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;
130 mutex_lock(&evdev->mutex);
133 input_flush_device(&evdev->handle, file);
135 mutex_unlock(&evdev->mutex);
139 static void evdev_free(struct device *dev)
141 struct evdev *evdev = container_of(dev, struct evdev, dev);
143 input_put_device(evdev->handle.dev);
148 * Grabs an event device (along with underlying input device).
149 * This function is called with evdev->mutex taken.
151 static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
158 error = input_grab_device(&evdev->handle);
162 rcu_assign_pointer(evdev->grab, client);
167 static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
169 if (evdev->grab != client)
172 rcu_assign_pointer(evdev->grab, NULL);
174 input_release_device(&evdev->handle);
179 static void evdev_attach_client(struct evdev *evdev,
180 struct evdev_client *client)
182 spin_lock(&evdev->client_lock);
183 list_add_tail_rcu(&client->node, &evdev->client_list);
184 spin_unlock(&evdev->client_lock);
187 static void evdev_detach_client(struct evdev *evdev,
188 struct evdev_client *client)
190 spin_lock(&evdev->client_lock);
191 list_del_rcu(&client->node);
192 spin_unlock(&evdev->client_lock);
196 static int evdev_open_device(struct evdev *evdev)
200 retval = mutex_lock_interruptible(&evdev->mutex);
206 else if (!evdev->open++) {
207 retval = input_open_device(&evdev->handle);
212 mutex_unlock(&evdev->mutex);
216 static void evdev_close_device(struct evdev *evdev)
218 mutex_lock(&evdev->mutex);
220 if (evdev->exist && !--evdev->open)
221 input_close_device(&evdev->handle);
223 mutex_unlock(&evdev->mutex);
227 * Wake up users waiting for IO so they can disconnect from
230 static void evdev_hangup(struct evdev *evdev)
232 struct evdev_client *client;
234 spin_lock(&evdev->client_lock);
235 list_for_each_entry(client, &evdev->client_list, node)
236 kill_fasync(&client->fasync, SIGIO, POLL_HUP);
237 spin_unlock(&evdev->client_lock);
239 wake_up_interruptible(&evdev->wait);
242 static int evdev_release(struct inode *inode, struct file *file)
244 struct evdev_client *client = file->private_data;
245 struct evdev *evdev = client->evdev;
247 mutex_lock(&evdev->mutex);
248 if (evdev->grab == client)
249 evdev_ungrab(evdev, client);
250 mutex_unlock(&evdev->mutex);
252 evdev_detach_client(evdev, client);
255 evdev_close_device(evdev);
256 put_device(&evdev->dev);
261 static unsigned int evdev_compute_buffer_size(struct input_dev *dev)
263 unsigned int n_events =
264 max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS,
265 EVDEV_MIN_BUFFER_SIZE);
267 return roundup_pow_of_two(n_events);
270 static int evdev_open(struct inode *inode, struct file *file)
273 struct evdev_client *client;
274 int i = iminor(inode) - EVDEV_MINOR_BASE;
275 unsigned int bufsize;
278 if (i >= EVDEV_MINORS)
281 error = mutex_lock_interruptible(&evdev_table_mutex);
284 evdev = evdev_table[i];
286 get_device(&evdev->dev);
287 mutex_unlock(&evdev_table_mutex);
292 bufsize = evdev_compute_buffer_size(evdev->handle.dev);
294 client = kzalloc(sizeof(struct evdev_client) +
295 bufsize * sizeof(struct input_event),
302 client->bufsize = bufsize;
303 spin_lock_init(&client->buffer_lock);
304 client->evdev = evdev;
305 evdev_attach_client(evdev, client);
307 error = evdev_open_device(evdev);
309 goto err_free_client;
311 file->private_data = client;
312 nonseekable_open(inode, file);
317 evdev_detach_client(evdev, client);
320 put_device(&evdev->dev);
324 static ssize_t evdev_write(struct file *file, const char __user *buffer,
325 size_t count, loff_t *ppos)
327 struct evdev_client *client = file->private_data;
328 struct evdev *evdev = client->evdev;
329 struct input_event event;
332 if (count < input_event_size())
335 retval = mutex_lock_interruptible(&evdev->mutex);
345 if (input_event_from_user(buffer + retval, &event)) {
349 retval += input_event_size();
351 input_inject_event(&evdev->handle,
352 event.type, event.code, event.value);
353 } while (retval + input_event_size() <= count);
356 mutex_unlock(&evdev->mutex);
360 static int evdev_fetch_next_event(struct evdev_client *client,
361 struct input_event *event)
365 spin_lock_irq(&client->buffer_lock);
367 have_event = client->head != client->tail;
369 *event = client->buffer[client->tail++];
370 client->tail &= client->bufsize - 1;
373 spin_unlock_irq(&client->buffer_lock);
378 static ssize_t evdev_read(struct file *file, char __user *buffer,
379 size_t count, loff_t *ppos)
381 struct evdev_client *client = file->private_data;
382 struct evdev *evdev = client->evdev;
383 struct input_event event;
386 if (count < input_event_size())
389 if (client->packet_head == client->tail && evdev->exist &&
390 (file->f_flags & O_NONBLOCK))
393 retval = wait_event_interruptible(evdev->wait,
394 client->packet_head != client->tail || !evdev->exist);
401 while (retval + input_event_size() <= count &&
402 evdev_fetch_next_event(client, &event)) {
404 if (input_event_to_user(buffer + retval, &event))
407 retval += input_event_size();
413 /* No kernel lock - fine */
414 static unsigned int evdev_poll(struct file *file, poll_table *wait)
416 struct evdev_client *client = file->private_data;
417 struct evdev *evdev = client->evdev;
420 poll_wait(file, &evdev->wait, wait);
422 mask = evdev->exist ? POLLOUT | POLLWRNORM : POLLHUP | POLLERR;
423 if (client->packet_head != client->tail)
424 mask |= POLLIN | POLLRDNORM;
431 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
432 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
435 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
436 unsigned int maxlen, void __user *p, int compat)
441 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
445 for (i = 0; i < len / sizeof(compat_long_t); i++)
446 if (copy_to_user((compat_long_t __user *) p + i,
447 (compat_long_t *) bits +
448 i + 1 - ((i % 2) << 1),
449 sizeof(compat_long_t)))
452 len = BITS_TO_LONGS(maxbit) * sizeof(long);
456 if (copy_to_user(p, bits, len))
463 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
464 unsigned int maxlen, void __user *p, int compat)
467 BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
468 BITS_TO_LONGS(maxbit) * sizeof(long);
473 return copy_to_user(p, bits, len) ? -EFAULT : len;
475 #endif /* __BIG_ENDIAN */
479 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
480 unsigned int maxlen, void __user *p, int compat)
482 int len = BITS_TO_LONGS(maxbit) * sizeof(long);
487 return copy_to_user(p, bits, len) ? -EFAULT : len;
490 #endif /* CONFIG_COMPAT */
492 static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
499 len = strlen(str) + 1;
503 return copy_to_user(p, str, len) ? -EFAULT : len;
506 #define OLD_KEY_MAX 0x1ff
507 static int handle_eviocgbit(struct input_dev *dev,
508 unsigned int type, unsigned int size,
509 void __user *p, int compat_mode)
511 static unsigned long keymax_warn_time;
517 case 0: bits = dev->evbit; len = EV_MAX; break;
518 case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
519 case EV_REL: bits = dev->relbit; len = REL_MAX; break;
520 case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
521 case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
522 case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
523 case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
524 case EV_FF: bits = dev->ffbit; len = FF_MAX; break;
525 case EV_SW: bits = dev->swbit; len = SW_MAX; break;
526 default: return -EINVAL;
530 * Work around bugs in userspace programs that like to do
531 * EVIOCGBIT(EV_KEY, KEY_MAX) and not realize that 'len'
532 * should be in bytes, not in bits.
534 if (type == EV_KEY && size == OLD_KEY_MAX) {
536 if (printk_timed_ratelimit(&keymax_warn_time, 10 * 1000))
537 pr_warning("(EVIOCGBIT): Suspicious buffer size %u, "
538 "limiting output to %zu bytes. See "
539 "http://userweb.kernel.org/~dtor/eviocgbit-bug.html\n",
541 BITS_TO_LONGS(OLD_KEY_MAX) * sizeof(long));
544 return bits_to_user(bits, len, size, p, compat_mode);
548 static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p)
550 struct input_keymap_entry ke = {
551 .len = sizeof(unsigned int),
554 int __user *ip = (int __user *)p;
558 if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
561 error = input_get_keycode(dev, &ke);
565 if (put_user(ke.keycode, ip + 1))
571 static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p)
573 struct input_keymap_entry ke;
576 if (copy_from_user(&ke, p, sizeof(ke)))
579 error = input_get_keycode(dev, &ke);
583 if (copy_to_user(p, &ke, sizeof(ke)))
589 static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p)
591 struct input_keymap_entry ke = {
592 .len = sizeof(unsigned int),
595 int __user *ip = (int __user *)p;
597 if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
600 if (get_user(ke.keycode, ip + 1))
603 return input_set_keycode(dev, &ke);
606 static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p)
608 struct input_keymap_entry ke;
610 if (copy_from_user(&ke, p, sizeof(ke)))
613 if (ke.len > sizeof(ke.scancode))
616 return input_set_keycode(dev, &ke);
619 static long evdev_do_ioctl(struct file *file, unsigned int cmd,
620 void __user *p, int compat_mode)
622 struct evdev_client *client = file->private_data;
623 struct evdev *evdev = client->evdev;
624 struct input_dev *dev = evdev->handle.dev;
625 struct input_absinfo abs;
626 struct ff_effect effect;
627 int __user *ip = (int __user *)p;
628 unsigned int i, t, u, v;
632 /* First we check for fixed-length commands */
636 return put_user(EV_VERSION, ip);
639 if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
644 if (!test_bit(EV_REP, dev->evbit))
646 if (put_user(dev->rep[REP_DELAY], ip))
648 if (put_user(dev->rep[REP_PERIOD], ip + 1))
653 if (!test_bit(EV_REP, dev->evbit))
657 if (get_user(v, ip + 1))
660 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
661 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
666 return input_ff_erase(dev, (int)(unsigned long) p, file);
669 i = test_bit(EV_FF, dev->evbit) ?
670 dev->ff->max_effects : 0;
677 return evdev_grab(evdev, client);
679 return evdev_ungrab(evdev, client);
682 return evdev_handle_get_keycode(dev, p);
685 return evdev_handle_set_keycode(dev, p);
687 case EVIOCGKEYCODE_V2:
688 return evdev_handle_get_keycode_v2(dev, p);
690 case EVIOCSKEYCODE_V2:
691 return evdev_handle_set_keycode_v2(dev, p);
694 size = _IOC_SIZE(cmd);
696 /* Now check variable-length commands */
697 #define EVIOC_MASK_SIZE(nr) ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
698 switch (EVIOC_MASK_SIZE(cmd)) {
701 return bits_to_user(dev->propbit, INPUT_PROP_MAX,
702 size, p, compat_mode);
705 return bits_to_user(dev->key, KEY_MAX, size, p, compat_mode);
708 return bits_to_user(dev->led, LED_MAX, size, p, compat_mode);
711 return bits_to_user(dev->snd, SND_MAX, size, p, compat_mode);
714 return bits_to_user(dev->sw, SW_MAX, size, p, compat_mode);
717 return str_to_user(dev->name, size, p);
720 return str_to_user(dev->phys, size, p);
723 return str_to_user(dev->uniq, size, p);
725 case EVIOC_MASK_SIZE(EVIOCSFF):
726 if (input_ff_effect_from_user(p, size, &effect))
729 error = input_ff_upload(dev, &effect, file);
731 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
737 /* Multi-number variable-length handlers */
738 if (_IOC_TYPE(cmd) != 'E')
741 if (_IOC_DIR(cmd) == _IOC_READ) {
743 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
744 return handle_eviocgbit(dev,
745 _IOC_NR(cmd) & EV_MAX, size,
748 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
753 t = _IOC_NR(cmd) & ABS_MAX;
754 abs = dev->absinfo[t];
756 if (copy_to_user(p, &abs, min_t(size_t,
757 size, sizeof(struct input_absinfo))))
764 if (_IOC_DIR(cmd) == _IOC_WRITE) {
766 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
771 t = _IOC_NR(cmd) & ABS_MAX;
773 if (copy_from_user(&abs, p, min_t(size_t,
774 size, sizeof(struct input_absinfo))))
777 if (size < sizeof(struct input_absinfo))
780 /* We can't change number of reserved MT slots */
781 if (t == ABS_MT_SLOT)
785 * Take event lock to ensure that we are not
786 * changing device parameters in the middle
789 spin_lock_irq(&dev->event_lock);
790 dev->absinfo[t] = abs;
791 spin_unlock_irq(&dev->event_lock);
800 static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
801 void __user *p, int compat_mode)
803 struct evdev_client *client = file->private_data;
804 struct evdev *evdev = client->evdev;
807 retval = mutex_lock_interruptible(&evdev->mutex);
816 retval = evdev_do_ioctl(file, cmd, p, compat_mode);
819 mutex_unlock(&evdev->mutex);
823 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
825 return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
829 static long evdev_ioctl_compat(struct file *file,
830 unsigned int cmd, unsigned long arg)
832 return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
836 static const struct file_operations evdev_fops = {
837 .owner = THIS_MODULE,
839 .write = evdev_write,
842 .release = evdev_release,
843 .unlocked_ioctl = evdev_ioctl,
845 .compat_ioctl = evdev_ioctl_compat,
847 .fasync = evdev_fasync,
848 .flush = evdev_flush,
852 static int evdev_install_chrdev(struct evdev *evdev)
855 * No need to do any locking here as calls to connect and
856 * disconnect are serialized by the input core
858 evdev_table[evdev->minor] = evdev;
862 static void evdev_remove_chrdev(struct evdev *evdev)
865 * Lock evdev table to prevent race with evdev_open()
867 mutex_lock(&evdev_table_mutex);
868 evdev_table[evdev->minor] = NULL;
869 mutex_unlock(&evdev_table_mutex);
873 * Mark device non-existent. This disables writes, ioctls and
874 * prevents new users from opening the device. Already posted
875 * blocking reads will stay, however new ones will fail.
877 static void evdev_mark_dead(struct evdev *evdev)
879 mutex_lock(&evdev->mutex);
880 evdev->exist = false;
881 mutex_unlock(&evdev->mutex);
884 static void evdev_cleanup(struct evdev *evdev)
886 struct input_handle *handle = &evdev->handle;
888 evdev_mark_dead(evdev);
890 evdev_remove_chrdev(evdev);
892 /* evdev is marked dead so no one else accesses evdev->open */
894 input_flush_device(handle, NULL);
895 input_close_device(handle);
900 * Create new evdev device. Note that input core serializes calls
901 * to connect and disconnect so we don't need to lock evdev_table here.
903 static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
904 const struct input_device_id *id)
910 for (minor = 0; minor < EVDEV_MINORS; minor++)
911 if (!evdev_table[minor])
914 if (minor == EVDEV_MINORS) {
915 pr_err("no more free evdev devices\n");
919 evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
923 INIT_LIST_HEAD(&evdev->client_list);
924 spin_lock_init(&evdev->client_lock);
925 mutex_init(&evdev->mutex);
926 init_waitqueue_head(&evdev->wait);
928 dev_set_name(&evdev->dev, "event%d", minor);
930 evdev->minor = minor;
932 evdev->handle.dev = input_get_device(dev);
933 evdev->handle.name = dev_name(&evdev->dev);
934 evdev->handle.handler = handler;
935 evdev->handle.private = evdev;
937 evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor);
938 evdev->dev.class = &input_class;
939 evdev->dev.parent = &dev->dev;
940 evdev->dev.release = evdev_free;
941 device_initialize(&evdev->dev);
943 error = input_register_handle(&evdev->handle);
947 error = evdev_install_chrdev(evdev);
949 goto err_unregister_handle;
951 error = device_add(&evdev->dev);
953 goto err_cleanup_evdev;
958 evdev_cleanup(evdev);
959 err_unregister_handle:
960 input_unregister_handle(&evdev->handle);
962 put_device(&evdev->dev);
966 static void evdev_disconnect(struct input_handle *handle)
968 struct evdev *evdev = handle->private;
970 device_del(&evdev->dev);
971 evdev_cleanup(evdev);
972 input_unregister_handle(handle);
973 put_device(&evdev->dev);
976 static const struct input_device_id evdev_ids[] = {
977 { .driver_info = 1 }, /* Matches all devices */
978 { }, /* Terminating zero entry */
981 MODULE_DEVICE_TABLE(input, evdev_ids);
983 static struct input_handler evdev_handler = {
984 .event = evdev_event,
985 .connect = evdev_connect,
986 .disconnect = evdev_disconnect,
988 .minor = EVDEV_MINOR_BASE,
990 .id_table = evdev_ids,
993 static int __init evdev_init(void)
995 return input_register_handler(&evdev_handler);
998 static void __exit evdev_exit(void)
1000 input_unregister_handler(&evdev_handler);
1003 module_init(evdev_init);
1004 module_exit(evdev_exit);
1006 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
1007 MODULE_DESCRIPTION("Input driver event char devices");
1008 MODULE_LICENSE("GPL");