&evdev->wait);
 412 }
 413
 414 static int evdev_release(struct inode *inode, struct file *file)
 415 {
 416         struct evdev_client *client = file->private_data;
 417         struct evdev *evdev = client->evdev;
 418
 419         mutex_lock(&evdev->mutex);
 420         evdev_ungrab(evdev, client);
 421         mutex_unlock(&evdev->mutex);
 422
 423         evdev_detach_client(evdev, client);
 424
 425         if (is_vmalloc_addr(client))
 426                 vfree(client);
 427         else
 428                 kfree(client);
 429
 430         evdev_close_device(evdev);
 431
 432         return 0;
 433 }
 434
 435 static unsigned int evdev_compute_buffer_size(struct input_dev *dev)
 436 {
 437         unsigned int n_events =
 438                 max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS,
 439                     EVDEV_MIN_BUFFER_SIZE);
 440
 441         return roundup_pow_of_two(n_events);
 442 }
 443
 444 static int evdev_open(struct inode *inode, struct file *file)
 445 {
 446         struct evdev *evdev = container_of(inode->i_cdev, struct evdev, cdev);
 447         unsigned int bufsize = evdev_compute_buffer_size(evdev->handle.dev);
 448         unsigned int size = sizeof(struct evdev_client) +
 449                                         bufsize * sizeof(struct input_event);
 450         struct evdev_client *client;
 451         int error;
 452
 453         client = kzalloc(size, GFP_KERNEL | __GFP_NOWARN);
 454         if (!client)
 455                 client = vzalloc(size);
 456         if (!client)
 457                 return -ENOMEM;
 458
 459         client->bufsize = bufsize;
 460         spin_lock_init(&client->buffer_lock);
 461         client->evdev = evdev;
 462         evdev_attach_client(evdev, client);
 463
 464         error = evdev_open_device(evdev);
 465         if (error)
 466                 goto err_free_client;
 467
 468         file->private_data = client;
 469         nonseekable_open(inode, file);
 470
 471         return 0;
 472
 473  err_free_client:
 474         evdev_detach_client(evdev, client);
 475         kvfree(client);
 476         return error;
 477 }
 478
 479 static ssize_t evdev_write(struct file *file, const char __user *buffer,
 480                            size_t count, loff_t *ppos)
 481 {
 482         struct evdev_client *client = file->private_data;
 483         struct evdev *evdev = client->evdev;
 484         struct input_event event;
 485         int retval = 0;
 486
 487         if (count != 0 && count < input_event_size())
 488                 return -EINVAL;
 489
 490         retval = mutex_lock_interruptible(&evdev->mutex);
 491         if (retval)
 492                 return retval;
 493
 494         if (!evdev->exist || client->revoked) {
 495                 retval = -ENODEV;
 496                 goto out;
 497         }
 498
 499         while (retval + input_event_size() <= count) {
 500
 501                 if (input_event_from_user(buffer + retval, &event)) {
 502                         retval = -EFAULT;
 503                         goto out;
 504                 }
 505                 retval += input_event_size();
 506
 507                 input_inject_event(&evdev->handle,
 508                                    event.type, event.code, event.value);
 509         }
 510
 511  out:
 512         mutex_unlock(&evdev->mutex);
 513         return retval;
 514 }
 515
 516 static int evdev_fetch_next_event(struct evdev_client *client,
 517                                   struct input_event *event)
 518 {
 519         int have_event;
 520
 521         spin_lock_irq(&client->buffer_lock);
 522
 523         have_event = client->packet_head != client->tail;
 524         if (have_event) {
 525                 *event = client->buffer[client->tail++];
 526                 client->tail &= client->bufsize - 1;
 527         }
 528
 529         spin_unlock_irq(&client->buffer_lock);
 530
 531         return have_event;
 532 }
 533
 534 static ssize_t evdev_read(struct file *file, char __user *buffer,
 535                           size_t count, loff_t *ppos)
 536 {
 537         struct evdev_client *client = file->private_data;
 538         struct evdev *evdev = client->evdev;
 539         struct input_event event;
 540         size_t read = 0;
 541         int error;
 542
 543         if (count != 0 && count < input_event_size())
 544                 return -EINVAL;
 545
 546         for (;;) {
 547                 if (!evdev->exist || client->revoked)
 548                         return -ENODEV;
 549
 550                 if (client->packet_head == client->tail &&
 551                     (file->f_flags & O_NONBLOCK))
 552                         return -EAGAIN;
 553
 554                 /*
 555                  * count == 0 is special - no IO is done but we check
 556                  * for error conditions (see above).
 557                  */
 558                 if (count == 0)
 559                         break;
 560
 561                 while (read + input_event_size() <= count &&
 562                        evdev_fetch_next_event(client, &event)) {
 563
 564                         if (input_event_to_user(buffer + read, &event))
 565                                 return -EFAULT;
 566
 567                         read += input_event_size();
 568                 }
 569
 570                 if (read)
 571                         break;
 572
 573                 if (!(file->f_flags & O_NONBLOCK)) {
 574                         error = wait_event_interruptible(evdev->wait,
 575                                         client->packet_head != client->tail ||
 576                                         !evdev->exist || client->revoked);
 577                         if (error)
 578                                 return error;
 579                 }
 580         }
 581
 582         return read;
 583 }
 584
 585 /* No kernel lock - fine */
 586 static unsigned int evdev_poll(struct file *file, poll_table *wait)
 587 {
 588         struct evdev_client *client = file->private_data;
 589         struct evdev *evdev = client->evdev;
 590         unsigned int mask;
 591
 592         poll_wait(file, &evdev->wait, wait);
 593
 594         if (evdev->exist && !client->revoked)
 595                 mask = POLLOUT | POLLWRNORM;
 596         else
 597                 mask = POLLHUP | POLLERR;
 598
 599         if (client->packet_head != client->tail)
 600                 mask |= POLLIN | POLLRDNORM;
 601
 602         return mask;
 603 }
 604
 605 #ifdef CONFIG_COMPAT
 606
 607 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
 608 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
 609
 610 #ifdef __BIG_ENDIAN
 611 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 612                         unsigned int maxlen, void __user *p, int compat)
 613 {
 614         int len, i;
 615
 616         if (compat) {
 617                 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
 618                 if (len > maxlen)
 619                         len = maxlen;
 620
 621                 for (i = 0; i < len / sizeof(compat_long_t); i++)
 622                         if (copy_to_user((compat_long_t __user *) p + i,
 623                                          (compat_long_t *) bits +
 624                                                 i + 1 - ((i % 2) << 1),
 625                                          sizeof(compat_long_t)))
 626                                 return -EFAULT;
 627         } else {
 628                 len = BITS_TO_LONGS(maxbit) * sizeof(long);
 629                 if (len > maxlen)
 630                         len = maxlen;
 631
 632                 if (copy_to_user(p, bits, len))
 633                         return -EFAULT;
 634         }
 635
 636         return len;
 637 }
 638 #else
 639 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 640                         unsigned int maxlen, void __user *p, int compat)
 641 {
 642         int len = compat ?
 643                         BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
 644                         BITS_TO_LONGS(maxbit) * sizeof(long);
 645
 646         if (len > maxlen)
 647                 len = maxlen;
 648
 649         return copy_to_user(p, bits, len) ? -EFAULT : len;
 650 }
 651 #endif /* __BIG_ENDIAN */
 652
 653 #else
 654
 655 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 656                         unsigned int maxlen, void __user *p, int compat)
 657 {
 658         int len = BITS_TO_LONGS(maxbit) * sizeof(long);
 659
 660         if (len > maxlen)
 661                 len = maxlen;
 662
 663         return copy_to_user(p, bits, len) ? -EFAULT : len;
 664 }
 665
 666 #endif /* CONFIG_COMPAT */
 667
 668 static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
 669 {
 670         int len;
 671
 672         if (!str)
 673                 return -ENOENT;
 674
 675         len = strlen(str) + 1;
 676         if (len > maxlen)
 677                 len = maxlen;
 678
 679         return copy_to_user(p, str, len) ? -EFAULT : len;
 680 }
 681
 682 static int handle_eviocgbit(struct input_dev *dev,
 683                             unsigned int type, unsigned int size,
 684                             void __user *p, int compat_mode)
 685 {
 686         unsigned long *bits;
 687         int len;
 688
 689         switch (type) {
 690
 691         case      0: bits = dev->evbit;  len = EV_MAX;  break;
 692         case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
 693         case EV_REL: bits = dev->relbit; len = REL_MAX; break;
 694         case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
 695         case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
 696         case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
 697         case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
 698         case EV_FF:  bits = dev->ffbit;  len = FF_MAX;  break;
 699         case EV_SW:  bits = dev->swbit;  len = SW_MAX;  break;
 700         default: return -EINVAL;
 701         }
 702
 703         return bits_to_user(bits, len, size, p, compat_mode);
 704 }
 705
 706 static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p)
 707 {
 708         struct input_keymap_entry ke = {
 709                 .len    = sizeof(unsigned int),
 710                 .flags  = 0,
 711         };
 712         int __user *ip = (int __user *)p;
 713         int error;
 714
 715         /* legacy case */
 716         if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
 717                 return -EFAULT;
 718
 719         error = input_get_keycode(dev, &ke);
 720         if (error)
 721                 return error;
 722
 723         if (put_user(ke.keycode, ip + 1))
 724                 return -EFAULT;
 725
 726         return 0;
 727 }
 728
 729 static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p)
 730 {
 731         struct input_keymap_entry ke;
 732         int error;
 733
 734         if (copy_from_user(&ke, p, sizeof(ke)))
 735                 return -EFAULT;
 736
 737         error = input_get_keycode(dev, &ke);
 738         if (error)
 739                 return error;
 740
 741         if (copy_to_user(p, &ke, sizeof(ke)))
 742                 return -EFAULT;
 743
 744         return 0;
 745 }
 746
 747 static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p)
 748 {
 749         struct input_keymap_entry ke = {
 750                 .len    = sizeof(unsigned int),
 751                 .flags  = 0,
 752         };
 753         int __user *ip = (int __user *)p;
 754
 755         if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
 756                 return -EFAULT;
 757
 758         if (get_user(ke.keycode, ip + 1))
 759                 return -EFAULT;
 760
 761         return input_set_keycode(dev, &ke);
 762 }
 763
 764 static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p)
 765 {
 766         struct input_keymap_entry ke;
 767
 768         if (copy_from_user(&ke, p, sizeof(ke)))
 769                 return -EFAULT;
 770
 771         if (ke.len > sizeof(ke.scancode))
 772                 return -EINVAL;
 773
 774         return input_set_keycode(dev, &ke);
 775 }
 776
 777 /*
 778  * If we transfer state to the user, we should flush all pending events
 779  * of the same type from the client's queue. Otherwise, they might end up
 780  * with duplicate events, which can screw up client's state tracking.
 781  * If bits_to_user fails after flushing the queue, we queue a SYN_DROPPED
 782  * event so user-space will notice missing events.
 783  *
 784  * LOCKING:
 785  * We need to take event_lock before buffer_lock to avoid dead-locks. But we
 786  * need the even_lock only to guarantee consistent state. We can safely release
 787  * it while flushing the queue. This allows input-core to handle filters while
 788  * we flush the queue.
 789  */
 790 static int evdev_handle_get_val(struct evdev_client *client,
 791                                 struct input_dev *dev, unsigned int type,
 792                                 unsigned long *bits, unsigned int maxbit,
 793                                 unsigned int maxlen, void __user *p,
 794                                 int compat)
 795 {
 796         int ret;
 797         unsigned long *mem;
 798         size_t len;
 799
 800         len = BITS_TO_LONGS(maxbit) * sizeof(unsigned long);
 801         mem = kmalloc(len, GFP_KERNEL);
 802         if (!mem)
 803                 return -ENOMEM;
 804
 805         spin_lock_irq(&dev->event_lock);
 806         spin_lock(&client->buffer_lock);
 807
 808         memcpy(mem, bits, len);
 809
 810         spin_unlock(&dev->event_lock);
 811
 812         __evdev_flush_queue(client, type);
 813
 814         spin_unlock_irq(&client->buffer_lock);
 815
 816         ret = bits_to_user(mem, maxbit, maxlen, p, compat);
 817         if (ret < 0)
 818                 evdev_queue_syn_dropped(client);
 819
 820         kfree(mem);
 821
 822         return ret;
 823 }
 824
 825 static int evdev_handle_mt_request(struct input_dev *dev,
 826                                    unsigned int size,
 827                                    int __user *ip)
 828 {
 829         const struct input_mt *mt = dev->mt;
 830         unsigned int code;
 831         int max_slots;
 832         int i;
 833
 834         if (get_user(code, &ip[0]))
 835                 return -EFAULT;
 836         if (!mt || !input_is_mt_value(code))
 837                 return -EINVAL;
 838
 839         max_slots = (size - sizeof(__u32)) / sizeof(__s32);
 840         for (i = 0; i < mt->num_slots && i < max_slots; i++) {
 841                 int value = input_mt_get_value(&mt->slots[i], code);
 842                 if (put_user(value, &ip[1 + i]))
 843                         return -EFAULT;
 844         }
 845
 846         return 0;
 847 }
 848
 849 static int evdev_revoke(struct evdev *evdev, struct evdev_client *client,
 850                         struct file *file)
 851 {
 852         client->revoked = true;
 853         evdev_ungrab(evdev, client);
 854         input_flush_device(&evdev->handle, file);
 855         wake_up_interruptible(&evdev->wait);
 856
 857         return 0;
 858 }
 859
 860 static long evdev_do_ioctl(struct file *file, unsigned int cmd,
 861                            void __user *p, int compat_mode)
 862 {
 863         struct evdev_client *client = file->private_data;
 864         struct evdev *evdev = client->evdev;
 865         struct input_dev *dev = evdev->handle.dev;
 866         struct input_absinfo abs;
 867         struct ff_effect effect;
 868         int __user *ip = (int __user *)p;
 869         unsigned int i, t, u, v;
 870         unsigned int size;
 871         int error;
 872
 873         /* First we check for fixed-length commands */
 874         switch (cmd) {
 875
 876         case EVIOCGVERSION:
 877                 return put_user(EV_VERSION, ip);
 878
 879         case EVIOCGID:
 880                 if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
 881                         return -EFAULT;
 882                 return 0;
 883
 884         case EVIOCGREP:
 885                 if (!test_bit(EV_REP, dev->evbit))
 886                         return -ENOSYS;
 887                 if (put_user(dev->rep[REP_DELAY], ip))
 888                         return -EFAULT;
 889                 if (put_user(dev->rep[REP_PERIOD], ip + 1))
 890                         return -EFAULT;
 891                 return 0;
 892
 893         case EVIOCSREP:
 894                 if (!test_bit(EV_REP, dev->evbit))
 895                         return -ENOSYS;
 896                 if (get_user(u, ip))
 897                         return -EFAULT;
 898                 if (get_user(v, ip + 1))
 899                         return -EFAULT;
 900
 901                 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
 902                 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
 903
 904                 return 0;
 905
 906         case EVIOCRMFF:
 907                 return input_ff_erase(dev, (int)(unsigned long) p, file);
 908
 909         case EVIOCGEFFECTS:
 910                 i = test_bit(EV_FF, dev->evbit) ?
 911                                 dev->ff->max_effects : 0;
 912                 if (put_user(i, ip))
 913                         return -EFAULT;
 914                 return 0;
 915
 916         case EVIOCGRAB:
 917                 if (p)
 918                         return evdev_grab(evdev, client);
 919                 else
 920                         return evdev_ungrab(evdev, client);
 921
 922         case EVIOCREVOKE:
 923                 if (p)
 924                         return -EINVAL;
 925                 else
 926                         return evdev_revoke(evdev, client, file);
 927
 928         case EVIOCSCLOCKID:
 929                 if (copy_from_user(&i, p, sizeof(unsigned int)))
 930                         return -EFAULT;
 931
 932                 return evdev_set_clk_type(client, i);
 933
 934         case EVIOCGKEYCODE:
 935                 return evdev_handle_get_keycode(dev, p);
 936
 937         case EVIOCSKEYCODE:
 938                 return evdev_handle_set_keycode(dev, p);
 939
 940         case EVIOCGKEYCODE_V2:
 941                 return evdev_handle_get_keycode_v2(dev, p);
 942
 943         case EVIOCSKEYCODE_V2:
 944                 return evdev_handle_set_keycode_v2(dev, p);
 945         }
 946
 947         size = _IOC_SIZE(cmd);
 948
 949         /* Now check variable-length commands */
 950 #define EVIOC_MASK_SIZE(nr)     ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
 951         switch (EVIOC_MASK_SIZE(cmd)) {
 952
 953         case EVIOCGPROP(0):
 954                 return bits_to_user(dev->propbit, INPUT_PROP_MAX,
 955                                     size, p, compat_mode);
 956
 957         case EVIOCGMTSLOTS(0):
 958                 return evdev_handle_mt_request(dev, size, ip);
 959
 960         case EVIOCGKEY(0):
 961                 return evdev_handle_get_val(client, dev, EV_KEY, dev->key,
 962                                             KEY_MAX, size, p, compat_mode);
 963
 964         case EVIOCGLED(0):
 965                 return evdev_handle_get_val(client, dev, EV_LED, dev->led,
 966                                             LED_MAX, size, p, compat_mode);
 967
 968         case EVIOCGSND(0):
 969                 return evdev_handle_get_val(client, dev, EV_SND, dev->snd,
 970                                             SND_MAX, size, p, compat_mode);
 971
 972         case EVIOCGSW(0):
 973                 return evdev_handle_get_val(client, dev, EV_SW, dev->sw,
 974                                             SW_MAX, size, p, compat_mode);
 975
 976         case EVIOCGNAME(0):
 977                 return str_to_user(dev->name, size, p);
 978
 979         case EVIOCGPHYS(0):
 980                 return str_to_user(dev->phys, size, p);
 981
 982         case EVIOCGUNIQ(0):
 983                 return str_to_user(dev->uniq, size, p);
 984
 985         case EVIOC_MASK_SIZE(EVIOCSFF):
 986                 if (input_ff_effect_from_user(p, size, &effect))
 987                         return -EFAULT;
 988
 989                 error = input_ff_upload(dev, &effect, file);
 990                 if (error)
 991                         return error;
 992
 993                 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
 994                         return -EFAULT;
 995
 996                 return 0;
 997         }
 998
 999         /* Multi-number variable-length handlers */
1000         if (_IOC_TYPE(cmd) != 'E')
1001                 return -EINVAL;
1002
1003         if (_IOC_DIR(cmd) == _IOC_READ) {
1004
1005                 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
1006                         return handle_eviocgbit(dev,
1007                                                 _IOC_NR(cmd) & EV_MAX, size,
1008                                                 p, compat_mode);
1009
1010                 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
1011
1012                         if (!dev->absinfo)
1013                                 return -EINVAL;
1014
1015                         t = _IOC_NR(cmd) & ABS_MAX;
1016                         abs = dev->absinfo[t];
1017
1018                         if (copy_to_user(p, &abs, min_t(size_t,
1019                                         size, sizeof(struct input_absinfo))))
1020                                 return -EFAULT;
1021
1022                         return 0;
1023                 }
1024         }
1025
1026         if (_IOC_DIR(cmd) == _IOC_WRITE) {
1027
1028                 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
1029
1030                         if (!dev->absinfo)
1031                                 return -EINVAL;
1032
1033                         t = _IOC_NR(cmd) & ABS_MAX;
1034
1035                         if (copy_from_user(&abs, p, min_t(size_t,
1036                                         size, sizeof(struct input_absinfo))))
1037                                 return -EFAULT;
1038
1039                         if (size < sizeof(struct input_absinfo))
1040                                 abs.resolution = 0;
1041
1042                         /* We can't change number of reserved MT slots */
1043                         if (t == ABS_MT_SLOT)
1044                                 return -EINVAL;
1045
1046                         /*
1047                          * Take event lock to ensure that we are not
1048                          * changing device parameters in the middle
1049                          * of event.
1050                          */
1051                         spin_lock_irq(&dev->event_lock);
1052                         dev->absinfo[t] = abs;
1053                         spin_unlock_irq(&dev->event_lock);
1054
1055                         return 0;
1056                 }
1057         }
1058
1059         return -EINVAL;
1060 }
1061
1062 static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
1063                                 void __user *p, int compat_mode)
1064 {
1065         struct evdev_client *client = file->private_data;
1066         struct evdev *evdev = client->evdev;
1067         int retval;
1068
1069         retval = mutex_lock_interruptible(&evdev->mutex);
1070         if (retval)
1071                 return retval;
1072
1073         if (!evdev->exist || client->revoked) {
1074                 retval = -ENODEV;
1075                 goto out;
1076         }
1077
1078         retval = evdev_do_ioctl(file, cmd, p, compat_mode);
1079
1080  out:
1081         mutex_unlock(&evdev->mutex);
1082         return retval;
1083 }
1084
1085 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1086 {
1087         return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
1088 }
1089
1090 #ifdef CONFIG_COMPAT
1091 static long evdev_ioctl_compat(struct file *file,
1092                                 unsigned int cmd, unsigned long arg)
1093 {
1094         return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
1095 }
1096 #endif
1097
1098 static const struct file_operations evdev_fops = {
1099         .owner          = THIS_MODULE,
1100         .read           = evdev_read,
1101         .write          = evdev_write,
1102         .poll           = evdev_poll,
1103         .open           = evdev_open,
1104         .release        = evdev_release,
1105         .unlocked_ioctl = evdev_ioctl,
1106 #ifdef CONFIG_COMPAT
1107         .compat_ioctl   = evdev_ioctl_compat,
1108 #endif
1109         .fasync         = evdev_fasync,
1110         .flush          = evdev_flush,
1111         .llseek         = no_llseek,
1112 };
1113
1114 /*
1115  * Mark device non-existent. This disables writes, ioctls and
1116  * prevents new users from opening the device. Already posted
1117  * blocking reads will stay, however new ones will fail.
1118  */
1119 static void evdev_mark_dead(struct evdev *evdev)
1120 {
1121         mutex_lock(&evdev->mutex);
1122         evdev->exist = false;
1123         mutex_unlock(&evdev->mutex);
1124 }
1125
1126 static void evdev_cleanup(struct evdev *evdev)
1127 {
1128         struct input_handle *handle = &evdev->handle;
1129
1130         evdev_mark_dead(evdev);
1131         evdev_hangup(evdev);
1132
1133         cdev_del(&evdev->cdev);
1134
1135         /* evdev is marked dead so no one else accesses evdev->open */
1136         if (evdev->open) {
1137                 input_flush_device(handle, NULL);
1138                 input_close_device(handle);
1139         }
1140 }
1141
1142 /*
1143  * Create new evdev device. Note that input core serializes calls
1144  * to connect and disconnect.
1145  */
1146 static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
1147                          const struct input_device_id *id)
1148 {
1149         struct evdev *evdev;
1150         int minor;
1151         int dev_no;
1152         int error;
1153
1154         minor = input_get_new_minor(EVDEV_MINOR_BASE, EVDEV_MINORS, true);
1155         if (minor < 0) {
1156                 error = minor;
1157                 pr_err("failed to reserve new minor: %d\n", error);
1158                 return error;
1159         }
1160
1161         evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
1162         if (!evdev) {
1163                 error = -ENOMEM;
1164                 goto err_free_minor;
1165         }
1166
1167         INIT_LIST_HEAD(&evdev->client_list);
1168         spin_lock_init(&evdev->client_lock);
1169         mutex_init(&evdev->mutex);
1170         init_waitqueue_head(&evdev->wait);
1171         evdev->exist = true;
1172
1173         dev_no = minor;
1174         /* Normalize device number if it falls into legacy range */
1175         if (dev_no < EVDEV_MINOR_BASE + EVDEV_MINORS)
1176                 dev_no -= EVDEV_MINOR_BASE;
1177         dev_set_name(&evdev->dev, "event%d", dev_no);
1178
1179         evdev->handle.dev = input_get_device(dev);
1180         evdev->handle.name = dev_name(&evdev->dev);
1181         evdev->handle.handler = handler;
1182         evdev->handle.private = evdev;
1183
1184         evdev->dev.devt = MKDEV(INPUT_MAJOR, minor);
1185         evdev->dev.class = &input_class;
1186         evdev->dev.parent = &dev->dev;
1187         evdev->dev.release = evdev_free;
1188         device_initialize(&evdev->dev);
1189
1190         error = input_register_handle(&evdev->handle);
1191         if (error)
1192                 goto err_free_evdev;
1193
1194         cdev_init(&evdev->cdev, &evdev_fops);
1195         evdev->cdev.kobj.parent = &evdev->dev.kobj;
1196         error = cdev_add(&evdev->cdev, evdev->dev.devt, 1);
1197         if (error)
1198                 goto err_unregister_handle;
1199
1200         error = device_add(&evdev->dev);
1201         if (error)
1202                 goto err_cleanup_evdev;
1203
1204         return 0;
1205
1206  err_cleanup_evdev:
1207         evdev_cleanup(evdev);
1208  err_unregister_handle:
1209         input_unregister_handle(&evdev->handle);
1210  err_free_evdev:
1211         put_device(&evdev->dev);
1212  err_free_minor:
1213         input_free_minor(minor);
1214         return error;
1215 }
1216
1217 static void evdev_disconnect(struct input_handle *handle)
1218 {
1219         struct evdev *evdev = handle->private;
1220
1221         device_del(&evdev->dev);
1222         evdev_cleanup(evdev);
1223         input_free_minor(MINOR(evdev->dev.devt));
1224         input_unregister_handle(handle);
1225         put_device(&evdev->dev);
1226 }
1227
1228 static const struct input_device_id evdev_ids[] = {
1229         { .driver_info = 1 },   /* Matches all devices */
1230         { },                    /* Terminating zero entry */
1231 };
1232
1233 MODULE_DEVICE_TABLE(input, evdev_ids);
1234
1235 static struct input_handler evdev_handler = {
1236         .event          = evdev_event,
1237         .events         = evdev_events,
1238         .connect        = evdev_connect,
1239         .disconnect     = evdev_disconnect,
1240         .legacy_minors  = true,
1241         .minor          = EVDEV_MINOR_BASE,
1242         .name           = "evdev",
1243         .id_table       = evdev_ids,
1244 };
1245
1246 static int __init evdev_init(void)
1247 {
1248         return input_register_handler(&evdev_handler);
1249 }
1250
1251 static void __exit evdev_exit(void)
1252 {
1253         input_unregister_handler(&evdev_handler);
1254 }
1255
1256 module_init(evdev_init);
1257 module_exit(evdev_exit);
1258
1259 MODULE_AUTHOR("Vojtech Pavlik <[email protected]>");
1260 MODULE_DESCRIPTION("Input driver event char devices");
1261 MODULE_LICENSE("GPL");