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1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  User level driver support for input subsystem
4  *
5  * Heavily based on evdev.c by Vojtech Pavlik
6  *
7  * Author: Aristeu Sergio Rozanski Filho <aris@cathedrallabs.org>
8  *
9  * Changes/Revisions:
10  *	0.4	01/09/2014 (Benjamin Tissoires <benjamin.tissoires@redhat.com>)
11  *		- add UI_GET_SYSNAME ioctl
12  *	0.3	09/04/2006 (Anssi Hannula <anssi.hannula@gmail.com>)
13  *		- updated ff support for the changes in kernel interface
14  *		- added MODULE_VERSION
15  *	0.2	16/10/2004 (Micah Dowty <micah@navi.cx>)
16  *		- added force feedback support
17  *              - added UI_SET_PHYS
18  *	0.1	20/06/2002
19  *		- first public version
20  */
21 #include <uapi/linux/uinput.h>
22 #include <linux/poll.h>
23 #include <linux/sched.h>
24 #include <linux/slab.h>
25 #include <linux/module.h>
26 #include <linux/init.h>
27 #include <linux/fs.h>
28 #include <linux/miscdevice.h>
29 #include <linux/overflow.h>
30 #include <linux/input/mt.h>
31 #include "../input-compat.h"
32 
33 #define UINPUT_NAME		"uinput"
34 #define UINPUT_BUFFER_SIZE	16
35 #define UINPUT_NUM_REQUESTS	16
36 
37 enum uinput_state { UIST_NEW_DEVICE, UIST_SETUP_COMPLETE, UIST_CREATED };
38 
39 struct uinput_request {
40 	unsigned int		id;
41 	unsigned int		code;	/* UI_FF_UPLOAD, UI_FF_ERASE */
42 
43 	int			retval;
44 	struct completion	done;
45 
46 	union {
47 		unsigned int	effect_id;
48 		struct {
49 			struct ff_effect *effect;
50 			struct ff_effect *old;
51 		} upload;
52 	} u;
53 };
54 
55 struct uinput_device {
56 	struct input_dev	*dev;
57 	struct mutex		mutex;
58 	enum uinput_state	state;
59 	wait_queue_head_t	waitq;
60 	unsigned char		ready;
61 	unsigned char		head;
62 	unsigned char		tail;
63 	struct input_event	buff[UINPUT_BUFFER_SIZE];
64 	unsigned int		ff_effects_max;
65 
66 	struct uinput_request	*requests[UINPUT_NUM_REQUESTS];
67 	wait_queue_head_t	requests_waitq;
68 	spinlock_t		requests_lock;
69 };
70 
uinput_dev_event(struct input_dev * dev,unsigned int type,unsigned int code,int value)71 static int uinput_dev_event(struct input_dev *dev,
72 			    unsigned int type, unsigned int code, int value)
73 {
74 	struct uinput_device	*udev = input_get_drvdata(dev);
75 	struct timespec64	ts;
76 
77 	ktime_get_ts64(&ts);
78 
79 	udev->buff[udev->head] = (struct input_event) {
80 		.input_event_sec = ts.tv_sec,
81 		.input_event_usec = ts.tv_nsec / NSEC_PER_USEC,
82 		.type = type,
83 		.code = code,
84 		.value = value,
85 	};
86 
87 	udev->head = (udev->head + 1) % UINPUT_BUFFER_SIZE;
88 
89 	wake_up_interruptible(&udev->waitq);
90 
91 	return 0;
92 }
93 
94 /* Atomically allocate an ID for the given request. Returns 0 on success. */
uinput_request_alloc_id(struct uinput_device * udev,struct uinput_request * request)95 static bool uinput_request_alloc_id(struct uinput_device *udev,
96 				    struct uinput_request *request)
97 {
98 	unsigned int id;
99 	bool reserved = false;
100 
101 	spin_lock(&udev->requests_lock);
102 
103 	for (id = 0; id < UINPUT_NUM_REQUESTS; id++) {
104 		if (!udev->requests[id]) {
105 			request->id = id;
106 			udev->requests[id] = request;
107 			reserved = true;
108 			break;
109 		}
110 	}
111 
112 	spin_unlock(&udev->requests_lock);
113 	return reserved;
114 }
115 
uinput_request_find(struct uinput_device * udev,unsigned int id)116 static struct uinput_request *uinput_request_find(struct uinput_device *udev,
117 						  unsigned int id)
118 {
119 	/* Find an input request, by ID. Returns NULL if the ID isn't valid. */
120 	if (id >= UINPUT_NUM_REQUESTS)
121 		return NULL;
122 
123 	return udev->requests[id];
124 }
125 
uinput_request_reserve_slot(struct uinput_device * udev,struct uinput_request * request)126 static int uinput_request_reserve_slot(struct uinput_device *udev,
127 				       struct uinput_request *request)
128 {
129 	/* Allocate slot. If none are available right away, wait. */
130 	return wait_event_interruptible(udev->requests_waitq,
131 					uinput_request_alloc_id(udev, request));
132 }
133 
uinput_request_release_slot(struct uinput_device * udev,unsigned int id)134 static void uinput_request_release_slot(struct uinput_device *udev,
135 					unsigned int id)
136 {
137 	/* Mark slot as available */
138 	spin_lock(&udev->requests_lock);
139 	udev->requests[id] = NULL;
140 	spin_unlock(&udev->requests_lock);
141 
142 	wake_up(&udev->requests_waitq);
143 }
144 
uinput_request_send(struct uinput_device * udev,struct uinput_request * request)145 static int uinput_request_send(struct uinput_device *udev,
146 			       struct uinput_request *request)
147 {
148 	int retval;
149 
150 	retval = mutex_lock_interruptible(&udev->mutex);
151 	if (retval)
152 		return retval;
153 
154 	if (udev->state != UIST_CREATED) {
155 		retval = -ENODEV;
156 		goto out;
157 	}
158 
159 	init_completion(&request->done);
160 
161 	/*
162 	 * Tell our userspace application about this new request
163 	 * by queueing an input event.
164 	 */
165 	uinput_dev_event(udev->dev, EV_UINPUT, request->code, request->id);
166 
167  out:
168 	mutex_unlock(&udev->mutex);
169 	return retval;
170 }
171 
uinput_request_submit(struct uinput_device * udev,struct uinput_request * request)172 static int uinput_request_submit(struct uinput_device *udev,
173 				 struct uinput_request *request)
174 {
175 	int retval;
176 
177 	retval = uinput_request_reserve_slot(udev, request);
178 	if (retval)
179 		return retval;
180 
181 	retval = uinput_request_send(udev, request);
182 	if (retval)
183 		goto out;
184 
185 	if (!wait_for_completion_timeout(&request->done, 30 * HZ)) {
186 		retval = -ETIMEDOUT;
187 		goto out;
188 	}
189 
190 	retval = request->retval;
191 
192  out:
193 	uinput_request_release_slot(udev, request->id);
194 	return retval;
195 }
196 
197 /*
198  * Fail all outstanding requests so handlers don't wait for the userspace
199  * to finish processing them.
200  */
uinput_flush_requests(struct uinput_device * udev)201 static void uinput_flush_requests(struct uinput_device *udev)
202 {
203 	struct uinput_request *request;
204 	int i;
205 
206 	spin_lock(&udev->requests_lock);
207 
208 	for (i = 0; i < UINPUT_NUM_REQUESTS; i++) {
209 		request = udev->requests[i];
210 		if (request) {
211 			request->retval = -ENODEV;
212 			complete(&request->done);
213 		}
214 	}
215 
216 	spin_unlock(&udev->requests_lock);
217 }
218 
uinput_dev_set_gain(struct input_dev * dev,u16 gain)219 static void uinput_dev_set_gain(struct input_dev *dev, u16 gain)
220 {
221 	uinput_dev_event(dev, EV_FF, FF_GAIN, gain);
222 }
223 
uinput_dev_set_autocenter(struct input_dev * dev,u16 magnitude)224 static void uinput_dev_set_autocenter(struct input_dev *dev, u16 magnitude)
225 {
226 	uinput_dev_event(dev, EV_FF, FF_AUTOCENTER, magnitude);
227 }
228 
uinput_dev_playback(struct input_dev * dev,int effect_id,int value)229 static int uinput_dev_playback(struct input_dev *dev, int effect_id, int value)
230 {
231 	return uinput_dev_event(dev, EV_FF, effect_id, value);
232 }
233 
uinput_dev_upload_effect(struct input_dev * dev,struct ff_effect * effect,struct ff_effect * old)234 static int uinput_dev_upload_effect(struct input_dev *dev,
235 				    struct ff_effect *effect,
236 				    struct ff_effect *old)
237 {
238 	struct uinput_device *udev = input_get_drvdata(dev);
239 	struct uinput_request request;
240 
241 	/*
242 	 * uinput driver does not currently support periodic effects with
243 	 * custom waveform since it does not have a way to pass buffer of
244 	 * samples (custom_data) to userspace. If ever there is a device
245 	 * supporting custom waveforms we would need to define an additional
246 	 * ioctl (UI_UPLOAD_SAMPLES) but for now we just bail out.
247 	 */
248 	if (effect->type == FF_PERIODIC &&
249 			effect->u.periodic.waveform == FF_CUSTOM)
250 		return -EINVAL;
251 
252 	request.code = UI_FF_UPLOAD;
253 	request.u.upload.effect = effect;
254 	request.u.upload.old = old;
255 
256 	return uinput_request_submit(udev, &request);
257 }
258 
uinput_dev_erase_effect(struct input_dev * dev,int effect_id)259 static int uinput_dev_erase_effect(struct input_dev *dev, int effect_id)
260 {
261 	struct uinput_device *udev = input_get_drvdata(dev);
262 	struct uinput_request request;
263 
264 	if (!test_bit(EV_FF, dev->evbit))
265 		return -ENOSYS;
266 
267 	request.code = UI_FF_ERASE;
268 	request.u.effect_id = effect_id;
269 
270 	return uinput_request_submit(udev, &request);
271 }
272 
uinput_dev_flush(struct input_dev * dev,struct file * file)273 static int uinput_dev_flush(struct input_dev *dev, struct file *file)
274 {
275 	/*
276 	 * If we are called with file == NULL that means we are tearing
277 	 * down the device, and therefore we can not handle FF erase
278 	 * requests: either we are handling UI_DEV_DESTROY (and holding
279 	 * the udev->mutex), or the file descriptor is closed and there is
280 	 * nobody on the other side anymore.
281 	 */
282 	return file ? input_ff_flush(dev, file) : 0;
283 }
284 
uinput_destroy_device(struct uinput_device * udev)285 static void uinput_destroy_device(struct uinput_device *udev)
286 {
287 	const char *name, *phys;
288 	struct input_dev *dev = udev->dev;
289 	enum uinput_state old_state = udev->state;
290 
291 	udev->state = UIST_NEW_DEVICE;
292 
293 	if (dev) {
294 		name = dev->name;
295 		phys = dev->phys;
296 		if (old_state == UIST_CREATED) {
297 			uinput_flush_requests(udev);
298 			input_unregister_device(dev);
299 		} else {
300 			input_free_device(dev);
301 		}
302 		kfree(name);
303 		kfree(phys);
304 		udev->dev = NULL;
305 	}
306 }
307 
uinput_create_device(struct uinput_device * udev)308 static int uinput_create_device(struct uinput_device *udev)
309 {
310 	struct input_dev *dev = udev->dev;
311 	int error, nslot;
312 
313 	if (udev->state != UIST_SETUP_COMPLETE) {
314 		printk(KERN_DEBUG "%s: write device info first\n", UINPUT_NAME);
315 		return -EINVAL;
316 	}
317 
318 	if (test_bit(EV_ABS, dev->evbit)) {
319 		input_alloc_absinfo(dev);
320 		if (!dev->absinfo) {
321 			error = -EINVAL;
322 			goto fail1;
323 		}
324 
325 		if (test_bit(ABS_MT_SLOT, dev->absbit)) {
326 			nslot = input_abs_get_max(dev, ABS_MT_SLOT) + 1;
327 			error = input_mt_init_slots(dev, nslot, 0);
328 			if (error)
329 				goto fail1;
330 		} else if (test_bit(ABS_MT_POSITION_X, dev->absbit)) {
331 			input_set_events_per_packet(dev, 60);
332 		}
333 	}
334 
335 	if (test_bit(EV_FF, dev->evbit) && !udev->ff_effects_max) {
336 		printk(KERN_DEBUG "%s: ff_effects_max should be non-zero when FF_BIT is set\n",
337 			UINPUT_NAME);
338 		error = -EINVAL;
339 		goto fail1;
340 	}
341 
342 	if (udev->ff_effects_max) {
343 		error = input_ff_create(dev, udev->ff_effects_max);
344 		if (error)
345 			goto fail1;
346 
347 		dev->ff->upload = uinput_dev_upload_effect;
348 		dev->ff->erase = uinput_dev_erase_effect;
349 		dev->ff->playback = uinput_dev_playback;
350 		dev->ff->set_gain = uinput_dev_set_gain;
351 		dev->ff->set_autocenter = uinput_dev_set_autocenter;
352 		/*
353 		 * The standard input_ff_flush() implementation does
354 		 * not quite work for uinput as we can't reasonably
355 		 * handle FF requests during device teardown.
356 		 */
357 		dev->flush = uinput_dev_flush;
358 	}
359 
360 	dev->event = uinput_dev_event;
361 
362 	input_set_drvdata(udev->dev, udev);
363 
364 	error = input_register_device(udev->dev);
365 	if (error)
366 		goto fail2;
367 
368 	udev->state = UIST_CREATED;
369 
370 	return 0;
371 
372  fail2:	input_ff_destroy(dev);
373  fail1: uinput_destroy_device(udev);
374 	return error;
375 }
376 
uinput_open(struct inode * inode,struct file * file)377 static int uinput_open(struct inode *inode, struct file *file)
378 {
379 	struct uinput_device *newdev;
380 
381 	newdev = kzalloc(sizeof(struct uinput_device), GFP_KERNEL);
382 	if (!newdev)
383 		return -ENOMEM;
384 
385 	mutex_init(&newdev->mutex);
386 	spin_lock_init(&newdev->requests_lock);
387 	init_waitqueue_head(&newdev->requests_waitq);
388 	init_waitqueue_head(&newdev->waitq);
389 	newdev->state = UIST_NEW_DEVICE;
390 
391 	file->private_data = newdev;
392 	stream_open(inode, file);
393 
394 	return 0;
395 }
396 
uinput_validate_absinfo(struct input_dev * dev,unsigned int code,const struct input_absinfo * abs)397 static int uinput_validate_absinfo(struct input_dev *dev, unsigned int code,
398 				   const struct input_absinfo *abs)
399 {
400 	int min, max, range;
401 
402 	min = abs->minimum;
403 	max = abs->maximum;
404 
405 	if ((min != 0 || max != 0) && max < min) {
406 		printk(KERN_DEBUG
407 		       "%s: invalid abs[%02x] min:%d max:%d\n",
408 		       UINPUT_NAME, code, min, max);
409 		return -EINVAL;
410 	}
411 
412 	if (!check_sub_overflow(max, min, &range) && abs->flat > range) {
413 		printk(KERN_DEBUG
414 		       "%s: abs_flat #%02x out of range: %d (min:%d/max:%d)\n",
415 		       UINPUT_NAME, code, abs->flat, min, max);
416 		return -EINVAL;
417 	}
418 
419 	return 0;
420 }
421 
uinput_validate_absbits(struct input_dev * dev)422 static int uinput_validate_absbits(struct input_dev *dev)
423 {
424 	unsigned int cnt;
425 	int error;
426 
427 	if (!test_bit(EV_ABS, dev->evbit))
428 		return 0;
429 
430 	/*
431 	 * Check if absmin/absmax/absfuzz/absflat are sane.
432 	 */
433 
434 	for_each_set_bit(cnt, dev->absbit, ABS_CNT) {
435 		if (!dev->absinfo)
436 			return -EINVAL;
437 
438 		error = uinput_validate_absinfo(dev, cnt, &dev->absinfo[cnt]);
439 		if (error)
440 			return error;
441 	}
442 
443 	return 0;
444 }
445 
uinput_dev_setup(struct uinput_device * udev,struct uinput_setup __user * arg)446 static int uinput_dev_setup(struct uinput_device *udev,
447 			    struct uinput_setup __user *arg)
448 {
449 	struct uinput_setup setup;
450 	struct input_dev *dev;
451 
452 	if (udev->state == UIST_CREATED)
453 		return -EINVAL;
454 
455 	if (copy_from_user(&setup, arg, sizeof(setup)))
456 		return -EFAULT;
457 
458 	if (!setup.name[0])
459 		return -EINVAL;
460 
461 	dev = udev->dev;
462 	dev->id = setup.id;
463 	udev->ff_effects_max = setup.ff_effects_max;
464 
465 	kfree(dev->name);
466 	dev->name = kstrndup(setup.name, UINPUT_MAX_NAME_SIZE, GFP_KERNEL);
467 	if (!dev->name)
468 		return -ENOMEM;
469 
470 	udev->state = UIST_SETUP_COMPLETE;
471 	return 0;
472 }
473 
uinput_abs_setup(struct uinput_device * udev,struct uinput_setup __user * arg,size_t size)474 static int uinput_abs_setup(struct uinput_device *udev,
475 			    struct uinput_setup __user *arg, size_t size)
476 {
477 	struct uinput_abs_setup setup = {};
478 	struct input_dev *dev;
479 	int error;
480 
481 	if (size > sizeof(setup))
482 		return -E2BIG;
483 
484 	if (udev->state == UIST_CREATED)
485 		return -EINVAL;
486 
487 	if (copy_from_user(&setup, arg, size))
488 		return -EFAULT;
489 
490 	if (setup.code > ABS_MAX)
491 		return -ERANGE;
492 
493 	dev = udev->dev;
494 
495 	error = uinput_validate_absinfo(dev, setup.code, &setup.absinfo);
496 	if (error)
497 		return error;
498 
499 	input_alloc_absinfo(dev);
500 	if (!dev->absinfo)
501 		return -ENOMEM;
502 
503 	set_bit(setup.code, dev->absbit);
504 	dev->absinfo[setup.code] = setup.absinfo;
505 	return 0;
506 }
507 
508 /* legacy setup via write() */
uinput_setup_device_legacy(struct uinput_device * udev,const char __user * buffer,size_t count)509 static int uinput_setup_device_legacy(struct uinput_device *udev,
510 				      const char __user *buffer, size_t count)
511 {
512 	struct uinput_user_dev	*user_dev;
513 	struct input_dev	*dev;
514 	int			i;
515 	int			retval;
516 
517 	if (count != sizeof(struct uinput_user_dev))
518 		return -EINVAL;
519 
520 	if (!udev->dev) {
521 		udev->dev = input_allocate_device();
522 		if (!udev->dev)
523 			return -ENOMEM;
524 	}
525 
526 	dev = udev->dev;
527 
528 	user_dev = memdup_user(buffer, sizeof(struct uinput_user_dev));
529 	if (IS_ERR(user_dev))
530 		return PTR_ERR(user_dev);
531 
532 	udev->ff_effects_max = user_dev->ff_effects_max;
533 
534 	/* Ensure name is filled in */
535 	if (!user_dev->name[0]) {
536 		retval = -EINVAL;
537 		goto exit;
538 	}
539 
540 	kfree(dev->name);
541 	dev->name = kstrndup(user_dev->name, UINPUT_MAX_NAME_SIZE,
542 			     GFP_KERNEL);
543 	if (!dev->name) {
544 		retval = -ENOMEM;
545 		goto exit;
546 	}
547 
548 	dev->id.bustype	= user_dev->id.bustype;
549 	dev->id.vendor	= user_dev->id.vendor;
550 	dev->id.product	= user_dev->id.product;
551 	dev->id.version	= user_dev->id.version;
552 
553 	for (i = 0; i < ABS_CNT; i++) {
554 		input_abs_set_max(dev, i, user_dev->absmax[i]);
555 		input_abs_set_min(dev, i, user_dev->absmin[i]);
556 		input_abs_set_fuzz(dev, i, user_dev->absfuzz[i]);
557 		input_abs_set_flat(dev, i, user_dev->absflat[i]);
558 	}
559 
560 	retval = uinput_validate_absbits(dev);
561 	if (retval < 0)
562 		goto exit;
563 
564 	udev->state = UIST_SETUP_COMPLETE;
565 	retval = count;
566 
567  exit:
568 	kfree(user_dev);
569 	return retval;
570 }
571 
uinput_inject_events(struct uinput_device * udev,const char __user * buffer,size_t count)572 static ssize_t uinput_inject_events(struct uinput_device *udev,
573 				    const char __user *buffer, size_t count)
574 {
575 	struct input_event ev;
576 	size_t bytes = 0;
577 
578 	if (count != 0 && count < input_event_size())
579 		return -EINVAL;
580 
581 	while (bytes + input_event_size() <= count) {
582 		/*
583 		 * Note that even if some events were fetched successfully
584 		 * we are still going to return EFAULT instead of partial
585 		 * count to let userspace know that it got it's buffers
586 		 * all wrong.
587 		 */
588 		if (input_event_from_user(buffer + bytes, &ev))
589 			return -EFAULT;
590 
591 		input_event(udev->dev, ev.type, ev.code, ev.value);
592 		bytes += input_event_size();
593 		cond_resched();
594 	}
595 
596 	return bytes;
597 }
598 
uinput_write(struct file * file,const char __user * buffer,size_t count,loff_t * ppos)599 static ssize_t uinput_write(struct file *file, const char __user *buffer,
600 			    size_t count, loff_t *ppos)
601 {
602 	struct uinput_device *udev = file->private_data;
603 	int retval;
604 
605 	if (count == 0)
606 		return 0;
607 
608 	retval = mutex_lock_interruptible(&udev->mutex);
609 	if (retval)
610 		return retval;
611 
612 	retval = udev->state == UIST_CREATED ?
613 			uinput_inject_events(udev, buffer, count) :
614 			uinput_setup_device_legacy(udev, buffer, count);
615 
616 	mutex_unlock(&udev->mutex);
617 
618 	return retval;
619 }
620 
uinput_fetch_next_event(struct uinput_device * udev,struct input_event * event)621 static bool uinput_fetch_next_event(struct uinput_device *udev,
622 				    struct input_event *event)
623 {
624 	bool have_event;
625 
626 	spin_lock_irq(&udev->dev->event_lock);
627 
628 	have_event = udev->head != udev->tail;
629 	if (have_event) {
630 		*event = udev->buff[udev->tail];
631 		udev->tail = (udev->tail + 1) % UINPUT_BUFFER_SIZE;
632 	}
633 
634 	spin_unlock_irq(&udev->dev->event_lock);
635 
636 	return have_event;
637 }
638 
uinput_events_to_user(struct uinput_device * udev,char __user * buffer,size_t count)639 static ssize_t uinput_events_to_user(struct uinput_device *udev,
640 				     char __user *buffer, size_t count)
641 {
642 	struct input_event event;
643 	size_t read = 0;
644 
645 	while (read + input_event_size() <= count &&
646 	       uinput_fetch_next_event(udev, &event)) {
647 
648 		if (input_event_to_user(buffer + read, &event))
649 			return -EFAULT;
650 
651 		read += input_event_size();
652 	}
653 
654 	return read;
655 }
656 
uinput_read(struct file * file,char __user * buffer,size_t count,loff_t * ppos)657 static ssize_t uinput_read(struct file *file, char __user *buffer,
658 			   size_t count, loff_t *ppos)
659 {
660 	struct uinput_device *udev = file->private_data;
661 	ssize_t retval;
662 
663 	if (count != 0 && count < input_event_size())
664 		return -EINVAL;
665 
666 	do {
667 		retval = mutex_lock_interruptible(&udev->mutex);
668 		if (retval)
669 			return retval;
670 
671 		if (udev->state != UIST_CREATED)
672 			retval = -ENODEV;
673 		else if (udev->head == udev->tail &&
674 			 (file->f_flags & O_NONBLOCK))
675 			retval = -EAGAIN;
676 		else
677 			retval = uinput_events_to_user(udev, buffer, count);
678 
679 		mutex_unlock(&udev->mutex);
680 
681 		if (retval || count == 0)
682 			break;
683 
684 		if (!(file->f_flags & O_NONBLOCK))
685 			retval = wait_event_interruptible(udev->waitq,
686 						  udev->head != udev->tail ||
687 						  udev->state != UIST_CREATED);
688 	} while (retval == 0);
689 
690 	return retval;
691 }
692 
uinput_poll(struct file * file,poll_table * wait)693 static __poll_t uinput_poll(struct file *file, poll_table *wait)
694 {
695 	struct uinput_device *udev = file->private_data;
696 
697 	poll_wait(file, &udev->waitq, wait);
698 
699 	if (udev->head != udev->tail)
700 		return EPOLLIN | EPOLLRDNORM;
701 
702 	return 0;
703 }
704 
uinput_release(struct inode * inode,struct file * file)705 static int uinput_release(struct inode *inode, struct file *file)
706 {
707 	struct uinput_device *udev = file->private_data;
708 
709 	uinput_destroy_device(udev);
710 	kfree(udev);
711 
712 	return 0;
713 }
714 
715 #ifdef CONFIG_COMPAT
716 struct uinput_ff_upload_compat {
717 	__u32			request_id;
718 	__s32			retval;
719 	struct ff_effect_compat	effect;
720 	struct ff_effect_compat	old;
721 };
722 
uinput_ff_upload_to_user(char __user * buffer,const struct uinput_ff_upload * ff_up)723 static int uinput_ff_upload_to_user(char __user *buffer,
724 				    const struct uinput_ff_upload *ff_up)
725 {
726 	if (in_compat_syscall()) {
727 		struct uinput_ff_upload_compat ff_up_compat;
728 
729 		ff_up_compat.request_id = ff_up->request_id;
730 		ff_up_compat.retval = ff_up->retval;
731 		/*
732 		 * It so happens that the pointer that gives us the trouble
733 		 * is the last field in the structure. Since we don't support
734 		 * custom waveforms in uinput anyway we can just copy the whole
735 		 * thing (to the compat size) and ignore the pointer.
736 		 */
737 		memcpy(&ff_up_compat.effect, &ff_up->effect,
738 			sizeof(struct ff_effect_compat));
739 		memcpy(&ff_up_compat.old, &ff_up->old,
740 			sizeof(struct ff_effect_compat));
741 
742 		if (copy_to_user(buffer, &ff_up_compat,
743 				 sizeof(struct uinput_ff_upload_compat)))
744 			return -EFAULT;
745 	} else {
746 		if (copy_to_user(buffer, ff_up,
747 				 sizeof(struct uinput_ff_upload)))
748 			return -EFAULT;
749 	}
750 
751 	return 0;
752 }
753 
uinput_ff_upload_from_user(const char __user * buffer,struct uinput_ff_upload * ff_up)754 static int uinput_ff_upload_from_user(const char __user *buffer,
755 				      struct uinput_ff_upload *ff_up)
756 {
757 	if (in_compat_syscall()) {
758 		struct uinput_ff_upload_compat ff_up_compat;
759 
760 		if (copy_from_user(&ff_up_compat, buffer,
761 				   sizeof(struct uinput_ff_upload_compat)))
762 			return -EFAULT;
763 
764 		ff_up->request_id = ff_up_compat.request_id;
765 		ff_up->retval = ff_up_compat.retval;
766 		memcpy(&ff_up->effect, &ff_up_compat.effect,
767 			sizeof(struct ff_effect_compat));
768 		memcpy(&ff_up->old, &ff_up_compat.old,
769 			sizeof(struct ff_effect_compat));
770 
771 	} else {
772 		if (copy_from_user(ff_up, buffer,
773 				   sizeof(struct uinput_ff_upload)))
774 			return -EFAULT;
775 	}
776 
777 	return 0;
778 }
779 
780 #else
781 
uinput_ff_upload_to_user(char __user * buffer,const struct uinput_ff_upload * ff_up)782 static int uinput_ff_upload_to_user(char __user *buffer,
783 				    const struct uinput_ff_upload *ff_up)
784 {
785 	if (copy_to_user(buffer, ff_up, sizeof(struct uinput_ff_upload)))
786 		return -EFAULT;
787 
788 	return 0;
789 }
790 
uinput_ff_upload_from_user(const char __user * buffer,struct uinput_ff_upload * ff_up)791 static int uinput_ff_upload_from_user(const char __user *buffer,
792 				      struct uinput_ff_upload *ff_up)
793 {
794 	if (copy_from_user(ff_up, buffer, sizeof(struct uinput_ff_upload)))
795 		return -EFAULT;
796 
797 	return 0;
798 }
799 
800 #endif
801 
802 #define uinput_set_bit(_arg, _bit, _max)		\
803 ({							\
804 	int __ret = 0;					\
805 	if (udev->state == UIST_CREATED)		\
806 		__ret =  -EINVAL;			\
807 	else if ((_arg) > (_max))			\
808 		__ret = -EINVAL;			\
809 	else set_bit((_arg), udev->dev->_bit);		\
810 	__ret;						\
811 })
812 
uinput_str_to_user(void __user * dest,const char * str,unsigned int maxlen)813 static int uinput_str_to_user(void __user *dest, const char *str,
814 			      unsigned int maxlen)
815 {
816 	char __user *p = dest;
817 	int len, ret;
818 
819 	if (!str)
820 		return -ENOENT;
821 
822 	if (maxlen == 0)
823 		return -EINVAL;
824 
825 	len = strlen(str) + 1;
826 	if (len > maxlen)
827 		len = maxlen;
828 
829 	ret = copy_to_user(p, str, len);
830 	if (ret)
831 		return -EFAULT;
832 
833 	/* force terminating '\0' */
834 	ret = put_user(0, p + len - 1);
835 	return ret ? -EFAULT : len;
836 }
837 
uinput_ioctl_handler(struct file * file,unsigned int cmd,unsigned long arg,void __user * p)838 static long uinput_ioctl_handler(struct file *file, unsigned int cmd,
839 				 unsigned long arg, void __user *p)
840 {
841 	int			retval;
842 	struct uinput_device	*udev = file->private_data;
843 	struct uinput_ff_upload ff_up;
844 	struct uinput_ff_erase  ff_erase;
845 	struct uinput_request   *req;
846 	char			*phys;
847 	const char		*name;
848 	unsigned int		size;
849 
850 	retval = mutex_lock_interruptible(&udev->mutex);
851 	if (retval)
852 		return retval;
853 
854 	if (!udev->dev) {
855 		udev->dev = input_allocate_device();
856 		if (!udev->dev) {
857 			retval = -ENOMEM;
858 			goto out;
859 		}
860 	}
861 
862 	switch (cmd) {
863 	case UI_GET_VERSION:
864 		if (put_user(UINPUT_VERSION, (unsigned int __user *)p))
865 			retval = -EFAULT;
866 		goto out;
867 
868 	case UI_DEV_CREATE:
869 		retval = uinput_create_device(udev);
870 		goto out;
871 
872 	case UI_DEV_DESTROY:
873 		uinput_destroy_device(udev);
874 		goto out;
875 
876 	case UI_DEV_SETUP:
877 		retval = uinput_dev_setup(udev, p);
878 		goto out;
879 
880 	/* UI_ABS_SETUP is handled in the variable size ioctls */
881 
882 	case UI_SET_EVBIT:
883 		retval = uinput_set_bit(arg, evbit, EV_MAX);
884 		goto out;
885 
886 	case UI_SET_KEYBIT:
887 		retval = uinput_set_bit(arg, keybit, KEY_MAX);
888 		goto out;
889 
890 	case UI_SET_RELBIT:
891 		retval = uinput_set_bit(arg, relbit, REL_MAX);
892 		goto out;
893 
894 	case UI_SET_ABSBIT:
895 		retval = uinput_set_bit(arg, absbit, ABS_MAX);
896 		goto out;
897 
898 	case UI_SET_MSCBIT:
899 		retval = uinput_set_bit(arg, mscbit, MSC_MAX);
900 		goto out;
901 
902 	case UI_SET_LEDBIT:
903 		retval = uinput_set_bit(arg, ledbit, LED_MAX);
904 		goto out;
905 
906 	case UI_SET_SNDBIT:
907 		retval = uinput_set_bit(arg, sndbit, SND_MAX);
908 		goto out;
909 
910 	case UI_SET_FFBIT:
911 		retval = uinput_set_bit(arg, ffbit, FF_MAX);
912 		goto out;
913 
914 	case UI_SET_SWBIT:
915 		retval = uinput_set_bit(arg, swbit, SW_MAX);
916 		goto out;
917 
918 	case UI_SET_PROPBIT:
919 		retval = uinput_set_bit(arg, propbit, INPUT_PROP_MAX);
920 		goto out;
921 
922 	case UI_SET_PHYS:
923 		if (udev->state == UIST_CREATED) {
924 			retval = -EINVAL;
925 			goto out;
926 		}
927 
928 		phys = strndup_user(p, 1024);
929 		if (IS_ERR(phys)) {
930 			retval = PTR_ERR(phys);
931 			goto out;
932 		}
933 
934 		kfree(udev->dev->phys);
935 		udev->dev->phys = phys;
936 		goto out;
937 
938 	case UI_BEGIN_FF_UPLOAD:
939 		retval = uinput_ff_upload_from_user(p, &ff_up);
940 		if (retval)
941 			goto out;
942 
943 		req = uinput_request_find(udev, ff_up.request_id);
944 		if (!req || req->code != UI_FF_UPLOAD ||
945 		    !req->u.upload.effect) {
946 			retval = -EINVAL;
947 			goto out;
948 		}
949 
950 		ff_up.retval = 0;
951 		ff_up.effect = *req->u.upload.effect;
952 		if (req->u.upload.old)
953 			ff_up.old = *req->u.upload.old;
954 		else
955 			memset(&ff_up.old, 0, sizeof(struct ff_effect));
956 
957 		retval = uinput_ff_upload_to_user(p, &ff_up);
958 		goto out;
959 
960 	case UI_BEGIN_FF_ERASE:
961 		if (copy_from_user(&ff_erase, p, sizeof(ff_erase))) {
962 			retval = -EFAULT;
963 			goto out;
964 		}
965 
966 		req = uinput_request_find(udev, ff_erase.request_id);
967 		if (!req || req->code != UI_FF_ERASE) {
968 			retval = -EINVAL;
969 			goto out;
970 		}
971 
972 		ff_erase.retval = 0;
973 		ff_erase.effect_id = req->u.effect_id;
974 		if (copy_to_user(p, &ff_erase, sizeof(ff_erase))) {
975 			retval = -EFAULT;
976 			goto out;
977 		}
978 
979 		goto out;
980 
981 	case UI_END_FF_UPLOAD:
982 		retval = uinput_ff_upload_from_user(p, &ff_up);
983 		if (retval)
984 			goto out;
985 
986 		req = uinput_request_find(udev, ff_up.request_id);
987 		if (!req || req->code != UI_FF_UPLOAD ||
988 		    !req->u.upload.effect) {
989 			retval = -EINVAL;
990 			goto out;
991 		}
992 
993 		req->retval = ff_up.retval;
994 		complete(&req->done);
995 		goto out;
996 
997 	case UI_END_FF_ERASE:
998 		if (copy_from_user(&ff_erase, p, sizeof(ff_erase))) {
999 			retval = -EFAULT;
1000 			goto out;
1001 		}
1002 
1003 		req = uinput_request_find(udev, ff_erase.request_id);
1004 		if (!req || req->code != UI_FF_ERASE) {
1005 			retval = -EINVAL;
1006 			goto out;
1007 		}
1008 
1009 		req->retval = ff_erase.retval;
1010 		complete(&req->done);
1011 		goto out;
1012 	}
1013 
1014 	size = _IOC_SIZE(cmd);
1015 
1016 	/* Now check variable-length commands */
1017 	switch (cmd & ~IOCSIZE_MASK) {
1018 	case UI_GET_SYSNAME(0):
1019 		if (udev->state != UIST_CREATED) {
1020 			retval = -ENOENT;
1021 			goto out;
1022 		}
1023 		name = dev_name(&udev->dev->dev);
1024 		retval = uinput_str_to_user(p, name, size);
1025 		goto out;
1026 
1027 	case UI_ABS_SETUP & ~IOCSIZE_MASK:
1028 		retval = uinput_abs_setup(udev, p, size);
1029 		goto out;
1030 	}
1031 
1032 	retval = -EINVAL;
1033  out:
1034 	mutex_unlock(&udev->mutex);
1035 	return retval;
1036 }
1037 
uinput_ioctl(struct file * file,unsigned int cmd,unsigned long arg)1038 static long uinput_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1039 {
1040 	return uinput_ioctl_handler(file, cmd, arg, (void __user *)arg);
1041 }
1042 
1043 #ifdef CONFIG_COMPAT
1044 
1045 /*
1046  * These IOCTLs change their size and thus their numbers between
1047  * 32 and 64 bits.
1048  */
1049 #define UI_SET_PHYS_COMPAT		\
1050 	_IOW(UINPUT_IOCTL_BASE, 108, compat_uptr_t)
1051 #define UI_BEGIN_FF_UPLOAD_COMPAT	\
1052 	_IOWR(UINPUT_IOCTL_BASE, 200, struct uinput_ff_upload_compat)
1053 #define UI_END_FF_UPLOAD_COMPAT		\
1054 	_IOW(UINPUT_IOCTL_BASE, 201, struct uinput_ff_upload_compat)
1055 
uinput_compat_ioctl(struct file * file,unsigned int cmd,unsigned long arg)1056 static long uinput_compat_ioctl(struct file *file,
1057 				unsigned int cmd, unsigned long arg)
1058 {
1059 	switch (cmd) {
1060 	case UI_SET_PHYS_COMPAT:
1061 		cmd = UI_SET_PHYS;
1062 		break;
1063 	case UI_BEGIN_FF_UPLOAD_COMPAT:
1064 		cmd = UI_BEGIN_FF_UPLOAD;
1065 		break;
1066 	case UI_END_FF_UPLOAD_COMPAT:
1067 		cmd = UI_END_FF_UPLOAD;
1068 		break;
1069 	}
1070 
1071 	return uinput_ioctl_handler(file, cmd, arg, compat_ptr(arg));
1072 }
1073 #endif
1074 
1075 static const struct file_operations uinput_fops = {
1076 	.owner		= THIS_MODULE,
1077 	.open		= uinput_open,
1078 	.release	= uinput_release,
1079 	.read		= uinput_read,
1080 	.write		= uinput_write,
1081 	.poll		= uinput_poll,
1082 	.unlocked_ioctl	= uinput_ioctl,
1083 #ifdef CONFIG_COMPAT
1084 	.compat_ioctl	= uinput_compat_ioctl,
1085 #endif
1086 	.llseek		= no_llseek,
1087 };
1088 
1089 static struct miscdevice uinput_misc = {
1090 	.fops		= &uinput_fops,
1091 	.minor		= UINPUT_MINOR,
1092 	.name		= UINPUT_NAME,
1093 };
1094 module_misc_device(uinput_misc);
1095 
1096 MODULE_ALIAS_MISCDEV(UINPUT_MINOR);
1097 MODULE_ALIAS("devname:" UINPUT_NAME);
1098 
1099 MODULE_AUTHOR("Aristeu Sergio Rozanski Filho");
1100 MODULE_DESCRIPTION("User level driver support for input subsystem");
1101 MODULE_LICENSE("GPL");
1102