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 unsigned int packet_head; /* [future] position of the first element of next packet */ 45 spinlock_t buffer_lock; /* protects access to buffer, head and tail */ 46 struct fasync_struct *fasync; 47 struct evdev *evdev; 48 struct list_head node; 49 unsigned int bufsize; 50 struct input_event buffer[]; 51 }; 52 53 static struct evdev *evdev_table[EVDEV_MINORS]; 54 static DEFINE_MUTEX(evdev_table_mutex); 55 56 static void evdev_pass_event(struct evdev_client *client, 57 struct input_event *event) 58 { 59 /* Interrupts are disabled, just acquire the lock. */ 60 spin_lock(&client->buffer_lock); 61 62 client->buffer[client->head++] = *event; 63 client->head &= client->bufsize - 1; 64 65 if (unlikely(client->head == client->tail)) { 66 /* 67 * This effectively "drops" all unconsumed events, leaving 68 * EV_SYN/SYN_DROPPED plus the newest event in the queue. 69 */ 70 client->tail = (client->head - 2) & (client->bufsize - 1); 71 72 client->buffer[client->tail].time = event->time; 73 client->buffer[client->tail].type = EV_SYN; 74 client->buffer[client->tail].code = SYN_DROPPED; 75 client->buffer[client->tail].value = 0; 76 77 client->packet_head = client->tail; 78 } 79 80 if (event->type == EV_SYN && event->code == SYN_REPORT) { 81 client->packet_head = client->head; 82 kill_fasync(&client->fasync, SIGIO, POLL_IN); 83 } 84 85 spin_unlock(&client->buffer_lock); 86 } 87 88 /* 89 * Pass incoming event to all connected clients. 90 */ 91 static void evdev_event(struct input_handle *handle, 92 unsigned int type, unsigned int code, int value) 93 { 94 struct evdev *evdev = handle->private; 95 struct evdev_client *client; 96 struct input_event event; 97 98 do_gettimeofday(&event.time); 99 event.type = type; 100 event.code = code; 101 event.value = value; 102 103 rcu_read_lock(); 104 105 client = rcu_dereference(evdev->grab); 106 if (client) 107 evdev_pass_event(client, &event); 108 else 109 list_for_each_entry_rcu(client, &evdev->client_list, node) 110 evdev_pass_event(client, &event); 111 112 rcu_read_unlock(); 113 114 if (type == EV_SYN && code == SYN_REPORT) 115 wake_up_interruptible(&evdev->wait); 116 } 117 118 static int evdev_fasync(int fd, struct file *file, int on) 119 { 120 struct evdev_client *client = file->private_data; 121 122 return fasync_helper(fd, file, on, &client->fasync); 123 } 124 125 static int evdev_flush(struct file *file, fl_owner_t id) 126 { 127 struct evdev_client *client = file->private_data; 128 struct evdev *evdev = client->evdev; 129 int retval; 130 131 retval = mutex_lock_interruptible(&evdev->mutex); 132 if (retval) 133 return retval; 134 135 if (!evdev->exist) 136 retval = -ENODEV; 137 else 138 retval = input_flush_device(&evdev->handle, file); 139 140 mutex_unlock(&evdev->mutex); 141 return retval; 142 } 143 144 static void evdev_free(struct device *dev) 145 { 146 struct evdev *evdev = container_of(dev, struct evdev, dev); 147 148 input_put_device(evdev->handle.dev); 149 kfree(evdev); 150 } 151 152 /* 153 * Grabs an event device (along with underlying input device). 154 * This function is called with evdev->mutex taken. 155 */ 156 static int evdev_grab(struct evdev *evdev, struct evdev_client *client) 157 { 158 int error; 159 160 if (evdev->grab) 161 return -EBUSY; 162 163 error = input_grab_device(&evdev->handle); 164 if (error) 165 return error; 166 167 rcu_assign_pointer(evdev->grab, client); 168 169 return 0; 170 } 171 172 static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client) 173 { 174 if (evdev->grab != client) 175 return -EINVAL; 176 177 rcu_assign_pointer(evdev->grab, NULL); 178 synchronize_rcu(); 179 input_release_device(&evdev->handle); 180 181 return 0; 182 } 183 184 static void evdev_attach_client(struct evdev *evdev, 185 struct evdev_client *client) 186 { 187 spin_lock(&evdev->client_lock); 188 list_add_tail_rcu(&client->node, &evdev->client_list); 189 spin_unlock(&evdev->client_lock); 190 } 191 192 static void evdev_detach_client(struct evdev *evdev, 193 struct evdev_client *client) 194 { 195 spin_lock(&evdev->client_lock); 196 list_del_rcu(&client->node); 197 spin_unlock(&evdev->client_lock); 198 synchronize_rcu(); 199 } 200 201 static int evdev_open_device(struct evdev *evdev) 202 { 203 int retval; 204 205 retval = mutex_lock_interruptible(&evdev->mutex); 206 if (retval) 207 return retval; 208 209 if (!evdev->exist) 210 retval = -ENODEV; 211 else if (!evdev->open++) { 212 retval = input_open_device(&evdev->handle); 213 if (retval) 214 evdev->open--; 215 } 216 217 mutex_unlock(&evdev->mutex); 218 return retval; 219 } 220 221 static void evdev_close_device(struct evdev *evdev) 222 { 223 mutex_lock(&evdev->mutex); 224 225 if (evdev->exist && !--evdev->open) 226 input_close_device(&evdev->handle); 227 228 mutex_unlock(&evdev->mutex); 229 } 230 231 /* 232 * Wake up users waiting for IO so they can disconnect from 233 * dead device. 234 */ 235 static void evdev_hangup(struct evdev *evdev) 236 { 237 struct evdev_client *client; 238 239 spin_lock(&evdev->client_lock); 240 list_for_each_entry(client, &evdev->client_list, node) 241 kill_fasync(&client->fasync, SIGIO, POLL_HUP); 242 spin_unlock(&evdev->client_lock); 243 244 wake_up_interruptible(&evdev->wait); 245 } 246 247 static int evdev_release(struct inode *inode, struct file *file) 248 { 249 struct evdev_client *client = file->private_data; 250 struct evdev *evdev = client->evdev; 251 252 mutex_lock(&evdev->mutex); 253 if (evdev->grab == client) 254 evdev_ungrab(evdev, client); 255 mutex_unlock(&evdev->mutex); 256 257 evdev_detach_client(evdev, client); 258 kfree(client); 259 260 evdev_close_device(evdev); 261 put_device(&evdev->dev); 262 263 return 0; 264 } 265 266 static unsigned int evdev_compute_buffer_size(struct input_dev *dev) 267 { 268 unsigned int n_events = 269 max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS, 270 EVDEV_MIN_BUFFER_SIZE); 271 272 return roundup_pow_of_two(n_events); 273 } 274 275 static int evdev_open(struct inode *inode, struct file *file) 276 { 277 struct evdev *evdev; 278 struct evdev_client *client; 279 int i = iminor(inode) - EVDEV_MINOR_BASE; 280 unsigned int bufsize; 281 int error; 282 283 if (i >= EVDEV_MINORS) 284 return -ENODEV; 285 286 error = mutex_lock_interruptible(&evdev_table_mutex); 287 if (error) 288 return error; 289 evdev = evdev_table[i]; 290 if (evdev) 291 get_device(&evdev->dev); 292 mutex_unlock(&evdev_table_mutex); 293 294 if (!evdev) 295 return -ENODEV; 296 297 bufsize = evdev_compute_buffer_size(evdev->handle.dev); 298 299 client = kzalloc(sizeof(struct evdev_client) + 300 bufsize * sizeof(struct input_event), 301 GFP_KERNEL); 302 if (!client) { 303 error = -ENOMEM; 304 goto err_put_evdev; 305 } 306 307 client->bufsize = bufsize; 308 spin_lock_init(&client->buffer_lock); 309 client->evdev = evdev; 310 evdev_attach_client(evdev, client); 311 312 error = evdev_open_device(evdev); 313 if (error) 314 goto err_free_client; 315 316 file->private_data = client; 317 nonseekable_open(inode, file); 318 319 return 0; 320 321 err_free_client: 322 evdev_detach_client(evdev, client); 323 kfree(client); 324 err_put_evdev: 325 put_device(&evdev->dev); 326 return error; 327 } 328 329 static ssize_t evdev_write(struct file *file, const char __user *buffer, 330 size_t count, loff_t *ppos) 331 { 332 struct evdev_client *client = file->private_data; 333 struct evdev *evdev = client->evdev; 334 struct input_event event; 335 int retval; 336 337 if (count < input_event_size()) 338 return -EINVAL; 339 340 retval = mutex_lock_interruptible(&evdev->mutex); 341 if (retval) 342 return retval; 343 344 if (!evdev->exist) { 345 retval = -ENODEV; 346 goto out; 347 } 348 349 do { 350 if (input_event_from_user(buffer + retval, &event)) { 351 retval = -EFAULT; 352 goto out; 353 } 354 retval += input_event_size(); 355 356 input_inject_event(&evdev->handle, 357 event.type, event.code, event.value); 358 } while (retval + input_event_size() <= count); 359 360 out: 361 mutex_unlock(&evdev->mutex); 362 return retval; 363 } 364 365 static int evdev_fetch_next_event(struct evdev_client *client, 366 struct input_event *event) 367 { 368 int have_event; 369 370 spin_lock_irq(&client->buffer_lock); 371 372 have_event = client->head != client->tail; 373 if (have_event) { 374 *event = client->buffer[client->tail++]; 375 client->tail &= client->bufsize - 1; 376 } 377 378 spin_unlock_irq(&client->buffer_lock); 379 380 return have_event; 381 } 382 383 static ssize_t evdev_read(struct file *file, char __user *buffer, 384 size_t count, loff_t *ppos) 385 { 386 struct evdev_client *client = file->private_data; 387 struct evdev *evdev = client->evdev; 388 struct input_event event; 389 int retval; 390 391 if (count < input_event_size()) 392 return -EINVAL; 393 394 if (client->packet_head == client->tail && evdev->exist && 395 (file->f_flags & O_NONBLOCK)) 396 return -EAGAIN; 397 398 retval = wait_event_interruptible(evdev->wait, 399 client->packet_head != client->tail || !evdev->exist); 400 if (retval) 401 return retval; 402 403 if (!evdev->exist) 404 return -ENODEV; 405 406 while (retval + input_event_size() <= count && 407 evdev_fetch_next_event(client, &event)) { 408 409 if (input_event_to_user(buffer + retval, &event)) 410 return -EFAULT; 411 412 retval += input_event_size(); 413 } 414 415 return retval; 416 } 417 418 /* No kernel lock - fine */ 419 static unsigned int evdev_poll(struct file *file, poll_table *wait) 420 { 421 struct evdev_client *client = file->private_data; 422 struct evdev *evdev = client->evdev; 423 unsigned int mask; 424 425 poll_wait(file, &evdev->wait, wait); 426 427 mask = evdev->exist ? POLLOUT | POLLWRNORM : POLLHUP | POLLERR; 428 if (client->packet_head != client->tail) 429 mask |= POLLIN | POLLRDNORM; 430 431 return mask; 432 } 433 434 #ifdef CONFIG_COMPAT 435 436 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8) 437 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1) 438 439 #ifdef __BIG_ENDIAN 440 static int bits_to_user(unsigned long *bits, unsigned int maxbit, 441 unsigned int maxlen, void __user *p, int compat) 442 { 443 int len, i; 444 445 if (compat) { 446 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t); 447 if (len > maxlen) 448 len = maxlen; 449 450 for (i = 0; i < len / sizeof(compat_long_t); i++) 451 if (copy_to_user((compat_long_t __user *) p + i, 452 (compat_long_t *) bits + 453 i + 1 - ((i % 2) << 1), 454 sizeof(compat_long_t))) 455 return -EFAULT; 456 } else { 457 len = BITS_TO_LONGS(maxbit) * sizeof(long); 458 if (len > maxlen) 459 len = maxlen; 460 461 if (copy_to_user(p, bits, len)) 462 return -EFAULT; 463 } 464 465 return len; 466 } 467 #else 468 static int bits_to_user(unsigned long *bits, unsigned int maxbit, 469 unsigned int maxlen, void __user *p, int compat) 470 { 471 int len = compat ? 472 BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) : 473 BITS_TO_LONGS(maxbit) * sizeof(long); 474 475 if (len > maxlen) 476 len = maxlen; 477 478 return copy_to_user(p, bits, len) ? -EFAULT : len; 479 } 480 #endif /* __BIG_ENDIAN */ 481 482 #else 483 484 static int bits_to_user(unsigned long *bits, unsigned int maxbit, 485 unsigned int maxlen, void __user *p, int compat) 486 { 487 int len = BITS_TO_LONGS(maxbit) * sizeof(long); 488 489 if (len > maxlen) 490 len = maxlen; 491 492 return copy_to_user(p, bits, len) ? -EFAULT : len; 493 } 494 495 #endif /* CONFIG_COMPAT */ 496 497 static int str_to_user(const char *str, unsigned int maxlen, void __user *p) 498 { 499 int len; 500 501 if (!str) 502 return -ENOENT; 503 504 len = strlen(str) + 1; 505 if (len > maxlen) 506 len = maxlen; 507 508 return copy_to_user(p, str, len) ? -EFAULT : len; 509 } 510 511 #define OLD_KEY_MAX 0x1ff 512 static int handle_eviocgbit(struct input_dev *dev, 513 unsigned int type, unsigned int size, 514 void __user *p, int compat_mode) 515 { 516 static unsigned long keymax_warn_time; 517 unsigned long *bits; 518 int len; 519 520 switch (type) { 521 522 case 0: bits = dev->evbit; len = EV_MAX; break; 523 case EV_KEY: bits = dev->keybit; len = KEY_MAX; break; 524 case EV_REL: bits = dev->relbit; len = REL_MAX; break; 525 case EV_ABS: bits = dev->absbit; len = ABS_MAX; break; 526 case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break; 527 case EV_LED: bits = dev->ledbit; len = LED_MAX; break; 528 case EV_SND: bits = dev->sndbit; len = SND_MAX; break; 529 case EV_FF: bits = dev->ffbit; len = FF_MAX; break; 530 case EV_SW: bits = dev->swbit; len = SW_MAX; break; 531 default: return -EINVAL; 532 } 533 534 /* 535 * Work around bugs in userspace programs that like to do 536 * EVIOCGBIT(EV_KEY, KEY_MAX) and not realize that 'len' 537 * should be in bytes, not in bits. 538 */ 539 if (type == EV_KEY && size == OLD_KEY_MAX) { 540 len = OLD_KEY_MAX; 541 if (printk_timed_ratelimit(&keymax_warn_time, 10 * 1000)) 542 pr_warning("(EVIOCGBIT): Suspicious buffer size %u, " 543 "limiting output to %zu bytes. See " 544 "http://userweb.kernel.org/~dtor/eviocgbit-bug.html\n", 545 OLD_KEY_MAX, 546 BITS_TO_LONGS(OLD_KEY_MAX) * sizeof(long)); 547 } 548 549 return bits_to_user(bits, len, size, p, compat_mode); 550 } 551 #undef OLD_KEY_MAX 552 553 static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p) 554 { 555 struct input_keymap_entry ke = { 556 .len = sizeof(unsigned int), 557 .flags = 0, 558 }; 559 int __user *ip = (int __user *)p; 560 int error; 561 562 /* legacy case */ 563 if (copy_from_user(ke.scancode, p, sizeof(unsigned int))) 564 return -EFAULT; 565 566 error = input_get_keycode(dev, &ke); 567 if (error) 568 return error; 569 570 if (put_user(ke.keycode, ip + 1)) 571 return -EFAULT; 572 573 return 0; 574 } 575 576 static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p) 577 { 578 struct input_keymap_entry ke; 579 int error; 580 581 if (copy_from_user(&ke, p, sizeof(ke))) 582 return -EFAULT; 583 584 error = input_get_keycode(dev, &ke); 585 if (error) 586 return error; 587 588 if (copy_to_user(p, &ke, sizeof(ke))) 589 return -EFAULT; 590 591 return 0; 592 } 593 594 static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p) 595 { 596 struct input_keymap_entry ke = { 597 .len = sizeof(unsigned int), 598 .flags = 0, 599 }; 600 int __user *ip = (int __user *)p; 601 602 if (copy_from_user(ke.scancode, p, sizeof(unsigned int))) 603 return -EFAULT; 604 605 if (get_user(ke.keycode, ip + 1)) 606 return -EFAULT; 607 608 return input_set_keycode(dev, &ke); 609 } 610 611 static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p) 612 { 613 struct input_keymap_entry ke; 614 615 if (copy_from_user(&ke, p, sizeof(ke))) 616 return -EFAULT; 617 618 if (ke.len > sizeof(ke.scancode)) 619 return -EINVAL; 620 621 return input_set_keycode(dev, &ke); 622 } 623 624 static long evdev_do_ioctl(struct file *file, unsigned int cmd, 625 void __user *p, int compat_mode) 626 { 627 struct evdev_client *client = file->private_data; 628 struct evdev *evdev = client->evdev; 629 struct input_dev *dev = evdev->handle.dev; 630 struct input_absinfo abs; 631 struct ff_effect effect; 632 int __user *ip = (int __user *)p; 633 unsigned int i, t, u, v; 634 unsigned int size; 635 int error; 636 637 /* First we check for fixed-length commands */ 638 switch (cmd) { 639 640 case EVIOCGVERSION: 641 return put_user(EV_VERSION, ip); 642 643 case EVIOCGID: 644 if (copy_to_user(p, &dev->id, sizeof(struct input_id))) 645 return -EFAULT; 646 return 0; 647 648 case EVIOCGREP: 649 if (!test_bit(EV_REP, dev->evbit)) 650 return -ENOSYS; 651 if (put_user(dev->rep[REP_DELAY], ip)) 652 return -EFAULT; 653 if (put_user(dev->rep[REP_PERIOD], ip + 1)) 654 return -EFAULT; 655 return 0; 656 657 case EVIOCSREP: 658 if (!test_bit(EV_REP, dev->evbit)) 659 return -ENOSYS; 660 if (get_user(u, ip)) 661 return -EFAULT; 662 if (get_user(v, ip + 1)) 663 return -EFAULT; 664 665 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u); 666 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v); 667 668 return 0; 669 670 case EVIOCRMFF: 671 return input_ff_erase(dev, (int)(unsigned long) p, file); 672 673 case EVIOCGEFFECTS: 674 i = test_bit(EV_FF, dev->evbit) ? 675 dev->ff->max_effects : 0; 676 if (put_user(i, ip)) 677 return -EFAULT; 678 return 0; 679 680 case EVIOCGRAB: 681 if (p) 682 return evdev_grab(evdev, client); 683 else 684 return evdev_ungrab(evdev, client); 685 686 case EVIOCGKEYCODE: 687 return evdev_handle_get_keycode(dev, p); 688 689 case EVIOCSKEYCODE: 690 return evdev_handle_set_keycode(dev, p); 691 692 case EVIOCGKEYCODE_V2: 693 return evdev_handle_get_keycode_v2(dev, p); 694 695 case EVIOCSKEYCODE_V2: 696 return evdev_handle_set_keycode_v2(dev, p); 697 } 698 699 size = _IOC_SIZE(cmd); 700 701 /* Now check variable-length commands */ 702 #define EVIOC_MASK_SIZE(nr) ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT)) 703 switch (EVIOC_MASK_SIZE(cmd)) { 704 705 case EVIOCGPROP(0): 706 return bits_to_user(dev->propbit, INPUT_PROP_MAX, 707 size, p, compat_mode); 708 709 case EVIOCGKEY(0): 710 return bits_to_user(dev->key, KEY_MAX, size, p, compat_mode); 711 712 case EVIOCGLED(0): 713 return bits_to_user(dev->led, LED_MAX, size, p, compat_mode); 714 715 case EVIOCGSND(0): 716 return bits_to_user(dev->snd, SND_MAX, size, p, compat_mode); 717 718 case EVIOCGSW(0): 719 return bits_to_user(dev->sw, SW_MAX, size, p, compat_mode); 720 721 case EVIOCGNAME(0): 722 return str_to_user(dev->name, size, p); 723 724 case EVIOCGPHYS(0): 725 return str_to_user(dev->phys, size, p); 726 727 case EVIOCGUNIQ(0): 728 return str_to_user(dev->uniq, size, p); 729 730 case EVIOC_MASK_SIZE(EVIOCSFF): 731 if (input_ff_effect_from_user(p, size, &effect)) 732 return -EFAULT; 733 734 error = input_ff_upload(dev, &effect, file); 735 736 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id))) 737 return -EFAULT; 738 739 return error; 740 } 741 742 /* Multi-number variable-length handlers */ 743 if (_IOC_TYPE(cmd) != 'E') 744 return -EINVAL; 745 746 if (_IOC_DIR(cmd) == _IOC_READ) { 747 748 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0))) 749 return handle_eviocgbit(dev, 750 _IOC_NR(cmd) & EV_MAX, size, 751 p, compat_mode); 752 753 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) { 754 755 if (!dev->absinfo) 756 return -EINVAL; 757 758 t = _IOC_NR(cmd) & ABS_MAX; 759 abs = dev->absinfo[t]; 760 761 if (copy_to_user(p, &abs, min_t(size_t, 762 size, sizeof(struct input_absinfo)))) 763 return -EFAULT; 764 765 return 0; 766 } 767 } 768 769 if (_IOC_DIR(cmd) == _IOC_WRITE) { 770 771 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) { 772 773 if (!dev->absinfo) 774 return -EINVAL; 775 776 t = _IOC_NR(cmd) & ABS_MAX; 777 778 if (copy_from_user(&abs, p, min_t(size_t, 779 size, sizeof(struct input_absinfo)))) 780 return -EFAULT; 781 782 if (size < sizeof(struct input_absinfo)) 783 abs.resolution = 0; 784 785 /* We can't change number of reserved MT slots */ 786 if (t == ABS_MT_SLOT) 787 return -EINVAL; 788 789 /* 790 * Take event lock to ensure that we are not 791 * changing device parameters in the middle 792 * of event. 793 */ 794 spin_lock_irq(&dev->event_lock); 795 dev->absinfo[t] = abs; 796 spin_unlock_irq(&dev->event_lock); 797 798 return 0; 799 } 800 } 801 802 return -EINVAL; 803 } 804 805 static long evdev_ioctl_handler(struct file *file, unsigned int cmd, 806 void __user *p, int compat_mode) 807 { 808 struct evdev_client *client = file->private_data; 809 struct evdev *evdev = client->evdev; 810 int retval; 811 812 retval = mutex_lock_interruptible(&evdev->mutex); 813 if (retval) 814 return retval; 815 816 if (!evdev->exist) { 817 retval = -ENODEV; 818 goto out; 819 } 820 821 retval = evdev_do_ioctl(file, cmd, p, compat_mode); 822 823 out: 824 mutex_unlock(&evdev->mutex); 825 return retval; 826 } 827 828 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 829 { 830 return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0); 831 } 832 833 #ifdef CONFIG_COMPAT 834 static long evdev_ioctl_compat(struct file *file, 835 unsigned int cmd, unsigned long arg) 836 { 837 return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1); 838 } 839 #endif 840 841 static const struct file_operations evdev_fops = { 842 .owner = THIS_MODULE, 843 .read = evdev_read, 844 .write = evdev_write, 845 .poll = evdev_poll, 846 .open = evdev_open, 847 .release = evdev_release, 848 .unlocked_ioctl = evdev_ioctl, 849 #ifdef CONFIG_COMPAT 850 .compat_ioctl = evdev_ioctl_compat, 851 #endif 852 .fasync = evdev_fasync, 853 .flush = evdev_flush, 854 .llseek = no_llseek, 855 }; 856 857 static int evdev_install_chrdev(struct evdev *evdev) 858 { 859 /* 860 * No need to do any locking here as calls to connect and 861 * disconnect are serialized by the input core 862 */ 863 evdev_table[evdev->minor] = evdev; 864 return 0; 865 } 866 867 static void evdev_remove_chrdev(struct evdev *evdev) 868 { 869 /* 870 * Lock evdev table to prevent race with evdev_open() 871 */ 872 mutex_lock(&evdev_table_mutex); 873 evdev_table[evdev->minor] = NULL; 874 mutex_unlock(&evdev_table_mutex); 875 } 876 877 /* 878 * Mark device non-existent. This disables writes, ioctls and 879 * prevents new users from opening the device. Already posted 880 * blocking reads will stay, however new ones will fail. 881 */ 882 static void evdev_mark_dead(struct evdev *evdev) 883 { 884 mutex_lock(&evdev->mutex); 885 evdev->exist = false; 886 mutex_unlock(&evdev->mutex); 887 } 888 889 static void evdev_cleanup(struct evdev *evdev) 890 { 891 struct input_handle *handle = &evdev->handle; 892 893 evdev_mark_dead(evdev); 894 evdev_hangup(evdev); 895 evdev_remove_chrdev(evdev); 896 897 /* evdev is marked dead so no one else accesses evdev->open */ 898 if (evdev->open) { 899 input_flush_device(handle, NULL); 900 input_close_device(handle); 901 } 902 } 903 904 /* 905 * Create new evdev device. Note that input core serializes calls 906 * to connect and disconnect so we don't need to lock evdev_table here. 907 */ 908 static int evdev_connect(struct input_handler *handler, struct input_dev *dev, 909 const struct input_device_id *id) 910 { 911 struct evdev *evdev; 912 int minor; 913 int error; 914 915 for (minor = 0; minor < EVDEV_MINORS; minor++) 916 if (!evdev_table[minor]) 917 break; 918 919 if (minor == EVDEV_MINORS) { 920 pr_err("no more free evdev devices\n"); 921 return -ENFILE; 922 } 923 924 evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL); 925 if (!evdev) 926 return -ENOMEM; 927 928 INIT_LIST_HEAD(&evdev->client_list); 929 spin_lock_init(&evdev->client_lock); 930 mutex_init(&evdev->mutex); 931 init_waitqueue_head(&evdev->wait); 932 933 dev_set_name(&evdev->dev, "event%d", minor); 934 evdev->exist = true; 935 evdev->minor = minor; 936 937 evdev->handle.dev = input_get_device(dev); 938 evdev->handle.name = dev_name(&evdev->dev); 939 evdev->handle.handler = handler; 940 evdev->handle.private = evdev; 941 942 evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor); 943 evdev->dev.class = &input_class; 944 evdev->dev.parent = &dev->dev; 945 evdev->dev.release = evdev_free; 946 device_initialize(&evdev->dev); 947 948 error = input_register_handle(&evdev->handle); 949 if (error) 950 goto err_free_evdev; 951 952 error = evdev_install_chrdev(evdev); 953 if (error) 954 goto err_unregister_handle; 955 956 error = device_add(&evdev->dev); 957 if (error) 958 goto err_cleanup_evdev; 959 960 return 0; 961 962 err_cleanup_evdev: 963 evdev_cleanup(evdev); 964 err_unregister_handle: 965 input_unregister_handle(&evdev->handle); 966 err_free_evdev: 967 put_device(&evdev->dev); 968 return error; 969 } 970 971 static void evdev_disconnect(struct input_handle *handle) 972 { 973 struct evdev *evdev = handle->private; 974 975 device_del(&evdev->dev); 976 evdev_cleanup(evdev); 977 input_unregister_handle(handle); 978 put_device(&evdev->dev); 979 } 980 981 static const struct input_device_id evdev_ids[] = { 982 { .driver_info = 1 }, /* Matches all devices */ 983 { }, /* Terminating zero entry */ 984 }; 985 986 MODULE_DEVICE_TABLE(input, evdev_ids); 987 988 static struct input_handler evdev_handler = { 989 .event = evdev_event, 990 .connect = evdev_connect, 991 .disconnect = evdev_disconnect, 992 .fops = &evdev_fops, 993 .minor = EVDEV_MINOR_BASE, 994 .name = "evdev", 995 .id_table = evdev_ids, 996 }; 997 998 static int __init evdev_init(void) 999 { 1000 return input_register_handler(&evdev_handler); 1001 } 1002 1003 static void __exit evdev_exit(void) 1004 { 1005 input_unregister_handler(&evdev_handler); 1006 } 1007 1008 module_init(evdev_init); 1009 module_exit(evdev_exit); 1010 1011 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>"); 1012 MODULE_DESCRIPTION("Input driver event char devices"); 1013 MODULE_LICENSE("GPL"); 1014