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/module.h> 22 #include <linux/init.h> 23 #include <linux/input.h> 24 #include <linux/major.h> 25 #include <linux/device.h> 26 #include "input-compat.h" 27 28 struct evdev { 29 int open; 30 int minor; 31 struct input_handle handle; 32 wait_queue_head_t wait; 33 struct evdev_client __rcu *grab; 34 struct list_head client_list; 35 spinlock_t client_lock; /* protects client_list */ 36 struct mutex mutex; 37 struct device dev; 38 bool exist; 39 }; 40 41 struct evdev_client { 42 int head; 43 int tail; 44 spinlock_t buffer_lock; /* protects access to buffer, head and tail */ 45 struct fasync_struct *fasync; 46 struct evdev *evdev; 47 struct list_head node; 48 int bufsize; 49 struct input_event buffer[]; 50 }; 51 52 static struct evdev *evdev_table[EVDEV_MINORS]; 53 static DEFINE_MUTEX(evdev_table_mutex); 54 55 static void evdev_pass_event(struct evdev_client *client, 56 struct input_event *event) 57 { 58 /* 59 * Interrupts are disabled, just acquire the lock. 60 * Make sure we don't leave with the client buffer 61 * "empty" by having client->head == client->tail. 62 */ 63 spin_lock(&client->buffer_lock); 64 do { 65 client->buffer[client->head++] = *event; 66 client->head &= client->bufsize - 1; 67 } while (client->head == client->tail); 68 spin_unlock(&client->buffer_lock); 69 70 if (event->type == EV_SYN) 71 kill_fasync(&client->fasync, SIGIO, POLL_IN); 72 } 73 74 /* 75 * Pass incoming event to all connected clients. 76 */ 77 static void evdev_event(struct input_handle *handle, 78 unsigned int type, unsigned int code, int value) 79 { 80 struct evdev *evdev = handle->private; 81 struct evdev_client *client; 82 struct input_event event; 83 84 do_gettimeofday(&event.time); 85 event.type = type; 86 event.code = code; 87 event.value = value; 88 89 rcu_read_lock(); 90 91 client = rcu_dereference(evdev->grab); 92 if (client) 93 evdev_pass_event(client, &event); 94 else 95 list_for_each_entry_rcu(client, &evdev->client_list, node) 96 evdev_pass_event(client, &event); 97 98 rcu_read_unlock(); 99 100 wake_up_interruptible(&evdev->wait); 101 } 102 103 static int evdev_fasync(int fd, struct file *file, int on) 104 { 105 struct evdev_client *client = file->private_data; 106 107 return fasync_helper(fd, file, on, &client->fasync); 108 } 109 110 static int evdev_flush(struct file *file, fl_owner_t id) 111 { 112 struct evdev_client *client = file->private_data; 113 struct evdev *evdev = client->evdev; 114 int retval; 115 116 retval = mutex_lock_interruptible(&evdev->mutex); 117 if (retval) 118 return retval; 119 120 if (!evdev->exist) 121 retval = -ENODEV; 122 else 123 retval = input_flush_device(&evdev->handle, file); 124 125 mutex_unlock(&evdev->mutex); 126 return retval; 127 } 128 129 static void evdev_free(struct device *dev) 130 { 131 struct evdev *evdev = container_of(dev, struct evdev, dev); 132 133 input_put_device(evdev->handle.dev); 134 kfree(evdev); 135 } 136 137 /* 138 * Grabs an event device (along with underlying input device). 139 * This function is called with evdev->mutex taken. 140 */ 141 static int evdev_grab(struct evdev *evdev, struct evdev_client *client) 142 { 143 int error; 144 145 if (evdev->grab) 146 return -EBUSY; 147 148 error = input_grab_device(&evdev->handle); 149 if (error) 150 return error; 151 152 rcu_assign_pointer(evdev->grab, client); 153 synchronize_rcu(); 154 155 return 0; 156 } 157 158 static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client) 159 { 160 if (evdev->grab != client) 161 return -EINVAL; 162 163 rcu_assign_pointer(evdev->grab, NULL); 164 synchronize_rcu(); 165 input_release_device(&evdev->handle); 166 167 return 0; 168 } 169 170 static void evdev_attach_client(struct evdev *evdev, 171 struct evdev_client *client) 172 { 173 spin_lock(&evdev->client_lock); 174 list_add_tail_rcu(&client->node, &evdev->client_list); 175 spin_unlock(&evdev->client_lock); 176 synchronize_rcu(); 177 } 178 179 static void evdev_detach_client(struct evdev *evdev, 180 struct evdev_client *client) 181 { 182 spin_lock(&evdev->client_lock); 183 list_del_rcu(&client->node); 184 spin_unlock(&evdev->client_lock); 185 synchronize_rcu(); 186 } 187 188 static int evdev_open_device(struct evdev *evdev) 189 { 190 int retval; 191 192 retval = mutex_lock_interruptible(&evdev->mutex); 193 if (retval) 194 return retval; 195 196 if (!evdev->exist) 197 retval = -ENODEV; 198 else if (!evdev->open++) { 199 retval = input_open_device(&evdev->handle); 200 if (retval) 201 evdev->open--; 202 } 203 204 mutex_unlock(&evdev->mutex); 205 return retval; 206 } 207 208 static void evdev_close_device(struct evdev *evdev) 209 { 210 mutex_lock(&evdev->mutex); 211 212 if (evdev->exist && !--evdev->open) 213 input_close_device(&evdev->handle); 214 215 mutex_unlock(&evdev->mutex); 216 } 217 218 /* 219 * Wake up users waiting for IO so they can disconnect from 220 * dead device. 221 */ 222 static void evdev_hangup(struct evdev *evdev) 223 { 224 struct evdev_client *client; 225 226 spin_lock(&evdev->client_lock); 227 list_for_each_entry(client, &evdev->client_list, node) 228 kill_fasync(&client->fasync, SIGIO, POLL_HUP); 229 spin_unlock(&evdev->client_lock); 230 231 wake_up_interruptible(&evdev->wait); 232 } 233 234 static int evdev_release(struct inode *inode, struct file *file) 235 { 236 struct evdev_client *client = file->private_data; 237 struct evdev *evdev = client->evdev; 238 239 mutex_lock(&evdev->mutex); 240 if (evdev->grab == client) 241 evdev_ungrab(evdev, client); 242 mutex_unlock(&evdev->mutex); 243 244 evdev_detach_client(evdev, client); 245 kfree(client); 246 247 evdev_close_device(evdev); 248 put_device(&evdev->dev); 249 250 return 0; 251 } 252 253 static unsigned int evdev_compute_buffer_size(struct input_dev *dev) 254 { 255 unsigned int n_events = 256 max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS, 257 EVDEV_MIN_BUFFER_SIZE); 258 259 return roundup_pow_of_two(n_events); 260 } 261 262 static int evdev_open(struct inode *inode, struct file *file) 263 { 264 struct evdev *evdev; 265 struct evdev_client *client; 266 int i = iminor(inode) - EVDEV_MINOR_BASE; 267 unsigned int bufsize; 268 int error; 269 270 if (i >= EVDEV_MINORS) 271 return -ENODEV; 272 273 error = mutex_lock_interruptible(&evdev_table_mutex); 274 if (error) 275 return error; 276 evdev = evdev_table[i]; 277 if (evdev) 278 get_device(&evdev->dev); 279 mutex_unlock(&evdev_table_mutex); 280 281 if (!evdev) 282 return -ENODEV; 283 284 bufsize = evdev_compute_buffer_size(evdev->handle.dev); 285 286 client = kzalloc(sizeof(struct evdev_client) + 287 bufsize * sizeof(struct input_event), 288 GFP_KERNEL); 289 if (!client) { 290 error = -ENOMEM; 291 goto err_put_evdev; 292 } 293 294 client->bufsize = bufsize; 295 spin_lock_init(&client->buffer_lock); 296 client->evdev = evdev; 297 evdev_attach_client(evdev, client); 298 299 error = evdev_open_device(evdev); 300 if (error) 301 goto err_free_client; 302 303 file->private_data = client; 304 nonseekable_open(inode, file); 305 306 return 0; 307 308 err_free_client: 309 evdev_detach_client(evdev, client); 310 kfree(client); 311 err_put_evdev: 312 put_device(&evdev->dev); 313 return error; 314 } 315 316 static ssize_t evdev_write(struct file *file, const char __user *buffer, 317 size_t count, loff_t *ppos) 318 { 319 struct evdev_client *client = file->private_data; 320 struct evdev *evdev = client->evdev; 321 struct input_event event; 322 int retval; 323 324 if (count < input_event_size()) 325 return -EINVAL; 326 327 retval = mutex_lock_interruptible(&evdev->mutex); 328 if (retval) 329 return retval; 330 331 if (!evdev->exist) { 332 retval = -ENODEV; 333 goto out; 334 } 335 336 do { 337 if (input_event_from_user(buffer + retval, &event)) { 338 retval = -EFAULT; 339 goto out; 340 } 341 retval += input_event_size(); 342 343 input_inject_event(&evdev->handle, 344 event.type, event.code, event.value); 345 } while (retval + input_event_size() <= count); 346 347 out: 348 mutex_unlock(&evdev->mutex); 349 return retval; 350 } 351 352 static int evdev_fetch_next_event(struct evdev_client *client, 353 struct input_event *event) 354 { 355 int have_event; 356 357 spin_lock_irq(&client->buffer_lock); 358 359 have_event = client->head != client->tail; 360 if (have_event) { 361 *event = client->buffer[client->tail++]; 362 client->tail &= client->bufsize - 1; 363 } 364 365 spin_unlock_irq(&client->buffer_lock); 366 367 return have_event; 368 } 369 370 static ssize_t evdev_read(struct file *file, char __user *buffer, 371 size_t count, loff_t *ppos) 372 { 373 struct evdev_client *client = file->private_data; 374 struct evdev *evdev = client->evdev; 375 struct input_event event; 376 int retval; 377 378 if (count < input_event_size()) 379 return -EINVAL; 380 381 if (client->head == client->tail && evdev->exist && 382 (file->f_flags & O_NONBLOCK)) 383 return -EAGAIN; 384 385 retval = wait_event_interruptible(evdev->wait, 386 client->head != client->tail || !evdev->exist); 387 if (retval) 388 return retval; 389 390 if (!evdev->exist) 391 return -ENODEV; 392 393 while (retval + input_event_size() <= count && 394 evdev_fetch_next_event(client, &event)) { 395 396 if (input_event_to_user(buffer + retval, &event)) 397 return -EFAULT; 398 399 retval += input_event_size(); 400 } 401 402 return retval; 403 } 404 405 /* No kernel lock - fine */ 406 static unsigned int evdev_poll(struct file *file, poll_table *wait) 407 { 408 struct evdev_client *client = file->private_data; 409 struct evdev *evdev = client->evdev; 410 unsigned int mask; 411 412 poll_wait(file, &evdev->wait, wait); 413 414 mask = evdev->exist ? POLLOUT | POLLWRNORM : POLLHUP | POLLERR; 415 if (client->head != client->tail) 416 mask |= POLLIN | POLLRDNORM; 417 418 return mask; 419 } 420 421 #ifdef CONFIG_COMPAT 422 423 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8) 424 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1) 425 426 #ifdef __BIG_ENDIAN 427 static int bits_to_user(unsigned long *bits, unsigned int maxbit, 428 unsigned int maxlen, void __user *p, int compat) 429 { 430 int len, i; 431 432 if (compat) { 433 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t); 434 if (len > maxlen) 435 len = maxlen; 436 437 for (i = 0; i < len / sizeof(compat_long_t); i++) 438 if (copy_to_user((compat_long_t __user *) p + i, 439 (compat_long_t *) bits + 440 i + 1 - ((i % 2) << 1), 441 sizeof(compat_long_t))) 442 return -EFAULT; 443 } else { 444 len = BITS_TO_LONGS(maxbit) * sizeof(long); 445 if (len > maxlen) 446 len = maxlen; 447 448 if (copy_to_user(p, bits, len)) 449 return -EFAULT; 450 } 451 452 return len; 453 } 454 #else 455 static int bits_to_user(unsigned long *bits, unsigned int maxbit, 456 unsigned int maxlen, void __user *p, int compat) 457 { 458 int len = compat ? 459 BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) : 460 BITS_TO_LONGS(maxbit) * sizeof(long); 461 462 if (len > maxlen) 463 len = maxlen; 464 465 return copy_to_user(p, bits, len) ? -EFAULT : len; 466 } 467 #endif /* __BIG_ENDIAN */ 468 469 #else 470 471 static int bits_to_user(unsigned long *bits, unsigned int maxbit, 472 unsigned int maxlen, void __user *p, int compat) 473 { 474 int len = BITS_TO_LONGS(maxbit) * sizeof(long); 475 476 if (len > maxlen) 477 len = maxlen; 478 479 return copy_to_user(p, bits, len) ? -EFAULT : len; 480 } 481 482 #endif /* CONFIG_COMPAT */ 483 484 static int str_to_user(const char *str, unsigned int maxlen, void __user *p) 485 { 486 int len; 487 488 if (!str) 489 return -ENOENT; 490 491 len = strlen(str) + 1; 492 if (len > maxlen) 493 len = maxlen; 494 495 return copy_to_user(p, str, len) ? -EFAULT : len; 496 } 497 498 #define OLD_KEY_MAX 0x1ff 499 static int handle_eviocgbit(struct input_dev *dev, 500 unsigned int type, unsigned int size, 501 void __user *p, int compat_mode) 502 { 503 static unsigned long keymax_warn_time; 504 unsigned long *bits; 505 int len; 506 507 switch (type) { 508 509 case 0: bits = dev->evbit; len = EV_MAX; break; 510 case EV_KEY: bits = dev->keybit; len = KEY_MAX; break; 511 case EV_REL: bits = dev->relbit; len = REL_MAX; break; 512 case EV_ABS: bits = dev->absbit; len = ABS_MAX; break; 513 case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break; 514 case EV_LED: bits = dev->ledbit; len = LED_MAX; break; 515 case EV_SND: bits = dev->sndbit; len = SND_MAX; break; 516 case EV_FF: bits = dev->ffbit; len = FF_MAX; break; 517 case EV_SW: bits = dev->swbit; len = SW_MAX; break; 518 default: return -EINVAL; 519 } 520 521 /* 522 * Work around bugs in userspace programs that like to do 523 * EVIOCGBIT(EV_KEY, KEY_MAX) and not realize that 'len' 524 * should be in bytes, not in bits. 525 */ 526 if (type == EV_KEY && size == OLD_KEY_MAX) { 527 len = OLD_KEY_MAX; 528 if (printk_timed_ratelimit(&keymax_warn_time, 10 * 1000)) 529 pr_warning("(EVIOCGBIT): Suspicious buffer size %u, " 530 "limiting output to %zu bytes. See " 531 "http://userweb.kernel.org/~dtor/eviocgbit-bug.html\n", 532 OLD_KEY_MAX, 533 BITS_TO_LONGS(OLD_KEY_MAX) * sizeof(long)); 534 } 535 536 return bits_to_user(bits, len, size, p, compat_mode); 537 } 538 #undef OLD_KEY_MAX 539 540 static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p) 541 { 542 struct input_keymap_entry ke = { 543 .len = sizeof(unsigned int), 544 .flags = 0, 545 }; 546 int __user *ip = (int __user *)p; 547 int error; 548 549 /* legacy case */ 550 if (copy_from_user(ke.scancode, p, sizeof(unsigned int))) 551 return -EFAULT; 552 553 error = input_get_keycode(dev, &ke); 554 if (error) 555 return error; 556 557 if (put_user(ke.keycode, ip + 1)) 558 return -EFAULT; 559 560 return 0; 561 } 562 563 static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p) 564 { 565 struct input_keymap_entry ke; 566 int error; 567 568 if (copy_from_user(&ke, p, sizeof(ke))) 569 return -EFAULT; 570 571 error = input_get_keycode(dev, &ke); 572 if (error) 573 return error; 574 575 if (copy_to_user(p, &ke, sizeof(ke))) 576 return -EFAULT; 577 578 return 0; 579 } 580 581 static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p) 582 { 583 struct input_keymap_entry ke = { 584 .len = sizeof(unsigned int), 585 .flags = 0, 586 }; 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 return input_set_keycode(dev, &ke); 596 } 597 598 static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p) 599 { 600 struct input_keymap_entry ke; 601 602 if (copy_from_user(&ke, p, sizeof(ke))) 603 return -EFAULT; 604 605 if (ke.len > sizeof(ke.scancode)) 606 return -EINVAL; 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 case EVIOCGKEYCODE: 674 return evdev_handle_get_keycode(dev, p); 675 676 case EVIOCSKEYCODE: 677 return evdev_handle_set_keycode(dev, p); 678 679 case EVIOCGKEYCODE_V2: 680 return evdev_handle_get_keycode_v2(dev, p); 681 682 case EVIOCSKEYCODE_V2: 683 return evdev_handle_set_keycode_v2(dev, p); 684 } 685 686 size = _IOC_SIZE(cmd); 687 688 /* Now check variable-length commands */ 689 #define EVIOC_MASK_SIZE(nr) ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT)) 690 switch (EVIOC_MASK_SIZE(cmd)) { 691 692 case EVIOCGPROP(0): 693 return bits_to_user(dev->propbit, INPUT_PROP_MAX, 694 size, p, compat_mode); 695 696 case EVIOCGKEY(0): 697 return bits_to_user(dev->key, KEY_MAX, size, p, compat_mode); 698 699 case EVIOCGLED(0): 700 return bits_to_user(dev->led, LED_MAX, size, p, compat_mode); 701 702 case EVIOCGSND(0): 703 return bits_to_user(dev->snd, SND_MAX, size, p, compat_mode); 704 705 case EVIOCGSW(0): 706 return bits_to_user(dev->sw, SW_MAX, size, p, compat_mode); 707 708 case EVIOCGNAME(0): 709 return str_to_user(dev->name, size, p); 710 711 case EVIOCGPHYS(0): 712 return str_to_user(dev->phys, size, p); 713 714 case EVIOCGUNIQ(0): 715 return str_to_user(dev->uniq, size, p); 716 717 case EVIOC_MASK_SIZE(EVIOCSFF): 718 if (input_ff_effect_from_user(p, size, &effect)) 719 return -EFAULT; 720 721 error = input_ff_upload(dev, &effect, file); 722 723 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id))) 724 return -EFAULT; 725 726 return error; 727 } 728 729 /* Multi-number variable-length handlers */ 730 if (_IOC_TYPE(cmd) != 'E') 731 return -EINVAL; 732 733 if (_IOC_DIR(cmd) == _IOC_READ) { 734 735 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0))) 736 return handle_eviocgbit(dev, 737 _IOC_NR(cmd) & EV_MAX, size, 738 p, compat_mode); 739 740 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) { 741 742 if (!dev->absinfo) 743 return -EINVAL; 744 745 t = _IOC_NR(cmd) & ABS_MAX; 746 abs = dev->absinfo[t]; 747 748 if (copy_to_user(p, &abs, min_t(size_t, 749 size, sizeof(struct input_absinfo)))) 750 return -EFAULT; 751 752 return 0; 753 } 754 } 755 756 if (_IOC_DIR(cmd) == _IOC_WRITE) { 757 758 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) { 759 760 if (!dev->absinfo) 761 return -EINVAL; 762 763 t = _IOC_NR(cmd) & ABS_MAX; 764 765 if (copy_from_user(&abs, p, min_t(size_t, 766 size, sizeof(struct input_absinfo)))) 767 return -EFAULT; 768 769 if (size < sizeof(struct input_absinfo)) 770 abs.resolution = 0; 771 772 /* We can't change number of reserved MT slots */ 773 if (t == ABS_MT_SLOT) 774 return -EINVAL; 775 776 /* 777 * Take event lock to ensure that we are not 778 * changing device parameters in the middle 779 * of event. 780 */ 781 spin_lock_irq(&dev->event_lock); 782 dev->absinfo[t] = abs; 783 spin_unlock_irq(&dev->event_lock); 784 785 return 0; 786 } 787 } 788 789 return -EINVAL; 790 } 791 792 static long evdev_ioctl_handler(struct file *file, unsigned int cmd, 793 void __user *p, int compat_mode) 794 { 795 struct evdev_client *client = file->private_data; 796 struct evdev *evdev = client->evdev; 797 int retval; 798 799 retval = mutex_lock_interruptible(&evdev->mutex); 800 if (retval) 801 return retval; 802 803 if (!evdev->exist) { 804 retval = -ENODEV; 805 goto out; 806 } 807 808 retval = evdev_do_ioctl(file, cmd, p, compat_mode); 809 810 out: 811 mutex_unlock(&evdev->mutex); 812 return retval; 813 } 814 815 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 816 { 817 return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0); 818 } 819 820 #ifdef CONFIG_COMPAT 821 static long evdev_ioctl_compat(struct file *file, 822 unsigned int cmd, unsigned long arg) 823 { 824 return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1); 825 } 826 #endif 827 828 static const struct file_operations evdev_fops = { 829 .owner = THIS_MODULE, 830 .read = evdev_read, 831 .write = evdev_write, 832 .poll = evdev_poll, 833 .open = evdev_open, 834 .release = evdev_release, 835 .unlocked_ioctl = evdev_ioctl, 836 #ifdef CONFIG_COMPAT 837 .compat_ioctl = evdev_ioctl_compat, 838 #endif 839 .fasync = evdev_fasync, 840 .flush = evdev_flush, 841 .llseek = no_llseek, 842 }; 843 844 static int evdev_install_chrdev(struct evdev *evdev) 845 { 846 /* 847 * No need to do any locking here as calls to connect and 848 * disconnect are serialized by the input core 849 */ 850 evdev_table[evdev->minor] = evdev; 851 return 0; 852 } 853 854 static void evdev_remove_chrdev(struct evdev *evdev) 855 { 856 /* 857 * Lock evdev table to prevent race with evdev_open() 858 */ 859 mutex_lock(&evdev_table_mutex); 860 evdev_table[evdev->minor] = NULL; 861 mutex_unlock(&evdev_table_mutex); 862 } 863 864 /* 865 * Mark device non-existent. This disables writes, ioctls and 866 * prevents new users from opening the device. Already posted 867 * blocking reads will stay, however new ones will fail. 868 */ 869 static void evdev_mark_dead(struct evdev *evdev) 870 { 871 mutex_lock(&evdev->mutex); 872 evdev->exist = false; 873 mutex_unlock(&evdev->mutex); 874 } 875 876 static void evdev_cleanup(struct evdev *evdev) 877 { 878 struct input_handle *handle = &evdev->handle; 879 880 evdev_mark_dead(evdev); 881 evdev_hangup(evdev); 882 evdev_remove_chrdev(evdev); 883 884 /* evdev is marked dead so no one else accesses evdev->open */ 885 if (evdev->open) { 886 input_flush_device(handle, NULL); 887 input_close_device(handle); 888 } 889 } 890 891 /* 892 * Create new evdev device. Note that input core serializes calls 893 * to connect and disconnect so we don't need to lock evdev_table here. 894 */ 895 static int evdev_connect(struct input_handler *handler, struct input_dev *dev, 896 const struct input_device_id *id) 897 { 898 struct evdev *evdev; 899 int minor; 900 int error; 901 902 for (minor = 0; minor < EVDEV_MINORS; minor++) 903 if (!evdev_table[minor]) 904 break; 905 906 if (minor == EVDEV_MINORS) { 907 pr_err("no more free evdev devices\n"); 908 return -ENFILE; 909 } 910 911 evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL); 912 if (!evdev) 913 return -ENOMEM; 914 915 INIT_LIST_HEAD(&evdev->client_list); 916 spin_lock_init(&evdev->client_lock); 917 mutex_init(&evdev->mutex); 918 init_waitqueue_head(&evdev->wait); 919 920 dev_set_name(&evdev->dev, "event%d", minor); 921 evdev->exist = true; 922 evdev->minor = minor; 923 924 evdev->handle.dev = input_get_device(dev); 925 evdev->handle.name = dev_name(&evdev->dev); 926 evdev->handle.handler = handler; 927 evdev->handle.private = evdev; 928 929 evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor); 930 evdev->dev.class = &input_class; 931 evdev->dev.parent = &dev->dev; 932 evdev->dev.release = evdev_free; 933 device_initialize(&evdev->dev); 934 935 error = input_register_handle(&evdev->handle); 936 if (error) 937 goto err_free_evdev; 938 939 error = evdev_install_chrdev(evdev); 940 if (error) 941 goto err_unregister_handle; 942 943 error = device_add(&evdev->dev); 944 if (error) 945 goto err_cleanup_evdev; 946 947 return 0; 948 949 err_cleanup_evdev: 950 evdev_cleanup(evdev); 951 err_unregister_handle: 952 input_unregister_handle(&evdev->handle); 953 err_free_evdev: 954 put_device(&evdev->dev); 955 return error; 956 } 957 958 static void evdev_disconnect(struct input_handle *handle) 959 { 960 struct evdev *evdev = handle->private; 961 962 device_del(&evdev->dev); 963 evdev_cleanup(evdev); 964 input_unregister_handle(handle); 965 put_device(&evdev->dev); 966 } 967 968 static const struct input_device_id evdev_ids[] = { 969 { .driver_info = 1 }, /* Matches all devices */ 970 { }, /* Terminating zero entry */ 971 }; 972 973 MODULE_DEVICE_TABLE(input, evdev_ids); 974 975 static struct input_handler evdev_handler = { 976 .event = evdev_event, 977 .connect = evdev_connect, 978 .disconnect = evdev_disconnect, 979 .fops = &evdev_fops, 980 .minor = EVDEV_MINOR_BASE, 981 .name = "evdev", 982 .id_table = evdev_ids, 983 }; 984 985 static int __init evdev_init(void) 986 { 987 return input_register_handler(&evdev_handler); 988 } 989 990 static void __exit evdev_exit(void) 991 { 992 input_unregister_handler(&evdev_handler); 993 } 994 995 module_init(evdev_init); 996 module_exit(evdev_exit); 997 998 MODULE_AUTHOR("Vojtech Pavlik <[email protected]>"); 999 MODULE_DESCRIPTION("Input driver event char devices"); 1000 MODULE_LICENSE("GPL"); 1001