Root/drivers/input/evdev.c

1/*
2 * Event char devices, giving access to raw input device events.
3 *
4 * Copyright (c) 1999-2002 Vojtech Pavlik
5 *
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.
9 */
10
11#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12
13#define EVDEV_MINOR_BASE 64
14#define EVDEV_MINORS 32
15#define EVDEV_MIN_BUFFER_SIZE 64U
16#define EVDEV_BUF_PACKETS 8
17
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/mt.h>
24#include <linux/major.h>
25#include <linux/device.h>
26#include <linux/cdev.h>
27#include "input-compat.h"
28
29struct evdev {
30    int open;
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 */
36    struct mutex mutex;
37    struct device dev;
38    struct cdev cdev;
39    bool exist;
40};
41
42struct evdev_client {
43    unsigned int head;
44    unsigned int tail;
45    unsigned int packet_head; /* [future] position of the first element of next packet */
46    spinlock_t buffer_lock; /* protects access to buffer, head and tail */
47    struct fasync_struct *fasync;
48    struct evdev *evdev;
49    struct list_head node;
50    int clkid;
51    unsigned int bufsize;
52    struct input_event buffer[];
53};
54
55static void __pass_event(struct evdev_client *client,
56             const struct input_event *event)
57{
58    client->buffer[client->head++] = *event;
59    client->head &= client->bufsize - 1;
60
61    if (unlikely(client->head == client->tail)) {
62        /*
63         * This effectively "drops" all unconsumed events, leaving
64         * EV_SYN/SYN_DROPPED plus the newest event in the queue.
65         */
66        client->tail = (client->head - 2) & (client->bufsize - 1);
67
68        client->buffer[client->tail].time = event->time;
69        client->buffer[client->tail].type = EV_SYN;
70        client->buffer[client->tail].code = SYN_DROPPED;
71        client->buffer[client->tail].value = 0;
72
73        client->packet_head = client->tail;
74    }
75
76    if (event->type == EV_SYN && event->code == SYN_REPORT) {
77        client->packet_head = client->head;
78        kill_fasync(&client->fasync, SIGIO, POLL_IN);
79    }
80}
81
82static void evdev_pass_values(struct evdev_client *client,
83            const struct input_value *vals, unsigned int count,
84            ktime_t mono, ktime_t real)
85{
86    struct evdev *evdev = client->evdev;
87    const struct input_value *v;
88    struct input_event event;
89    bool wakeup = false;
90
91    event.time = ktime_to_timeval(client->clkid == CLOCK_MONOTONIC ?
92                      mono : real);
93
94    /* Interrupts are disabled, just acquire the lock. */
95    spin_lock(&client->buffer_lock);
96
97    for (v = vals; v != vals + count; v++) {
98        event.type = v->type;
99        event.code = v->code;
100        event.value = v->value;
101        __pass_event(client, &event);
102        if (v->type == EV_SYN && v->code == SYN_REPORT)
103            wakeup = true;
104    }
105
106    spin_unlock(&client->buffer_lock);
107
108    if (wakeup)
109        wake_up_interruptible(&evdev->wait);
110}
111
112/*
113 * Pass incoming events to all connected clients.
114 */
115static void evdev_events(struct input_handle *handle,
116             const struct input_value *vals, unsigned int count)
117{
118    struct evdev *evdev = handle->private;
119    struct evdev_client *client;
120    ktime_t time_mono, time_real;
121
122    time_mono = ktime_get();
123    time_real = ktime_sub(time_mono, ktime_get_monotonic_offset());
124
125    rcu_read_lock();
126
127    client = rcu_dereference(evdev->grab);
128
129    if (client)
130        evdev_pass_values(client, vals, count, time_mono, time_real);
131    else
132        list_for_each_entry_rcu(client, &evdev->client_list, node)
133            evdev_pass_values(client, vals, count,
134                      time_mono, time_real);
135
136    rcu_read_unlock();
137}
138
139/*
140 * Pass incoming event to all connected clients.
141 */
142static void evdev_event(struct input_handle *handle,
143            unsigned int type, unsigned int code, int value)
144{
145    struct input_value vals[] = { { type, code, value } };
146
147    evdev_events(handle, vals, 1);
148}
149
150static int evdev_fasync(int fd, struct file *file, int on)
151{
152    struct evdev_client *client = file->private_data;
153
154    return fasync_helper(fd, file, on, &client->fasync);
155}
156
157static int evdev_flush(struct file *file, fl_owner_t id)
158{
159    struct evdev_client *client = file->private_data;
160    struct evdev *evdev = client->evdev;
161    int retval;
162
163    retval = mutex_lock_interruptible(&evdev->mutex);
164    if (retval)
165        return retval;
166
167    if (!evdev->exist)
168        retval = -ENODEV;
169    else
170        retval = input_flush_device(&evdev->handle, file);
171
172    mutex_unlock(&evdev->mutex);
173    return retval;
174}
175
176static void evdev_free(struct device *dev)
177{
178    struct evdev *evdev = container_of(dev, struct evdev, dev);
179
180    input_put_device(evdev->handle.dev);
181    kfree(evdev);
182}
183
184/*
185 * Grabs an event device (along with underlying input device).
186 * This function is called with evdev->mutex taken.
187 */
188static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
189{
190    int error;
191
192    if (evdev->grab)
193        return -EBUSY;
194
195    error = input_grab_device(&evdev->handle);
196    if (error)
197        return error;
198
199    rcu_assign_pointer(evdev->grab, client);
200
201    return 0;
202}
203
204static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
205{
206    struct evdev_client *grab = rcu_dereference_protected(evdev->grab,
207                    lockdep_is_held(&evdev->mutex));
208
209    if (grab != client)
210        return -EINVAL;
211
212    rcu_assign_pointer(evdev->grab, NULL);
213    synchronize_rcu();
214    input_release_device(&evdev->handle);
215
216    return 0;
217}
218
219static void evdev_attach_client(struct evdev *evdev,
220                struct evdev_client *client)
221{
222    spin_lock(&evdev->client_lock);
223    list_add_tail_rcu(&client->node, &evdev->client_list);
224    spin_unlock(&evdev->client_lock);
225}
226
227static void evdev_detach_client(struct evdev *evdev,
228                struct evdev_client *client)
229{
230    spin_lock(&evdev->client_lock);
231    list_del_rcu(&client->node);
232    spin_unlock(&evdev->client_lock);
233    synchronize_rcu();
234}
235
236static int evdev_open_device(struct evdev *evdev)
237{
238    int retval;
239
240    retval = mutex_lock_interruptible(&evdev->mutex);
241    if (retval)
242        return retval;
243
244    if (!evdev->exist)
245        retval = -ENODEV;
246    else if (!evdev->open++) {
247        retval = input_open_device(&evdev->handle);
248        if (retval)
249            evdev->open--;
250    }
251
252    mutex_unlock(&evdev->mutex);
253    return retval;
254}
255
256static void evdev_close_device(struct evdev *evdev)
257{
258    mutex_lock(&evdev->mutex);
259
260    if (evdev->exist && !--evdev->open)
261        input_close_device(&evdev->handle);
262
263    mutex_unlock(&evdev->mutex);
264}
265
266/*
267 * Wake up users waiting for IO so they can disconnect from
268 * dead device.
269 */
270static void evdev_hangup(struct evdev *evdev)
271{
272    struct evdev_client *client;
273
274    spin_lock(&evdev->client_lock);
275    list_for_each_entry(client, &evdev->client_list, node)
276        kill_fasync(&client->fasync, SIGIO, POLL_HUP);
277    spin_unlock(&evdev->client_lock);
278
279    wake_up_interruptible(&evdev->wait);
280}
281
282static int evdev_release(struct inode *inode, struct file *file)
283{
284    struct evdev_client *client = file->private_data;
285    struct evdev *evdev = client->evdev;
286
287    mutex_lock(&evdev->mutex);
288    evdev_ungrab(evdev, client);
289    mutex_unlock(&evdev->mutex);
290
291    evdev_detach_client(evdev, client);
292    kfree(client);
293
294    evdev_close_device(evdev);
295
296    return 0;
297}
298
299static unsigned int evdev_compute_buffer_size(struct input_dev *dev)
300{
301    unsigned int n_events =
302        max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS,
303            EVDEV_MIN_BUFFER_SIZE);
304
305    return roundup_pow_of_two(n_events);
306}
307
308static int evdev_open(struct inode *inode, struct file *file)
309{
310    struct evdev *evdev = container_of(inode->i_cdev, struct evdev, cdev);
311    unsigned int bufsize = evdev_compute_buffer_size(evdev->handle.dev);
312    struct evdev_client *client;
313    int error;
314
315    client = kzalloc(sizeof(struct evdev_client) +
316                bufsize * sizeof(struct input_event),
317             GFP_KERNEL);
318    if (!client)
319        return -ENOMEM;
320
321    client->bufsize = bufsize;
322    spin_lock_init(&client->buffer_lock);
323    client->evdev = evdev;
324    evdev_attach_client(evdev, client);
325
326    error = evdev_open_device(evdev);
327    if (error)
328        goto err_free_client;
329
330    file->private_data = client;
331    nonseekable_open(inode, file);
332
333    return 0;
334
335 err_free_client:
336    evdev_detach_client(evdev, client);
337    kfree(client);
338    return error;
339}
340
341static ssize_t evdev_write(struct file *file, const char __user *buffer,
342               size_t count, loff_t *ppos)
343{
344    struct evdev_client *client = file->private_data;
345    struct evdev *evdev = client->evdev;
346    struct input_event event;
347    int retval = 0;
348
349    if (count != 0 && count < input_event_size())
350        return -EINVAL;
351
352    retval = mutex_lock_interruptible(&evdev->mutex);
353    if (retval)
354        return retval;
355
356    if (!evdev->exist) {
357        retval = -ENODEV;
358        goto out;
359    }
360
361    while (retval + input_event_size() <= count) {
362
363        if (input_event_from_user(buffer + retval, &event)) {
364            retval = -EFAULT;
365            goto out;
366        }
367        retval += input_event_size();
368
369        input_inject_event(&evdev->handle,
370                   event.type, event.code, event.value);
371    }
372
373 out:
374    mutex_unlock(&evdev->mutex);
375    return retval;
376}
377
378static int evdev_fetch_next_event(struct evdev_client *client,
379                  struct input_event *event)
380{
381    int have_event;
382
383    spin_lock_irq(&client->buffer_lock);
384
385    have_event = client->packet_head != client->tail;
386    if (have_event) {
387        *event = client->buffer[client->tail++];
388        client->tail &= client->bufsize - 1;
389    }
390
391    spin_unlock_irq(&client->buffer_lock);
392
393    return have_event;
394}
395
396static ssize_t evdev_read(struct file *file, char __user *buffer,
397              size_t count, loff_t *ppos)
398{
399    struct evdev_client *client = file->private_data;
400    struct evdev *evdev = client->evdev;
401    struct input_event event;
402    size_t read = 0;
403    int error;
404
405    if (count != 0 && count < input_event_size())
406        return -EINVAL;
407
408    for (;;) {
409        if (!evdev->exist)
410            return -ENODEV;
411
412        if (client->packet_head == client->tail &&
413            (file->f_flags & O_NONBLOCK))
414            return -EAGAIN;
415
416        /*
417         * count == 0 is special - no IO is done but we check
418         * for error conditions (see above).
419         */
420        if (count == 0)
421            break;
422
423        while (read + input_event_size() <= count &&
424               evdev_fetch_next_event(client, &event)) {
425
426            if (input_event_to_user(buffer + read, &event))
427                return -EFAULT;
428
429            read += input_event_size();
430        }
431
432        if (read)
433            break;
434
435        if (!(file->f_flags & O_NONBLOCK)) {
436            error = wait_event_interruptible(evdev->wait,
437                    client->packet_head != client->tail ||
438                    !evdev->exist);
439            if (error)
440                return error;
441        }
442    }
443
444    return read;
445}
446
447/* No kernel lock - fine */
448static unsigned int evdev_poll(struct file *file, poll_table *wait)
449{
450    struct evdev_client *client = file->private_data;
451    struct evdev *evdev = client->evdev;
452    unsigned int mask;
453
454    poll_wait(file, &evdev->wait, wait);
455
456    mask = evdev->exist ? POLLOUT | POLLWRNORM : POLLHUP | POLLERR;
457    if (client->packet_head != client->tail)
458        mask |= POLLIN | POLLRDNORM;
459
460    return mask;
461}
462
463#ifdef CONFIG_COMPAT
464
465#define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
466#define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
467
468#ifdef __BIG_ENDIAN
469static int bits_to_user(unsigned long *bits, unsigned int maxbit,
470            unsigned int maxlen, void __user *p, int compat)
471{
472    int len, i;
473
474    if (compat) {
475        len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
476        if (len > maxlen)
477            len = maxlen;
478
479        for (i = 0; i < len / sizeof(compat_long_t); i++)
480            if (copy_to_user((compat_long_t __user *) p + i,
481                     (compat_long_t *) bits +
482                        i + 1 - ((i % 2) << 1),
483                     sizeof(compat_long_t)))
484                return -EFAULT;
485    } else {
486        len = BITS_TO_LONGS(maxbit) * sizeof(long);
487        if (len > maxlen)
488            len = maxlen;
489
490        if (copy_to_user(p, bits, len))
491            return -EFAULT;
492    }
493
494    return len;
495}
496#else
497static int bits_to_user(unsigned long *bits, unsigned int maxbit,
498            unsigned int maxlen, void __user *p, int compat)
499{
500    int len = compat ?
501            BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
502            BITS_TO_LONGS(maxbit) * sizeof(long);
503
504    if (len > maxlen)
505        len = maxlen;
506
507    return copy_to_user(p, bits, len) ? -EFAULT : len;
508}
509#endif /* __BIG_ENDIAN */
510
511#else
512
513static int bits_to_user(unsigned long *bits, unsigned int maxbit,
514            unsigned int maxlen, void __user *p, int compat)
515{
516    int len = BITS_TO_LONGS(maxbit) * sizeof(long);
517
518    if (len > maxlen)
519        len = maxlen;
520
521    return copy_to_user(p, bits, len) ? -EFAULT : len;
522}
523
524#endif /* CONFIG_COMPAT */
525
526static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
527{
528    int len;
529
530    if (!str)
531        return -ENOENT;
532
533    len = strlen(str) + 1;
534    if (len > maxlen)
535        len = maxlen;
536
537    return copy_to_user(p, str, len) ? -EFAULT : len;
538}
539
540#define OLD_KEY_MAX 0x1ff
541static int handle_eviocgbit(struct input_dev *dev,
542                unsigned int type, unsigned int size,
543                void __user *p, int compat_mode)
544{
545    static unsigned long keymax_warn_time;
546    unsigned long *bits;
547    int len;
548
549    switch (type) {
550
551    case 0: bits = dev->evbit; len = EV_MAX; break;
552    case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
553    case EV_REL: bits = dev->relbit; len = REL_MAX; break;
554    case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
555    case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
556    case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
557    case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
558    case EV_FF: bits = dev->ffbit; len = FF_MAX; break;
559    case EV_SW: bits = dev->swbit; len = SW_MAX; break;
560    default: return -EINVAL;
561    }
562
563    /*
564     * Work around bugs in userspace programs that like to do
565     * EVIOCGBIT(EV_KEY, KEY_MAX) and not realize that 'len'
566     * should be in bytes, not in bits.
567     */
568    if (type == EV_KEY && size == OLD_KEY_MAX) {
569        len = OLD_KEY_MAX;
570        if (printk_timed_ratelimit(&keymax_warn_time, 10 * 1000))
571            pr_warning("(EVIOCGBIT): Suspicious buffer size %u, "
572                   "limiting output to %zu bytes. See "
573                   "http://userweb.kernel.org/~dtor/eviocgbit-bug.html\n",
574                   OLD_KEY_MAX,
575                   BITS_TO_LONGS(OLD_KEY_MAX) * sizeof(long));
576    }
577
578    return bits_to_user(bits, len, size, p, compat_mode);
579}
580#undef OLD_KEY_MAX
581
582static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p)
583{
584    struct input_keymap_entry ke = {
585        .len = sizeof(unsigned int),
586        .flags = 0,
587    };
588    int __user *ip = (int __user *)p;
589    int error;
590
591    /* legacy case */
592    if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
593        return -EFAULT;
594
595    error = input_get_keycode(dev, &ke);
596    if (error)
597        return error;
598
599    if (put_user(ke.keycode, ip + 1))
600        return -EFAULT;
601
602    return 0;
603}
604
605static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p)
606{
607    struct input_keymap_entry ke;
608    int error;
609
610    if (copy_from_user(&ke, p, sizeof(ke)))
611        return -EFAULT;
612
613    error = input_get_keycode(dev, &ke);
614    if (error)
615        return error;
616
617    if (copy_to_user(p, &ke, sizeof(ke)))
618        return -EFAULT;
619
620    return 0;
621}
622
623static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p)
624{
625    struct input_keymap_entry ke = {
626        .len = sizeof(unsigned int),
627        .flags = 0,
628    };
629    int __user *ip = (int __user *)p;
630
631    if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
632        return -EFAULT;
633
634    if (get_user(ke.keycode, ip + 1))
635        return -EFAULT;
636
637    return input_set_keycode(dev, &ke);
638}
639
640static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p)
641{
642    struct input_keymap_entry ke;
643
644    if (copy_from_user(&ke, p, sizeof(ke)))
645        return -EFAULT;
646
647    if (ke.len > sizeof(ke.scancode))
648        return -EINVAL;
649
650    return input_set_keycode(dev, &ke);
651}
652
653static int evdev_handle_mt_request(struct input_dev *dev,
654                   unsigned int size,
655                   int __user *ip)
656{
657    const struct input_mt *mt = dev->mt;
658    unsigned int code;
659    int max_slots;
660    int i;
661
662    if (get_user(code, &ip[0]))
663        return -EFAULT;
664    if (!mt || !input_is_mt_value(code))
665        return -EINVAL;
666
667    max_slots = (size - sizeof(__u32)) / sizeof(__s32);
668    for (i = 0; i < mt->num_slots && i < max_slots; i++) {
669        int value = input_mt_get_value(&mt->slots[i], code);
670        if (put_user(value, &ip[1 + i]))
671            return -EFAULT;
672    }
673
674    return 0;
675}
676
677static long evdev_do_ioctl(struct file *file, unsigned int cmd,
678               void __user *p, int compat_mode)
679{
680    struct evdev_client *client = file->private_data;
681    struct evdev *evdev = client->evdev;
682    struct input_dev *dev = evdev->handle.dev;
683    struct input_absinfo abs;
684    struct ff_effect effect;
685    int __user *ip = (int __user *)p;
686    unsigned int i, t, u, v;
687    unsigned int size;
688    int error;
689
690    /* First we check for fixed-length commands */
691    switch (cmd) {
692
693    case EVIOCGVERSION:
694        return put_user(EV_VERSION, ip);
695
696    case EVIOCGID:
697        if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
698            return -EFAULT;
699        return 0;
700
701    case EVIOCGREP:
702        if (!test_bit(EV_REP, dev->evbit))
703            return -ENOSYS;
704        if (put_user(dev->rep[REP_DELAY], ip))
705            return -EFAULT;
706        if (put_user(dev->rep[REP_PERIOD], ip + 1))
707            return -EFAULT;
708        return 0;
709
710    case EVIOCSREP:
711        if (!test_bit(EV_REP, dev->evbit))
712            return -ENOSYS;
713        if (get_user(u, ip))
714            return -EFAULT;
715        if (get_user(v, ip + 1))
716            return -EFAULT;
717
718        input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
719        input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
720
721        return 0;
722
723    case EVIOCRMFF:
724        return input_ff_erase(dev, (int)(unsigned long) p, file);
725
726    case EVIOCGEFFECTS:
727        i = test_bit(EV_FF, dev->evbit) ?
728                dev->ff->max_effects : 0;
729        if (put_user(i, ip))
730            return -EFAULT;
731        return 0;
732
733    case EVIOCGRAB:
734        if (p)
735            return evdev_grab(evdev, client);
736        else
737            return evdev_ungrab(evdev, client);
738
739    case EVIOCSCLOCKID:
740        if (copy_from_user(&i, p, sizeof(unsigned int)))
741            return -EFAULT;
742        if (i != CLOCK_MONOTONIC && i != CLOCK_REALTIME)
743            return -EINVAL;
744        client->clkid = i;
745        return 0;
746
747    case EVIOCGKEYCODE:
748        return evdev_handle_get_keycode(dev, p);
749
750    case EVIOCSKEYCODE:
751        return evdev_handle_set_keycode(dev, p);
752
753    case EVIOCGKEYCODE_V2:
754        return evdev_handle_get_keycode_v2(dev, p);
755
756    case EVIOCSKEYCODE_V2:
757        return evdev_handle_set_keycode_v2(dev, p);
758    }
759
760    size = _IOC_SIZE(cmd);
761
762    /* Now check variable-length commands */
763#define EVIOC_MASK_SIZE(nr) ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
764    switch (EVIOC_MASK_SIZE(cmd)) {
765
766    case EVIOCGPROP(0):
767        return bits_to_user(dev->propbit, INPUT_PROP_MAX,
768                    size, p, compat_mode);
769
770    case EVIOCGMTSLOTS(0):
771        return evdev_handle_mt_request(dev, size, ip);
772
773    case EVIOCGKEY(0):
774        return bits_to_user(dev->key, KEY_MAX, size, p, compat_mode);
775
776    case EVIOCGLED(0):
777        return bits_to_user(dev->led, LED_MAX, size, p, compat_mode);
778
779    case EVIOCGSND(0):
780        return bits_to_user(dev->snd, SND_MAX, size, p, compat_mode);
781
782    case EVIOCGSW(0):
783        return bits_to_user(dev->sw, SW_MAX, size, p, compat_mode);
784
785    case EVIOCGNAME(0):
786        return str_to_user(dev->name, size, p);
787
788    case EVIOCGPHYS(0):
789        return str_to_user(dev->phys, size, p);
790
791    case EVIOCGUNIQ(0):
792        return str_to_user(dev->uniq, size, p);
793
794    case EVIOC_MASK_SIZE(EVIOCSFF):
795        if (input_ff_effect_from_user(p, size, &effect))
796            return -EFAULT;
797
798        error = input_ff_upload(dev, &effect, file);
799
800        if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
801            return -EFAULT;
802
803        return error;
804    }
805
806    /* Multi-number variable-length handlers */
807    if (_IOC_TYPE(cmd) != 'E')
808        return -EINVAL;
809
810    if (_IOC_DIR(cmd) == _IOC_READ) {
811
812        if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
813            return handle_eviocgbit(dev,
814                        _IOC_NR(cmd) & EV_MAX, size,
815                        p, compat_mode);
816
817        if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
818
819            if (!dev->absinfo)
820                return -EINVAL;
821
822            t = _IOC_NR(cmd) & ABS_MAX;
823            abs = dev->absinfo[t];
824
825            if (copy_to_user(p, &abs, min_t(size_t,
826                    size, sizeof(struct input_absinfo))))
827                return -EFAULT;
828
829            return 0;
830        }
831    }
832
833    if (_IOC_DIR(cmd) == _IOC_WRITE) {
834
835        if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
836
837            if (!dev->absinfo)
838                return -EINVAL;
839
840            t = _IOC_NR(cmd) & ABS_MAX;
841
842            if (copy_from_user(&abs, p, min_t(size_t,
843                    size, sizeof(struct input_absinfo))))
844                return -EFAULT;
845
846            if (size < sizeof(struct input_absinfo))
847                abs.resolution = 0;
848
849            /* We can't change number of reserved MT slots */
850            if (t == ABS_MT_SLOT)
851                return -EINVAL;
852
853            /*
854             * Take event lock to ensure that we are not
855             * changing device parameters in the middle
856             * of event.
857             */
858            spin_lock_irq(&dev->event_lock);
859            dev->absinfo[t] = abs;
860            spin_unlock_irq(&dev->event_lock);
861
862            return 0;
863        }
864    }
865
866    return -EINVAL;
867}
868
869static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
870                void __user *p, int compat_mode)
871{
872    struct evdev_client *client = file->private_data;
873    struct evdev *evdev = client->evdev;
874    int retval;
875
876    retval = mutex_lock_interruptible(&evdev->mutex);
877    if (retval)
878        return retval;
879
880    if (!evdev->exist) {
881        retval = -ENODEV;
882        goto out;
883    }
884
885    retval = evdev_do_ioctl(file, cmd, p, compat_mode);
886
887 out:
888    mutex_unlock(&evdev->mutex);
889    return retval;
890}
891
892static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
893{
894    return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
895}
896
897#ifdef CONFIG_COMPAT
898static long evdev_ioctl_compat(struct file *file,
899                unsigned int cmd, unsigned long arg)
900{
901    return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
902}
903#endif
904
905static const struct file_operations evdev_fops = {
906    .owner = THIS_MODULE,
907    .read = evdev_read,
908    .write = evdev_write,
909    .poll = evdev_poll,
910    .open = evdev_open,
911    .release = evdev_release,
912    .unlocked_ioctl = evdev_ioctl,
913#ifdef CONFIG_COMPAT
914    .compat_ioctl = evdev_ioctl_compat,
915#endif
916    .fasync = evdev_fasync,
917    .flush = evdev_flush,
918    .llseek = no_llseek,
919};
920
921/*
922 * Mark device non-existent. This disables writes, ioctls and
923 * prevents new users from opening the device. Already posted
924 * blocking reads will stay, however new ones will fail.
925 */
926static void evdev_mark_dead(struct evdev *evdev)
927{
928    mutex_lock(&evdev->mutex);
929    evdev->exist = false;
930    mutex_unlock(&evdev->mutex);
931}
932
933static void evdev_cleanup(struct evdev *evdev)
934{
935    struct input_handle *handle = &evdev->handle;
936
937    evdev_mark_dead(evdev);
938    evdev_hangup(evdev);
939
940    cdev_del(&evdev->cdev);
941
942    /* evdev is marked dead so no one else accesses evdev->open */
943    if (evdev->open) {
944        input_flush_device(handle, NULL);
945        input_close_device(handle);
946    }
947}
948
949/*
950 * Create new evdev device. Note that input core serializes calls
951 * to connect and disconnect.
952 */
953static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
954             const struct input_device_id *id)
955{
956    struct evdev *evdev;
957    int minor;
958    int dev_no;
959    int error;
960
961    minor = input_get_new_minor(EVDEV_MINOR_BASE, EVDEV_MINORS, true);
962    if (minor < 0) {
963        error = minor;
964        pr_err("failed to reserve new minor: %d\n", error);
965        return error;
966    }
967
968    evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
969    if (!evdev) {
970        error = -ENOMEM;
971        goto err_free_minor;
972    }
973
974    INIT_LIST_HEAD(&evdev->client_list);
975    spin_lock_init(&evdev->client_lock);
976    mutex_init(&evdev->mutex);
977    init_waitqueue_head(&evdev->wait);
978    evdev->exist = true;
979
980    dev_no = minor;
981    /* Normalize device number if it falls into legacy range */
982    if (dev_no < EVDEV_MINOR_BASE + EVDEV_MINORS)
983        dev_no -= EVDEV_MINOR_BASE;
984    dev_set_name(&evdev->dev, "event%d", dev_no);
985
986    evdev->handle.dev = input_get_device(dev);
987    evdev->handle.name = dev_name(&evdev->dev);
988    evdev->handle.handler = handler;
989    evdev->handle.private = evdev;
990
991    evdev->dev.devt = MKDEV(INPUT_MAJOR, minor);
992    evdev->dev.class = &input_class;
993    evdev->dev.parent = &dev->dev;
994    evdev->dev.release = evdev_free;
995    device_initialize(&evdev->dev);
996
997    error = input_register_handle(&evdev->handle);
998    if (error)
999        goto err_free_evdev;
1000
1001    cdev_init(&evdev->cdev, &evdev_fops);
1002    evdev->cdev.kobj.parent = &evdev->dev.kobj;
1003    error = cdev_add(&evdev->cdev, evdev->dev.devt, 1);
1004    if (error)
1005        goto err_unregister_handle;
1006
1007    error = device_add(&evdev->dev);
1008    if (error)
1009        goto err_cleanup_evdev;
1010
1011    return 0;
1012
1013 err_cleanup_evdev:
1014    evdev_cleanup(evdev);
1015 err_unregister_handle:
1016    input_unregister_handle(&evdev->handle);
1017 err_free_evdev:
1018    put_device(&evdev->dev);
1019 err_free_minor:
1020    input_free_minor(minor);
1021    return error;
1022}
1023
1024static void evdev_disconnect(struct input_handle *handle)
1025{
1026    struct evdev *evdev = handle->private;
1027
1028    device_del(&evdev->dev);
1029    evdev_cleanup(evdev);
1030    input_free_minor(MINOR(evdev->dev.devt));
1031    input_unregister_handle(handle);
1032    put_device(&evdev->dev);
1033}
1034
1035static const struct input_device_id evdev_ids[] = {
1036    { .driver_info = 1 }, /* Matches all devices */
1037    { }, /* Terminating zero entry */
1038};
1039
1040MODULE_DEVICE_TABLE(input, evdev_ids);
1041
1042static struct input_handler evdev_handler = {
1043    .event = evdev_event,
1044    .events = evdev_events,
1045    .connect = evdev_connect,
1046    .disconnect = evdev_disconnect,
1047    .legacy_minors = true,
1048    .minor = EVDEV_MINOR_BASE,
1049    .name = "evdev",
1050    .id_table = evdev_ids,
1051};
1052
1053static int __init evdev_init(void)
1054{
1055    return input_register_handler(&evdev_handler);
1056}
1057
1058static void __exit evdev_exit(void)
1059{
1060    input_unregister_handler(&evdev_handler);
1061}
1062
1063module_init(evdev_init);
1064module_exit(evdev_exit);
1065
1066MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
1067MODULE_DESCRIPTION("Input driver event char devices");
1068MODULE_LICENSE("GPL");
1069

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