1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * User level driver support for input subsystem
5 * Heavily based on evdev.c by Vojtech Pavlik
7 * Author: Aristeu Sergio Rozanski Filho <aris@cathedrallabs.org>
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
19 * - first public version
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>
28 #include <linux/miscdevice.h>
29 #include <linux/overflow.h>
30 #include <linux/input/mt.h>
31 #include "../input-compat.h"
33 #define UINPUT_NAME "uinput"
34 #define UINPUT_BUFFER_SIZE 16
35 #define UINPUT_NUM_REQUESTS 16
37 enum uinput_state { UIST_NEW_DEVICE, UIST_SETUP_COMPLETE, UIST_CREATED };
39 struct uinput_request {
41 unsigned int code; /* UI_FF_UPLOAD, UI_FF_ERASE */
44 struct completion done;
47 unsigned int effect_id;
49 struct ff_effect *effect;
50 struct ff_effect *old;
55 struct uinput_device {
56 struct input_dev *dev;
58 enum uinput_state state;
59 wait_queue_head_t waitq;
63 struct input_event buff[UINPUT_BUFFER_SIZE];
64 unsigned int ff_effects_max;
66 struct uinput_request *requests[UINPUT_NUM_REQUESTS];
67 wait_queue_head_t requests_waitq;
68 spinlock_t requests_lock;
71 static int uinput_dev_event(struct input_dev *dev,
72 unsigned int type, unsigned int code, int value)
74 struct uinput_device *udev = input_get_drvdata(dev);
77 udev->buff[udev->head].type = type;
78 udev->buff[udev->head].code = code;
79 udev->buff[udev->head].value = value;
81 udev->buff[udev->head].input_event_sec = ts.tv_sec;
82 udev->buff[udev->head].input_event_usec = ts.tv_nsec / NSEC_PER_USEC;
83 udev->head = (udev->head + 1) % UINPUT_BUFFER_SIZE;
85 wake_up_interruptible(&udev->waitq);
90 /* Atomically allocate an ID for the given request. Returns 0 on success. */
91 static bool uinput_request_alloc_id(struct uinput_device *udev,
92 struct uinput_request *request)
95 bool reserved = false;
97 spin_lock(&udev->requests_lock);
99 for (id = 0; id < UINPUT_NUM_REQUESTS; id++) {
100 if (!udev->requests[id]) {
102 udev->requests[id] = request;
108 spin_unlock(&udev->requests_lock);
112 static struct uinput_request *uinput_request_find(struct uinput_device *udev,
115 /* Find an input request, by ID. Returns NULL if the ID isn't valid. */
116 if (id >= UINPUT_NUM_REQUESTS)
119 return udev->requests[id];
122 static int uinput_request_reserve_slot(struct uinput_device *udev,
123 struct uinput_request *request)
125 /* Allocate slot. If none are available right away, wait. */
126 return wait_event_interruptible(udev->requests_waitq,
127 uinput_request_alloc_id(udev, request));
130 static void uinput_request_release_slot(struct uinput_device *udev,
133 /* Mark slot as available */
134 spin_lock(&udev->requests_lock);
135 udev->requests[id] = NULL;
136 spin_unlock(&udev->requests_lock);
138 wake_up(&udev->requests_waitq);
141 static int uinput_request_send(struct uinput_device *udev,
142 struct uinput_request *request)
146 retval = mutex_lock_interruptible(&udev->mutex);
150 if (udev->state != UIST_CREATED) {
155 init_completion(&request->done);
158 * Tell our userspace application about this new request
159 * by queueing an input event.
161 uinput_dev_event(udev->dev, EV_UINPUT, request->code, request->id);
164 mutex_unlock(&udev->mutex);
168 static int uinput_request_submit(struct uinput_device *udev,
169 struct uinput_request *request)
173 retval = uinput_request_reserve_slot(udev, request);
177 retval = uinput_request_send(udev, request);
181 if (!wait_for_completion_timeout(&request->done, 30 * HZ)) {
186 retval = request->retval;
189 uinput_request_release_slot(udev, request->id);
194 * Fail all outstanding requests so handlers don't wait for the userspace
195 * to finish processing them.
197 static void uinput_flush_requests(struct uinput_device *udev)
199 struct uinput_request *request;
202 spin_lock(&udev->requests_lock);
204 for (i = 0; i < UINPUT_NUM_REQUESTS; i++) {
205 request = udev->requests[i];
207 request->retval = -ENODEV;
208 complete(&request->done);
212 spin_unlock(&udev->requests_lock);
215 static void uinput_dev_set_gain(struct input_dev *dev, u16 gain)
217 uinput_dev_event(dev, EV_FF, FF_GAIN, gain);
220 static void uinput_dev_set_autocenter(struct input_dev *dev, u16 magnitude)
222 uinput_dev_event(dev, EV_FF, FF_AUTOCENTER, magnitude);
225 static int uinput_dev_playback(struct input_dev *dev, int effect_id, int value)
227 return uinput_dev_event(dev, EV_FF, effect_id, value);
230 static int uinput_dev_upload_effect(struct input_dev *dev,
231 struct ff_effect *effect,
232 struct ff_effect *old)
234 struct uinput_device *udev = input_get_drvdata(dev);
235 struct uinput_request request;
238 * uinput driver does not currently support periodic effects with
239 * custom waveform since it does not have a way to pass buffer of
240 * samples (custom_data) to userspace. If ever there is a device
241 * supporting custom waveforms we would need to define an additional
242 * ioctl (UI_UPLOAD_SAMPLES) but for now we just bail out.
244 if (effect->type == FF_PERIODIC &&
245 effect->u.periodic.waveform == FF_CUSTOM)
248 request.code = UI_FF_UPLOAD;
249 request.u.upload.effect = effect;
250 request.u.upload.old = old;
252 return uinput_request_submit(udev, &request);
255 static int uinput_dev_erase_effect(struct input_dev *dev, int effect_id)
257 struct uinput_device *udev = input_get_drvdata(dev);
258 struct uinput_request request;
260 if (!test_bit(EV_FF, dev->evbit))
263 request.code = UI_FF_ERASE;
264 request.u.effect_id = effect_id;
266 return uinput_request_submit(udev, &request);
269 static int uinput_dev_flush(struct input_dev *dev, struct file *file)
272 * If we are called with file == NULL that means we are tearing
273 * down the device, and therefore we can not handle FF erase
274 * requests: either we are handling UI_DEV_DESTROY (and holding
275 * the udev->mutex), or the file descriptor is closed and there is
276 * nobody on the other side anymore.
278 return file ? input_ff_flush(dev, file) : 0;
281 static void uinput_destroy_device(struct uinput_device *udev)
283 const char *name, *phys;
284 struct input_dev *dev = udev->dev;
285 enum uinput_state old_state = udev->state;
287 udev->state = UIST_NEW_DEVICE;
292 if (old_state == UIST_CREATED) {
293 uinput_flush_requests(udev);
294 input_unregister_device(dev);
296 input_free_device(dev);
304 static int uinput_create_device(struct uinput_device *udev)
306 struct input_dev *dev = udev->dev;
309 if (udev->state != UIST_SETUP_COMPLETE) {
310 printk(KERN_DEBUG "%s: write device info first\n", UINPUT_NAME);
314 if (test_bit(EV_ABS, dev->evbit)) {
315 input_alloc_absinfo(dev);
321 if (test_bit(ABS_MT_SLOT, dev->absbit)) {
322 nslot = input_abs_get_max(dev, ABS_MT_SLOT) + 1;
323 error = input_mt_init_slots(dev, nslot, 0);
326 } else if (test_bit(ABS_MT_POSITION_X, dev->absbit)) {
327 input_set_events_per_packet(dev, 60);
331 if (test_bit(EV_FF, dev->evbit) && !udev->ff_effects_max) {
332 printk(KERN_DEBUG "%s: ff_effects_max should be non-zero when FF_BIT is set\n",
338 if (udev->ff_effects_max) {
339 error = input_ff_create(dev, udev->ff_effects_max);
343 dev->ff->upload = uinput_dev_upload_effect;
344 dev->ff->erase = uinput_dev_erase_effect;
345 dev->ff->playback = uinput_dev_playback;
346 dev->ff->set_gain = uinput_dev_set_gain;
347 dev->ff->set_autocenter = uinput_dev_set_autocenter;
349 * The standard input_ff_flush() implementation does
350 * not quite work for uinput as we can't reasonably
351 * handle FF requests during device teardown.
353 dev->flush = uinput_dev_flush;
356 dev->event = uinput_dev_event;
358 input_set_drvdata(udev->dev, udev);
360 error = input_register_device(udev->dev);
364 udev->state = UIST_CREATED;
368 fail2: input_ff_destroy(dev);
369 fail1: uinput_destroy_device(udev);
373 static int uinput_open(struct inode *inode, struct file *file)
375 struct uinput_device *newdev;
377 newdev = kzalloc(sizeof(struct uinput_device), GFP_KERNEL);
381 mutex_init(&newdev->mutex);
382 spin_lock_init(&newdev->requests_lock);
383 init_waitqueue_head(&newdev->requests_waitq);
384 init_waitqueue_head(&newdev->waitq);
385 newdev->state = UIST_NEW_DEVICE;
387 file->private_data = newdev;
388 stream_open(inode, file);
393 static int uinput_validate_absinfo(struct input_dev *dev, unsigned int code,
394 const struct input_absinfo *abs)
401 if ((min != 0 || max != 0) && max < min) {
403 "%s: invalid abs[%02x] min:%d max:%d\n",
404 UINPUT_NAME, code, min, max);
408 if (!check_sub_overflow(max, min, &range) && abs->flat > range) {
410 "%s: abs_flat #%02x out of range: %d (min:%d/max:%d)\n",
411 UINPUT_NAME, code, abs->flat, min, max);
418 static int uinput_validate_absbits(struct input_dev *dev)
423 if (!test_bit(EV_ABS, dev->evbit))
427 * Check if absmin/absmax/absfuzz/absflat are sane.
430 for_each_set_bit(cnt, dev->absbit, ABS_CNT) {
434 error = uinput_validate_absinfo(dev, cnt, &dev->absinfo[cnt]);
442 static int uinput_dev_setup(struct uinput_device *udev,
443 struct uinput_setup __user *arg)
445 struct uinput_setup setup;
446 struct input_dev *dev;
448 if (udev->state == UIST_CREATED)
451 if (copy_from_user(&setup, arg, sizeof(setup)))
459 udev->ff_effects_max = setup.ff_effects_max;
462 dev->name = kstrndup(setup.name, UINPUT_MAX_NAME_SIZE, GFP_KERNEL);
466 udev->state = UIST_SETUP_COMPLETE;
470 static int uinput_abs_setup(struct uinput_device *udev,
471 struct uinput_setup __user *arg, size_t size)
473 struct uinput_abs_setup setup = {};
474 struct input_dev *dev;
477 if (size > sizeof(setup))
480 if (udev->state == UIST_CREATED)
483 if (copy_from_user(&setup, arg, size))
486 if (setup.code > ABS_MAX)
491 error = uinput_validate_absinfo(dev, setup.code, &setup.absinfo);
495 input_alloc_absinfo(dev);
499 set_bit(setup.code, dev->absbit);
500 dev->absinfo[setup.code] = setup.absinfo;
504 /* legacy setup via write() */
505 static int uinput_setup_device_legacy(struct uinput_device *udev,
506 const char __user *buffer, size_t count)
508 struct uinput_user_dev *user_dev;
509 struct input_dev *dev;
513 if (count != sizeof(struct uinput_user_dev))
517 udev->dev = input_allocate_device();
524 user_dev = memdup_user(buffer, sizeof(struct uinput_user_dev));
525 if (IS_ERR(user_dev))
526 return PTR_ERR(user_dev);
528 udev->ff_effects_max = user_dev->ff_effects_max;
530 /* Ensure name is filled in */
531 if (!user_dev->name[0]) {
537 dev->name = kstrndup(user_dev->name, UINPUT_MAX_NAME_SIZE,
544 dev->id.bustype = user_dev->id.bustype;
545 dev->id.vendor = user_dev->id.vendor;
546 dev->id.product = user_dev->id.product;
547 dev->id.version = user_dev->id.version;
549 for (i = 0; i < ABS_CNT; i++) {
550 input_abs_set_max(dev, i, user_dev->absmax[i]);
551 input_abs_set_min(dev, i, user_dev->absmin[i]);
552 input_abs_set_fuzz(dev, i, user_dev->absfuzz[i]);
553 input_abs_set_flat(dev, i, user_dev->absflat[i]);
556 retval = uinput_validate_absbits(dev);
560 udev->state = UIST_SETUP_COMPLETE;
568 static ssize_t uinput_inject_events(struct uinput_device *udev,
569 const char __user *buffer, size_t count)
571 struct input_event ev;
574 if (count != 0 && count < input_event_size())
577 while (bytes + input_event_size() <= count) {
579 * Note that even if some events were fetched successfully
580 * we are still going to return EFAULT instead of partial
581 * count to let userspace know that it got it's buffers
584 if (input_event_from_user(buffer + bytes, &ev))
587 input_event(udev->dev, ev.type, ev.code, ev.value);
588 bytes += input_event_size();
595 static ssize_t uinput_write(struct file *file, const char __user *buffer,
596 size_t count, loff_t *ppos)
598 struct uinput_device *udev = file->private_data;
604 retval = mutex_lock_interruptible(&udev->mutex);
608 retval = udev->state == UIST_CREATED ?
609 uinput_inject_events(udev, buffer, count) :
610 uinput_setup_device_legacy(udev, buffer, count);
612 mutex_unlock(&udev->mutex);
617 static bool uinput_fetch_next_event(struct uinput_device *udev,
618 struct input_event *event)
622 spin_lock_irq(&udev->dev->event_lock);
624 have_event = udev->head != udev->tail;
626 *event = udev->buff[udev->tail];
627 udev->tail = (udev->tail + 1) % UINPUT_BUFFER_SIZE;
630 spin_unlock_irq(&udev->dev->event_lock);
635 static ssize_t uinput_events_to_user(struct uinput_device *udev,
636 char __user *buffer, size_t count)
638 struct input_event event;
641 while (read + input_event_size() <= count &&
642 uinput_fetch_next_event(udev, &event)) {
644 if (input_event_to_user(buffer + read, &event))
647 read += input_event_size();
653 static ssize_t uinput_read(struct file *file, char __user *buffer,
654 size_t count, loff_t *ppos)
656 struct uinput_device *udev = file->private_data;
659 if (count != 0 && count < input_event_size())
663 retval = mutex_lock_interruptible(&udev->mutex);
667 if (udev->state != UIST_CREATED)
669 else if (udev->head == udev->tail &&
670 (file->f_flags & O_NONBLOCK))
673 retval = uinput_events_to_user(udev, buffer, count);
675 mutex_unlock(&udev->mutex);
677 if (retval || count == 0)
680 if (!(file->f_flags & O_NONBLOCK))
681 retval = wait_event_interruptible(udev->waitq,
682 udev->head != udev->tail ||
683 udev->state != UIST_CREATED);
684 } while (retval == 0);
689 static __poll_t uinput_poll(struct file *file, poll_table *wait)
691 struct uinput_device *udev = file->private_data;
693 poll_wait(file, &udev->waitq, wait);
695 if (udev->head != udev->tail)
696 return EPOLLIN | EPOLLRDNORM;
701 static int uinput_release(struct inode *inode, struct file *file)
703 struct uinput_device *udev = file->private_data;
705 uinput_destroy_device(udev);
712 struct uinput_ff_upload_compat {
715 struct ff_effect_compat effect;
716 struct ff_effect_compat old;
719 static int uinput_ff_upload_to_user(char __user *buffer,
720 const struct uinput_ff_upload *ff_up)
722 if (in_compat_syscall()) {
723 struct uinput_ff_upload_compat ff_up_compat;
725 ff_up_compat.request_id = ff_up->request_id;
726 ff_up_compat.retval = ff_up->retval;
728 * It so happens that the pointer that gives us the trouble
729 * is the last field in the structure. Since we don't support
730 * custom waveforms in uinput anyway we can just copy the whole
731 * thing (to the compat size) and ignore the pointer.
733 memcpy(&ff_up_compat.effect, &ff_up->effect,
734 sizeof(struct ff_effect_compat));
735 memcpy(&ff_up_compat.old, &ff_up->old,
736 sizeof(struct ff_effect_compat));
738 if (copy_to_user(buffer, &ff_up_compat,
739 sizeof(struct uinput_ff_upload_compat)))
742 if (copy_to_user(buffer, ff_up,
743 sizeof(struct uinput_ff_upload)))
750 static int uinput_ff_upload_from_user(const char __user *buffer,
751 struct uinput_ff_upload *ff_up)
753 if (in_compat_syscall()) {
754 struct uinput_ff_upload_compat ff_up_compat;
756 if (copy_from_user(&ff_up_compat, buffer,
757 sizeof(struct uinput_ff_upload_compat)))
760 ff_up->request_id = ff_up_compat.request_id;
761 ff_up->retval = ff_up_compat.retval;
762 memcpy(&ff_up->effect, &ff_up_compat.effect,
763 sizeof(struct ff_effect_compat));
764 memcpy(&ff_up->old, &ff_up_compat.old,
765 sizeof(struct ff_effect_compat));
768 if (copy_from_user(ff_up, buffer,
769 sizeof(struct uinput_ff_upload)))
778 static int uinput_ff_upload_to_user(char __user *buffer,
779 const struct uinput_ff_upload *ff_up)
781 if (copy_to_user(buffer, ff_up, sizeof(struct uinput_ff_upload)))
787 static int uinput_ff_upload_from_user(const char __user *buffer,
788 struct uinput_ff_upload *ff_up)
790 if (copy_from_user(ff_up, buffer, sizeof(struct uinput_ff_upload)))
798 #define uinput_set_bit(_arg, _bit, _max) \
801 if (udev->state == UIST_CREATED) \
803 else if ((_arg) > (_max)) \
805 else set_bit((_arg), udev->dev->_bit); \
809 static int uinput_str_to_user(void __user *dest, const char *str,
812 char __user *p = dest;
821 len = strlen(str) + 1;
825 ret = copy_to_user(p, str, len);
829 /* force terminating '\0' */
830 ret = put_user(0, p + len - 1);
831 return ret ? -EFAULT : len;
834 static long uinput_ioctl_handler(struct file *file, unsigned int cmd,
835 unsigned long arg, void __user *p)
838 struct uinput_device *udev = file->private_data;
839 struct uinput_ff_upload ff_up;
840 struct uinput_ff_erase ff_erase;
841 struct uinput_request *req;
846 retval = mutex_lock_interruptible(&udev->mutex);
851 udev->dev = input_allocate_device();
860 if (put_user(UINPUT_VERSION, (unsigned int __user *)p))
865 retval = uinput_create_device(udev);
869 uinput_destroy_device(udev);
873 retval = uinput_dev_setup(udev, p);
876 /* UI_ABS_SETUP is handled in the variable size ioctls */
879 retval = uinput_set_bit(arg, evbit, EV_MAX);
883 retval = uinput_set_bit(arg, keybit, KEY_MAX);
887 retval = uinput_set_bit(arg, relbit, REL_MAX);
891 retval = uinput_set_bit(arg, absbit, ABS_MAX);
895 retval = uinput_set_bit(arg, mscbit, MSC_MAX);
899 retval = uinput_set_bit(arg, ledbit, LED_MAX);
903 retval = uinput_set_bit(arg, sndbit, SND_MAX);
907 retval = uinput_set_bit(arg, ffbit, FF_MAX);
911 retval = uinput_set_bit(arg, swbit, SW_MAX);
915 retval = uinput_set_bit(arg, propbit, INPUT_PROP_MAX);
919 if (udev->state == UIST_CREATED) {
924 phys = strndup_user(p, 1024);
926 retval = PTR_ERR(phys);
930 kfree(udev->dev->phys);
931 udev->dev->phys = phys;
934 case UI_BEGIN_FF_UPLOAD:
935 retval = uinput_ff_upload_from_user(p, &ff_up);
939 req = uinput_request_find(udev, ff_up.request_id);
940 if (!req || req->code != UI_FF_UPLOAD ||
941 !req->u.upload.effect) {
947 ff_up.effect = *req->u.upload.effect;
948 if (req->u.upload.old)
949 ff_up.old = *req->u.upload.old;
951 memset(&ff_up.old, 0, sizeof(struct ff_effect));
953 retval = uinput_ff_upload_to_user(p, &ff_up);
956 case UI_BEGIN_FF_ERASE:
957 if (copy_from_user(&ff_erase, p, sizeof(ff_erase))) {
962 req = uinput_request_find(udev, ff_erase.request_id);
963 if (!req || req->code != UI_FF_ERASE) {
969 ff_erase.effect_id = req->u.effect_id;
970 if (copy_to_user(p, &ff_erase, sizeof(ff_erase))) {
977 case UI_END_FF_UPLOAD:
978 retval = uinput_ff_upload_from_user(p, &ff_up);
982 req = uinput_request_find(udev, ff_up.request_id);
983 if (!req || req->code != UI_FF_UPLOAD ||
984 !req->u.upload.effect) {
989 req->retval = ff_up.retval;
990 complete(&req->done);
993 case UI_END_FF_ERASE:
994 if (copy_from_user(&ff_erase, p, sizeof(ff_erase))) {
999 req = uinput_request_find(udev, ff_erase.request_id);
1000 if (!req || req->code != UI_FF_ERASE) {
1005 req->retval = ff_erase.retval;
1006 complete(&req->done);
1010 size = _IOC_SIZE(cmd);
1012 /* Now check variable-length commands */
1013 switch (cmd & ~IOCSIZE_MASK) {
1014 case UI_GET_SYSNAME(0):
1015 if (udev->state != UIST_CREATED) {
1019 name = dev_name(&udev->dev->dev);
1020 retval = uinput_str_to_user(p, name, size);
1023 case UI_ABS_SETUP & ~IOCSIZE_MASK:
1024 retval = uinput_abs_setup(udev, p, size);
1030 mutex_unlock(&udev->mutex);
1034 static long uinput_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1036 return uinput_ioctl_handler(file, cmd, arg, (void __user *)arg);
1039 #ifdef CONFIG_COMPAT
1041 #define UI_SET_PHYS_COMPAT _IOW(UINPUT_IOCTL_BASE, 108, compat_uptr_t)
1043 static long uinput_compat_ioctl(struct file *file,
1044 unsigned int cmd, unsigned long arg)
1046 if (cmd == UI_SET_PHYS_COMPAT)
1049 return uinput_ioctl_handler(file, cmd, arg, compat_ptr(arg));
1053 static const struct file_operations uinput_fops = {
1054 .owner = THIS_MODULE,
1055 .open = uinput_open,
1056 .release = uinput_release,
1057 .read = uinput_read,
1058 .write = uinput_write,
1059 .poll = uinput_poll,
1060 .unlocked_ioctl = uinput_ioctl,
1061 #ifdef CONFIG_COMPAT
1062 .compat_ioctl = uinput_compat_ioctl,
1064 .llseek = no_llseek,
1067 static struct miscdevice uinput_misc = {
1068 .fops = &uinput_fops,
1069 .minor = UINPUT_MINOR,
1070 .name = UINPUT_NAME,
1072 module_misc_device(uinput_misc);
1074 MODULE_ALIAS_MISCDEV(UINPUT_MINOR);
1075 MODULE_ALIAS("devname:" UINPUT_NAME);
1077 MODULE_AUTHOR("Aristeu Sergio Rozanski Filho");
1078 MODULE_DESCRIPTION("User level driver support for input subsystem");
1079 MODULE_LICENSE("GPL");