2 * Event char devices, giving access to raw input device events.
4 * Copyright (c) 1999-2002 Vojtech Pavlik
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.
11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13 #define EVDEV_MINOR_BASE 64
14 #define EVDEV_MINORS 32
15 #define EVDEV_MIN_BUFFER_SIZE 64U
16 #define EVDEV_BUF_PACKETS 8
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"
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 */
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;
48 struct list_head node;
51 struct input_event buffer[];
54 static struct evdev *evdev_table[EVDEV_MINORS];
55 static DEFINE_MUTEX(evdev_table_mutex);
57 static void evdev_pass_event(struct evdev_client *client,
58 struct input_event *event,
59 ktime_t mono, ktime_t real)
61 event->time = ktime_to_timeval(client->clkid == CLOCK_MONOTONIC ?
64 /* Interrupts are disabled, just acquire the lock. */
65 spin_lock(&client->buffer_lock);
67 client->buffer[client->head++] = *event;
68 client->head &= client->bufsize - 1;
70 if (unlikely(client->head == client->tail)) {
72 * This effectively "drops" all unconsumed events, leaving
73 * EV_SYN/SYN_DROPPED plus the newest event in the queue.
75 client->tail = (client->head - 2) & (client->bufsize - 1);
77 client->buffer[client->tail].time = event->time;
78 client->buffer[client->tail].type = EV_SYN;
79 client->buffer[client->tail].code = SYN_DROPPED;
80 client->buffer[client->tail].value = 0;
82 client->packet_head = client->tail;
85 if (event->type == EV_SYN && event->code == SYN_REPORT) {
86 client->packet_head = client->head;
87 kill_fasync(&client->fasync, SIGIO, POLL_IN);
90 spin_unlock(&client->buffer_lock);
94 * Pass incoming event to all connected clients.
96 static void evdev_event(struct input_handle *handle,
97 unsigned int type, unsigned int code, int value)
99 struct evdev *evdev = handle->private;
100 struct evdev_client *client;
101 struct input_event event;
102 ktime_t time_mono, time_real;
104 time_mono = ktime_get();
105 time_real = ktime_sub(time_mono, ktime_get_monotonic_offset());
113 client = rcu_dereference(evdev->grab);
116 evdev_pass_event(client, &event, time_mono, time_real);
118 list_for_each_entry_rcu(client, &evdev->client_list, node)
119 evdev_pass_event(client, &event, time_mono, time_real);
123 if (type == EV_SYN && code == SYN_REPORT)
124 wake_up_interruptible(&evdev->wait);
127 static int evdev_fasync(int fd, struct file *file, int on)
129 struct evdev_client *client = file->private_data;
131 return fasync_helper(fd, file, on, &client->fasync);
134 static int evdev_flush(struct file *file, fl_owner_t id)
136 struct evdev_client *client = file->private_data;
137 struct evdev *evdev = client->evdev;
140 retval = mutex_lock_interruptible(&evdev->mutex);
147 retval = input_flush_device(&evdev->handle, file);
149 mutex_unlock(&evdev->mutex);
153 static void evdev_free(struct device *dev)
155 struct evdev *evdev = container_of(dev, struct evdev, dev);
157 input_put_device(evdev->handle.dev);
162 * Grabs an event device (along with underlying input device).
163 * This function is called with evdev->mutex taken.
165 static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
172 error = input_grab_device(&evdev->handle);
176 rcu_assign_pointer(evdev->grab, client);
181 static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
183 if (evdev->grab != client)
186 rcu_assign_pointer(evdev->grab, NULL);
188 input_release_device(&evdev->handle);
193 static void evdev_attach_client(struct evdev *evdev,
194 struct evdev_client *client)
196 spin_lock(&evdev->client_lock);
197 list_add_tail_rcu(&client->node, &evdev->client_list);
198 spin_unlock(&evdev->client_lock);
201 static void evdev_detach_client(struct evdev *evdev,
202 struct evdev_client *client)
204 spin_lock(&evdev->client_lock);
205 list_del_rcu(&client->node);
206 spin_unlock(&evdev->client_lock);
210 static int evdev_open_device(struct evdev *evdev)
214 retval = mutex_lock_interruptible(&evdev->mutex);
220 else if (!evdev->open++) {
221 retval = input_open_device(&evdev->handle);
226 mutex_unlock(&evdev->mutex);
230 static void evdev_close_device(struct evdev *evdev)
232 mutex_lock(&evdev->mutex);
234 if (evdev->exist && !--evdev->open)
235 input_close_device(&evdev->handle);
237 mutex_unlock(&evdev->mutex);
241 * Wake up users waiting for IO so they can disconnect from
244 static void evdev_hangup(struct evdev *evdev)
246 struct evdev_client *client;
248 spin_lock(&evdev->client_lock);
249 list_for_each_entry(client, &evdev->client_list, node)
250 kill_fasync(&client->fasync, SIGIO, POLL_HUP);
251 spin_unlock(&evdev->client_lock);
253 wake_up_interruptible(&evdev->wait);
256 static int evdev_release(struct inode *inode, struct file *file)
258 struct evdev_client *client = file->private_data;
259 struct evdev *evdev = client->evdev;
261 mutex_lock(&evdev->mutex);
262 if (evdev->grab == client)
263 evdev_ungrab(evdev, client);
264 mutex_unlock(&evdev->mutex);
266 evdev_detach_client(evdev, client);
269 evdev_close_device(evdev);
270 put_device(&evdev->dev);
275 static unsigned int evdev_compute_buffer_size(struct input_dev *dev)
277 unsigned int n_events =
278 max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS,
279 EVDEV_MIN_BUFFER_SIZE);
281 return roundup_pow_of_two(n_events);
284 static int evdev_open(struct inode *inode, struct file *file)
287 struct evdev_client *client;
288 int i = iminor(inode) - EVDEV_MINOR_BASE;
289 unsigned int bufsize;
292 if (i >= EVDEV_MINORS)
295 error = mutex_lock_interruptible(&evdev_table_mutex);
298 evdev = evdev_table[i];
300 get_device(&evdev->dev);
301 mutex_unlock(&evdev_table_mutex);
306 bufsize = evdev_compute_buffer_size(evdev->handle.dev);
308 client = kzalloc(sizeof(struct evdev_client) +
309 bufsize * sizeof(struct input_event),
316 client->bufsize = bufsize;
317 spin_lock_init(&client->buffer_lock);
318 client->evdev = evdev;
319 evdev_attach_client(evdev, client);
321 error = evdev_open_device(evdev);
323 goto err_free_client;
325 file->private_data = client;
326 nonseekable_open(inode, file);
331 evdev_detach_client(evdev, client);
334 put_device(&evdev->dev);
338 static ssize_t evdev_write(struct file *file, const char __user *buffer,
339 size_t count, loff_t *ppos)
341 struct evdev_client *client = file->private_data;
342 struct evdev *evdev = client->evdev;
343 struct input_event event;
346 if (count < input_event_size())
349 retval = mutex_lock_interruptible(&evdev->mutex);
359 if (input_event_from_user(buffer + retval, &event)) {
363 retval += input_event_size();
365 input_inject_event(&evdev->handle,
366 event.type, event.code, event.value);
367 } while (retval + input_event_size() <= count);
370 mutex_unlock(&evdev->mutex);
374 static int evdev_fetch_next_event(struct evdev_client *client,
375 struct input_event *event)
379 spin_lock_irq(&client->buffer_lock);
381 have_event = client->packet_head != client->tail;
383 *event = client->buffer[client->tail++];
384 client->tail &= client->bufsize - 1;
387 spin_unlock_irq(&client->buffer_lock);
392 static ssize_t evdev_read(struct file *file, char __user *buffer,
393 size_t count, loff_t *ppos)
395 struct evdev_client *client = file->private_data;
396 struct evdev *evdev = client->evdev;
397 struct input_event event;
400 if (count < input_event_size())
403 if (!(file->f_flags & O_NONBLOCK)) {
404 retval = wait_event_interruptible(evdev->wait,
405 client->packet_head != client->tail ||
414 while (retval + input_event_size() <= count &&
415 evdev_fetch_next_event(client, &event)) {
417 if (input_event_to_user(buffer + retval, &event))
420 retval += input_event_size();
423 if (retval == 0 && (file->f_flags & O_NONBLOCK))
429 /* No kernel lock - fine */
430 static unsigned int evdev_poll(struct file *file, poll_table *wait)
432 struct evdev_client *client = file->private_data;
433 struct evdev *evdev = client->evdev;
436 poll_wait(file, &evdev->wait, wait);
438 mask = evdev->exist ? POLLOUT | POLLWRNORM : POLLHUP | POLLERR;
439 if (client->packet_head != client->tail)
440 mask |= POLLIN | POLLRDNORM;
447 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
448 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
451 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
452 unsigned int maxlen, void __user *p, int compat)
457 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
461 for (i = 0; i < len / sizeof(compat_long_t); i++)
462 if (copy_to_user((compat_long_t __user *) p + i,
463 (compat_long_t *) bits +
464 i + 1 - ((i % 2) << 1),
465 sizeof(compat_long_t)))
468 len = BITS_TO_LONGS(maxbit) * sizeof(long);
472 if (copy_to_user(p, bits, len))
479 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
480 unsigned int maxlen, void __user *p, int compat)
483 BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
484 BITS_TO_LONGS(maxbit) * sizeof(long);
489 return copy_to_user(p, bits, len) ? -EFAULT : len;
491 #endif /* __BIG_ENDIAN */
495 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
496 unsigned int maxlen, void __user *p, int compat)
498 int len = BITS_TO_LONGS(maxbit) * sizeof(long);
503 return copy_to_user(p, bits, len) ? -EFAULT : len;
506 #endif /* CONFIG_COMPAT */
508 static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
515 len = strlen(str) + 1;
519 return copy_to_user(p, str, len) ? -EFAULT : len;
522 #define OLD_KEY_MAX 0x1ff
523 static int handle_eviocgbit(struct input_dev *dev,
524 unsigned int type, unsigned int size,
525 void __user *p, int compat_mode)
527 static unsigned long keymax_warn_time;
533 case 0: bits = dev->evbit; len = EV_MAX; break;
534 case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
535 case EV_REL: bits = dev->relbit; len = REL_MAX; break;
536 case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
537 case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
538 case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
539 case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
540 case EV_FF: bits = dev->ffbit; len = FF_MAX; break;
541 case EV_SW: bits = dev->swbit; len = SW_MAX; break;
542 default: return -EINVAL;
546 * Work around bugs in userspace programs that like to do
547 * EVIOCGBIT(EV_KEY, KEY_MAX) and not realize that 'len'
548 * should be in bytes, not in bits.
550 if (type == EV_KEY && size == OLD_KEY_MAX) {
552 if (printk_timed_ratelimit(&keymax_warn_time, 10 * 1000))
553 pr_warning("(EVIOCGBIT): Suspicious buffer size %u, "
554 "limiting output to %zu bytes. See "
555 "http://userweb.kernel.org/~dtor/eviocgbit-bug.html\n",
557 BITS_TO_LONGS(OLD_KEY_MAX) * sizeof(long));
560 return bits_to_user(bits, len, size, p, compat_mode);
564 static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p)
566 struct input_keymap_entry ke = {
567 .len = sizeof(unsigned int),
570 int __user *ip = (int __user *)p;
574 if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
577 error = input_get_keycode(dev, &ke);
581 if (put_user(ke.keycode, ip + 1))
587 static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p)
589 struct input_keymap_entry ke;
592 if (copy_from_user(&ke, p, sizeof(ke)))
595 error = input_get_keycode(dev, &ke);
599 if (copy_to_user(p, &ke, sizeof(ke)))
605 static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p)
607 struct input_keymap_entry ke = {
608 .len = sizeof(unsigned int),
611 int __user *ip = (int __user *)p;
613 if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
616 if (get_user(ke.keycode, ip + 1))
619 return input_set_keycode(dev, &ke);
622 static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p)
624 struct input_keymap_entry ke;
626 if (copy_from_user(&ke, p, sizeof(ke)))
629 if (ke.len > sizeof(ke.scancode))
632 return input_set_keycode(dev, &ke);
635 static long evdev_do_ioctl(struct file *file, unsigned int cmd,
636 void __user *p, int compat_mode)
638 struct evdev_client *client = file->private_data;
639 struct evdev *evdev = client->evdev;
640 struct input_dev *dev = evdev->handle.dev;
641 struct input_absinfo abs;
642 struct ff_effect effect;
643 int __user *ip = (int __user *)p;
644 unsigned int i, t, u, v;
648 /* First we check for fixed-length commands */
652 return put_user(EV_VERSION, ip);
655 if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
660 if (!test_bit(EV_REP, dev->evbit))
662 if (put_user(dev->rep[REP_DELAY], ip))
664 if (put_user(dev->rep[REP_PERIOD], ip + 1))
669 if (!test_bit(EV_REP, dev->evbit))
673 if (get_user(v, ip + 1))
676 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
677 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
682 return input_ff_erase(dev, (int)(unsigned long) p, file);
685 i = test_bit(EV_FF, dev->evbit) ?
686 dev->ff->max_effects : 0;
693 return evdev_grab(evdev, client);
695 return evdev_ungrab(evdev, client);
698 if (copy_from_user(&i, p, sizeof(unsigned int)))
700 if (i != CLOCK_MONOTONIC && i != CLOCK_REALTIME)
706 return evdev_handle_get_keycode(dev, p);
709 return evdev_handle_set_keycode(dev, p);
711 case EVIOCGKEYCODE_V2:
712 return evdev_handle_get_keycode_v2(dev, p);
714 case EVIOCSKEYCODE_V2:
715 return evdev_handle_set_keycode_v2(dev, p);
718 size = _IOC_SIZE(cmd);
720 /* Now check variable-length commands */
721 #define EVIOC_MASK_SIZE(nr) ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
722 switch (EVIOC_MASK_SIZE(cmd)) {
725 return bits_to_user(dev->propbit, INPUT_PROP_MAX,
726 size, p, compat_mode);
729 return bits_to_user(dev->key, KEY_MAX, size, p, compat_mode);
732 return bits_to_user(dev->led, LED_MAX, size, p, compat_mode);
735 return bits_to_user(dev->snd, SND_MAX, size, p, compat_mode);
738 return bits_to_user(dev->sw, SW_MAX, size, p, compat_mode);
741 return str_to_user(dev->name, size, p);
744 return str_to_user(dev->phys, size, p);
747 return str_to_user(dev->uniq, size, p);
749 case EVIOC_MASK_SIZE(EVIOCSFF):
750 if (input_ff_effect_from_user(p, size, &effect))
753 error = input_ff_upload(dev, &effect, file);
755 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
761 /* Multi-number variable-length handlers */
762 if (_IOC_TYPE(cmd) != 'E')
765 if (_IOC_DIR(cmd) == _IOC_READ) {
767 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
768 return handle_eviocgbit(dev,
769 _IOC_NR(cmd) & EV_MAX, size,
772 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
777 t = _IOC_NR(cmd) & ABS_MAX;
778 abs = dev->absinfo[t];
780 if (copy_to_user(p, &abs, min_t(size_t,
781 size, sizeof(struct input_absinfo))))
788 if (_IOC_DIR(cmd) == _IOC_WRITE) {
790 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
795 t = _IOC_NR(cmd) & ABS_MAX;
797 if (copy_from_user(&abs, p, min_t(size_t,
798 size, sizeof(struct input_absinfo))))
801 if (size < sizeof(struct input_absinfo))
804 /* We can't change number of reserved MT slots */
805 if (t == ABS_MT_SLOT)
809 * Take event lock to ensure that we are not
810 * changing device parameters in the middle
813 spin_lock_irq(&dev->event_lock);
814 dev->absinfo[t] = abs;
815 spin_unlock_irq(&dev->event_lock);
824 static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
825 void __user *p, int compat_mode)
827 struct evdev_client *client = file->private_data;
828 struct evdev *evdev = client->evdev;
831 retval = mutex_lock_interruptible(&evdev->mutex);
840 retval = evdev_do_ioctl(file, cmd, p, compat_mode);
843 mutex_unlock(&evdev->mutex);
847 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
849 return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
853 static long evdev_ioctl_compat(struct file *file,
854 unsigned int cmd, unsigned long arg)
856 return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
860 static const struct file_operations evdev_fops = {
861 .owner = THIS_MODULE,
863 .write = evdev_write,
866 .release = evdev_release,
867 .unlocked_ioctl = evdev_ioctl,
869 .compat_ioctl = evdev_ioctl_compat,
871 .fasync = evdev_fasync,
872 .flush = evdev_flush,
876 static int evdev_install_chrdev(struct evdev *evdev)
879 * No need to do any locking here as calls to connect and
880 * disconnect are serialized by the input core
882 evdev_table[evdev->minor] = evdev;
886 static void evdev_remove_chrdev(struct evdev *evdev)
889 * Lock evdev table to prevent race with evdev_open()
891 mutex_lock(&evdev_table_mutex);
892 evdev_table[evdev->minor] = NULL;
893 mutex_unlock(&evdev_table_mutex);
897 * Mark device non-existent. This disables writes, ioctls and
898 * prevents new users from opening the device. Already posted
899 * blocking reads will stay, however new ones will fail.
901 static void evdev_mark_dead(struct evdev *evdev)
903 mutex_lock(&evdev->mutex);
904 evdev->exist = false;
905 mutex_unlock(&evdev->mutex);
908 static void evdev_cleanup(struct evdev *evdev)
910 struct input_handle *handle = &evdev->handle;
912 evdev_mark_dead(evdev);
914 evdev_remove_chrdev(evdev);
916 /* evdev is marked dead so no one else accesses evdev->open */
918 input_flush_device(handle, NULL);
919 input_close_device(handle);
924 * Create new evdev device. Note that input core serializes calls
925 * to connect and disconnect so we don't need to lock evdev_table here.
927 static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
928 const struct input_device_id *id)
934 for (minor = 0; minor < EVDEV_MINORS; minor++)
935 if (!evdev_table[minor])
938 if (minor == EVDEV_MINORS) {
939 pr_err("no more free evdev devices\n");
943 evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
947 INIT_LIST_HEAD(&evdev->client_list);
948 spin_lock_init(&evdev->client_lock);
949 mutex_init(&evdev->mutex);
950 init_waitqueue_head(&evdev->wait);
952 dev_set_name(&evdev->dev, "event%d", minor);
954 evdev->minor = minor;
956 evdev->handle.dev = input_get_device(dev);
957 evdev->handle.name = dev_name(&evdev->dev);
958 evdev->handle.handler = handler;
959 evdev->handle.private = evdev;
961 evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor);
962 evdev->dev.class = &input_class;
963 evdev->dev.parent = &dev->dev;
964 evdev->dev.release = evdev_free;
965 device_initialize(&evdev->dev);
967 error = input_register_handle(&evdev->handle);
971 error = evdev_install_chrdev(evdev);
973 goto err_unregister_handle;
975 error = device_add(&evdev->dev);
977 goto err_cleanup_evdev;
982 evdev_cleanup(evdev);
983 err_unregister_handle:
984 input_unregister_handle(&evdev->handle);
986 put_device(&evdev->dev);
990 static void evdev_disconnect(struct input_handle *handle)
992 struct evdev *evdev = handle->private;
994 device_del(&evdev->dev);
995 evdev_cleanup(evdev);
996 input_unregister_handle(handle);
997 put_device(&evdev->dev);
1000 static const struct input_device_id evdev_ids[] = {
1001 { .driver_info = 1 }, /* Matches all devices */
1002 { }, /* Terminating zero entry */
1005 MODULE_DEVICE_TABLE(input, evdev_ids);
1007 static struct input_handler evdev_handler = {
1008 .event = evdev_event,
1009 .connect = evdev_connect,
1010 .disconnect = evdev_disconnect,
1011 .fops = &evdev_fops,
1012 .minor = EVDEV_MINOR_BASE,
1014 .id_table = evdev_ids,
1017 static int __init evdev_init(void)
1019 return input_register_handler(&evdev_handler);
1022 static void __exit evdev_exit(void)
1024 input_unregister_handler(&evdev_handler);
1027 module_init(evdev_init);
1028 module_exit(evdev_exit);
1030 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
1031 MODULE_DESCRIPTION("Input driver event char devices");
1032 MODULE_LICENSE("GPL");