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 if (type == EV_SYN && code == SYN_REPORT)
115 wake_up_interruptible(&evdev->wait);
118 static int evdev_fasync(int fd, struct file *file, int on)
120 struct evdev_client *client = file->private_data;
122 return fasync_helper(fd, file, on, &client->fasync);
125 static int evdev_flush(struct file *file, fl_owner_t id)
127 struct evdev_client *client = file->private_data;
128 struct evdev *evdev = client->evdev;
131 retval = mutex_lock_interruptible(&evdev->mutex);
138 retval = input_flush_device(&evdev->handle, file);
140 mutex_unlock(&evdev->mutex);
144 static void evdev_free(struct device *dev)
146 struct evdev *evdev = container_of(dev, struct evdev, dev);
148 input_put_device(evdev->handle.dev);
153 * Grabs an event device (along with underlying input device).
154 * This function is called with evdev->mutex taken.
156 static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
163 error = input_grab_device(&evdev->handle);
167 rcu_assign_pointer(evdev->grab, client);
172 static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
174 if (evdev->grab != client)
177 rcu_assign_pointer(evdev->grab, NULL);
179 input_release_device(&evdev->handle);
184 static void evdev_attach_client(struct evdev *evdev,
185 struct evdev_client *client)
187 spin_lock(&evdev->client_lock);
188 list_add_tail_rcu(&client->node, &evdev->client_list);
189 spin_unlock(&evdev->client_lock);
192 static void evdev_detach_client(struct evdev *evdev,
193 struct evdev_client *client)
195 spin_lock(&evdev->client_lock);
196 list_del_rcu(&client->node);
197 spin_unlock(&evdev->client_lock);
201 static int evdev_open_device(struct evdev *evdev)
205 retval = mutex_lock_interruptible(&evdev->mutex);
211 else if (!evdev->open++) {
212 retval = input_open_device(&evdev->handle);
217 mutex_unlock(&evdev->mutex);
221 static void evdev_close_device(struct evdev *evdev)
223 mutex_lock(&evdev->mutex);
225 if (evdev->exist && !--evdev->open)
226 input_close_device(&evdev->handle);
228 mutex_unlock(&evdev->mutex);
232 * Wake up users waiting for IO so they can disconnect from
235 static void evdev_hangup(struct evdev *evdev)
237 struct evdev_client *client;
239 spin_lock(&evdev->client_lock);
240 list_for_each_entry(client, &evdev->client_list, node)
241 kill_fasync(&client->fasync, SIGIO, POLL_HUP);
242 spin_unlock(&evdev->client_lock);
244 wake_up_interruptible(&evdev->wait);
247 static int evdev_release(struct inode *inode, struct file *file)
249 struct evdev_client *client = file->private_data;
250 struct evdev *evdev = client->evdev;
252 mutex_lock(&evdev->mutex);
253 if (evdev->grab == client)
254 evdev_ungrab(evdev, client);
255 mutex_unlock(&evdev->mutex);
257 evdev_detach_client(evdev, client);
260 evdev_close_device(evdev);
261 put_device(&evdev->dev);
266 static unsigned int evdev_compute_buffer_size(struct input_dev *dev)
268 unsigned int n_events =
269 max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS,
270 EVDEV_MIN_BUFFER_SIZE);
272 return roundup_pow_of_two(n_events);
275 static int evdev_open(struct inode *inode, struct file *file)
278 struct evdev_client *client;
279 int i = iminor(inode) - EVDEV_MINOR_BASE;
280 unsigned int bufsize;
283 if (i >= EVDEV_MINORS)
286 error = mutex_lock_interruptible(&evdev_table_mutex);
289 evdev = evdev_table[i];
291 get_device(&evdev->dev);
292 mutex_unlock(&evdev_table_mutex);
297 bufsize = evdev_compute_buffer_size(evdev->handle.dev);
299 client = kzalloc(sizeof(struct evdev_client) +
300 bufsize * sizeof(struct input_event),
307 client->bufsize = bufsize;
308 spin_lock_init(&client->buffer_lock);
309 client->evdev = evdev;
310 evdev_attach_client(evdev, client);
312 error = evdev_open_device(evdev);
314 goto err_free_client;
316 file->private_data = client;
317 nonseekable_open(inode, file);
322 evdev_detach_client(evdev, client);
325 put_device(&evdev->dev);
329 static ssize_t evdev_write(struct file *file, const char __user *buffer,
330 size_t count, loff_t *ppos)
332 struct evdev_client *client = file->private_data;
333 struct evdev *evdev = client->evdev;
334 struct input_event event;
337 if (count < input_event_size())
340 retval = mutex_lock_interruptible(&evdev->mutex);
350 if (input_event_from_user(buffer + retval, &event)) {
354 retval += input_event_size();
356 input_inject_event(&evdev->handle,
357 event.type, event.code, event.value);
358 } while (retval + input_event_size() <= count);
361 mutex_unlock(&evdev->mutex);
365 static int evdev_fetch_next_event(struct evdev_client *client,
366 struct input_event *event)
370 spin_lock_irq(&client->buffer_lock);
372 have_event = client->head != client->tail;
374 *event = client->buffer[client->tail++];
375 client->tail &= client->bufsize - 1;
378 spin_unlock_irq(&client->buffer_lock);
383 static ssize_t evdev_read(struct file *file, char __user *buffer,
384 size_t count, loff_t *ppos)
386 struct evdev_client *client = file->private_data;
387 struct evdev *evdev = client->evdev;
388 struct input_event event;
391 if (count < input_event_size())
394 if (client->packet_head == client->tail && evdev->exist &&
395 (file->f_flags & O_NONBLOCK))
398 retval = wait_event_interruptible(evdev->wait,
399 client->packet_head != client->tail || !evdev->exist);
406 while (retval + input_event_size() <= count &&
407 evdev_fetch_next_event(client, &event)) {
409 if (input_event_to_user(buffer + retval, &event))
412 retval += input_event_size();
418 /* No kernel lock - fine */
419 static unsigned int evdev_poll(struct file *file, poll_table *wait)
421 struct evdev_client *client = file->private_data;
422 struct evdev *evdev = client->evdev;
425 poll_wait(file, &evdev->wait, wait);
427 mask = evdev->exist ? POLLOUT | POLLWRNORM : POLLHUP | POLLERR;
428 if (client->packet_head != client->tail)
429 mask |= POLLIN | POLLRDNORM;
436 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
437 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
440 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
441 unsigned int maxlen, void __user *p, int compat)
446 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
450 for (i = 0; i < len / sizeof(compat_long_t); i++)
451 if (copy_to_user((compat_long_t __user *) p + i,
452 (compat_long_t *) bits +
453 i + 1 - ((i % 2) << 1),
454 sizeof(compat_long_t)))
457 len = BITS_TO_LONGS(maxbit) * sizeof(long);
461 if (copy_to_user(p, bits, len))
468 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
469 unsigned int maxlen, void __user *p, int compat)
472 BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
473 BITS_TO_LONGS(maxbit) * sizeof(long);
478 return copy_to_user(p, bits, len) ? -EFAULT : len;
480 #endif /* __BIG_ENDIAN */
484 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
485 unsigned int maxlen, void __user *p, int compat)
487 int len = BITS_TO_LONGS(maxbit) * sizeof(long);
492 return copy_to_user(p, bits, len) ? -EFAULT : len;
495 #endif /* CONFIG_COMPAT */
497 static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
504 len = strlen(str) + 1;
508 return copy_to_user(p, str, len) ? -EFAULT : len;
511 #define OLD_KEY_MAX 0x1ff
512 static int handle_eviocgbit(struct input_dev *dev,
513 unsigned int type, unsigned int size,
514 void __user *p, int compat_mode)
516 static unsigned long keymax_warn_time;
522 case 0: bits = dev->evbit; len = EV_MAX; break;
523 case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
524 case EV_REL: bits = dev->relbit; len = REL_MAX; break;
525 case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
526 case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
527 case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
528 case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
529 case EV_FF: bits = dev->ffbit; len = FF_MAX; break;
530 case EV_SW: bits = dev->swbit; len = SW_MAX; break;
531 default: return -EINVAL;
535 * Work around bugs in userspace programs that like to do
536 * EVIOCGBIT(EV_KEY, KEY_MAX) and not realize that 'len'
537 * should be in bytes, not in bits.
539 if (type == EV_KEY && size == OLD_KEY_MAX) {
541 if (printk_timed_ratelimit(&keymax_warn_time, 10 * 1000))
542 pr_warning("(EVIOCGBIT): Suspicious buffer size %u, "
543 "limiting output to %zu bytes. See "
544 "http://userweb.kernel.org/~dtor/eviocgbit-bug.html\n",
546 BITS_TO_LONGS(OLD_KEY_MAX) * sizeof(long));
549 return bits_to_user(bits, len, size, p, compat_mode);
553 static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p)
555 struct input_keymap_entry ke = {
556 .len = sizeof(unsigned int),
559 int __user *ip = (int __user *)p;
563 if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
566 error = input_get_keycode(dev, &ke);
570 if (put_user(ke.keycode, ip + 1))
576 static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p)
578 struct input_keymap_entry ke;
581 if (copy_from_user(&ke, p, sizeof(ke)))
584 error = input_get_keycode(dev, &ke);
588 if (copy_to_user(p, &ke, sizeof(ke)))
594 static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p)
596 struct input_keymap_entry ke = {
597 .len = sizeof(unsigned int),
600 int __user *ip = (int __user *)p;
602 if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
605 if (get_user(ke.keycode, ip + 1))
608 return input_set_keycode(dev, &ke);
611 static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p)
613 struct input_keymap_entry ke;
615 if (copy_from_user(&ke, p, sizeof(ke)))
618 if (ke.len > sizeof(ke.scancode))
621 return input_set_keycode(dev, &ke);
624 static long evdev_do_ioctl(struct file *file, unsigned int cmd,
625 void __user *p, int compat_mode)
627 struct evdev_client *client = file->private_data;
628 struct evdev *evdev = client->evdev;
629 struct input_dev *dev = evdev->handle.dev;
630 struct input_absinfo abs;
631 struct ff_effect effect;
632 int __user *ip = (int __user *)p;
633 unsigned int i, t, u, v;
637 /* First we check for fixed-length commands */
641 return put_user(EV_VERSION, ip);
644 if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
649 if (!test_bit(EV_REP, dev->evbit))
651 if (put_user(dev->rep[REP_DELAY], ip))
653 if (put_user(dev->rep[REP_PERIOD], ip + 1))
658 if (!test_bit(EV_REP, dev->evbit))
662 if (get_user(v, ip + 1))
665 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
666 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
671 return input_ff_erase(dev, (int)(unsigned long) p, file);
674 i = test_bit(EV_FF, dev->evbit) ?
675 dev->ff->max_effects : 0;
682 return evdev_grab(evdev, client);
684 return evdev_ungrab(evdev, client);
687 return evdev_handle_get_keycode(dev, p);
690 return evdev_handle_set_keycode(dev, p);
692 case EVIOCGKEYCODE_V2:
693 return evdev_handle_get_keycode_v2(dev, p);
695 case EVIOCSKEYCODE_V2:
696 return evdev_handle_set_keycode_v2(dev, p);
699 size = _IOC_SIZE(cmd);
701 /* Now check variable-length commands */
702 #define EVIOC_MASK_SIZE(nr) ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
703 switch (EVIOC_MASK_SIZE(cmd)) {
706 return bits_to_user(dev->propbit, INPUT_PROP_MAX,
707 size, p, compat_mode);
710 return bits_to_user(dev->key, KEY_MAX, size, p, compat_mode);
713 return bits_to_user(dev->led, LED_MAX, size, p, compat_mode);
716 return bits_to_user(dev->snd, SND_MAX, size, p, compat_mode);
719 return bits_to_user(dev->sw, SW_MAX, size, p, compat_mode);
722 return str_to_user(dev->name, size, p);
725 return str_to_user(dev->phys, size, p);
728 return str_to_user(dev->uniq, size, p);
730 case EVIOC_MASK_SIZE(EVIOCSFF):
731 if (input_ff_effect_from_user(p, size, &effect))
734 error = input_ff_upload(dev, &effect, file);
736 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
742 /* Multi-number variable-length handlers */
743 if (_IOC_TYPE(cmd) != 'E')
746 if (_IOC_DIR(cmd) == _IOC_READ) {
748 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
749 return handle_eviocgbit(dev,
750 _IOC_NR(cmd) & EV_MAX, size,
753 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
758 t = _IOC_NR(cmd) & ABS_MAX;
759 abs = dev->absinfo[t];
761 if (copy_to_user(p, &abs, min_t(size_t,
762 size, sizeof(struct input_absinfo))))
769 if (_IOC_DIR(cmd) == _IOC_WRITE) {
771 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
776 t = _IOC_NR(cmd) & ABS_MAX;
778 if (copy_from_user(&abs, p, min_t(size_t,
779 size, sizeof(struct input_absinfo))))
782 if (size < sizeof(struct input_absinfo))
785 /* We can't change number of reserved MT slots */
786 if (t == ABS_MT_SLOT)
790 * Take event lock to ensure that we are not
791 * changing device parameters in the middle
794 spin_lock_irq(&dev->event_lock);
795 dev->absinfo[t] = abs;
796 spin_unlock_irq(&dev->event_lock);
805 static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
806 void __user *p, int compat_mode)
808 struct evdev_client *client = file->private_data;
809 struct evdev *evdev = client->evdev;
812 retval = mutex_lock_interruptible(&evdev->mutex);
821 retval = evdev_do_ioctl(file, cmd, p, compat_mode);
824 mutex_unlock(&evdev->mutex);
828 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
830 return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
834 static long evdev_ioctl_compat(struct file *file,
835 unsigned int cmd, unsigned long arg)
837 return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
841 static const struct file_operations evdev_fops = {
842 .owner = THIS_MODULE,
844 .write = evdev_write,
847 .release = evdev_release,
848 .unlocked_ioctl = evdev_ioctl,
850 .compat_ioctl = evdev_ioctl_compat,
852 .fasync = evdev_fasync,
853 .flush = evdev_flush,
857 static int evdev_install_chrdev(struct evdev *evdev)
860 * No need to do any locking here as calls to connect and
861 * disconnect are serialized by the input core
863 evdev_table[evdev->minor] = evdev;
867 static void evdev_remove_chrdev(struct evdev *evdev)
870 * Lock evdev table to prevent race with evdev_open()
872 mutex_lock(&evdev_table_mutex);
873 evdev_table[evdev->minor] = NULL;
874 mutex_unlock(&evdev_table_mutex);
878 * Mark device non-existent. This disables writes, ioctls and
879 * prevents new users from opening the device. Already posted
880 * blocking reads will stay, however new ones will fail.
882 static void evdev_mark_dead(struct evdev *evdev)
884 mutex_lock(&evdev->mutex);
885 evdev->exist = false;
886 mutex_unlock(&evdev->mutex);
889 static void evdev_cleanup(struct evdev *evdev)
891 struct input_handle *handle = &evdev->handle;
893 evdev_mark_dead(evdev);
895 evdev_remove_chrdev(evdev);
897 /* evdev is marked dead so no one else accesses evdev->open */
899 input_flush_device(handle, NULL);
900 input_close_device(handle);
905 * Create new evdev device. Note that input core serializes calls
906 * to connect and disconnect so we don't need to lock evdev_table here.
908 static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
909 const struct input_device_id *id)
915 for (minor = 0; minor < EVDEV_MINORS; minor++)
916 if (!evdev_table[minor])
919 if (minor == EVDEV_MINORS) {
920 pr_err("no more free evdev devices\n");
924 evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
928 INIT_LIST_HEAD(&evdev->client_list);
929 spin_lock_init(&evdev->client_lock);
930 mutex_init(&evdev->mutex);
931 init_waitqueue_head(&evdev->wait);
933 dev_set_name(&evdev->dev, "event%d", minor);
935 evdev->minor = minor;
937 evdev->handle.dev = input_get_device(dev);
938 evdev->handle.name = dev_name(&evdev->dev);
939 evdev->handle.handler = handler;
940 evdev->handle.private = evdev;
942 evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor);
943 evdev->dev.class = &input_class;
944 evdev->dev.parent = &dev->dev;
945 evdev->dev.release = evdev_free;
946 device_initialize(&evdev->dev);
948 error = input_register_handle(&evdev->handle);
952 error = evdev_install_chrdev(evdev);
954 goto err_unregister_handle;
956 error = device_add(&evdev->dev);
958 goto err_cleanup_evdev;
963 evdev_cleanup(evdev);
964 err_unregister_handle:
965 input_unregister_handle(&evdev->handle);
967 put_device(&evdev->dev);
971 static void evdev_disconnect(struct input_handle *handle)
973 struct evdev *evdev = handle->private;
975 device_del(&evdev->dev);
976 evdev_cleanup(evdev);
977 input_unregister_handle(handle);
978 put_device(&evdev->dev);
981 static const struct input_device_id evdev_ids[] = {
982 { .driver_info = 1 }, /* Matches all devices */
983 { }, /* Terminating zero entry */
986 MODULE_DEVICE_TABLE(input, evdev_ids);
988 static struct input_handler evdev_handler = {
989 .event = evdev_event,
990 .connect = evdev_connect,
991 .disconnect = evdev_disconnect,
993 .minor = EVDEV_MINOR_BASE,
995 .id_table = evdev_ids,
998 static int __init evdev_init(void)
1000 return input_register_handler(&evdev_handler);
1003 static void __exit evdev_exit(void)
1005 input_unregister_handler(&evdev_handler);
1008 module_init(evdev_init);
1009 module_exit(evdev_exit);
1011 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
1012 MODULE_DESCRIPTION("Input driver event char devices");
1013 MODULE_LICENSE("GPL");