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 unsigned int head; 43 unsigned 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 unsigned 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 /* Interrupts are disabled, just acquire the lock. */ 59 spin_lock(&client->buffer_lock); 60 61 client->buffer[client->head++] = *event; 62 client->head &= client->bufsize - 1; 63 64 if (unlikely(client->head == client->tail)) { 65 /* 66 * This effectively "drops" all unconsumed events, leaving 67 * EV_SYN/SYN_DROPPED plus the newest event in the queue. 68 */ 69 client->tail = (client->head - 2) & (client->bufsize - 1); 70 71 client->buffer[client->tail].time = event->time; 72 client->buffer[client->tail].type = EV_SYN; 73 client->buffer[client->tail].code = SYN_DROPPED; 74 client->buffer[client->tail].value = 0; 75 } 76 77 spin_unlock(&client->buffer_lock); 78 79 if (event->type == EV_SYN) 80 kill_fasync(&client->fasync, SIGIO, POLL_IN); 81 } 82 83 /* 84 * Pass incoming event to all connected clients. 85 */ 86 static void evdev_event(struct input_handle *handle, 87 unsigned int type, unsigned int code, int value) 88 { 89 struct evdev *evdev = handle->private; 90 struct evdev_client *client; 91 struct input_event event; 92 93 do_gettimeofday(&event.time); 94 event.type = type; 95 event.code = code; 96 event.value = value; 97 98 rcu_read_lock(); 99 100 client = rcu_dereference(evdev->grab); 101 if (client) 102 evdev_pass_event(client, &event); 103 else 104 list_for_each_entry_rcu(client, &evdev->client_list, node) 105 evdev_pass_event(client, &event); 106 107 rcu_read_unlock(); 108 109 wake_up_interruptible(&evdev->wait); 110 } 111 112 static int evdev_fasync(int fd, struct file *file, int on) 113 { 114 struct evdev_client *client = file->private_data; 115 116 return fasync_helper(fd, file, on, &client->fasync); 117 } 118 119 static int evdev_flush(struct file *file, fl_owner_t id) 120 { 121 struct evdev_client *client = file->private_data; 122 struct evdev *evdev = client->evdev; 123 int retval; 124 125 retval = mutex_lock_interruptible(&evdev->mutex); 126 if (retval) 127 return retval; 128 129 if (!evdev->exist) 130 retval = -ENODEV; 131 else 132 retval = input_flush_device(&evdev->handle, file); 133 134 mutex_unlock(&evdev->mutex); 135 return retval; 136 } 137 138 static void evdev_free(struct device *dev) 139 { 140 struct evdev *evdev = container_of(dev, struct evdev, dev); 141 142 input_put_device(evdev->handle.dev); 143 kfree(evdev); 144 } 145 146 /* 147 * Grabs an event device (along with underlying input device). 148 * This function is called with evdev->mutex taken. 149 */ 150 static int evdev_grab(struct evdev *evdev, struct evdev_client *client) 151 { 152 int error; 153 154 if (evdev->grab) 155 return -EBUSY; 156 157 error = input_grab_device(&evdev->handle); 158 if (error) 159 return error; 160 161 rcu_assign_pointer(evdev->grab, client); 162 synchronize_rcu(); 163 164 return 0; 165 } 166 167 static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client) 168 { 169 if (evdev->grab != client) 170 return -EINVAL; 171 172 rcu_assign_pointer(evdev->grab, NULL); 173 synchronize_rcu(); 174 input_release_device(&evdev->handle); 175 176 return 0; 177 } 178 179 static void evdev_attach_client(struct evdev *evdev, 180 struct evdev_client *client) 181 { 182 spin_lock(&evdev->client_lock); 183 list_add_tail_rcu(&client->node, &evdev->client_list); 184 spin_unlock(&evdev->client_lock); 185 synchronize_rcu(); 186 } 187 188 static void evdev_detach_client(struct evdev *evdev, 189 struct evdev_client *client) 190 { 191 spin_lock(&evdev->client_lock); 192 list_del_rcu(&client->node); 193 spin_unlock(&evdev->client_lock); 194 synchronize_rcu(); 195 } 196 197 static int evdev_open_device(struct evdev *evdev) 198 { 199 int retval; 200 201 retval = mutex_lock_interruptible(&evdev->mutex); 202 if (retval) 203 return retval; 204 205 if (!evdev->exist) 206 retval = -ENODEV; 207 else if (!evdev->open++) { 208 retval = input_open_device(&evdev->handle); 209 if (retval) 210 evdev->open--; 211 } 212 213 mutex_unlock(&evdev->mutex); 214 return retval; 215 } 216 217 static void evdev_close_device(struct evdev *evdev) 218 { 219 mutex_lock(&evdev->mutex); 220 221 if (evdev->exist && !--evdev->open) 222 input_close_device(&evdev->handle); 223 224 mutex_unlock(&evdev->mutex); 225 } 226 227 /* 228 * Wake up users waiting for IO so they can disconnect from 229 * dead device. 230 */ 231 static void evdev_hangup(struct evdev *evdev) 232 { 233 struct evdev_client *client; 234 235 spin_lock(&evdev->client_lock); 236 list_for_each_entry(client, &evdev->client_list, node) 237 kill_fasync(&client->fasync, SIGIO, POLL_HUP); 238 spin_unlock(&evdev->client_lock); 239 240 wake_up_interruptible(&evdev->wait); 241 } 242 243 static int evdev_release(struct inode *inode, struct file *file) 244 { 245 struct evdev_client *client = file->private_data; 246 struct evdev *evdev = client->evdev; 247 248 mutex_lock(&evdev->mutex); 249 if (evdev->grab == client) 250 evdev_ungrab(evdev, client); 251 mutex_unlock(&evdev->mutex); 252 253 evdev_detach_client(evdev, client); 254 kfree(client); 255 256 evdev_close_device(evdev); 257 put_device(&evdev->dev); 258 259 return 0; 260 } 261 262 static unsigned int evdev_compute_buffer_size(struct input_dev *dev) 263 { 264 unsigned int n_events = 265 max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS, 266 EVDEV_MIN_BUFFER_SIZE); 267 268 return roundup_pow_of_two(n_events); 269 } 270 271 static int evdev_open(struct inode *inode, struct file *file) 272 { 273 struct evdev *evdev; 274 struct evdev_client *client; 275 int i = iminor(inode) - EVDEV_MINOR_BASE; 276 unsigned int bufsize; 277 int error; 278 279 if (i >= EVDEV_MINORS) 280 return -ENODEV; 281 282 error = mutex_lock_interruptible(&evdev_table_mutex); 283 if (error) 284 return error; 285 evdev = evdev_table[i]; 286 if (evdev) 287 get_device(&evdev->dev); 288 mutex_unlock(&evdev_table_mutex); 289 290 if (!evdev) 291 return -ENODEV; 292 293 bufsize = evdev_compute_buffer_size(evdev->handle.dev); 294 295 client = kzalloc(sizeof(struct evdev_client) + 296 bufsize * sizeof(struct input_event), 297 GFP_KERNEL); 298 if (!client) { 299 error = -ENOMEM; 300 goto err_put_evdev; 301 } 302 303 client->bufsize = bufsize; 304 spin_lock_init(&client->buffer_lock); 305 client->evdev = evdev; 306 evdev_attach_client(evdev, client); 307 308 error = evdev_open_device(evdev); 309 if (error) 310 goto err_free_client; 311 312 file->private_data = client; 313 nonseekable_open(inode, file); 314 315 return 0; 316 317 err_free_client: 318 evdev_detach_client(evdev, client); 319 kfree(client); 320 err_put_evdev: 321 put_device(&evdev->dev); 322 return error; 323 } 324 325 static ssize_t evdev_write(struct file *file, const char __user *buffer, 326 size_t count, loff_t *ppos) 327 { 328 struct evdev_client *client = file->private_data; 329 struct evdev *evdev = client->evdev; 330 struct input_event event; 331 int retval; 332 333 if (count < input_event_size()) 334 return -EINVAL; 335 336 retval = mutex_lock_interruptible(&evdev->mutex); 337 if (retval) 338 return retval; 339 340 if (!evdev->exist) { 341 retval = -ENODEV; 342 goto out; 343 } 344 345 do { 346 if (input_event_from_user(buffer + retval, &event)) { 347 retval = -EFAULT; 348 goto out; 349 } 350 retval += input_event_size(); 351 352 input_inject_event(&evdev->handle, 353 event.type, event.code, event.value); 354 } while (retval + input_event_size() <= count); 355 356 out: 357 mutex_unlock(&evdev->mutex); 358 return retval; 359 } 360 361 static int evdev_fetch_next_event(struct evdev_client *client, 362 struct input_event *event) 363 { 364 int have_event; 365 366 spin_lock_irq(&client->buffer_lock); 367 368 have_event = client->head != client->tail; 369 if (have_event) { 370 *event = client->buffer[client->tail++]; 371 client->tail &= client->bufsize - 1; 372 } 373 374 spin_unlock_irq(&client->buffer_lock); 375 376 return have_event; 377 } 378 379 static ssize_t evdev_read(struct file *file, char __user *buffer, 380 size_t count, loff_t *ppos) 381 { 382 struct evdev_client *client = file->private_data; 383 struct evdev *evdev = client->evdev; 384 struct input_event event; 385 int retval; 386 387 if (count < input_event_size()) 388 return -EINVAL; 389 390 if (client->head == client->tail && evdev->exist && 391 (file->f_flags & O_NONBLOCK)) 392 return -EAGAIN; 393 394 retval = wait_event_interruptible(evdev->wait, 395 client->head != client->tail || !evdev->exist); 396 if (retval) 397 return retval; 398 399 if (!evdev->exist) 400 return -ENODEV; 401 402 while (retval + input_event_size() <= count && 403 evdev_fetch_next_event(client, &event)) { 404 405 if (input_event_to_user(buffer + retval, &event)) 406 return -EFAULT; 407 408 retval += input_event_size(); 409 } 410 411 return retval; 412 } 413 414 /* No kernel lock - fine */ 415 static unsigned int evdev_poll(struct file *file, poll_table *wait) 416 { 417 struct evdev_client *client = file->private_data; 418 struct evdev *evdev = client->evdev; 419 unsigned int mask; 420 421 poll_wait(file, &evdev->wait, wait); 422 423 mask = evdev->exist ? POLLOUT | POLLWRNORM : POLLHUP | POLLERR; 424 if (client->head != client->tail) 425 mask |= POLLIN | POLLRDNORM; 426 427 return mask; 428 } 429 430 #ifdef CONFIG_COMPAT 431 432 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8) 433 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1) 434 435 #ifdef __BIG_ENDIAN 436 static int bits_to_user(unsigned long *bits, unsigned int maxbit, 437 unsigned int maxlen, void __user *p, int compat) 438 { 439 int len, i; 440 441 if (compat) { 442 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t); 443 if (len > maxlen) 444 len = maxlen; 445 446 for (i = 0; i < len / sizeof(compat_long_t); i++) 447 if (copy_to_user((compat_long_t __user *) p + i, 448 (compat_long_t *) bits + 449 i + 1 - ((i % 2) << 1), 450 sizeof(compat_long_t))) 451 return -EFAULT; 452 } else { 453 len = BITS_TO_LONGS(maxbit) * sizeof(long); 454 if (len > maxlen) 455 len = maxlen; 456 457 if (copy_to_user(p, bits, len)) 458 return -EFAULT; 459 } 460 461 return len; 462 } 463 #else 464 static int bits_to_user(unsigned long *bits, unsigned int maxbit, 465 unsigned int maxlen, void __user *p, int compat) 466 { 467 int len = compat ? 468 BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) : 469 BITS_TO_LONGS(maxbit) * sizeof(long); 470 471 if (len > maxlen) 472 len = maxlen; 473 474 return copy_to_user(p, bits, len) ? -EFAULT : len; 475 } 476 #endif /* __BIG_ENDIAN */ 477 478 #else 479 480 static int bits_to_user(unsigned long *bits, unsigned int maxbit, 481 unsigned int maxlen, void __user *p, int compat) 482 { 483 int len = BITS_TO_LONGS(maxbit) * sizeof(long); 484 485 if (len > maxlen) 486 len = maxlen; 487 488 return copy_to_user(p, bits, len) ? -EFAULT : len; 489 } 490 491 #endif /* CONFIG_COMPAT */ 492 493 static int str_to_user(const char *str, unsigned int maxlen, void __user *p) 494 { 495 int len; 496 497 if (!str) 498 return -ENOENT; 499 500 len = strlen(str) + 1; 501 if (len > maxlen) 502 len = maxlen; 503 504 return copy_to_user(p, str, len) ? -EFAULT : len; 505 } 506 507 #define OLD_KEY_MAX 0x1ff 508 static int handle_eviocgbit(struct input_dev *dev, 509 unsigned int type, unsigned int size, 510 void __user *p, int compat_mode) 511 { 512 static unsigned long keymax_warn_time; 513 unsigned long *bits; 514 int len; 515 516 switch (type) { 517 518 case 0: bits = dev->evbit; len = EV_MAX; break; 519 case EV_KEY: bits = dev->keybit; len = KEY_MAX; break; 520 case EV_REL: bits = dev->relbit; len = REL_MAX; break; 521 case EV_ABS: bits = dev->absbit; len = ABS_MAX; break; 522 case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break; 523 case EV_LED: bits = dev->ledbit; len = LED_MAX; break; 524 case EV_SND: bits = dev->sndbit; len = SND_MAX; break; 525 case EV_FF: bits = dev->ffbit; len = FF_MAX; break; 526 case EV_SW: bits = dev->swbit; len = SW_MAX; break; 527 default: return -EINVAL; 528 } 529 530 /* 531 * Work around bugs in userspace programs that like to do 532 * EVIOCGBIT(EV_KEY, KEY_MAX) and not realize that 'len' 533 * should be in bytes, not in bits. 534 */ 535 if (type == EV_KEY && size == OLD_KEY_MAX) { 536 len = OLD_KEY_MAX; 537 if (printk_timed_ratelimit(&keymax_warn_time, 10 * 1000)) 538 pr_warning("(EVIOCGBIT): Suspicious buffer size %u, " 539 "limiting output to %zu bytes. See " 540 "http://userweb.kernel.org/~dtor/eviocgbit-bug.html\n", 541 OLD_KEY_MAX, 542 BITS_TO_LONGS(OLD_KEY_MAX) * sizeof(long)); 543 } 544 545 return bits_to_user(bits, len, size, p, compat_mode); 546 } 547 #undef OLD_KEY_MAX 548 549 static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p) 550 { 551 struct input_keymap_entry ke = { 552 .len = sizeof(unsigned int), 553 .flags = 0, 554 }; 555 int __user *ip = (int __user *)p; 556 int error; 557 558 /* legacy case */ 559 if (copy_from_user(ke.scancode, p, sizeof(unsigned int))) 560 return -EFAULT; 561 562 error = input_get_keycode(dev, &ke); 563 if (error) 564 return error; 565 566 if (put_user(ke.keycode, ip + 1)) 567 return -EFAULT; 568 569 return 0; 570 } 571 572 static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p) 573 { 574 struct input_keymap_entry ke; 575 int error; 576 577 if (copy_from_user(&ke, p, sizeof(ke))) 578 return -EFAULT; 579 580 error = input_get_keycode(dev, &ke); 581 if (error) 582 return error; 583 584 if (copy_to_user(p, &ke, sizeof(ke))) 585 return -EFAULT; 586 587 return 0; 588 } 589 590 static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p) 591 { 592 struct input_keymap_entry ke = { 593 .len = sizeof(unsigned int), 594 .flags = 0, 595 }; 596 int __user *ip = (int __user *)p; 597 598 if (copy_from_user(ke.scancode, p, sizeof(unsigned int))) 599 return -EFAULT; 600 601 if (get_user(ke.keycode, ip + 1)) 602 return -EFAULT; 603 604 return input_set_keycode(dev, &ke); 605 } 606 607 static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p) 608 { 609 struct input_keymap_entry ke; 610 611 if (copy_from_user(&ke, p, sizeof(ke))) 612 return -EFAULT; 613 614 if (ke.len > sizeof(ke.scancode)) 615 return -EINVAL; 616 617 return input_set_keycode(dev, &ke); 618 } 619 620 static long evdev_do_ioctl(struct file *file, unsigned int cmd, 621 void __user *p, int compat_mode) 622 { 623 struct evdev_client *client = file->private_data; 624 struct evdev *evdev = client->evdev; 625 struct input_dev *dev = evdev->handle.dev; 626 struct input_absinfo abs; 627 struct ff_effect effect; 628 int __user *ip = (int __user *)p; 629 unsigned int i, t, u, v; 630 unsigned int size; 631 int error; 632 633 /* First we check for fixed-length commands */ 634 switch (cmd) { 635 636 case EVIOCGVERSION: 637 return put_user(EV_VERSION, ip); 638 639 case EVIOCGID: 640 if (copy_to_user(p, &dev->id, sizeof(struct input_id))) 641 return -EFAULT; 642 return 0; 643 644 case EVIOCGREP: 645 if (!test_bit(EV_REP, dev->evbit)) 646 return -ENOSYS; 647 if (put_user(dev->rep[REP_DELAY], ip)) 648 return -EFAULT; 649 if (put_user(dev->rep[REP_PERIOD], ip + 1)) 650 return -EFAULT; 651 return 0; 652 653 case EVIOCSREP: 654 if (!test_bit(EV_REP, dev->evbit)) 655 return -ENOSYS; 656 if (get_user(u, ip)) 657 return -EFAULT; 658 if (get_user(v, ip + 1)) 659 return -EFAULT; 660 661 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u); 662 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v); 663 664 return 0; 665 666 case EVIOCRMFF: 667 return input_ff_erase(dev, (int)(unsigned long) p, file); 668 669 case EVIOCGEFFECTS: 670 i = test_bit(EV_FF, dev->evbit) ? 671 dev->ff->max_effects : 0; 672 if (put_user(i, ip)) 673 return -EFAULT; 674 return 0; 675 676 case EVIOCGRAB: 677 if (p) 678 return evdev_grab(evdev, client); 679 else 680 return evdev_ungrab(evdev, client); 681 682 case EVIOCGKEYCODE: 683 return evdev_handle_get_keycode(dev, p); 684 685 case EVIOCSKEYCODE: 686 return evdev_handle_set_keycode(dev, p); 687 688 case EVIOCGKEYCODE_V2: 689 return evdev_handle_get_keycode_v2(dev, p); 690 691 case EVIOCSKEYCODE_V2: 692 return evdev_handle_set_keycode_v2(dev, p); 693 } 694 695 size = _IOC_SIZE(cmd); 696 697 /* Now check variable-length commands */ 698 #define EVIOC_MASK_SIZE(nr) ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT)) 699 switch (EVIOC_MASK_SIZE(cmd)) { 700 701 case EVIOCGPROP(0): 702 return bits_to_user(dev->propbit, INPUT_PROP_MAX, 703 size, p, compat_mode); 704 705 case EVIOCGKEY(0): 706 return bits_to_user(dev->key, KEY_MAX, size, p, compat_mode); 707 708 case EVIOCGLED(0): 709 return bits_to_user(dev->led, LED_MAX, size, p, compat_mode); 710 711 case EVIOCGSND(0): 712 return bits_to_user(dev->snd, SND_MAX, size, p, compat_mode); 713 714 case EVIOCGSW(0): 715 return bits_to_user(dev->sw, SW_MAX, size, p, compat_mode); 716 717 case EVIOCGNAME(0): 718 return str_to_user(dev->name, size, p); 719 720 case EVIOCGPHYS(0): 721 return str_to_user(dev->phys, size, p); 722 723 case EVIOCGUNIQ(0): 724 return str_to_user(dev->uniq, size, p); 725 726 case EVIOC_MASK_SIZE(EVIOCSFF): 727 if (input_ff_effect_from_user(p, size, &effect)) 728 return -EFAULT; 729 730 error = input_ff_upload(dev, &effect, file); 731 732 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id))) 733 return -EFAULT; 734 735 return error; 736 } 737 738 /* Multi-number variable-length handlers */ 739 if (_IOC_TYPE(cmd) != 'E') 740 return -EINVAL; 741 742 if (_IOC_DIR(cmd) == _IOC_READ) { 743 744 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0))) 745 return handle_eviocgbit(dev, 746 _IOC_NR(cmd) & EV_MAX, size, 747 p, compat_mode); 748 749 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) { 750 751 if (!dev->absinfo) 752 return -EINVAL; 753 754 t = _IOC_NR(cmd) & ABS_MAX; 755 abs = dev->absinfo[t]; 756 757 if (copy_to_user(p, &abs, min_t(size_t, 758 size, sizeof(struct input_absinfo)))) 759 return -EFAULT; 760 761 return 0; 762 } 763 } 764 765 if (_IOC_DIR(cmd) == _IOC_WRITE) { 766 767 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) { 768 769 if (!dev->absinfo) 770 return -EINVAL; 771 772 t = _IOC_NR(cmd) & ABS_MAX; 773 774 if (copy_from_user(&abs, p, min_t(size_t, 775 size, sizeof(struct input_absinfo)))) 776 return -EFAULT; 777 778 if (size < sizeof(struct input_absinfo)) 779 abs.resolution = 0; 780 781 /* We can't change number of reserved MT slots */ 782 if (t == ABS_MT_SLOT) 783 return -EINVAL; 784 785 /* 786 * Take event lock to ensure that we are not 787 * changing device parameters in the middle 788 * of event. 789 */ 790 spin_lock_irq(&dev->event_lock); 791 dev->absinfo[t] = abs; 792 spin_unlock_irq(&dev->event_lock); 793 794 return 0; 795 } 796 } 797 798 return -EINVAL; 799 } 800 801 static long evdev_ioctl_handler(struct file *file, unsigned int cmd, 802 void __user *p, int compat_mode) 803 { 804 struct evdev_client *client = file->private_data; 805 struct evdev *evdev = client->evdev; 806 int retval; 807 808 retval = mutex_lock_interruptible(&evdev->mutex); 809 if (retval) 810 return retval; 811 812 if (!evdev->exist) { 813 retval = -ENODEV; 814 goto out; 815 } 816 817 retval = evdev_do_ioctl(file, cmd, p, compat_mode); 818 819 out: 820 mutex_unlock(&evdev->mutex); 821 return retval; 822 } 823 824 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 825 { 826 return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0); 827 } 828 829 #ifdef CONFIG_COMPAT 830 static long evdev_ioctl_compat(struct file *file, 831 unsigned int cmd, unsigned long arg) 832 { 833 return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1); 834 } 835 #endif 836 837 static const struct file_operations evdev_fops = { 838 .owner = THIS_MODULE, 839 .read = evdev_read, 840 .write = evdev_write, 841 .poll = evdev_poll, 842 .open = evdev_open, 843 .release = evdev_release, 844 .unlocked_ioctl = evdev_ioctl, 845 #ifdef CONFIG_COMPAT 846 .compat_ioctl = evdev_ioctl_compat, 847 #endif 848 .fasync = evdev_fasync, 849 .flush = evdev_flush, 850 .llseek = no_llseek, 851 }; 852 853 static int evdev_install_chrdev(struct evdev *evdev) 854 { 855 /* 856 * No need to do any locking here as calls to connect and 857 * disconnect are serialized by the input core 858 */ 859 evdev_table[evdev->minor] = evdev; 860 return 0; 861 } 862 863 static void evdev_remove_chrdev(struct evdev *evdev) 864 { 865 /* 866 * Lock evdev table to prevent race with evdev_open() 867 */ 868 mutex_lock(&evdev_table_mutex); 869 evdev_table[evdev->minor] = NULL; 870 mutex_unlock(&evdev_table_mutex); 871 } 872 873 /* 874 * Mark device non-existent. This disables writes, ioctls and 875 * prevents new users from opening the device. Already posted 876 * blocking reads will stay, however new ones will fail. 877 */ 878 static void evdev_mark_dead(struct evdev *evdev) 879 { 880 mutex_lock(&evdev->mutex); 881 evdev->exist = false; 882 mutex_unlock(&evdev->mutex); 883 } 884 885 static void evdev_cleanup(struct evdev *evdev) 886 { 887 struct input_handle *handle = &evdev->handle; 888 889 evdev_mark_dead(evdev); 890 evdev_hangup(evdev); 891 evdev_remove_chrdev(evdev); 892 893 /* evdev is marked dead so no one else accesses evdev->open */ 894 if (evdev->open) { 895 input_flush_device(handle, NULL); 896 input_close_device(handle); 897 } 898 } 899 900 /* 901 * Create new evdev device. Note that input core serializes calls 902 * to connect and disconnect so we don't need to lock evdev_table here. 903 */ 904 static int evdev_connect(struct input_handler *handler, struct input_dev *dev, 905 const struct input_device_id *id) 906 { 907 struct evdev *evdev; 908 int minor; 909 int error; 910 911 for (minor = 0; minor < EVDEV_MINORS; minor++) 912 if (!evdev_table[minor]) 913 break; 914 915 if (minor == EVDEV_MINORS) { 916 pr_err("no more free evdev devices\n"); 917 return -ENFILE; 918 } 919 920 evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL); 921 if (!evdev) 922 return -ENOMEM; 923 924 INIT_LIST_HEAD(&evdev->client_list); 925 spin_lock_init(&evdev->client_lock); 926 mutex_init(&evdev->mutex); 927 init_waitqueue_head(&evdev->wait); 928 929 dev_set_name(&evdev->dev, "event%d", minor); 930 evdev->exist = true; 931 evdev->minor = minor; 932 933 evdev->handle.dev = input_get_device(dev); 934 evdev->handle.name = dev_name(&evdev->dev); 935 evdev->handle.handler = handler; 936 evdev->handle.private = evdev; 937 938 evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor); 939 evdev->dev.class = &input_class; 940 evdev->dev.parent = &dev->dev; 941 evdev->dev.release = evdev_free; 942 device_initialize(&evdev->dev); 943 944 error = input_register_handle(&evdev->handle); 945 if (error) 946 goto err_free_evdev; 947 948 error = evdev_install_chrdev(evdev); 949 if (error) 950 goto err_unregister_handle; 951 952 error = device_add(&evdev->dev); 953 if (error) 954 goto err_cleanup_evdev; 955 956 return 0; 957 958 err_cleanup_evdev: 959 evdev_cleanup(evdev); 960 err_unregister_handle: 961 input_unregister_handle(&evdev->handle); 962 err_free_evdev: 963 put_device(&evdev->dev); 964 return error; 965 } 966 967 static void evdev_disconnect(struct input_handle *handle) 968 { 969 struct evdev *evdev = handle->private; 970 971 device_del(&evdev->dev); 972 evdev_cleanup(evdev); 973 input_unregister_handle(handle); 974 put_device(&evdev->dev); 975 } 976 977 static const struct input_device_id evdev_ids[] = { 978 { .driver_info = 1 }, /* Matches all devices */ 979 { }, /* Terminating zero entry */ 980 }; 981 982 MODULE_DEVICE_TABLE(input, evdev_ids); 983 984 static struct input_handler evdev_handler = { 985 .event = evdev_event, 986 .connect = evdev_connect, 987 .disconnect = evdev_disconnect, 988 .fops = &evdev_fops, 989 .minor = EVDEV_MINOR_BASE, 990 .name = "evdev", 991 .id_table = evdev_ids, 992 }; 993 994 static int __init evdev_init(void) 995 { 996 return input_register_handler(&evdev_handler); 997 } 998 999 static void __exit evdev_exit(void) 1000 { 1001 input_unregister_handler(&evdev_handler); 1002 } 1003 1004 module_init(evdev_init); 1005 module_exit(evdev_exit); 1006 1007 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>"); 1008 MODULE_DESCRIPTION("Input driver event char devices"); 1009 MODULE_LICENSE("GPL"); 1010