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 retval = mutex_lock_interruptible(&evdev->mutex); 325 if (retval) 326 return retval; 327 328 if (!evdev->exist) { 329 retval = -ENODEV; 330 goto out; 331 } 332 333 while (retval < count) { 334 335 if (input_event_from_user(buffer + retval, &event)) { 336 retval = -EFAULT; 337 goto out; 338 } 339 340 input_inject_event(&evdev->handle, 341 event.type, event.code, event.value); 342 retval += input_event_size(); 343 } 344 345 out: 346 mutex_unlock(&evdev->mutex); 347 return retval; 348 } 349 350 static int evdev_fetch_next_event(struct evdev_client *client, 351 struct input_event *event) 352 { 353 int have_event; 354 355 spin_lock_irq(&client->buffer_lock); 356 357 have_event = client->head != client->tail; 358 if (have_event) { 359 *event = client->buffer[client->tail++]; 360 client->tail &= client->bufsize - 1; 361 } 362 363 spin_unlock_irq(&client->buffer_lock); 364 365 return have_event; 366 } 367 368 static ssize_t evdev_read(struct file *file, char __user *buffer, 369 size_t count, loff_t *ppos) 370 { 371 struct evdev_client *client = file->private_data; 372 struct evdev *evdev = client->evdev; 373 struct input_event event; 374 int retval; 375 376 if (count < input_event_size()) 377 return -EINVAL; 378 379 if (client->head == client->tail && evdev->exist && 380 (file->f_flags & O_NONBLOCK)) 381 return -EAGAIN; 382 383 retval = wait_event_interruptible(evdev->wait, 384 client->head != client->tail || !evdev->exist); 385 if (retval) 386 return retval; 387 388 if (!evdev->exist) 389 return -ENODEV; 390 391 while (retval + input_event_size() <= count && 392 evdev_fetch_next_event(client, &event)) { 393 394 if (input_event_to_user(buffer + retval, &event)) 395 return -EFAULT; 396 397 retval += input_event_size(); 398 } 399 400 return retval; 401 } 402 403 /* No kernel lock - fine */ 404 static unsigned int evdev_poll(struct file *file, poll_table *wait) 405 { 406 struct evdev_client *client = file->private_data; 407 struct evdev *evdev = client->evdev; 408 unsigned int mask; 409 410 poll_wait(file, &evdev->wait, wait); 411 412 mask = evdev->exist ? POLLOUT | POLLWRNORM : POLLHUP | POLLERR; 413 if (client->head != client->tail) 414 mask |= POLLIN | POLLRDNORM; 415 416 return mask; 417 } 418 419 #ifdef CONFIG_COMPAT 420 421 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8) 422 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1) 423 424 #ifdef __BIG_ENDIAN 425 static int bits_to_user(unsigned long *bits, unsigned int maxbit, 426 unsigned int maxlen, void __user *p, int compat) 427 { 428 int len, i; 429 430 if (compat) { 431 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t); 432 if (len > maxlen) 433 len = maxlen; 434 435 for (i = 0; i < len / sizeof(compat_long_t); i++) 436 if (copy_to_user((compat_long_t __user *) p + i, 437 (compat_long_t *) bits + 438 i + 1 - ((i % 2) << 1), 439 sizeof(compat_long_t))) 440 return -EFAULT; 441 } else { 442 len = BITS_TO_LONGS(maxbit) * sizeof(long); 443 if (len > maxlen) 444 len = maxlen; 445 446 if (copy_to_user(p, bits, len)) 447 return -EFAULT; 448 } 449 450 return len; 451 } 452 #else 453 static int bits_to_user(unsigned long *bits, unsigned int maxbit, 454 unsigned int maxlen, void __user *p, int compat) 455 { 456 int len = compat ? 457 BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) : 458 BITS_TO_LONGS(maxbit) * sizeof(long); 459 460 if (len > maxlen) 461 len = maxlen; 462 463 return copy_to_user(p, bits, len) ? -EFAULT : len; 464 } 465 #endif /* __BIG_ENDIAN */ 466 467 #else 468 469 static int bits_to_user(unsigned long *bits, unsigned int maxbit, 470 unsigned int maxlen, void __user *p, int compat) 471 { 472 int len = BITS_TO_LONGS(maxbit) * sizeof(long); 473 474 if (len > maxlen) 475 len = maxlen; 476 477 return copy_to_user(p, bits, len) ? -EFAULT : len; 478 } 479 480 #endif /* CONFIG_COMPAT */ 481 482 static int str_to_user(const char *str, unsigned int maxlen, void __user *p) 483 { 484 int len; 485 486 if (!str) 487 return -ENOENT; 488 489 len = strlen(str) + 1; 490 if (len > maxlen) 491 len = maxlen; 492 493 return copy_to_user(p, str, len) ? -EFAULT : len; 494 } 495 496 #define OLD_KEY_MAX 0x1ff 497 static int handle_eviocgbit(struct input_dev *dev, 498 unsigned int type, unsigned int size, 499 void __user *p, int compat_mode) 500 { 501 static unsigned long keymax_warn_time; 502 unsigned long *bits; 503 int len; 504 505 switch (type) { 506 507 case 0: bits = dev->evbit; len = EV_MAX; break; 508 case EV_KEY: bits = dev->keybit; len = KEY_MAX; break; 509 case EV_REL: bits = dev->relbit; len = REL_MAX; break; 510 case EV_ABS: bits = dev->absbit; len = ABS_MAX; break; 511 case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break; 512 case EV_LED: bits = dev->ledbit; len = LED_MAX; break; 513 case EV_SND: bits = dev->sndbit; len = SND_MAX; break; 514 case EV_FF: bits = dev->ffbit; len = FF_MAX; break; 515 case EV_SW: bits = dev->swbit; len = SW_MAX; break; 516 default: return -EINVAL; 517 } 518 519 /* 520 * Work around bugs in userspace programs that like to do 521 * EVIOCGBIT(EV_KEY, KEY_MAX) and not realize that 'len' 522 * should be in bytes, not in bits. 523 */ 524 if (type == EV_KEY && size == OLD_KEY_MAX) { 525 len = OLD_KEY_MAX; 526 if (printk_timed_ratelimit(&keymax_warn_time, 10 * 1000)) 527 pr_warning("(EVIOCGBIT): Suspicious buffer size %u, " 528 "limiting output to %zu bytes. See " 529 "http://userweb.kernel.org/~dtor/eviocgbit-bug.html\n", 530 OLD_KEY_MAX, 531 BITS_TO_LONGS(OLD_KEY_MAX) * sizeof(long)); 532 } 533 534 return bits_to_user(bits, len, size, p, compat_mode); 535 } 536 #undef OLD_KEY_MAX 537 538 static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p) 539 { 540 struct input_keymap_entry ke = { 541 .len = sizeof(unsigned int), 542 .flags = 0, 543 }; 544 int __user *ip = (int __user *)p; 545 int error; 546 547 /* legacy case */ 548 if (copy_from_user(ke.scancode, p, sizeof(unsigned int))) 549 return -EFAULT; 550 551 error = input_get_keycode(dev, &ke); 552 if (error) 553 return error; 554 555 if (put_user(ke.keycode, ip + 1)) 556 return -EFAULT; 557 558 return 0; 559 } 560 561 static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p) 562 { 563 struct input_keymap_entry ke; 564 int error; 565 566 if (copy_from_user(&ke, p, sizeof(ke))) 567 return -EFAULT; 568 569 error = input_get_keycode(dev, &ke); 570 if (error) 571 return error; 572 573 if (copy_to_user(p, &ke, sizeof(ke))) 574 return -EFAULT; 575 576 return 0; 577 } 578 579 static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p) 580 { 581 struct input_keymap_entry ke = { 582 .len = sizeof(unsigned int), 583 .flags = 0, 584 }; 585 int __user *ip = (int __user *)p; 586 587 if (copy_from_user(ke.scancode, p, sizeof(unsigned int))) 588 return -EFAULT; 589 590 if (get_user(ke.keycode, ip + 1)) 591 return -EFAULT; 592 593 return input_set_keycode(dev, &ke); 594 } 595 596 static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p) 597 { 598 struct input_keymap_entry ke; 599 600 if (copy_from_user(&ke, p, sizeof(ke))) 601 return -EFAULT; 602 603 if (ke.len > sizeof(ke.scancode)) 604 return -EINVAL; 605 606 return input_set_keycode(dev, &ke); 607 } 608 609 static long evdev_do_ioctl(struct file *file, unsigned int cmd, 610 void __user *p, int compat_mode) 611 { 612 struct evdev_client *client = file->private_data; 613 struct evdev *evdev = client->evdev; 614 struct input_dev *dev = evdev->handle.dev; 615 struct input_absinfo abs; 616 struct ff_effect effect; 617 int __user *ip = (int __user *)p; 618 unsigned int i, t, u, v; 619 unsigned int size; 620 int error; 621 622 /* First we check for fixed-length commands */ 623 switch (cmd) { 624 625 case EVIOCGVERSION: 626 return put_user(EV_VERSION, ip); 627 628 case EVIOCGID: 629 if (copy_to_user(p, &dev->id, sizeof(struct input_id))) 630 return -EFAULT; 631 return 0; 632 633 case EVIOCGREP: 634 if (!test_bit(EV_REP, dev->evbit)) 635 return -ENOSYS; 636 if (put_user(dev->rep[REP_DELAY], ip)) 637 return -EFAULT; 638 if (put_user(dev->rep[REP_PERIOD], ip + 1)) 639 return -EFAULT; 640 return 0; 641 642 case EVIOCSREP: 643 if (!test_bit(EV_REP, dev->evbit)) 644 return -ENOSYS; 645 if (get_user(u, ip)) 646 return -EFAULT; 647 if (get_user(v, ip + 1)) 648 return -EFAULT; 649 650 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u); 651 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v); 652 653 return 0; 654 655 case EVIOCRMFF: 656 return input_ff_erase(dev, (int)(unsigned long) p, file); 657 658 case EVIOCGEFFECTS: 659 i = test_bit(EV_FF, dev->evbit) ? 660 dev->ff->max_effects : 0; 661 if (put_user(i, ip)) 662 return -EFAULT; 663 return 0; 664 665 case EVIOCGRAB: 666 if (p) 667 return evdev_grab(evdev, client); 668 else 669 return evdev_ungrab(evdev, client); 670 671 case EVIOCGKEYCODE: 672 return evdev_handle_get_keycode(dev, p); 673 674 case EVIOCSKEYCODE: 675 return evdev_handle_set_keycode(dev, p); 676 677 case EVIOCGKEYCODE_V2: 678 return evdev_handle_get_keycode_v2(dev, p); 679 680 case EVIOCSKEYCODE_V2: 681 return evdev_handle_set_keycode_v2(dev, p); 682 } 683 684 size = _IOC_SIZE(cmd); 685 686 /* Now check variable-length commands */ 687 #define EVIOC_MASK_SIZE(nr) ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT)) 688 switch (EVIOC_MASK_SIZE(cmd)) { 689 690 case EVIOCGPROP(0): 691 return bits_to_user(dev->propbit, INPUT_PROP_MAX, 692 size, p, compat_mode); 693 694 case EVIOCGKEY(0): 695 return bits_to_user(dev->key, KEY_MAX, size, p, compat_mode); 696 697 case EVIOCGLED(0): 698 return bits_to_user(dev->led, LED_MAX, size, p, compat_mode); 699 700 case EVIOCGSND(0): 701 return bits_to_user(dev->snd, SND_MAX, size, p, compat_mode); 702 703 case EVIOCGSW(0): 704 return bits_to_user(dev->sw, SW_MAX, size, p, compat_mode); 705 706 case EVIOCGNAME(0): 707 return str_to_user(dev->name, size, p); 708 709 case EVIOCGPHYS(0): 710 return str_to_user(dev->phys, size, p); 711 712 case EVIOCGUNIQ(0): 713 return str_to_user(dev->uniq, size, p); 714 715 case EVIOC_MASK_SIZE(EVIOCSFF): 716 if (input_ff_effect_from_user(p, size, &effect)) 717 return -EFAULT; 718 719 error = input_ff_upload(dev, &effect, file); 720 721 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id))) 722 return -EFAULT; 723 724 return error; 725 } 726 727 /* Multi-number variable-length handlers */ 728 if (_IOC_TYPE(cmd) != 'E') 729 return -EINVAL; 730 731 if (_IOC_DIR(cmd) == _IOC_READ) { 732 733 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0))) 734 return handle_eviocgbit(dev, 735 _IOC_NR(cmd) & EV_MAX, size, 736 p, compat_mode); 737 738 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) { 739 740 if (!dev->absinfo) 741 return -EINVAL; 742 743 t = _IOC_NR(cmd) & ABS_MAX; 744 abs = dev->absinfo[t]; 745 746 if (copy_to_user(p, &abs, min_t(size_t, 747 size, sizeof(struct input_absinfo)))) 748 return -EFAULT; 749 750 return 0; 751 } 752 } 753 754 if (_IOC_DIR(cmd) == _IOC_WRITE) { 755 756 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) { 757 758 if (!dev->absinfo) 759 return -EINVAL; 760 761 t = _IOC_NR(cmd) & ABS_MAX; 762 763 if (copy_from_user(&abs, p, min_t(size_t, 764 size, sizeof(struct input_absinfo)))) 765 return -EFAULT; 766 767 if (size < sizeof(struct input_absinfo)) 768 abs.resolution = 0; 769 770 /* We can't change number of reserved MT slots */ 771 if (t == ABS_MT_SLOT) 772 return -EINVAL; 773 774 /* 775 * Take event lock to ensure that we are not 776 * changing device parameters in the middle 777 * of event. 778 */ 779 spin_lock_irq(&dev->event_lock); 780 dev->absinfo[t] = abs; 781 spin_unlock_irq(&dev->event_lock); 782 783 return 0; 784 } 785 } 786 787 return -EINVAL; 788 } 789 790 static long evdev_ioctl_handler(struct file *file, unsigned int cmd, 791 void __user *p, int compat_mode) 792 { 793 struct evdev_client *client = file->private_data; 794 struct evdev *evdev = client->evdev; 795 int retval; 796 797 retval = mutex_lock_interruptible(&evdev->mutex); 798 if (retval) 799 return retval; 800 801 if (!evdev->exist) { 802 retval = -ENODEV; 803 goto out; 804 } 805 806 retval = evdev_do_ioctl(file, cmd, p, compat_mode); 807 808 out: 809 mutex_unlock(&evdev->mutex); 810 return retval; 811 } 812 813 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 814 { 815 return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0); 816 } 817 818 #ifdef CONFIG_COMPAT 819 static long evdev_ioctl_compat(struct file *file, 820 unsigned int cmd, unsigned long arg) 821 { 822 return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1); 823 } 824 #endif 825 826 static const struct file_operations evdev_fops = { 827 .owner = THIS_MODULE, 828 .read = evdev_read, 829 .write = evdev_write, 830 .poll = evdev_poll, 831 .open = evdev_open, 832 .release = evdev_release, 833 .unlocked_ioctl = evdev_ioctl, 834 #ifdef CONFIG_COMPAT 835 .compat_ioctl = evdev_ioctl_compat, 836 #endif 837 .fasync = evdev_fasync, 838 .flush = evdev_flush, 839 .llseek = no_llseek, 840 }; 841 842 static int evdev_install_chrdev(struct evdev *evdev) 843 { 844 /* 845 * No need to do any locking here as calls to connect and 846 * disconnect are serialized by the input core 847 */ 848 evdev_table[evdev->minor] = evdev; 849 return 0; 850 } 851 852 static void evdev_remove_chrdev(struct evdev *evdev) 853 { 854 /* 855 * Lock evdev table to prevent race with evdev_open() 856 */ 857 mutex_lock(&evdev_table_mutex); 858 evdev_table[evdev->minor] = NULL; 859 mutex_unlock(&evdev_table_mutex); 860 } 861 862 /* 863 * Mark device non-existent. This disables writes, ioctls and 864 * prevents new users from opening the device. Already posted 865 * blocking reads will stay, however new ones will fail. 866 */ 867 static void evdev_mark_dead(struct evdev *evdev) 868 { 869 mutex_lock(&evdev->mutex); 870 evdev->exist = false; 871 mutex_unlock(&evdev->mutex); 872 } 873 874 static void evdev_cleanup(struct evdev *evdev) 875 { 876 struct input_handle *handle = &evdev->handle; 877 878 evdev_mark_dead(evdev); 879 evdev_hangup(evdev); 880 evdev_remove_chrdev(evdev); 881 882 /* evdev is marked dead so no one else accesses evdev->open */ 883 if (evdev->open) { 884 input_flush_device(handle, NULL); 885 input_close_device(handle); 886 } 887 } 888 889 /* 890 * Create new evdev device. Note that input core serializes calls 891 * to connect and disconnect so we don't need to lock evdev_table here. 892 */ 893 static int evdev_connect(struct input_handler *handler, struct input_dev *dev, 894 const struct input_device_id *id) 895 { 896 struct evdev *evdev; 897 int minor; 898 int error; 899 900 for (minor = 0; minor < EVDEV_MINORS; minor++) 901 if (!evdev_table[minor]) 902 break; 903 904 if (minor == EVDEV_MINORS) { 905 pr_err("no more free evdev devices\n"); 906 return -ENFILE; 907 } 908 909 evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL); 910 if (!evdev) 911 return -ENOMEM; 912 913 INIT_LIST_HEAD(&evdev->client_list); 914 spin_lock_init(&evdev->client_lock); 915 mutex_init(&evdev->mutex); 916 init_waitqueue_head(&evdev->wait); 917 918 dev_set_name(&evdev->dev, "event%d", minor); 919 evdev->exist = true; 920 evdev->minor = minor; 921 922 evdev->handle.dev = input_get_device(dev); 923 evdev->handle.name = dev_name(&evdev->dev); 924 evdev->handle.handler = handler; 925 evdev->handle.private = evdev; 926 927 evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor); 928 evdev->dev.class = &input_class; 929 evdev->dev.parent = &dev->dev; 930 evdev->dev.release = evdev_free; 931 device_initialize(&evdev->dev); 932 933 error = input_register_handle(&evdev->handle); 934 if (error) 935 goto err_free_evdev; 936 937 error = evdev_install_chrdev(evdev); 938 if (error) 939 goto err_unregister_handle; 940 941 error = device_add(&evdev->dev); 942 if (error) 943 goto err_cleanup_evdev; 944 945 return 0; 946 947 err_cleanup_evdev: 948 evdev_cleanup(evdev); 949 err_unregister_handle: 950 input_unregister_handle(&evdev->handle); 951 err_free_evdev: 952 put_device(&evdev->dev); 953 return error; 954 } 955 956 static void evdev_disconnect(struct input_handle *handle) 957 { 958 struct evdev *evdev = handle->private; 959 960 device_del(&evdev->dev); 961 evdev_cleanup(evdev); 962 input_unregister_handle(handle); 963 put_device(&evdev->dev); 964 } 965 966 static const struct input_device_id evdev_ids[] = { 967 { .driver_info = 1 }, /* Matches all devices */ 968 { }, /* Terminating zero entry */ 969 }; 970 971 MODULE_DEVICE_TABLE(input, evdev_ids); 972 973 static struct input_handler evdev_handler = { 974 .event = evdev_event, 975 .connect = evdev_connect, 976 .disconnect = evdev_disconnect, 977 .fops = &evdev_fops, 978 .minor = EVDEV_MINOR_BASE, 979 .name = "evdev", 980 .id_table = evdev_ids, 981 }; 982 983 static int __init evdev_init(void) 984 { 985 return input_register_handler(&evdev_handler); 986 } 987 988 static void __exit evdev_exit(void) 989 { 990 input_unregister_handler(&evdev_handler); 991 } 992 993 module_init(evdev_init); 994 module_exit(evdev_exit); 995 996 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>"); 997 MODULE_DESCRIPTION("Input driver event char devices"); 998 MODULE_LICENSE("GPL"); 999