xref: /openbmc/linux/drivers/input/misc/uinput.c (revision 4cff79e9)
1 /*
2  *  User level driver support for input subsystem
3  *
4  * Heavily based on evdev.c by Vojtech Pavlik
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19  *
20  * Author: Aristeu Sergio Rozanski Filho <aris@cathedrallabs.org>
21  *
22  * Changes/Revisions:
23  *	0.4	01/09/2014 (Benjamin Tissoires <benjamin.tissoires@redhat.com>)
24  *		- add UI_GET_SYSNAME ioctl
25  *	0.3	09/04/2006 (Anssi Hannula <anssi.hannula@gmail.com>)
26  *		- updated ff support for the changes in kernel interface
27  *		- added MODULE_VERSION
28  *	0.2	16/10/2004 (Micah Dowty <micah@navi.cx>)
29  *		- added force feedback support
30  *              - added UI_SET_PHYS
31  *	0.1	20/06/2002
32  *		- first public version
33  */
34 #include <uapi/linux/uinput.h>
35 #include <linux/poll.h>
36 #include <linux/sched.h>
37 #include <linux/slab.h>
38 #include <linux/module.h>
39 #include <linux/init.h>
40 #include <linux/fs.h>
41 #include <linux/miscdevice.h>
42 #include <linux/input/mt.h>
43 #include "../input-compat.h"
44 
45 #define UINPUT_NAME		"uinput"
46 #define UINPUT_BUFFER_SIZE	16
47 #define UINPUT_NUM_REQUESTS	16
48 
49 enum uinput_state { UIST_NEW_DEVICE, UIST_SETUP_COMPLETE, UIST_CREATED };
50 
51 struct uinput_request {
52 	unsigned int		id;
53 	unsigned int		code;	/* UI_FF_UPLOAD, UI_FF_ERASE */
54 
55 	int			retval;
56 	struct completion	done;
57 
58 	union {
59 		unsigned int	effect_id;
60 		struct {
61 			struct ff_effect *effect;
62 			struct ff_effect *old;
63 		} upload;
64 	} u;
65 };
66 
67 struct uinput_device {
68 	struct input_dev	*dev;
69 	struct mutex		mutex;
70 	enum uinput_state	state;
71 	wait_queue_head_t	waitq;
72 	unsigned char		ready;
73 	unsigned char		head;
74 	unsigned char		tail;
75 	struct input_event	buff[UINPUT_BUFFER_SIZE];
76 	unsigned int		ff_effects_max;
77 
78 	struct uinput_request	*requests[UINPUT_NUM_REQUESTS];
79 	wait_queue_head_t	requests_waitq;
80 	spinlock_t		requests_lock;
81 };
82 
83 static int uinput_dev_event(struct input_dev *dev,
84 			    unsigned int type, unsigned int code, int value)
85 {
86 	struct uinput_device	*udev = input_get_drvdata(dev);
87 	struct timespec64	ts;
88 
89 	udev->buff[udev->head].type = type;
90 	udev->buff[udev->head].code = code;
91 	udev->buff[udev->head].value = value;
92 	ktime_get_ts64(&ts);
93 	udev->buff[udev->head].input_event_sec = ts.tv_sec;
94 	udev->buff[udev->head].input_event_usec = ts.tv_nsec / NSEC_PER_USEC;
95 	udev->head = (udev->head + 1) % UINPUT_BUFFER_SIZE;
96 
97 	wake_up_interruptible(&udev->waitq);
98 
99 	return 0;
100 }
101 
102 /* Atomically allocate an ID for the given request. Returns 0 on success. */
103 static bool uinput_request_alloc_id(struct uinput_device *udev,
104 				    struct uinput_request *request)
105 {
106 	unsigned int id;
107 	bool reserved = false;
108 
109 	spin_lock(&udev->requests_lock);
110 
111 	for (id = 0; id < UINPUT_NUM_REQUESTS; id++) {
112 		if (!udev->requests[id]) {
113 			request->id = id;
114 			udev->requests[id] = request;
115 			reserved = true;
116 			break;
117 		}
118 	}
119 
120 	spin_unlock(&udev->requests_lock);
121 	return reserved;
122 }
123 
124 static struct uinput_request *uinput_request_find(struct uinput_device *udev,
125 						  unsigned int id)
126 {
127 	/* Find an input request, by ID. Returns NULL if the ID isn't valid. */
128 	if (id >= UINPUT_NUM_REQUESTS)
129 		return NULL;
130 
131 	return udev->requests[id];
132 }
133 
134 static int uinput_request_reserve_slot(struct uinput_device *udev,
135 				       struct uinput_request *request)
136 {
137 	/* Allocate slot. If none are available right away, wait. */
138 	return wait_event_interruptible(udev->requests_waitq,
139 					uinput_request_alloc_id(udev, request));
140 }
141 
142 static void uinput_request_release_slot(struct uinput_device *udev,
143 					unsigned int id)
144 {
145 	/* Mark slot as available */
146 	spin_lock(&udev->requests_lock);
147 	udev->requests[id] = NULL;
148 	spin_unlock(&udev->requests_lock);
149 
150 	wake_up(&udev->requests_waitq);
151 }
152 
153 static int uinput_request_send(struct uinput_device *udev,
154 			       struct uinput_request *request)
155 {
156 	int retval;
157 
158 	retval = mutex_lock_interruptible(&udev->mutex);
159 	if (retval)
160 		return retval;
161 
162 	if (udev->state != UIST_CREATED) {
163 		retval = -ENODEV;
164 		goto out;
165 	}
166 
167 	init_completion(&request->done);
168 
169 	/*
170 	 * Tell our userspace application about this new request
171 	 * by queueing an input event.
172 	 */
173 	uinput_dev_event(udev->dev, EV_UINPUT, request->code, request->id);
174 
175  out:
176 	mutex_unlock(&udev->mutex);
177 	return retval;
178 }
179 
180 static int uinput_request_submit(struct uinput_device *udev,
181 				 struct uinput_request *request)
182 {
183 	int retval;
184 
185 	retval = uinput_request_reserve_slot(udev, request);
186 	if (retval)
187 		return retval;
188 
189 	retval = uinput_request_send(udev, request);
190 	if (retval)
191 		goto out;
192 
193 	if (!wait_for_completion_timeout(&request->done, 30 * HZ)) {
194 		retval = -ETIMEDOUT;
195 		goto out;
196 	}
197 
198 	retval = request->retval;
199 
200  out:
201 	uinput_request_release_slot(udev, request->id);
202 	return retval;
203 }
204 
205 /*
206  * Fail all outstanding requests so handlers don't wait for the userspace
207  * to finish processing them.
208  */
209 static void uinput_flush_requests(struct uinput_device *udev)
210 {
211 	struct uinput_request *request;
212 	int i;
213 
214 	spin_lock(&udev->requests_lock);
215 
216 	for (i = 0; i < UINPUT_NUM_REQUESTS; i++) {
217 		request = udev->requests[i];
218 		if (request) {
219 			request->retval = -ENODEV;
220 			complete(&request->done);
221 		}
222 	}
223 
224 	spin_unlock(&udev->requests_lock);
225 }
226 
227 static void uinput_dev_set_gain(struct input_dev *dev, u16 gain)
228 {
229 	uinput_dev_event(dev, EV_FF, FF_GAIN, gain);
230 }
231 
232 static void uinput_dev_set_autocenter(struct input_dev *dev, u16 magnitude)
233 {
234 	uinput_dev_event(dev, EV_FF, FF_AUTOCENTER, magnitude);
235 }
236 
237 static int uinput_dev_playback(struct input_dev *dev, int effect_id, int value)
238 {
239 	return uinput_dev_event(dev, EV_FF, effect_id, value);
240 }
241 
242 static int uinput_dev_upload_effect(struct input_dev *dev,
243 				    struct ff_effect *effect,
244 				    struct ff_effect *old)
245 {
246 	struct uinput_device *udev = input_get_drvdata(dev);
247 	struct uinput_request request;
248 
249 	/*
250 	 * uinput driver does not currently support periodic effects with
251 	 * custom waveform since it does not have a way to pass buffer of
252 	 * samples (custom_data) to userspace. If ever there is a device
253 	 * supporting custom waveforms we would need to define an additional
254 	 * ioctl (UI_UPLOAD_SAMPLES) but for now we just bail out.
255 	 */
256 	if (effect->type == FF_PERIODIC &&
257 			effect->u.periodic.waveform == FF_CUSTOM)
258 		return -EINVAL;
259 
260 	request.code = UI_FF_UPLOAD;
261 	request.u.upload.effect = effect;
262 	request.u.upload.old = old;
263 
264 	return uinput_request_submit(udev, &request);
265 }
266 
267 static int uinput_dev_erase_effect(struct input_dev *dev, int effect_id)
268 {
269 	struct uinput_device *udev = input_get_drvdata(dev);
270 	struct uinput_request request;
271 
272 	if (!test_bit(EV_FF, dev->evbit))
273 		return -ENOSYS;
274 
275 	request.code = UI_FF_ERASE;
276 	request.u.effect_id = effect_id;
277 
278 	return uinput_request_submit(udev, &request);
279 }
280 
281 static int uinput_dev_flush(struct input_dev *dev, struct file *file)
282 {
283 	/*
284 	 * If we are called with file == NULL that means we are tearing
285 	 * down the device, and therefore we can not handle FF erase
286 	 * requests: either we are handling UI_DEV_DESTROY (and holding
287 	 * the udev->mutex), or the file descriptor is closed and there is
288 	 * nobody on the other side anymore.
289 	 */
290 	return file ? input_ff_flush(dev, file) : 0;
291 }
292 
293 static void uinput_destroy_device(struct uinput_device *udev)
294 {
295 	const char *name, *phys;
296 	struct input_dev *dev = udev->dev;
297 	enum uinput_state old_state = udev->state;
298 
299 	udev->state = UIST_NEW_DEVICE;
300 
301 	if (dev) {
302 		name = dev->name;
303 		phys = dev->phys;
304 		if (old_state == UIST_CREATED) {
305 			uinput_flush_requests(udev);
306 			input_unregister_device(dev);
307 		} else {
308 			input_free_device(dev);
309 		}
310 		kfree(name);
311 		kfree(phys);
312 		udev->dev = NULL;
313 	}
314 }
315 
316 static int uinput_create_device(struct uinput_device *udev)
317 {
318 	struct input_dev *dev = udev->dev;
319 	int error, nslot;
320 
321 	if (udev->state != UIST_SETUP_COMPLETE) {
322 		printk(KERN_DEBUG "%s: write device info first\n", UINPUT_NAME);
323 		return -EINVAL;
324 	}
325 
326 	if (test_bit(EV_ABS, dev->evbit)) {
327 		input_alloc_absinfo(dev);
328 		if (!dev->absinfo) {
329 			error = -EINVAL;
330 			goto fail1;
331 		}
332 
333 		if (test_bit(ABS_MT_SLOT, dev->absbit)) {
334 			nslot = input_abs_get_max(dev, ABS_MT_SLOT) + 1;
335 			error = input_mt_init_slots(dev, nslot, 0);
336 			if (error)
337 				goto fail1;
338 		} else if (test_bit(ABS_MT_POSITION_X, dev->absbit)) {
339 			input_set_events_per_packet(dev, 60);
340 		}
341 	}
342 
343 	if (test_bit(EV_FF, dev->evbit) && !udev->ff_effects_max) {
344 		printk(KERN_DEBUG "%s: ff_effects_max should be non-zero when FF_BIT is set\n",
345 			UINPUT_NAME);
346 		error = -EINVAL;
347 		goto fail1;
348 	}
349 
350 	if (udev->ff_effects_max) {
351 		error = input_ff_create(dev, udev->ff_effects_max);
352 		if (error)
353 			goto fail1;
354 
355 		dev->ff->upload = uinput_dev_upload_effect;
356 		dev->ff->erase = uinput_dev_erase_effect;
357 		dev->ff->playback = uinput_dev_playback;
358 		dev->ff->set_gain = uinput_dev_set_gain;
359 		dev->ff->set_autocenter = uinput_dev_set_autocenter;
360 		/*
361 		 * The standard input_ff_flush() implementation does
362 		 * not quite work for uinput as we can't reasonably
363 		 * handle FF requests during device teardown.
364 		 */
365 		dev->flush = uinput_dev_flush;
366 	}
367 
368 	dev->event = uinput_dev_event;
369 
370 	input_set_drvdata(udev->dev, udev);
371 
372 	error = input_register_device(udev->dev);
373 	if (error)
374 		goto fail2;
375 
376 	udev->state = UIST_CREATED;
377 
378 	return 0;
379 
380  fail2:	input_ff_destroy(dev);
381  fail1: uinput_destroy_device(udev);
382 	return error;
383 }
384 
385 static int uinput_open(struct inode *inode, struct file *file)
386 {
387 	struct uinput_device *newdev;
388 
389 	newdev = kzalloc(sizeof(struct uinput_device), GFP_KERNEL);
390 	if (!newdev)
391 		return -ENOMEM;
392 
393 	mutex_init(&newdev->mutex);
394 	spin_lock_init(&newdev->requests_lock);
395 	init_waitqueue_head(&newdev->requests_waitq);
396 	init_waitqueue_head(&newdev->waitq);
397 	newdev->state = UIST_NEW_DEVICE;
398 
399 	file->private_data = newdev;
400 	nonseekable_open(inode, file);
401 
402 	return 0;
403 }
404 
405 static int uinput_validate_absinfo(struct input_dev *dev, unsigned int code,
406 				   const struct input_absinfo *abs)
407 {
408 	int min, max;
409 
410 	min = abs->minimum;
411 	max = abs->maximum;
412 
413 	if ((min != 0 || max != 0) && max <= min) {
414 		printk(KERN_DEBUG
415 		       "%s: invalid abs[%02x] min:%d max:%d\n",
416 		       UINPUT_NAME, code, min, max);
417 		return -EINVAL;
418 	}
419 
420 	if (abs->flat > max - min) {
421 		printk(KERN_DEBUG
422 		       "%s: abs_flat #%02x out of range: %d (min:%d/max:%d)\n",
423 		       UINPUT_NAME, code, abs->flat, min, max);
424 		return -EINVAL;
425 	}
426 
427 	return 0;
428 }
429 
430 static int uinput_validate_absbits(struct input_dev *dev)
431 {
432 	unsigned int cnt;
433 	int error;
434 
435 	if (!test_bit(EV_ABS, dev->evbit))
436 		return 0;
437 
438 	/*
439 	 * Check if absmin/absmax/absfuzz/absflat are sane.
440 	 */
441 
442 	for_each_set_bit(cnt, dev->absbit, ABS_CNT) {
443 		if (!dev->absinfo)
444 			return -EINVAL;
445 
446 		error = uinput_validate_absinfo(dev, cnt, &dev->absinfo[cnt]);
447 		if (error)
448 			return error;
449 	}
450 
451 	return 0;
452 }
453 
454 static int uinput_dev_setup(struct uinput_device *udev,
455 			    struct uinput_setup __user *arg)
456 {
457 	struct uinput_setup setup;
458 	struct input_dev *dev;
459 
460 	if (udev->state == UIST_CREATED)
461 		return -EINVAL;
462 
463 	if (copy_from_user(&setup, arg, sizeof(setup)))
464 		return -EFAULT;
465 
466 	if (!setup.name[0])
467 		return -EINVAL;
468 
469 	dev = udev->dev;
470 	dev->id = setup.id;
471 	udev->ff_effects_max = setup.ff_effects_max;
472 
473 	kfree(dev->name);
474 	dev->name = kstrndup(setup.name, UINPUT_MAX_NAME_SIZE, GFP_KERNEL);
475 	if (!dev->name)
476 		return -ENOMEM;
477 
478 	udev->state = UIST_SETUP_COMPLETE;
479 	return 0;
480 }
481 
482 static int uinput_abs_setup(struct uinput_device *udev,
483 			    struct uinput_setup __user *arg, size_t size)
484 {
485 	struct uinput_abs_setup setup = {};
486 	struct input_dev *dev;
487 	int error;
488 
489 	if (size > sizeof(setup))
490 		return -E2BIG;
491 
492 	if (udev->state == UIST_CREATED)
493 		return -EINVAL;
494 
495 	if (copy_from_user(&setup, arg, size))
496 		return -EFAULT;
497 
498 	if (setup.code > ABS_MAX)
499 		return -ERANGE;
500 
501 	dev = udev->dev;
502 
503 	error = uinput_validate_absinfo(dev, setup.code, &setup.absinfo);
504 	if (error)
505 		return error;
506 
507 	input_alloc_absinfo(dev);
508 	if (!dev->absinfo)
509 		return -ENOMEM;
510 
511 	set_bit(setup.code, dev->absbit);
512 	dev->absinfo[setup.code] = setup.absinfo;
513 	return 0;
514 }
515 
516 /* legacy setup via write() */
517 static int uinput_setup_device_legacy(struct uinput_device *udev,
518 				      const char __user *buffer, size_t count)
519 {
520 	struct uinput_user_dev	*user_dev;
521 	struct input_dev	*dev;
522 	int			i;
523 	int			retval;
524 
525 	if (count != sizeof(struct uinput_user_dev))
526 		return -EINVAL;
527 
528 	if (!udev->dev) {
529 		udev->dev = input_allocate_device();
530 		if (!udev->dev)
531 			return -ENOMEM;
532 	}
533 
534 	dev = udev->dev;
535 
536 	user_dev = memdup_user(buffer, sizeof(struct uinput_user_dev));
537 	if (IS_ERR(user_dev))
538 		return PTR_ERR(user_dev);
539 
540 	udev->ff_effects_max = user_dev->ff_effects_max;
541 
542 	/* Ensure name is filled in */
543 	if (!user_dev->name[0]) {
544 		retval = -EINVAL;
545 		goto exit;
546 	}
547 
548 	kfree(dev->name);
549 	dev->name = kstrndup(user_dev->name, UINPUT_MAX_NAME_SIZE,
550 			     GFP_KERNEL);
551 	if (!dev->name) {
552 		retval = -ENOMEM;
553 		goto exit;
554 	}
555 
556 	dev->id.bustype	= user_dev->id.bustype;
557 	dev->id.vendor	= user_dev->id.vendor;
558 	dev->id.product	= user_dev->id.product;
559 	dev->id.version	= user_dev->id.version;
560 
561 	for (i = 0; i < ABS_CNT; i++) {
562 		input_abs_set_max(dev, i, user_dev->absmax[i]);
563 		input_abs_set_min(dev, i, user_dev->absmin[i]);
564 		input_abs_set_fuzz(dev, i, user_dev->absfuzz[i]);
565 		input_abs_set_flat(dev, i, user_dev->absflat[i]);
566 	}
567 
568 	retval = uinput_validate_absbits(dev);
569 	if (retval < 0)
570 		goto exit;
571 
572 	udev->state = UIST_SETUP_COMPLETE;
573 	retval = count;
574 
575  exit:
576 	kfree(user_dev);
577 	return retval;
578 }
579 
580 static ssize_t uinput_inject_events(struct uinput_device *udev,
581 				    const char __user *buffer, size_t count)
582 {
583 	struct input_event ev;
584 	size_t bytes = 0;
585 
586 	if (count != 0 && count < input_event_size())
587 		return -EINVAL;
588 
589 	while (bytes + input_event_size() <= count) {
590 		/*
591 		 * Note that even if some events were fetched successfully
592 		 * we are still going to return EFAULT instead of partial
593 		 * count to let userspace know that it got it's buffers
594 		 * all wrong.
595 		 */
596 		if (input_event_from_user(buffer + bytes, &ev))
597 			return -EFAULT;
598 
599 		input_event(udev->dev, ev.type, ev.code, ev.value);
600 		bytes += input_event_size();
601 	}
602 
603 	return bytes;
604 }
605 
606 static ssize_t uinput_write(struct file *file, const char __user *buffer,
607 			    size_t count, loff_t *ppos)
608 {
609 	struct uinput_device *udev = file->private_data;
610 	int retval;
611 
612 	if (count == 0)
613 		return 0;
614 
615 	retval = mutex_lock_interruptible(&udev->mutex);
616 	if (retval)
617 		return retval;
618 
619 	retval = udev->state == UIST_CREATED ?
620 			uinput_inject_events(udev, buffer, count) :
621 			uinput_setup_device_legacy(udev, buffer, count);
622 
623 	mutex_unlock(&udev->mutex);
624 
625 	return retval;
626 }
627 
628 static bool uinput_fetch_next_event(struct uinput_device *udev,
629 				    struct input_event *event)
630 {
631 	bool have_event;
632 
633 	spin_lock_irq(&udev->dev->event_lock);
634 
635 	have_event = udev->head != udev->tail;
636 	if (have_event) {
637 		*event = udev->buff[udev->tail];
638 		udev->tail = (udev->tail + 1) % UINPUT_BUFFER_SIZE;
639 	}
640 
641 	spin_unlock_irq(&udev->dev->event_lock);
642 
643 	return have_event;
644 }
645 
646 static ssize_t uinput_events_to_user(struct uinput_device *udev,
647 				     char __user *buffer, size_t count)
648 {
649 	struct input_event event;
650 	size_t read = 0;
651 
652 	while (read + input_event_size() <= count &&
653 	       uinput_fetch_next_event(udev, &event)) {
654 
655 		if (input_event_to_user(buffer + read, &event))
656 			return -EFAULT;
657 
658 		read += input_event_size();
659 	}
660 
661 	return read;
662 }
663 
664 static ssize_t uinput_read(struct file *file, char __user *buffer,
665 			   size_t count, loff_t *ppos)
666 {
667 	struct uinput_device *udev = file->private_data;
668 	ssize_t retval;
669 
670 	if (count != 0 && count < input_event_size())
671 		return -EINVAL;
672 
673 	do {
674 		retval = mutex_lock_interruptible(&udev->mutex);
675 		if (retval)
676 			return retval;
677 
678 		if (udev->state != UIST_CREATED)
679 			retval = -ENODEV;
680 		else if (udev->head == udev->tail &&
681 			 (file->f_flags & O_NONBLOCK))
682 			retval = -EAGAIN;
683 		else
684 			retval = uinput_events_to_user(udev, buffer, count);
685 
686 		mutex_unlock(&udev->mutex);
687 
688 		if (retval || count == 0)
689 			break;
690 
691 		if (!(file->f_flags & O_NONBLOCK))
692 			retval = wait_event_interruptible(udev->waitq,
693 						  udev->head != udev->tail ||
694 						  udev->state != UIST_CREATED);
695 	} while (retval == 0);
696 
697 	return retval;
698 }
699 
700 static __poll_t uinput_poll(struct file *file, poll_table *wait)
701 {
702 	struct uinput_device *udev = file->private_data;
703 
704 	poll_wait(file, &udev->waitq, wait);
705 
706 	if (udev->head != udev->tail)
707 		return EPOLLIN | EPOLLRDNORM;
708 
709 	return 0;
710 }
711 
712 static int uinput_release(struct inode *inode, struct file *file)
713 {
714 	struct uinput_device *udev = file->private_data;
715 
716 	uinput_destroy_device(udev);
717 	kfree(udev);
718 
719 	return 0;
720 }
721 
722 #ifdef CONFIG_COMPAT
723 struct uinput_ff_upload_compat {
724 	__u32			request_id;
725 	__s32			retval;
726 	struct ff_effect_compat	effect;
727 	struct ff_effect_compat	old;
728 };
729 
730 static int uinput_ff_upload_to_user(char __user *buffer,
731 				    const struct uinput_ff_upload *ff_up)
732 {
733 	if (in_compat_syscall()) {
734 		struct uinput_ff_upload_compat ff_up_compat;
735 
736 		ff_up_compat.request_id = ff_up->request_id;
737 		ff_up_compat.retval = ff_up->retval;
738 		/*
739 		 * It so happens that the pointer that gives us the trouble
740 		 * is the last field in the structure. Since we don't support
741 		 * custom waveforms in uinput anyway we can just copy the whole
742 		 * thing (to the compat size) and ignore the pointer.
743 		 */
744 		memcpy(&ff_up_compat.effect, &ff_up->effect,
745 			sizeof(struct ff_effect_compat));
746 		memcpy(&ff_up_compat.old, &ff_up->old,
747 			sizeof(struct ff_effect_compat));
748 
749 		if (copy_to_user(buffer, &ff_up_compat,
750 				 sizeof(struct uinput_ff_upload_compat)))
751 			return -EFAULT;
752 	} else {
753 		if (copy_to_user(buffer, ff_up,
754 				 sizeof(struct uinput_ff_upload)))
755 			return -EFAULT;
756 	}
757 
758 	return 0;
759 }
760 
761 static int uinput_ff_upload_from_user(const char __user *buffer,
762 				      struct uinput_ff_upload *ff_up)
763 {
764 	if (in_compat_syscall()) {
765 		struct uinput_ff_upload_compat ff_up_compat;
766 
767 		if (copy_from_user(&ff_up_compat, buffer,
768 				   sizeof(struct uinput_ff_upload_compat)))
769 			return -EFAULT;
770 
771 		ff_up->request_id = ff_up_compat.request_id;
772 		ff_up->retval = ff_up_compat.retval;
773 		memcpy(&ff_up->effect, &ff_up_compat.effect,
774 			sizeof(struct ff_effect_compat));
775 		memcpy(&ff_up->old, &ff_up_compat.old,
776 			sizeof(struct ff_effect_compat));
777 
778 	} else {
779 		if (copy_from_user(ff_up, buffer,
780 				   sizeof(struct uinput_ff_upload)))
781 			return -EFAULT;
782 	}
783 
784 	return 0;
785 }
786 
787 #else
788 
789 static int uinput_ff_upload_to_user(char __user *buffer,
790 				    const struct uinput_ff_upload *ff_up)
791 {
792 	if (copy_to_user(buffer, ff_up, sizeof(struct uinput_ff_upload)))
793 		return -EFAULT;
794 
795 	return 0;
796 }
797 
798 static int uinput_ff_upload_from_user(const char __user *buffer,
799 				      struct uinput_ff_upload *ff_up)
800 {
801 	if (copy_from_user(ff_up, buffer, sizeof(struct uinput_ff_upload)))
802 		return -EFAULT;
803 
804 	return 0;
805 }
806 
807 #endif
808 
809 #define uinput_set_bit(_arg, _bit, _max)		\
810 ({							\
811 	int __ret = 0;					\
812 	if (udev->state == UIST_CREATED)		\
813 		__ret =  -EINVAL;			\
814 	else if ((_arg) > (_max))			\
815 		__ret = -EINVAL;			\
816 	else set_bit((_arg), udev->dev->_bit);		\
817 	__ret;						\
818 })
819 
820 static int uinput_str_to_user(void __user *dest, const char *str,
821 			      unsigned int maxlen)
822 {
823 	char __user *p = dest;
824 	int len, ret;
825 
826 	if (!str)
827 		return -ENOENT;
828 
829 	if (maxlen == 0)
830 		return -EINVAL;
831 
832 	len = strlen(str) + 1;
833 	if (len > maxlen)
834 		len = maxlen;
835 
836 	ret = copy_to_user(p, str, len);
837 	if (ret)
838 		return -EFAULT;
839 
840 	/* force terminating '\0' */
841 	ret = put_user(0, p + len - 1);
842 	return ret ? -EFAULT : len;
843 }
844 
845 static long uinput_ioctl_handler(struct file *file, unsigned int cmd,
846 				 unsigned long arg, void __user *p)
847 {
848 	int			retval;
849 	struct uinput_device	*udev = file->private_data;
850 	struct uinput_ff_upload ff_up;
851 	struct uinput_ff_erase  ff_erase;
852 	struct uinput_request   *req;
853 	char			*phys;
854 	const char		*name;
855 	unsigned int		size;
856 
857 	retval = mutex_lock_interruptible(&udev->mutex);
858 	if (retval)
859 		return retval;
860 
861 	if (!udev->dev) {
862 		udev->dev = input_allocate_device();
863 		if (!udev->dev) {
864 			retval = -ENOMEM;
865 			goto out;
866 		}
867 	}
868 
869 	switch (cmd) {
870 	case UI_GET_VERSION:
871 		if (put_user(UINPUT_VERSION, (unsigned int __user *)p))
872 			retval = -EFAULT;
873 		goto out;
874 
875 	case UI_DEV_CREATE:
876 		retval = uinput_create_device(udev);
877 		goto out;
878 
879 	case UI_DEV_DESTROY:
880 		uinput_destroy_device(udev);
881 		goto out;
882 
883 	case UI_DEV_SETUP:
884 		retval = uinput_dev_setup(udev, p);
885 		goto out;
886 
887 	/* UI_ABS_SETUP is handled in the variable size ioctls */
888 
889 	case UI_SET_EVBIT:
890 		retval = uinput_set_bit(arg, evbit, EV_MAX);
891 		goto out;
892 
893 	case UI_SET_KEYBIT:
894 		retval = uinput_set_bit(arg, keybit, KEY_MAX);
895 		goto out;
896 
897 	case UI_SET_RELBIT:
898 		retval = uinput_set_bit(arg, relbit, REL_MAX);
899 		goto out;
900 
901 	case UI_SET_ABSBIT:
902 		retval = uinput_set_bit(arg, absbit, ABS_MAX);
903 		goto out;
904 
905 	case UI_SET_MSCBIT:
906 		retval = uinput_set_bit(arg, mscbit, MSC_MAX);
907 		goto out;
908 
909 	case UI_SET_LEDBIT:
910 		retval = uinput_set_bit(arg, ledbit, LED_MAX);
911 		goto out;
912 
913 	case UI_SET_SNDBIT:
914 		retval = uinput_set_bit(arg, sndbit, SND_MAX);
915 		goto out;
916 
917 	case UI_SET_FFBIT:
918 		retval = uinput_set_bit(arg, ffbit, FF_MAX);
919 		goto out;
920 
921 	case UI_SET_SWBIT:
922 		retval = uinput_set_bit(arg, swbit, SW_MAX);
923 		goto out;
924 
925 	case UI_SET_PROPBIT:
926 		retval = uinput_set_bit(arg, propbit, INPUT_PROP_MAX);
927 		goto out;
928 
929 	case UI_SET_PHYS:
930 		if (udev->state == UIST_CREATED) {
931 			retval = -EINVAL;
932 			goto out;
933 		}
934 
935 		phys = strndup_user(p, 1024);
936 		if (IS_ERR(phys)) {
937 			retval = PTR_ERR(phys);
938 			goto out;
939 		}
940 
941 		kfree(udev->dev->phys);
942 		udev->dev->phys = phys;
943 		goto out;
944 
945 	case UI_BEGIN_FF_UPLOAD:
946 		retval = uinput_ff_upload_from_user(p, &ff_up);
947 		if (retval)
948 			goto out;
949 
950 		req = uinput_request_find(udev, ff_up.request_id);
951 		if (!req || req->code != UI_FF_UPLOAD ||
952 		    !req->u.upload.effect) {
953 			retval = -EINVAL;
954 			goto out;
955 		}
956 
957 		ff_up.retval = 0;
958 		ff_up.effect = *req->u.upload.effect;
959 		if (req->u.upload.old)
960 			ff_up.old = *req->u.upload.old;
961 		else
962 			memset(&ff_up.old, 0, sizeof(struct ff_effect));
963 
964 		retval = uinput_ff_upload_to_user(p, &ff_up);
965 		goto out;
966 
967 	case UI_BEGIN_FF_ERASE:
968 		if (copy_from_user(&ff_erase, p, sizeof(ff_erase))) {
969 			retval = -EFAULT;
970 			goto out;
971 		}
972 
973 		req = uinput_request_find(udev, ff_erase.request_id);
974 		if (!req || req->code != UI_FF_ERASE) {
975 			retval = -EINVAL;
976 			goto out;
977 		}
978 
979 		ff_erase.retval = 0;
980 		ff_erase.effect_id = req->u.effect_id;
981 		if (copy_to_user(p, &ff_erase, sizeof(ff_erase))) {
982 			retval = -EFAULT;
983 			goto out;
984 		}
985 
986 		goto out;
987 
988 	case UI_END_FF_UPLOAD:
989 		retval = uinput_ff_upload_from_user(p, &ff_up);
990 		if (retval)
991 			goto out;
992 
993 		req = uinput_request_find(udev, ff_up.request_id);
994 		if (!req || req->code != UI_FF_UPLOAD ||
995 		    !req->u.upload.effect) {
996 			retval = -EINVAL;
997 			goto out;
998 		}
999 
1000 		req->retval = ff_up.retval;
1001 		complete(&req->done);
1002 		goto out;
1003 
1004 	case UI_END_FF_ERASE:
1005 		if (copy_from_user(&ff_erase, p, sizeof(ff_erase))) {
1006 			retval = -EFAULT;
1007 			goto out;
1008 		}
1009 
1010 		req = uinput_request_find(udev, ff_erase.request_id);
1011 		if (!req || req->code != UI_FF_ERASE) {
1012 			retval = -EINVAL;
1013 			goto out;
1014 		}
1015 
1016 		req->retval = ff_erase.retval;
1017 		complete(&req->done);
1018 		goto out;
1019 	}
1020 
1021 	size = _IOC_SIZE(cmd);
1022 
1023 	/* Now check variable-length commands */
1024 	switch (cmd & ~IOCSIZE_MASK) {
1025 	case UI_GET_SYSNAME(0):
1026 		if (udev->state != UIST_CREATED) {
1027 			retval = -ENOENT;
1028 			goto out;
1029 		}
1030 		name = dev_name(&udev->dev->dev);
1031 		retval = uinput_str_to_user(p, name, size);
1032 		goto out;
1033 
1034 	case UI_ABS_SETUP & ~IOCSIZE_MASK:
1035 		retval = uinput_abs_setup(udev, p, size);
1036 		goto out;
1037 	}
1038 
1039 	retval = -EINVAL;
1040  out:
1041 	mutex_unlock(&udev->mutex);
1042 	return retval;
1043 }
1044 
1045 static long uinput_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1046 {
1047 	return uinput_ioctl_handler(file, cmd, arg, (void __user *)arg);
1048 }
1049 
1050 #ifdef CONFIG_COMPAT
1051 
1052 #define UI_SET_PHYS_COMPAT	_IOW(UINPUT_IOCTL_BASE, 108, compat_uptr_t)
1053 
1054 static long uinput_compat_ioctl(struct file *file,
1055 				unsigned int cmd, unsigned long arg)
1056 {
1057 	if (cmd == UI_SET_PHYS_COMPAT)
1058 		cmd = UI_SET_PHYS;
1059 
1060 	return uinput_ioctl_handler(file, cmd, arg, compat_ptr(arg));
1061 }
1062 #endif
1063 
1064 static const struct file_operations uinput_fops = {
1065 	.owner		= THIS_MODULE,
1066 	.open		= uinput_open,
1067 	.release	= uinput_release,
1068 	.read		= uinput_read,
1069 	.write		= uinput_write,
1070 	.poll		= uinput_poll,
1071 	.unlocked_ioctl	= uinput_ioctl,
1072 #ifdef CONFIG_COMPAT
1073 	.compat_ioctl	= uinput_compat_ioctl,
1074 #endif
1075 	.llseek		= no_llseek,
1076 };
1077 
1078 static struct miscdevice uinput_misc = {
1079 	.fops		= &uinput_fops,
1080 	.minor		= UINPUT_MINOR,
1081 	.name		= UINPUT_NAME,
1082 };
1083 module_misc_device(uinput_misc);
1084 
1085 MODULE_ALIAS_MISCDEV(UINPUT_MINOR);
1086 MODULE_ALIAS("devname:" UINPUT_NAME);
1087 
1088 MODULE_AUTHOR("Aristeu Sergio Rozanski Filho");
1089 MODULE_DESCRIPTION("User level driver support for input subsystem");
1090 MODULE_LICENSE("GPL");
1091