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 EVDEV_MINOR_BASE 64 12 #define EVDEV_MINORS 32 13 #define EVDEV_MIN_BUFFER_SIZE 64U 14 #define EVDEV_BUF_PACKETS 8 15 16 #include <linux/poll.h> 17 #include <linux/sched.h> 18 #include <linux/slab.h> 19 #include <linux/module.h> 20 #include <linux/init.h> 21 #include <linux/input.h> 22 #include <linux/major.h> 23 #include <linux/device.h> 24 #include "input-compat.h" 25 26 struct evdev { 27 int open; 28 int minor; 29 struct input_handle handle; 30 wait_queue_head_t wait; 31 struct evdev_client __rcu *grab; 32 struct list_head client_list; 33 spinlock_t client_lock; /* protects client_list */ 34 struct mutex mutex; 35 struct device dev; 36 bool exist; 37 }; 38 39 struct evdev_client { 40 int head; 41 int tail; 42 spinlock_t buffer_lock; /* protects access to buffer, head and tail */ 43 struct fasync_struct *fasync; 44 struct evdev *evdev; 45 struct list_head node; 46 int bufsize; 47 struct input_event buffer[]; 48 }; 49 50 static struct evdev *evdev_table[EVDEV_MINORS]; 51 static DEFINE_MUTEX(evdev_table_mutex); 52 53 static void evdev_pass_event(struct evdev_client *client, 54 struct input_event *event) 55 { 56 /* 57 * Interrupts are disabled, just acquire the lock. 58 * Make sure we don't leave with the client buffer 59 * "empty" by having client->head == client->tail. 60 */ 61 spin_lock(&client->buffer_lock); 62 do { 63 client->buffer[client->head++] = *event; 64 client->head &= client->bufsize - 1; 65 } while (client->head == client->tail); 66 spin_unlock(&client->buffer_lock); 67 68 if (event->type == EV_SYN) 69 kill_fasync(&client->fasync, SIGIO, POLL_IN); 70 } 71 72 /* 73 * Pass incoming event to all connected clients. 74 */ 75 static void evdev_event(struct input_handle *handle, 76 unsigned int type, unsigned int code, int value) 77 { 78 struct evdev *evdev = handle->private; 79 struct evdev_client *client; 80 struct input_event event; 81 82 do_gettimeofday(&event.time); 83 event.type = type; 84 event.code = code; 85 event.value = value; 86 87 rcu_read_lock(); 88 89 client = rcu_dereference(evdev->grab); 90 if (client) 91 evdev_pass_event(client, &event); 92 else 93 list_for_each_entry_rcu(client, &evdev->client_list, node) 94 evdev_pass_event(client, &event); 95 96 rcu_read_unlock(); 97 98 wake_up_interruptible(&evdev->wait); 99 } 100 101 static int evdev_fasync(int fd, struct file *file, int on) 102 { 103 struct evdev_client *client = file->private_data; 104 105 return fasync_helper(fd, file, on, &client->fasync); 106 } 107 108 static int evdev_flush(struct file *file, fl_owner_t id) 109 { 110 struct evdev_client *client = file->private_data; 111 struct evdev *evdev = client->evdev; 112 int retval; 113 114 retval = mutex_lock_interruptible(&evdev->mutex); 115 if (retval) 116 return retval; 117 118 if (!evdev->exist) 119 retval = -ENODEV; 120 else 121 retval = input_flush_device(&evdev->handle, file); 122 123 mutex_unlock(&evdev->mutex); 124 return retval; 125 } 126 127 static void evdev_free(struct device *dev) 128 { 129 struct evdev *evdev = container_of(dev, struct evdev, dev); 130 131 input_put_device(evdev->handle.dev); 132 kfree(evdev); 133 } 134 135 /* 136 * Grabs an event device (along with underlying input device). 137 * This function is called with evdev->mutex taken. 138 */ 139 static int evdev_grab(struct evdev *evdev, struct evdev_client *client) 140 { 141 int error; 142 143 if (evdev->grab) 144 return -EBUSY; 145 146 error = input_grab_device(&evdev->handle); 147 if (error) 148 return error; 149 150 rcu_assign_pointer(evdev->grab, client); 151 synchronize_rcu(); 152 153 return 0; 154 } 155 156 static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client) 157 { 158 if (evdev->grab != client) 159 return -EINVAL; 160 161 rcu_assign_pointer(evdev->grab, NULL); 162 synchronize_rcu(); 163 input_release_device(&evdev->handle); 164 165 return 0; 166 } 167 168 static void evdev_attach_client(struct evdev *evdev, 169 struct evdev_client *client) 170 { 171 spin_lock(&evdev->client_lock); 172 list_add_tail_rcu(&client->node, &evdev->client_list); 173 spin_unlock(&evdev->client_lock); 174 synchronize_rcu(); 175 } 176 177 static void evdev_detach_client(struct evdev *evdev, 178 struct evdev_client *client) 179 { 180 spin_lock(&evdev->client_lock); 181 list_del_rcu(&client->node); 182 spin_unlock(&evdev->client_lock); 183 synchronize_rcu(); 184 } 185 186 static int evdev_open_device(struct evdev *evdev) 187 { 188 int retval; 189 190 retval = mutex_lock_interruptible(&evdev->mutex); 191 if (retval) 192 return retval; 193 194 if (!evdev->exist) 195 retval = -ENODEV; 196 else if (!evdev->open++) { 197 retval = input_open_device(&evdev->handle); 198 if (retval) 199 evdev->open--; 200 } 201 202 mutex_unlock(&evdev->mutex); 203 return retval; 204 } 205 206 static void evdev_close_device(struct evdev *evdev) 207 { 208 mutex_lock(&evdev->mutex); 209 210 if (evdev->exist && !--evdev->open) 211 input_close_device(&evdev->handle); 212 213 mutex_unlock(&evdev->mutex); 214 } 215 216 /* 217 * Wake up users waiting for IO so they can disconnect from 218 * dead device. 219 */ 220 static void evdev_hangup(struct evdev *evdev) 221 { 222 struct evdev_client *client; 223 224 spin_lock(&evdev->client_lock); 225 list_for_each_entry(client, &evdev->client_list, node) 226 kill_fasync(&client->fasync, SIGIO, POLL_HUP); 227 spin_unlock(&evdev->client_lock); 228 229 wake_up_interruptible(&evdev->wait); 230 } 231 232 static int evdev_release(struct inode *inode, struct file *file) 233 { 234 struct evdev_client *client = file->private_data; 235 struct evdev *evdev = client->evdev; 236 237 mutex_lock(&evdev->mutex); 238 if (evdev->grab == client) 239 evdev_ungrab(evdev, client); 240 mutex_unlock(&evdev->mutex); 241 242 evdev_detach_client(evdev, client); 243 kfree(client); 244 245 evdev_close_device(evdev); 246 put_device(&evdev->dev); 247 248 return 0; 249 } 250 251 static unsigned int evdev_compute_buffer_size(struct input_dev *dev) 252 { 253 unsigned int n_events = 254 max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS, 255 EVDEV_MIN_BUFFER_SIZE); 256 257 return roundup_pow_of_two(n_events); 258 } 259 260 static int evdev_open(struct inode *inode, struct file *file) 261 { 262 struct evdev *evdev; 263 struct evdev_client *client; 264 int i = iminor(inode) - EVDEV_MINOR_BASE; 265 unsigned int bufsize; 266 int error; 267 268 if (i >= EVDEV_MINORS) 269 return -ENODEV; 270 271 error = mutex_lock_interruptible(&evdev_table_mutex); 272 if (error) 273 return error; 274 evdev = evdev_table[i]; 275 if (evdev) 276 get_device(&evdev->dev); 277 mutex_unlock(&evdev_table_mutex); 278 279 if (!evdev) 280 return -ENODEV; 281 282 bufsize = evdev_compute_buffer_size(evdev->handle.dev); 283 284 client = kzalloc(sizeof(struct evdev_client) + 285 bufsize * sizeof(struct input_event), 286 GFP_KERNEL); 287 if (!client) { 288 error = -ENOMEM; 289 goto err_put_evdev; 290 } 291 292 client->bufsize = bufsize; 293 spin_lock_init(&client->buffer_lock); 294 client->evdev = evdev; 295 evdev_attach_client(evdev, client); 296 297 error = evdev_open_device(evdev); 298 if (error) 299 goto err_free_client; 300 301 file->private_data = client; 302 nonseekable_open(inode, file); 303 304 return 0; 305 306 err_free_client: 307 evdev_detach_client(evdev, client); 308 kfree(client); 309 err_put_evdev: 310 put_device(&evdev->dev); 311 return error; 312 } 313 314 static ssize_t evdev_write(struct file *file, const char __user *buffer, 315 size_t count, loff_t *ppos) 316 { 317 struct evdev_client *client = file->private_data; 318 struct evdev *evdev = client->evdev; 319 struct input_event event; 320 int retval; 321 322 retval = mutex_lock_interruptible(&evdev->mutex); 323 if (retval) 324 return retval; 325 326 if (!evdev->exist) { 327 retval = -ENODEV; 328 goto out; 329 } 330 331 while (retval < count) { 332 333 if (input_event_from_user(buffer + retval, &event)) { 334 retval = -EFAULT; 335 goto out; 336 } 337 338 input_inject_event(&evdev->handle, 339 event.type, event.code, event.value); 340 retval += input_event_size(); 341 } 342 343 out: 344 mutex_unlock(&evdev->mutex); 345 return retval; 346 } 347 348 static int evdev_fetch_next_event(struct evdev_client *client, 349 struct input_event *event) 350 { 351 int have_event; 352 353 spin_lock_irq(&client->buffer_lock); 354 355 have_event = client->head != client->tail; 356 if (have_event) { 357 *event = client->buffer[client->tail++]; 358 client->tail &= client->bufsize - 1; 359 } 360 361 spin_unlock_irq(&client->buffer_lock); 362 363 return have_event; 364 } 365 366 static ssize_t evdev_read(struct file *file, char __user *buffer, 367 size_t count, loff_t *ppos) 368 { 369 struct evdev_client *client = file->private_data; 370 struct evdev *evdev = client->evdev; 371 struct input_event event; 372 int retval; 373 374 if (count < input_event_size()) 375 return -EINVAL; 376 377 if (client->head == client->tail && evdev->exist && 378 (file->f_flags & O_NONBLOCK)) 379 return -EAGAIN; 380 381 retval = wait_event_interruptible(evdev->wait, 382 client->head != client->tail || !evdev->exist); 383 if (retval) 384 return retval; 385 386 if (!evdev->exist) 387 return -ENODEV; 388 389 while (retval + input_event_size() <= count && 390 evdev_fetch_next_event(client, &event)) { 391 392 if (input_event_to_user(buffer + retval, &event)) 393 return -EFAULT; 394 395 retval += input_event_size(); 396 } 397 398 return retval; 399 } 400 401 /* No kernel lock - fine */ 402 static unsigned int evdev_poll(struct file *file, poll_table *wait) 403 { 404 struct evdev_client *client = file->private_data; 405 struct evdev *evdev = client->evdev; 406 unsigned int mask; 407 408 poll_wait(file, &evdev->wait, wait); 409 410 mask = evdev->exist ? POLLOUT | POLLWRNORM : POLLHUP | POLLERR; 411 if (client->head != client->tail) 412 mask |= POLLIN | POLLRDNORM; 413 414 return mask; 415 } 416 417 #ifdef CONFIG_COMPAT 418 419 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8) 420 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1) 421 422 #ifdef __BIG_ENDIAN 423 static int bits_to_user(unsigned long *bits, unsigned int maxbit, 424 unsigned int maxlen, void __user *p, int compat) 425 { 426 int len, i; 427 428 if (compat) { 429 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t); 430 if (len > maxlen) 431 len = maxlen; 432 433 for (i = 0; i < len / sizeof(compat_long_t); i++) 434 if (copy_to_user((compat_long_t __user *) p + i, 435 (compat_long_t *) bits + 436 i + 1 - ((i % 2) << 1), 437 sizeof(compat_long_t))) 438 return -EFAULT; 439 } else { 440 len = BITS_TO_LONGS(maxbit) * sizeof(long); 441 if (len > maxlen) 442 len = maxlen; 443 444 if (copy_to_user(p, bits, len)) 445 return -EFAULT; 446 } 447 448 return len; 449 } 450 #else 451 static int bits_to_user(unsigned long *bits, unsigned int maxbit, 452 unsigned int maxlen, void __user *p, int compat) 453 { 454 int len = compat ? 455 BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) : 456 BITS_TO_LONGS(maxbit) * sizeof(long); 457 458 if (len > maxlen) 459 len = maxlen; 460 461 return copy_to_user(p, bits, len) ? -EFAULT : len; 462 } 463 #endif /* __BIG_ENDIAN */ 464 465 #else 466 467 static int bits_to_user(unsigned long *bits, unsigned int maxbit, 468 unsigned int maxlen, void __user *p, int compat) 469 { 470 int len = BITS_TO_LONGS(maxbit) * sizeof(long); 471 472 if (len > maxlen) 473 len = maxlen; 474 475 return copy_to_user(p, bits, len) ? -EFAULT : len; 476 } 477 478 #endif /* CONFIG_COMPAT */ 479 480 static int str_to_user(const char *str, unsigned int maxlen, void __user *p) 481 { 482 int len; 483 484 if (!str) 485 return -ENOENT; 486 487 len = strlen(str) + 1; 488 if (len > maxlen) 489 len = maxlen; 490 491 return copy_to_user(p, str, len) ? -EFAULT : len; 492 } 493 494 #define OLD_KEY_MAX 0x1ff 495 static int handle_eviocgbit(struct input_dev *dev, 496 unsigned int type, unsigned int size, 497 void __user *p, int compat_mode) 498 { 499 static unsigned long keymax_warn_time; 500 unsigned long *bits; 501 int len; 502 503 switch (type) { 504 505 case 0: bits = dev->evbit; len = EV_MAX; break; 506 case EV_KEY: bits = dev->keybit; len = KEY_MAX; break; 507 case EV_REL: bits = dev->relbit; len = REL_MAX; break; 508 case EV_ABS: bits = dev->absbit; len = ABS_MAX; break; 509 case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break; 510 case EV_LED: bits = dev->ledbit; len = LED_MAX; break; 511 case EV_SND: bits = dev->sndbit; len = SND_MAX; break; 512 case EV_FF: bits = dev->ffbit; len = FF_MAX; break; 513 case EV_SW: bits = dev->swbit; len = SW_MAX; break; 514 default: return -EINVAL; 515 } 516 517 /* 518 * Work around bugs in userspace programs that like to do 519 * EVIOCGBIT(EV_KEY, KEY_MAX) and not realize that 'len' 520 * should be in bytes, not in bits. 521 */ 522 if (type == EV_KEY && size == OLD_KEY_MAX) { 523 len = OLD_KEY_MAX; 524 if (printk_timed_ratelimit(&keymax_warn_time, 10 * 1000)) 525 printk(KERN_WARNING 526 "evdev.c(EVIOCGBIT): Suspicious buffer size %u, " 527 "limiting output to %zu bytes. See " 528 "http://userweb.kernel.org/~dtor/eviocgbit-bug.html\n", 529 OLD_KEY_MAX, 530 BITS_TO_LONGS(OLD_KEY_MAX) * sizeof(long)); 531 } 532 533 return bits_to_user(bits, len, size, p, compat_mode); 534 } 535 #undef OLD_KEY_MAX 536 537 static int evdev_handle_get_keycode(struct input_dev *dev, 538 void __user *p, size_t size) 539 { 540 struct input_keymap_entry ke; 541 int error; 542 543 memset(&ke, 0, sizeof(ke)); 544 545 if (size == sizeof(unsigned int[2])) { 546 /* legacy case */ 547 int __user *ip = (int __user *)p; 548 549 if (copy_from_user(ke.scancode, p, sizeof(unsigned int))) 550 return -EFAULT; 551 552 ke.len = sizeof(unsigned int); 553 ke.flags = 0; 554 555 error = input_get_keycode(dev, &ke); 556 if (error) 557 return error; 558 559 if (put_user(ke.keycode, ip + 1)) 560 return -EFAULT; 561 562 } else { 563 size = min(size, sizeof(ke)); 564 565 if (copy_from_user(&ke, p, size)) 566 return -EFAULT; 567 568 error = input_get_keycode(dev, &ke); 569 if (error) 570 return error; 571 572 if (copy_to_user(p, &ke, size)) 573 return -EFAULT; 574 } 575 return 0; 576 } 577 578 static int evdev_handle_set_keycode(struct input_dev *dev, 579 void __user *p, size_t size) 580 { 581 struct input_keymap_entry ke; 582 583 memset(&ke, 0, sizeof(ke)); 584 585 if (size == sizeof(unsigned int[2])) { 586 /* legacy case */ 587 int __user *ip = (int __user *)p; 588 589 if (copy_from_user(ke.scancode, p, sizeof(unsigned int))) 590 return -EFAULT; 591 592 if (get_user(ke.keycode, ip + 1)) 593 return -EFAULT; 594 595 ke.len = sizeof(unsigned int); 596 ke.flags = 0; 597 598 } else { 599 size = min(size, sizeof(ke)); 600 601 if (copy_from_user(&ke, p, size)) 602 return -EFAULT; 603 604 if (ke.len > sizeof(ke.scancode)) 605 return -EINVAL; 606 } 607 608 return input_set_keycode(dev, &ke); 609 } 610 611 static long evdev_do_ioctl(struct file *file, unsigned int cmd, 612 void __user *p, int compat_mode) 613 { 614 struct evdev_client *client = file->private_data; 615 struct evdev *evdev = client->evdev; 616 struct input_dev *dev = evdev->handle.dev; 617 struct input_absinfo abs; 618 struct ff_effect effect; 619 int __user *ip = (int __user *)p; 620 unsigned int i, t, u, v; 621 unsigned int size; 622 int error; 623 624 /* First we check for fixed-length commands */ 625 switch (cmd) { 626 627 case EVIOCGVERSION: 628 return put_user(EV_VERSION, ip); 629 630 case EVIOCGID: 631 if (copy_to_user(p, &dev->id, sizeof(struct input_id))) 632 return -EFAULT; 633 return 0; 634 635 case EVIOCGREP: 636 if (!test_bit(EV_REP, dev->evbit)) 637 return -ENOSYS; 638 if (put_user(dev->rep[REP_DELAY], ip)) 639 return -EFAULT; 640 if (put_user(dev->rep[REP_PERIOD], ip + 1)) 641 return -EFAULT; 642 return 0; 643 644 case EVIOCSREP: 645 if (!test_bit(EV_REP, dev->evbit)) 646 return -ENOSYS; 647 if (get_user(u, ip)) 648 return -EFAULT; 649 if (get_user(v, ip + 1)) 650 return -EFAULT; 651 652 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u); 653 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v); 654 655 return 0; 656 657 case EVIOCRMFF: 658 return input_ff_erase(dev, (int)(unsigned long) p, file); 659 660 case EVIOCGEFFECTS: 661 i = test_bit(EV_FF, dev->evbit) ? 662 dev->ff->max_effects : 0; 663 if (put_user(i, ip)) 664 return -EFAULT; 665 return 0; 666 667 case EVIOCGRAB: 668 if (p) 669 return evdev_grab(evdev, client); 670 else 671 return evdev_ungrab(evdev, client); 672 } 673 674 size = _IOC_SIZE(cmd); 675 676 /* Now check variable-length commands */ 677 #define EVIOC_MASK_SIZE(nr) ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT)) 678 switch (EVIOC_MASK_SIZE(cmd)) { 679 680 case EVIOCGKEY(0): 681 return bits_to_user(dev->key, KEY_MAX, size, p, compat_mode); 682 683 case EVIOCGLED(0): 684 return bits_to_user(dev->led, LED_MAX, size, p, compat_mode); 685 686 case EVIOCGSND(0): 687 return bits_to_user(dev->snd, SND_MAX, size, p, compat_mode); 688 689 case EVIOCGSW(0): 690 return bits_to_user(dev->sw, SW_MAX, size, p, compat_mode); 691 692 case EVIOCGNAME(0): 693 return str_to_user(dev->name, size, p); 694 695 case EVIOCGPHYS(0): 696 return str_to_user(dev->phys, size, p); 697 698 case EVIOCGUNIQ(0): 699 return str_to_user(dev->uniq, size, p); 700 701 case EVIOC_MASK_SIZE(EVIOCSFF): 702 if (input_ff_effect_from_user(p, size, &effect)) 703 return -EFAULT; 704 705 error = input_ff_upload(dev, &effect, file); 706 707 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id))) 708 return -EFAULT; 709 710 return error; 711 712 case EVIOC_MASK_SIZE(EVIOCGKEYCODE): 713 return evdev_handle_get_keycode(dev, p, size); 714 715 case EVIOC_MASK_SIZE(EVIOCSKEYCODE): 716 return evdev_handle_set_keycode(dev, p, size); 717 } 718 719 /* Multi-number variable-length handlers */ 720 if (_IOC_TYPE(cmd) != 'E') 721 return -EINVAL; 722 723 if (_IOC_DIR(cmd) == _IOC_READ) { 724 725 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0))) 726 return handle_eviocgbit(dev, 727 _IOC_NR(cmd) & EV_MAX, size, 728 p, compat_mode); 729 730 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) { 731 732 if (!dev->absinfo) 733 return -EINVAL; 734 735 t = _IOC_NR(cmd) & ABS_MAX; 736 abs = dev->absinfo[t]; 737 738 if (copy_to_user(p, &abs, min_t(size_t, 739 size, sizeof(struct input_absinfo)))) 740 return -EFAULT; 741 742 return 0; 743 } 744 } 745 746 if (_IOC_DIR(cmd) == _IOC_WRITE) { 747 748 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) { 749 750 if (!dev->absinfo) 751 return -EINVAL; 752 753 t = _IOC_NR(cmd) & ABS_MAX; 754 755 if (copy_from_user(&abs, p, min_t(size_t, 756 size, sizeof(struct input_absinfo)))) 757 return -EFAULT; 758 759 if (size < sizeof(struct input_absinfo)) 760 abs.resolution = 0; 761 762 /* We can't change number of reserved MT slots */ 763 if (t == ABS_MT_SLOT) 764 return -EINVAL; 765 766 /* 767 * Take event lock to ensure that we are not 768 * changing device parameters in the middle 769 * of event. 770 */ 771 spin_lock_irq(&dev->event_lock); 772 dev->absinfo[t] = abs; 773 spin_unlock_irq(&dev->event_lock); 774 775 return 0; 776 } 777 } 778 779 return -EINVAL; 780 } 781 782 static long evdev_ioctl_handler(struct file *file, unsigned int cmd, 783 void __user *p, int compat_mode) 784 { 785 struct evdev_client *client = file->private_data; 786 struct evdev *evdev = client->evdev; 787 int retval; 788 789 retval = mutex_lock_interruptible(&evdev->mutex); 790 if (retval) 791 return retval; 792 793 if (!evdev->exist) { 794 retval = -ENODEV; 795 goto out; 796 } 797 798 retval = evdev_do_ioctl(file, cmd, p, compat_mode); 799 800 out: 801 mutex_unlock(&evdev->mutex); 802 return retval; 803 } 804 805 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 806 { 807 return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0); 808 } 809 810 #ifdef CONFIG_COMPAT 811 static long evdev_ioctl_compat(struct file *file, 812 unsigned int cmd, unsigned long arg) 813 { 814 return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1); 815 } 816 #endif 817 818 static const struct file_operations evdev_fops = { 819 .owner = THIS_MODULE, 820 .read = evdev_read, 821 .write = evdev_write, 822 .poll = evdev_poll, 823 .open = evdev_open, 824 .release = evdev_release, 825 .unlocked_ioctl = evdev_ioctl, 826 #ifdef CONFIG_COMPAT 827 .compat_ioctl = evdev_ioctl_compat, 828 #endif 829 .fasync = evdev_fasync, 830 .flush = evdev_flush, 831 .llseek = no_llseek, 832 }; 833 834 static int evdev_install_chrdev(struct evdev *evdev) 835 { 836 /* 837 * No need to do any locking here as calls to connect and 838 * disconnect are serialized by the input core 839 */ 840 evdev_table[evdev->minor] = evdev; 841 return 0; 842 } 843 844 static void evdev_remove_chrdev(struct evdev *evdev) 845 { 846 /* 847 * Lock evdev table to prevent race with evdev_open() 848 */ 849 mutex_lock(&evdev_table_mutex); 850 evdev_table[evdev->minor] = NULL; 851 mutex_unlock(&evdev_table_mutex); 852 } 853 854 /* 855 * Mark device non-existent. This disables writes, ioctls and 856 * prevents new users from opening the device. Already posted 857 * blocking reads will stay, however new ones will fail. 858 */ 859 static void evdev_mark_dead(struct evdev *evdev) 860 { 861 mutex_lock(&evdev->mutex); 862 evdev->exist = false; 863 mutex_unlock(&evdev->mutex); 864 } 865 866 static void evdev_cleanup(struct evdev *evdev) 867 { 868 struct input_handle *handle = &evdev->handle; 869 870 evdev_mark_dead(evdev); 871 evdev_hangup(evdev); 872 evdev_remove_chrdev(evdev); 873 874 /* evdev is marked dead so no one else accesses evdev->open */ 875 if (evdev->open) { 876 input_flush_device(handle, NULL); 877 input_close_device(handle); 878 } 879 } 880 881 /* 882 * Create new evdev device. Note that input core serializes calls 883 * to connect and disconnect so we don't need to lock evdev_table here. 884 */ 885 static int evdev_connect(struct input_handler *handler, struct input_dev *dev, 886 const struct input_device_id *id) 887 { 888 struct evdev *evdev; 889 int minor; 890 int error; 891 892 for (minor = 0; minor < EVDEV_MINORS; minor++) 893 if (!evdev_table[minor]) 894 break; 895 896 if (minor == EVDEV_MINORS) { 897 printk(KERN_ERR "evdev: no more free evdev devices\n"); 898 return -ENFILE; 899 } 900 901 evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL); 902 if (!evdev) 903 return -ENOMEM; 904 905 INIT_LIST_HEAD(&evdev->client_list); 906 spin_lock_init(&evdev->client_lock); 907 mutex_init(&evdev->mutex); 908 init_waitqueue_head(&evdev->wait); 909 910 dev_set_name(&evdev->dev, "event%d", minor); 911 evdev->exist = true; 912 evdev->minor = minor; 913 914 evdev->handle.dev = input_get_device(dev); 915 evdev->handle.name = dev_name(&evdev->dev); 916 evdev->handle.handler = handler; 917 evdev->handle.private = evdev; 918 919 evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor); 920 evdev->dev.class = &input_class; 921 evdev->dev.parent = &dev->dev; 922 evdev->dev.release = evdev_free; 923 device_initialize(&evdev->dev); 924 925 error = input_register_handle(&evdev->handle); 926 if (error) 927 goto err_free_evdev; 928 929 error = evdev_install_chrdev(evdev); 930 if (error) 931 goto err_unregister_handle; 932 933 error = device_add(&evdev->dev); 934 if (error) 935 goto err_cleanup_evdev; 936 937 return 0; 938 939 err_cleanup_evdev: 940 evdev_cleanup(evdev); 941 err_unregister_handle: 942 input_unregister_handle(&evdev->handle); 943 err_free_evdev: 944 put_device(&evdev->dev); 945 return error; 946 } 947 948 static void evdev_disconnect(struct input_handle *handle) 949 { 950 struct evdev *evdev = handle->private; 951 952 device_del(&evdev->dev); 953 evdev_cleanup(evdev); 954 input_unregister_handle(handle); 955 put_device(&evdev->dev); 956 } 957 958 static const struct input_device_id evdev_ids[] = { 959 { .driver_info = 1 }, /* Matches all devices */ 960 { }, /* Terminating zero entry */ 961 }; 962 963 MODULE_DEVICE_TABLE(input, evdev_ids); 964 965 static struct input_handler evdev_handler = { 966 .event = evdev_event, 967 .connect = evdev_connect, 968 .disconnect = evdev_disconnect, 969 .fops = &evdev_fops, 970 .minor = EVDEV_MINOR_BASE, 971 .name = "evdev", 972 .id_table = evdev_ids, 973 }; 974 975 static int __init evdev_init(void) 976 { 977 return input_register_handler(&evdev_handler); 978 } 979 980 static void __exit evdev_exit(void) 981 { 982 input_unregister_handler(&evdev_handler); 983 } 984 985 module_init(evdev_init); 986 module_exit(evdev_exit); 987 988 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>"); 989 MODULE_DESCRIPTION("Input driver event char devices"); 990 MODULE_LICENSE("GPL"); 991