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