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;
50 struct input_event buffer[];
53 static struct evdev *evdev_table[EVDEV_MINORS];
54 static DEFINE_MUTEX(evdev_table_mutex);
56 static void evdev_pass_event(struct evdev_client *client,
57 struct input_event *event)
59 /* Interrupts are disabled, just acquire the lock. */
60 spin_lock(&client->buffer_lock);
62 client->buffer[client->head++] = *event;
63 client->head &= client->bufsize - 1;
65 if (unlikely(client->head == client->tail)) {
67 * This effectively "drops" all unconsumed events, leaving
68 * EV_SYN/SYN_DROPPED plus the newest event in the queue.
70 client->tail = (client->head - 2) & (client->bufsize - 1);
72 client->buffer[client->tail].time = event->time;
73 client->buffer[client->tail].type = EV_SYN;
74 client->buffer[client->tail].code = SYN_DROPPED;
75 client->buffer[client->tail].value = 0;
77 client->packet_head = client->tail;
80 if (event->type == EV_SYN && event->code == SYN_REPORT) {
81 client->packet_head = client->head;
82 kill_fasync(&client->fasync, SIGIO, POLL_IN);
85 spin_unlock(&client->buffer_lock);
89 * Pass incoming event to all connected clients.
91 static void evdev_event(struct input_handle *handle,
92 unsigned int type, unsigned int code, int value)
94 struct evdev *evdev = handle->private;
95 struct evdev_client *client;
96 struct input_event event;
98 do_gettimeofday(&event.time);
105 client = rcu_dereference(evdev->grab);
107 evdev_pass_event(client, &event);
109 list_for_each_entry_rcu(client, &evdev->client_list, node)
110 evdev_pass_event(client, &event);
114 wake_up_interruptible(&evdev->wait);
117 static int evdev_fasync(int fd, struct file *file, int on)
119 struct evdev_client *client = file->private_data;
121 return fasync_helper(fd, file, on, &client->fasync);
124 static int evdev_flush(struct file *file, fl_owner_t id)
126 struct evdev_client *client = file->private_data;
127 struct evdev *evdev = client->evdev;
130 retval = mutex_lock_interruptible(&evdev->mutex);
137 retval = input_flush_device(&evdev->handle, file);
139 mutex_unlock(&evdev->mutex);
143 static void evdev_free(struct device *dev)
145 struct evdev *evdev = container_of(dev, struct evdev, dev);
147 input_put_device(evdev->handle.dev);
152 * Grabs an event device (along with underlying input device).
153 * This function is called with evdev->mutex taken.
155 static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
162 error = input_grab_device(&evdev->handle);
166 rcu_assign_pointer(evdev->grab, client);
171 static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
173 if (evdev->grab != client)
176 rcu_assign_pointer(evdev->grab, NULL);
178 input_release_device(&evdev->handle);
183 static void evdev_attach_client(struct evdev *evdev,
184 struct evdev_client *client)
186 spin_lock(&evdev->client_lock);
187 list_add_tail_rcu(&client->node, &evdev->client_list);
188 spin_unlock(&evdev->client_lock);
191 static void evdev_detach_client(struct evdev *evdev,
192 struct evdev_client *client)
194 spin_lock(&evdev->client_lock);
195 list_del_rcu(&client->node);
196 spin_unlock(&evdev->client_lock);
200 static int evdev_open_device(struct evdev *evdev)
204 retval = mutex_lock_interruptible(&evdev->mutex);
210 else if (!evdev->open++) {
211 retval = input_open_device(&evdev->handle);
216 mutex_unlock(&evdev->mutex);
220 static void evdev_close_device(struct evdev *evdev)
222 mutex_lock(&evdev->mutex);
224 if (evdev->exist && !--evdev->open)
225 input_close_device(&evdev->handle);
227 mutex_unlock(&evdev->mutex);
231 * Wake up users waiting for IO so they can disconnect from
234 static void evdev_hangup(struct evdev *evdev)
236 struct evdev_client *client;
238 spin_lock(&evdev->client_lock);
239 list_for_each_entry(client, &evdev->client_list, node)
240 kill_fasync(&client->fasync, SIGIO, POLL_HUP);
241 spin_unlock(&evdev->client_lock);
243 wake_up_interruptible(&evdev->wait);
246 static int evdev_release(struct inode *inode, struct file *file)
248 struct evdev_client *client = file->private_data;
249 struct evdev *evdev = client->evdev;
251 mutex_lock(&evdev->mutex);
252 if (evdev->grab == client)
253 evdev_ungrab(evdev, client);
254 mutex_unlock(&evdev->mutex);
256 evdev_detach_client(evdev, client);
259 evdev_close_device(evdev);
260 put_device(&evdev->dev);
265 static unsigned int evdev_compute_buffer_size(struct input_dev *dev)
267 unsigned int n_events =
268 max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS,
269 EVDEV_MIN_BUFFER_SIZE);
271 return roundup_pow_of_two(n_events);
274 static int evdev_open(struct inode *inode, struct file *file)
277 struct evdev_client *client;
278 int i = iminor(inode) - EVDEV_MINOR_BASE;
279 unsigned int bufsize;
282 if (i >= EVDEV_MINORS)
285 error = mutex_lock_interruptible(&evdev_table_mutex);
288 evdev = evdev_table[i];
290 get_device(&evdev->dev);
291 mutex_unlock(&evdev_table_mutex);
296 bufsize = evdev_compute_buffer_size(evdev->handle.dev);
298 client = kzalloc(sizeof(struct evdev_client) +
299 bufsize * sizeof(struct input_event),
306 client->bufsize = bufsize;
307 spin_lock_init(&client->buffer_lock);
308 client->evdev = evdev;
309 evdev_attach_client(evdev, client);
311 error = evdev_open_device(evdev);
313 goto err_free_client;
315 file->private_data = client;
316 nonseekable_open(inode, file);
321 evdev_detach_client(evdev, client);
324 put_device(&evdev->dev);
328 static ssize_t evdev_write(struct file *file, const char __user *buffer,
329 size_t count, loff_t *ppos)
331 struct evdev_client *client = file->private_data;
332 struct evdev *evdev = client->evdev;
333 struct input_event event;
336 if (count < input_event_size())
339 retval = mutex_lock_interruptible(&evdev->mutex);
349 if (input_event_from_user(buffer + retval, &event)) {
353 retval += input_event_size();
355 input_inject_event(&evdev->handle,
356 event.type, event.code, event.value);
357 } while (retval + input_event_size() <= count);
360 mutex_unlock(&evdev->mutex);
364 static int evdev_fetch_next_event(struct evdev_client *client,
365 struct input_event *event)
369 spin_lock_irq(&client->buffer_lock);
371 have_event = client->head != client->tail;
373 *event = client->buffer[client->tail++];
374 client->tail &= client->bufsize - 1;
377 spin_unlock_irq(&client->buffer_lock);
382 static ssize_t evdev_read(struct file *file, char __user *buffer,
383 size_t count, loff_t *ppos)
385 struct evdev_client *client = file->private_data;
386 struct evdev *evdev = client->evdev;
387 struct input_event event;
390 if (count < input_event_size())
393 if (client->packet_head == client->tail && evdev->exist &&
394 (file->f_flags & O_NONBLOCK))
397 retval = wait_event_interruptible(evdev->wait,
398 client->packet_head != client->tail || !evdev->exist);
405 while (retval + input_event_size() <= count &&
406 evdev_fetch_next_event(client, &event)) {
408 if (input_event_to_user(buffer + retval, &event))
411 retval += input_event_size();
417 /* No kernel lock - fine */
418 static unsigned int evdev_poll(struct file *file, poll_table *wait)
420 struct evdev_client *client = file->private_data;
421 struct evdev *evdev = client->evdev;
424 poll_wait(file, &evdev->wait, wait);
426 mask = evdev->exist ? POLLOUT | POLLWRNORM : POLLHUP | POLLERR;
427 if (client->packet_head != client->tail)
428 mask |= POLLIN | POLLRDNORM;
435 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
436 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
439 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
440 unsigned int maxlen, void __user *p, int compat)
445 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
449 for (i = 0; i < len / sizeof(compat_long_t); i++)
450 if (copy_to_user((compat_long_t __user *) p + i,
451 (compat_long_t *) bits +
452 i + 1 - ((i % 2) << 1),
453 sizeof(compat_long_t)))
456 len = BITS_TO_LONGS(maxbit) * sizeof(long);
460 if (copy_to_user(p, bits, len))
467 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
468 unsigned int maxlen, void __user *p, int compat)
471 BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
472 BITS_TO_LONGS(maxbit) * sizeof(long);
477 return copy_to_user(p, bits, len) ? -EFAULT : len;
479 #endif /* __BIG_ENDIAN */
483 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
484 unsigned int maxlen, void __user *p, int compat)
486 int len = BITS_TO_LONGS(maxbit) * sizeof(long);
491 return copy_to_user(p, bits, len) ? -EFAULT : len;
494 #endif /* CONFIG_COMPAT */
496 static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
503 len = strlen(str) + 1;
507 return copy_to_user(p, str, len) ? -EFAULT : len;
510 #define OLD_KEY_MAX 0x1ff
511 static int handle_eviocgbit(struct input_dev *dev,
512 unsigned int type, unsigned int size,
513 void __user *p, int compat_mode)
515 static unsigned long keymax_warn_time;
521 case 0: bits = dev->evbit; len = EV_MAX; break;
522 case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
523 case EV_REL: bits = dev->relbit; len = REL_MAX; break;
524 case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
525 case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
526 case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
527 case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
528 case EV_FF: bits = dev->ffbit; len = FF_MAX; break;
529 case EV_SW: bits = dev->swbit; len = SW_MAX; break;
530 default: return -EINVAL;
534 * Work around bugs in userspace programs that like to do
535 * EVIOCGBIT(EV_KEY, KEY_MAX) and not realize that 'len'
536 * should be in bytes, not in bits.
538 if (type == EV_KEY && size == OLD_KEY_MAX) {
540 if (printk_timed_ratelimit(&keymax_warn_time, 10 * 1000))
541 pr_warning("(EVIOCGBIT): Suspicious buffer size %u, "
542 "limiting output to %zu bytes. See "
543 "http://userweb.kernel.org/~dtor/eviocgbit-bug.html\n",
545 BITS_TO_LONGS(OLD_KEY_MAX) * sizeof(long));
548 return bits_to_user(bits, len, size, p, compat_mode);
552 static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p)
554 struct input_keymap_entry ke = {
555 .len = sizeof(unsigned int),
558 int __user *ip = (int __user *)p;
562 if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
565 error = input_get_keycode(dev, &ke);
569 if (put_user(ke.keycode, ip + 1))
575 static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p)
577 struct input_keymap_entry ke;
580 if (copy_from_user(&ke, p, sizeof(ke)))
583 error = input_get_keycode(dev, &ke);
587 if (copy_to_user(p, &ke, sizeof(ke)))
593 static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p)
595 struct input_keymap_entry ke = {
596 .len = sizeof(unsigned int),
599 int __user *ip = (int __user *)p;
601 if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
604 if (get_user(ke.keycode, ip + 1))
607 return input_set_keycode(dev, &ke);
610 static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p)
612 struct input_keymap_entry ke;
614 if (copy_from_user(&ke, p, sizeof(ke)))
617 if (ke.len > sizeof(ke.scancode))
620 return input_set_keycode(dev, &ke);
623 static long evdev_do_ioctl(struct file *file, unsigned int cmd,
624 void __user *p, int compat_mode)
626 struct evdev_client *client = file->private_data;
627 struct evdev *evdev = client->evdev;
628 struct input_dev *dev = evdev->handle.dev;
629 struct input_absinfo abs;
630 struct ff_effect effect;
631 int __user *ip = (int __user *)p;
632 unsigned int i, t, u, v;
636 /* First we check for fixed-length commands */
640 return put_user(EV_VERSION, ip);
643 if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
648 if (!test_bit(EV_REP, dev->evbit))
650 if (put_user(dev->rep[REP_DELAY], ip))
652 if (put_user(dev->rep[REP_PERIOD], ip + 1))
657 if (!test_bit(EV_REP, dev->evbit))
661 if (get_user(v, ip + 1))
664 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
665 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
670 return input_ff_erase(dev, (int)(unsigned long) p, file);
673 i = test_bit(EV_FF, dev->evbit) ?
674 dev->ff->max_effects : 0;
681 return evdev_grab(evdev, client);
683 return evdev_ungrab(evdev, client);
686 return evdev_handle_get_keycode(dev, p);
689 return evdev_handle_set_keycode(dev, p);
691 case EVIOCGKEYCODE_V2:
692 return evdev_handle_get_keycode_v2(dev, p);
694 case EVIOCSKEYCODE_V2:
695 return evdev_handle_set_keycode_v2(dev, p);
698 size = _IOC_SIZE(cmd);
700 /* Now check variable-length commands */
701 #define EVIOC_MASK_SIZE(nr) ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
702 switch (EVIOC_MASK_SIZE(cmd)) {
705 return bits_to_user(dev->propbit, INPUT_PROP_MAX,
706 size, p, compat_mode);
709 return bits_to_user(dev->key, KEY_MAX, size, p, compat_mode);
712 return bits_to_user(dev->led, LED_MAX, size, p, compat_mode);
715 return bits_to_user(dev->snd, SND_MAX, size, p, compat_mode);
718 return bits_to_user(dev->sw, SW_MAX, size, p, compat_mode);
721 return str_to_user(dev->name, size, p);
724 return str_to_user(dev->phys, size, p);
727 return str_to_user(dev->uniq, size, p);
729 case EVIOC_MASK_SIZE(EVIOCSFF):
730 if (input_ff_effect_from_user(p, size, &effect))
733 error = input_ff_upload(dev, &effect, file);
735 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
741 /* Multi-number variable-length handlers */
742 if (_IOC_TYPE(cmd) != 'E')
745 if (_IOC_DIR(cmd) == _IOC_READ) {
747 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
748 return handle_eviocgbit(dev,
749 _IOC_NR(cmd) & EV_MAX, size,
752 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
757 t = _IOC_NR(cmd) & ABS_MAX;
758 abs = dev->absinfo[t];
760 if (copy_to_user(p, &abs, min_t(size_t,
761 size, sizeof(struct input_absinfo))))
768 if (_IOC_DIR(cmd) == _IOC_WRITE) {
770 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
775 t = _IOC_NR(cmd) & ABS_MAX;
777 if (copy_from_user(&abs, p, min_t(size_t,
778 size, sizeof(struct input_absinfo))))
781 if (size < sizeof(struct input_absinfo))
784 /* We can't change number of reserved MT slots */
785 if (t == ABS_MT_SLOT)
789 * Take event lock to ensure that we are not
790 * changing device parameters in the middle
793 spin_lock_irq(&dev->event_lock);
794 dev->absinfo[t] = abs;
795 spin_unlock_irq(&dev->event_lock);
804 static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
805 void __user *p, int compat_mode)
807 struct evdev_client *client = file->private_data;
808 struct evdev *evdev = client->evdev;
811 retval = mutex_lock_interruptible(&evdev->mutex);
820 retval = evdev_do_ioctl(file, cmd, p, compat_mode);
823 mutex_unlock(&evdev->mutex);
827 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
829 return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
833 static long evdev_ioctl_compat(struct file *file,
834 unsigned int cmd, unsigned long arg)
836 return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
840 static const struct file_operations evdev_fops = {
841 .owner = THIS_MODULE,
843 .write = evdev_write,
846 .release = evdev_release,
847 .unlocked_ioctl = evdev_ioctl,
849 .compat_ioctl = evdev_ioctl_compat,
851 .fasync = evdev_fasync,
852 .flush = evdev_flush,
856 static int evdev_install_chrdev(struct evdev *evdev)
859 * No need to do any locking here as calls to connect and
860 * disconnect are serialized by the input core
862 evdev_table[evdev->minor] = evdev;
866 static void evdev_remove_chrdev(struct evdev *evdev)
869 * Lock evdev table to prevent race with evdev_open()
871 mutex_lock(&evdev_table_mutex);
872 evdev_table[evdev->minor] = NULL;
873 mutex_unlock(&evdev_table_mutex);
877 * Mark device non-existent. This disables writes, ioctls and
878 * prevents new users from opening the device. Already posted
879 * blocking reads will stay, however new ones will fail.
881 static void evdev_mark_dead(struct evdev *evdev)
883 mutex_lock(&evdev->mutex);
884 evdev->exist = false;
885 mutex_unlock(&evdev->mutex);
888 static void evdev_cleanup(struct evdev *evdev)
890 struct input_handle *handle = &evdev->handle;
892 evdev_mark_dead(evdev);
894 evdev_remove_chrdev(evdev);
896 /* evdev is marked dead so no one else accesses evdev->open */
898 input_flush_device(handle, NULL);
899 input_close_device(handle);
904 * Create new evdev device. Note that input core serializes calls
905 * to connect and disconnect so we don't need to lock evdev_table here.
907 static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
908 const struct input_device_id *id)
914 for (minor = 0; minor < EVDEV_MINORS; minor++)
915 if (!evdev_table[minor])
918 if (minor == EVDEV_MINORS) {
919 pr_err("no more free evdev devices\n");
923 evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
927 INIT_LIST_HEAD(&evdev->client_list);
928 spin_lock_init(&evdev->client_lock);
929 mutex_init(&evdev->mutex);
930 init_waitqueue_head(&evdev->wait);
932 dev_set_name(&evdev->dev, "event%d", minor);
934 evdev->minor = minor;
936 evdev->handle.dev = input_get_device(dev);
937 evdev->handle.name = dev_name(&evdev->dev);
938 evdev->handle.handler = handler;
939 evdev->handle.private = evdev;
941 evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor);
942 evdev->dev.class = &input_class;
943 evdev->dev.parent = &dev->dev;
944 evdev->dev.release = evdev_free;
945 device_initialize(&evdev->dev);
947 error = input_register_handle(&evdev->handle);
951 error = evdev_install_chrdev(evdev);
953 goto err_unregister_handle;
955 error = device_add(&evdev->dev);
957 goto err_cleanup_evdev;
962 evdev_cleanup(evdev);
963 err_unregister_handle:
964 input_unregister_handle(&evdev->handle);
966 put_device(&evdev->dev);
970 static void evdev_disconnect(struct input_handle *handle)
972 struct evdev *evdev = handle->private;
974 device_del(&evdev->dev);
975 evdev_cleanup(evdev);
976 input_unregister_handle(handle);
977 put_device(&evdev->dev);
980 static const struct input_device_id evdev_ids[] = {
981 { .driver_info = 1 }, /* Matches all devices */
982 { }, /* Terminating zero entry */
985 MODULE_DEVICE_TABLE(input, evdev_ids);
987 static struct input_handler evdev_handler = {
988 .event = evdev_event,
989 .connect = evdev_connect,
990 .disconnect = evdev_disconnect,
992 .minor = EVDEV_MINOR_BASE,
994 .id_table = evdev_ids,
997 static int __init evdev_init(void)
999 return input_register_handler(&evdev_handler);
1002 static void __exit evdev_exit(void)
1004 input_unregister_handler(&evdev_handler);
1007 module_init(evdev_init);
1008 module_exit(evdev_exit);
1010 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
1011 MODULE_DESCRIPTION("Input driver event char devices");
1012 MODULE_LICENSE("GPL");