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 "input-compat.h"
27
28struct evdev {
29    int open;
30    int minor;
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    bool exist;
39};
40
41struct evdev_client {
42    unsigned int head;
43    unsigned int tail;
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;
47    struct evdev *evdev;
48    struct list_head node;
49    int clkid;
50    unsigned int bufsize;
51    struct input_event buffer[];
52};
53
54static struct evdev *evdev_table[EVDEV_MINORS];
55static DEFINE_MUTEX(evdev_table_mutex);
56
57static void evdev_pass_event(struct evdev_client *client,
58                 struct input_event *event,
59                 ktime_t mono, ktime_t real)
60{
61    event->time = ktime_to_timeval(client->clkid == CLOCK_MONOTONIC ?
62                    mono : real);
63
64    /* Interrupts are disabled, just acquire the lock. */
65    spin_lock(&client->buffer_lock);
66
67    client->buffer[client->head++] = *event;
68    client->head &= client->bufsize - 1;
69
70    if (unlikely(client->head == client->tail)) {
71        /*
72         * This effectively "drops" all unconsumed events, leaving
73         * EV_SYN/SYN_DROPPED plus the newest event in the queue.
74         */
75        client->tail = (client->head - 2) & (client->bufsize - 1);
76
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;
81
82        client->packet_head = client->tail;
83    }
84
85    if (event->type == EV_SYN && event->code == SYN_REPORT) {
86        client->packet_head = client->head;
87        kill_fasync(&client->fasync, SIGIO, POLL_IN);
88    }
89
90    spin_unlock(&client->buffer_lock);
91}
92
93/*
94 * Pass incoming event to all connected clients.
95 */
96static void evdev_event(struct input_handle *handle,
97            unsigned int type, unsigned int code, int value)
98{
99    struct evdev *evdev = handle->private;
100    struct evdev_client *client;
101    struct input_event event;
102    ktime_t time_mono, time_real;
103
104    time_mono = ktime_get();
105    time_real = ktime_sub(time_mono, ktime_get_monotonic_offset());
106
107    event.type = type;
108    event.code = code;
109    event.value = value;
110
111    rcu_read_lock();
112
113    client = rcu_dereference(evdev->grab);
114
115    if (client)
116        evdev_pass_event(client, &event, time_mono, time_real);
117    else
118        list_for_each_entry_rcu(client, &evdev->client_list, node)
119            evdev_pass_event(client, &event, time_mono, time_real);
120
121    rcu_read_unlock();
122
123    if (type == EV_SYN && code == SYN_REPORT)
124        wake_up_interruptible(&evdev->wait);
125}
126
127static int evdev_fasync(int fd, struct file *file, int on)
128{
129    struct evdev_client *client = file->private_data;
130
131    return fasync_helper(fd, file, on, &client->fasync);
132}
133
134static int evdev_flush(struct file *file, fl_owner_t id)
135{
136    struct evdev_client *client = file->private_data;
137    struct evdev *evdev = client->evdev;
138    int retval;
139
140    retval = mutex_lock_interruptible(&evdev->mutex);
141    if (retval)
142        return retval;
143
144    if (!evdev->exist)
145        retval = -ENODEV;
146    else
147        retval = input_flush_device(&evdev->handle, file);
148
149    mutex_unlock(&evdev->mutex);
150    return retval;
151}
152
153static void evdev_free(struct device *dev)
154{
155    struct evdev *evdev = container_of(dev, struct evdev, dev);
156
157    input_put_device(evdev->handle.dev);
158    kfree(evdev);
159}
160
161/*
162 * Grabs an event device (along with underlying input device).
163 * This function is called with evdev->mutex taken.
164 */
165static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
166{
167    int error;
168
169    if (evdev->grab)
170        return -EBUSY;
171
172    error = input_grab_device(&evdev->handle);
173    if (error)
174        return error;
175
176    rcu_assign_pointer(evdev->grab, client);
177
178    return 0;
179}
180
181static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
182{
183    struct evdev_client *grab = rcu_dereference_protected(evdev->grab,
184                    lockdep_is_held(&evdev->mutex));
185
186    if (grab != client)
187        return -EINVAL;
188
189    rcu_assign_pointer(evdev->grab, NULL);
190    synchronize_rcu();
191    input_release_device(&evdev->handle);
192
193    return 0;
194}
195
196static void evdev_attach_client(struct evdev *evdev,
197                struct evdev_client *client)
198{
199    spin_lock(&evdev->client_lock);
200    list_add_tail_rcu(&client->node, &evdev->client_list);
201    spin_unlock(&evdev->client_lock);
202}
203
204static void evdev_detach_client(struct evdev *evdev,
205                struct evdev_client *client)
206{
207    spin_lock(&evdev->client_lock);
208    list_del_rcu(&client->node);
209    spin_unlock(&evdev->client_lock);
210    synchronize_rcu();
211}
212
213static int evdev_open_device(struct evdev *evdev)
214{
215    int retval;
216
217    retval = mutex_lock_interruptible(&evdev->mutex);
218    if (retval)
219        return retval;
220
221    if (!evdev->exist)
222        retval = -ENODEV;
223    else if (!evdev->open++) {
224        retval = input_open_device(&evdev->handle);
225        if (retval)
226            evdev->open--;
227    }
228
229    mutex_unlock(&evdev->mutex);
230    return retval;
231}
232
233static void evdev_close_device(struct evdev *evdev)
234{
235    mutex_lock(&evdev->mutex);
236
237    if (evdev->exist && !--evdev->open)
238        input_close_device(&evdev->handle);
239
240    mutex_unlock(&evdev->mutex);
241}
242
243/*
244 * Wake up users waiting for IO so they can disconnect from
245 * dead device.
246 */
247static void evdev_hangup(struct evdev *evdev)
248{
249    struct evdev_client *client;
250
251    spin_lock(&evdev->client_lock);
252    list_for_each_entry(client, &evdev->client_list, node)
253        kill_fasync(&client->fasync, SIGIO, POLL_HUP);
254    spin_unlock(&evdev->client_lock);
255
256    wake_up_interruptible(&evdev->wait);
257}
258
259static int evdev_release(struct inode *inode, struct file *file)
260{
261    struct evdev_client *client = file->private_data;
262    struct evdev *evdev = client->evdev;
263
264    mutex_lock(&evdev->mutex);
265    evdev_ungrab(evdev, client);
266    mutex_unlock(&evdev->mutex);
267
268    evdev_detach_client(evdev, client);
269    kfree(client);
270
271    evdev_close_device(evdev);
272    put_device(&evdev->dev);
273
274    return 0;
275}
276
277static unsigned int evdev_compute_buffer_size(struct input_dev *dev)
278{
279    unsigned int n_events =
280        max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS,
281            EVDEV_MIN_BUFFER_SIZE);
282
283    return roundup_pow_of_two(n_events);
284}
285
286static int evdev_open(struct inode *inode, struct file *file)
287{
288    struct evdev *evdev;
289    struct evdev_client *client;
290    int i = iminor(inode) - EVDEV_MINOR_BASE;
291    unsigned int bufsize;
292    int error;
293
294    if (i >= EVDEV_MINORS)
295        return -ENODEV;
296
297    error = mutex_lock_interruptible(&evdev_table_mutex);
298    if (error)
299        return error;
300    evdev = evdev_table[i];
301    if (evdev)
302        get_device(&evdev->dev);
303    mutex_unlock(&evdev_table_mutex);
304
305    if (!evdev)
306        return -ENODEV;
307
308    bufsize = evdev_compute_buffer_size(evdev->handle.dev);
309
310    client = kzalloc(sizeof(struct evdev_client) +
311                bufsize * sizeof(struct input_event),
312             GFP_KERNEL);
313    if (!client) {
314        error = -ENOMEM;
315        goto err_put_evdev;
316    }
317
318    client->bufsize = bufsize;
319    spin_lock_init(&client->buffer_lock);
320    client->evdev = evdev;
321    evdev_attach_client(evdev, client);
322
323    error = evdev_open_device(evdev);
324    if (error)
325        goto err_free_client;
326
327    file->private_data = client;
328    nonseekable_open(inode, file);
329
330    return 0;
331
332 err_free_client:
333    evdev_detach_client(evdev, client);
334    kfree(client);
335 err_put_evdev:
336    put_device(&evdev->dev);
337    return error;
338}
339
340static ssize_t evdev_write(struct file *file, const char __user *buffer,
341               size_t count, loff_t *ppos)
342{
343    struct evdev_client *client = file->private_data;
344    struct evdev *evdev = client->evdev;
345    struct input_event event;
346    int retval = 0;
347
348    if (count != 0 && count < input_event_size())
349        return -EINVAL;
350
351    retval = mutex_lock_interruptible(&evdev->mutex);
352    if (retval)
353        return retval;
354
355    if (!evdev->exist) {
356        retval = -ENODEV;
357        goto out;
358    }
359
360    while (retval + input_event_size() <= count) {
361
362        if (input_event_from_user(buffer + retval, &event)) {
363            retval = -EFAULT;
364            goto out;
365        }
366        retval += input_event_size();
367
368        input_inject_event(&evdev->handle,
369                   event.type, event.code, event.value);
370    }
371
372 out:
373    mutex_unlock(&evdev->mutex);
374    return retval;
375}
376
377static int evdev_fetch_next_event(struct evdev_client *client,
378                  struct input_event *event)
379{
380    int have_event;
381
382    spin_lock_irq(&client->buffer_lock);
383
384    have_event = client->packet_head != client->tail;
385    if (have_event) {
386        *event = client->buffer[client->tail++];
387        client->tail &= client->bufsize - 1;
388    }
389
390    spin_unlock_irq(&client->buffer_lock);
391
392    return have_event;
393}
394
395static ssize_t evdev_read(struct file *file, char __user *buffer,
396              size_t count, loff_t *ppos)
397{
398    struct evdev_client *client = file->private_data;
399    struct evdev *evdev = client->evdev;
400    struct input_event event;
401    size_t read = 0;
402    int error;
403
404    if (count != 0 && count < input_event_size())
405        return -EINVAL;
406
407    for (;;) {
408        if (!evdev->exist)
409            return -ENODEV;
410
411        if (client->packet_head == client->tail &&
412            (file->f_flags & O_NONBLOCK))
413            return -EAGAIN;
414
415        /*
416         * count == 0 is special - no IO is done but we check
417         * for error conditions (see above).
418         */
419        if (count == 0)
420            break;
421
422        while (read + input_event_size() <= count &&
423               evdev_fetch_next_event(client, &event)) {
424
425            if (input_event_to_user(buffer + read, &event))
426                return -EFAULT;
427
428            read += input_event_size();
429        }
430
431        if (read)
432            break;
433
434        if (!(file->f_flags & O_NONBLOCK)) {
435            error = wait_event_interruptible(evdev->wait,
436                    client->packet_head != client->tail ||
437                    !evdev->exist);
438            if (error)
439                return error;
440        }
441    }
442
443    return read;
444}
445
446/* No kernel lock - fine */
447static unsigned int evdev_poll(struct file *file, poll_table *wait)
448{
449    struct evdev_client *client = file->private_data;
450    struct evdev *evdev = client->evdev;
451    unsigned int mask;
452
453    poll_wait(file, &evdev->wait, wait);
454
455    mask = evdev->exist ? POLLOUT | POLLWRNORM : POLLHUP | POLLERR;
456    if (client->packet_head != client->tail)
457        mask |= POLLIN | POLLRDNORM;
458
459    return mask;
460}
461
462#ifdef CONFIG_COMPAT
463
464#define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
465#define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
466
467#ifdef __BIG_ENDIAN
468static int bits_to_user(unsigned long *bits, unsigned int maxbit,
469            unsigned int maxlen, void __user *p, int compat)
470{
471    int len, i;
472
473    if (compat) {
474        len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
475        if (len > maxlen)
476            len = maxlen;
477
478        for (i = 0; i < len / sizeof(compat_long_t); i++)
479            if (copy_to_user((compat_long_t __user *) p + i,
480                     (compat_long_t *) bits +
481                        i + 1 - ((i % 2) << 1),
482                     sizeof(compat_long_t)))
483                return -EFAULT;
484    } else {
485        len = BITS_TO_LONGS(maxbit) * sizeof(long);
486        if (len > maxlen)
487            len = maxlen;
488
489        if (copy_to_user(p, bits, len))
490            return -EFAULT;
491    }
492
493    return len;
494}
495#else
496static int bits_to_user(unsigned long *bits, unsigned int maxbit,
497            unsigned int maxlen, void __user *p, int compat)
498{
499    int len = compat ?
500            BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
501            BITS_TO_LONGS(maxbit) * sizeof(long);
502
503    if (len > maxlen)
504        len = maxlen;
505
506    return copy_to_user(p, bits, len) ? -EFAULT : len;
507}
508#endif /* __BIG_ENDIAN */
509
510#else
511
512static int bits_to_user(unsigned long *bits, unsigned int maxbit,
513            unsigned int maxlen, void __user *p, int compat)
514{
515    int len = BITS_TO_LONGS(maxbit) * sizeof(long);
516
517    if (len > maxlen)
518        len = maxlen;
519
520    return copy_to_user(p, bits, len) ? -EFAULT : len;
521}
522
523#endif /* CONFIG_COMPAT */
524
525static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
526{
527    int len;
528
529    if (!str)
530        return -ENOENT;
531
532    len = strlen(str) + 1;
533    if (len > maxlen)
534        len = maxlen;
535
536    return copy_to_user(p, str, len) ? -EFAULT : len;
537}
538
539#define OLD_KEY_MAX 0x1ff
540static int handle_eviocgbit(struct input_dev *dev,
541                unsigned int type, unsigned int size,
542                void __user *p, int compat_mode)
543{
544    static unsigned long keymax_warn_time;
545    unsigned long *bits;
546    int len;
547
548    switch (type) {
549
550    case 0: bits = dev->evbit; len = EV_MAX; break;
551    case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
552    case EV_REL: bits = dev->relbit; len = REL_MAX; break;
553    case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
554    case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
555    case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
556    case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
557    case EV_FF: bits = dev->ffbit; len = FF_MAX; break;
558    case EV_SW: bits = dev->swbit; len = SW_MAX; break;
559    default: return -EINVAL;
560    }
561
562    /*
563     * Work around bugs in userspace programs that like to do
564     * EVIOCGBIT(EV_KEY, KEY_MAX) and not realize that 'len'
565     * should be in bytes, not in bits.
566     */
567    if (type == EV_KEY && size == OLD_KEY_MAX) {
568        len = OLD_KEY_MAX;
569        if (printk_timed_ratelimit(&keymax_warn_time, 10 * 1000))
570            pr_warning("(EVIOCGBIT): Suspicious buffer size %u, "
571                   "limiting output to %zu bytes. See "
572                   "http://userweb.kernel.org/~dtor/eviocgbit-bug.html\n",
573                   OLD_KEY_MAX,
574                   BITS_TO_LONGS(OLD_KEY_MAX) * sizeof(long));
575    }
576
577    return bits_to_user(bits, len, size, p, compat_mode);
578}
579#undef OLD_KEY_MAX
580
581static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p)
582{
583    struct input_keymap_entry ke = {
584        .len = sizeof(unsigned int),
585        .flags = 0,
586    };
587    int __user *ip = (int __user *)p;
588    int error;
589
590    /* legacy case */
591    if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
592        return -EFAULT;
593
594    error = input_get_keycode(dev, &ke);
595    if (error)
596        return error;
597
598    if (put_user(ke.keycode, ip + 1))
599        return -EFAULT;
600
601    return 0;
602}
603
604static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p)
605{
606    struct input_keymap_entry ke;
607    int error;
608
609    if (copy_from_user(&ke, p, sizeof(ke)))
610        return -EFAULT;
611
612    error = input_get_keycode(dev, &ke);
613    if (error)
614        return error;
615
616    if (copy_to_user(p, &ke, sizeof(ke)))
617        return -EFAULT;
618
619    return 0;
620}
621
622static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p)
623{
624    struct input_keymap_entry ke = {
625        .len = sizeof(unsigned int),
626        .flags = 0,
627    };
628    int __user *ip = (int __user *)p;
629
630    if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
631        return -EFAULT;
632
633    if (get_user(ke.keycode, ip + 1))
634        return -EFAULT;
635
636    return input_set_keycode(dev, &ke);
637}
638
639static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p)
640{
641    struct input_keymap_entry ke;
642
643    if (copy_from_user(&ke, p, sizeof(ke)))
644        return -EFAULT;
645
646    if (ke.len > sizeof(ke.scancode))
647        return -EINVAL;
648
649    return input_set_keycode(dev, &ke);
650}
651
652static int evdev_handle_mt_request(struct input_dev *dev,
653                   unsigned int size,
654                   int __user *ip)
655{
656    const struct input_mt_slot *mt = dev->mt;
657    unsigned int code;
658    int max_slots;
659    int i;
660
661    if (get_user(code, &ip[0]))
662        return -EFAULT;
663    if (!input_is_mt_value(code))
664        return -EINVAL;
665
666    max_slots = (size - sizeof(__u32)) / sizeof(__s32);
667    for (i = 0; i < dev->mtsize && i < max_slots; i++)
668        if (put_user(input_mt_get_value(&mt[i], code), &ip[1 + i]))
669            return -EFAULT;
670
671    return 0;
672}
673
674static long evdev_do_ioctl(struct file *file, unsigned int cmd,
675               void __user *p, int compat_mode)
676{
677    struct evdev_client *client = file->private_data;
678    struct evdev *evdev = client->evdev;
679    struct input_dev *dev = evdev->handle.dev;
680    struct input_absinfo abs;
681    struct ff_effect effect;
682    int __user *ip = (int __user *)p;
683    unsigned int i, t, u, v;
684    unsigned int size;
685    int error;
686
687    /* First we check for fixed-length commands */
688    switch (cmd) {
689
690    case EVIOCGVERSION:
691        return put_user(EV_VERSION, ip);
692
693    case EVIOCGID:
694        if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
695            return -EFAULT;
696        return 0;
697
698    case EVIOCGREP:
699        if (!test_bit(EV_REP, dev->evbit))
700            return -ENOSYS;
701        if (put_user(dev->rep[REP_DELAY], ip))
702            return -EFAULT;
703        if (put_user(dev->rep[REP_PERIOD], ip + 1))
704            return -EFAULT;
705        return 0;
706
707    case EVIOCSREP:
708        if (!test_bit(EV_REP, dev->evbit))
709            return -ENOSYS;
710        if (get_user(u, ip))
711            return -EFAULT;
712        if (get_user(v, ip + 1))
713            return -EFAULT;
714
715        input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
716        input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
717
718        return 0;
719
720    case EVIOCRMFF:
721        return input_ff_erase(dev, (int)(unsigned long) p, file);
722
723    case EVIOCGEFFECTS:
724        i = test_bit(EV_FF, dev->evbit) ?
725                dev->ff->max_effects : 0;
726        if (put_user(i, ip))
727            return -EFAULT;
728        return 0;
729
730    case EVIOCGRAB:
731        if (p)
732            return evdev_grab(evdev, client);
733        else
734            return evdev_ungrab(evdev, client);
735
736    case EVIOCSCLOCKID:
737        if (copy_from_user(&i, p, sizeof(unsigned int)))
738            return -EFAULT;
739        if (i != CLOCK_MONOTONIC && i != CLOCK_REALTIME)
740            return -EINVAL;
741        client->clkid = i;
742        return 0;
743
744    case EVIOCGKEYCODE:
745        return evdev_handle_get_keycode(dev, p);
746
747    case EVIOCSKEYCODE:
748        return evdev_handle_set_keycode(dev, p);
749
750    case EVIOCGKEYCODE_V2:
751        return evdev_handle_get_keycode_v2(dev, p);
752
753    case EVIOCSKEYCODE_V2:
754        return evdev_handle_set_keycode_v2(dev, p);
755    }
756
757    size = _IOC_SIZE(cmd);
758
759    /* Now check variable-length commands */
760#define EVIOC_MASK_SIZE(nr) ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
761    switch (EVIOC_MASK_SIZE(cmd)) {
762
763    case EVIOCGPROP(0):
764        return bits_to_user(dev->propbit, INPUT_PROP_MAX,
765                    size, p, compat_mode);
766
767    case EVIOCGMTSLOTS(0):
768        return evdev_handle_mt_request(dev, size, ip);
769
770    case EVIOCGKEY(0):
771        return bits_to_user(dev->key, KEY_MAX, size, p, compat_mode);
772
773    case EVIOCGLED(0):
774        return bits_to_user(dev->led, LED_MAX, size, p, compat_mode);
775
776    case EVIOCGSND(0):
777        return bits_to_user(dev->snd, SND_MAX, size, p, compat_mode);
778
779    case EVIOCGSW(0):
780        return bits_to_user(dev->sw, SW_MAX, size, p, compat_mode);
781
782    case EVIOCGNAME(0):
783        return str_to_user(dev->name, size, p);
784
785    case EVIOCGPHYS(0):
786        return str_to_user(dev->phys, size, p);
787
788    case EVIOCGUNIQ(0):
789        return str_to_user(dev->uniq, size, p);
790
791    case EVIOC_MASK_SIZE(EVIOCSFF):
792        if (input_ff_effect_from_user(p, size, &effect))
793            return -EFAULT;
794
795        error = input_ff_upload(dev, &effect, file);
796
797        if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
798            return -EFAULT;
799
800        return error;
801    }
802
803    /* Multi-number variable-length handlers */
804    if (_IOC_TYPE(cmd) != 'E')
805        return -EINVAL;
806
807    if (_IOC_DIR(cmd) == _IOC_READ) {
808
809        if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
810            return handle_eviocgbit(dev,
811                        _IOC_NR(cmd) & EV_MAX, size,
812                        p, compat_mode);
813
814        if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
815
816            if (!dev->absinfo)
817                return -EINVAL;
818
819            t = _IOC_NR(cmd) & ABS_MAX;
820            abs = dev->absinfo[t];
821
822            if (copy_to_user(p, &abs, min_t(size_t,
823                    size, sizeof(struct input_absinfo))))
824                return -EFAULT;
825
826            return 0;
827        }
828    }
829
830    if (_IOC_DIR(cmd) == _IOC_WRITE) {
831
832        if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
833
834            if (!dev->absinfo)
835                return -EINVAL;
836
837            t = _IOC_NR(cmd) & ABS_MAX;
838
839            if (copy_from_user(&abs, p, min_t(size_t,
840                    size, sizeof(struct input_absinfo))))
841                return -EFAULT;
842
843            if (size < sizeof(struct input_absinfo))
844                abs.resolution = 0;
845
846            /* We can't change number of reserved MT slots */
847            if (t == ABS_MT_SLOT)
848                return -EINVAL;
849
850            /*
851             * Take event lock to ensure that we are not
852             * changing device parameters in the middle
853             * of event.
854             */
855            spin_lock_irq(&dev->event_lock);
856            dev->absinfo[t] = abs;
857            spin_unlock_irq(&dev->event_lock);
858
859            return 0;
860        }
861    }
862
863    return -EINVAL;
864}
865
866static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
867                void __user *p, int compat_mode)
868{
869    struct evdev_client *client = file->private_data;
870    struct evdev *evdev = client->evdev;
871    int retval;
872
873    retval = mutex_lock_interruptible(&evdev->mutex);
874    if (retval)
875        return retval;
876
877    if (!evdev->exist) {
878        retval = -ENODEV;
879        goto out;
880    }
881
882    retval = evdev_do_ioctl(file, cmd, p, compat_mode);
883
884 out:
885    mutex_unlock(&evdev->mutex);
886    return retval;
887}
888
889static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
890{
891    return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
892}
893
894#ifdef CONFIG_COMPAT
895static long evdev_ioctl_compat(struct file *file,
896                unsigned int cmd, unsigned long arg)
897{
898    return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
899}
900#endif
901
902static const struct file_operations evdev_fops = {
903    .owner = THIS_MODULE,
904    .read = evdev_read,
905    .write = evdev_write,
906    .poll = evdev_poll,
907    .open = evdev_open,
908    .release = evdev_release,
909    .unlocked_ioctl = evdev_ioctl,
910#ifdef CONFIG_COMPAT
911    .compat_ioctl = evdev_ioctl_compat,
912#endif
913    .fasync = evdev_fasync,
914    .flush = evdev_flush,
915    .llseek = no_llseek,
916};
917
918static int evdev_install_chrdev(struct evdev *evdev)
919{
920    /*
921     * No need to do any locking here as calls to connect and
922     * disconnect are serialized by the input core
923     */
924    evdev_table[evdev->minor] = evdev;
925    return 0;
926}
927
928static void evdev_remove_chrdev(struct evdev *evdev)
929{
930    /*
931     * Lock evdev table to prevent race with evdev_open()
932     */
933    mutex_lock(&evdev_table_mutex);
934    evdev_table[evdev->minor] = NULL;
935    mutex_unlock(&evdev_table_mutex);
936}
937
938/*
939 * Mark device non-existent. This disables writes, ioctls and
940 * prevents new users from opening the device. Already posted
941 * blocking reads will stay, however new ones will fail.
942 */
943static void evdev_mark_dead(struct evdev *evdev)
944{
945    mutex_lock(&evdev->mutex);
946    evdev->exist = false;
947    mutex_unlock(&evdev->mutex);
948}
949
950static void evdev_cleanup(struct evdev *evdev)
951{
952    struct input_handle *handle = &evdev->handle;
953
954    evdev_mark_dead(evdev);
955    evdev_hangup(evdev);
956    evdev_remove_chrdev(evdev);
957
958    /* evdev is marked dead so no one else accesses evdev->open */
959    if (evdev->open) {
960        input_flush_device(handle, NULL);
961        input_close_device(handle);
962    }
963}
964
965/*
966 * Create new evdev device. Note that input core serializes calls
967 * to connect and disconnect so we don't need to lock evdev_table here.
968 */
969static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
970             const struct input_device_id *id)
971{
972    struct evdev *evdev;
973    int minor;
974    int error;
975
976    for (minor = 0; minor < EVDEV_MINORS; minor++)
977        if (!evdev_table[minor])
978            break;
979
980    if (minor == EVDEV_MINORS) {
981        pr_err("no more free evdev devices\n");
982        return -ENFILE;
983    }
984
985    evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
986    if (!evdev)
987        return -ENOMEM;
988
989    INIT_LIST_HEAD(&evdev->client_list);
990    spin_lock_init(&evdev->client_lock);
991    mutex_init(&evdev->mutex);
992    init_waitqueue_head(&evdev->wait);
993
994    dev_set_name(&evdev->dev, "event%d", minor);
995    evdev->exist = true;
996    evdev->minor = minor;
997
998    evdev->handle.dev = input_get_device(dev);
999    evdev->handle.name = dev_name(&evdev->dev);
1000    evdev->handle.handler = handler;
1001    evdev->handle.private = evdev;
1002
1003    evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor);
1004    evdev->dev.class = &input_class;
1005    evdev->dev.parent = &dev->dev;
1006    evdev->dev.release = evdev_free;
1007    device_initialize(&evdev->dev);
1008
1009    error = input_register_handle(&evdev->handle);
1010    if (error)
1011        goto err_free_evdev;
1012
1013    error = evdev_install_chrdev(evdev);
1014    if (error)
1015        goto err_unregister_handle;
1016
1017    error = device_add(&evdev->dev);
1018    if (error)
1019        goto err_cleanup_evdev;
1020
1021    return 0;
1022
1023 err_cleanup_evdev:
1024    evdev_cleanup(evdev);
1025 err_unregister_handle:
1026    input_unregister_handle(&evdev->handle);
1027 err_free_evdev:
1028    put_device(&evdev->dev);
1029    return error;
1030}
1031
1032static void evdev_disconnect(struct input_handle *handle)
1033{
1034    struct evdev *evdev = handle->private;
1035
1036    device_del(&evdev->dev);
1037    evdev_cleanup(evdev);
1038    input_unregister_handle(handle);
1039    put_device(&evdev->dev);
1040}
1041
1042static const struct input_device_id evdev_ids[] = {
1043    { .driver_info = 1 }, /* Matches all devices */
1044    { }, /* Terminating zero entry */
1045};
1046
1047MODULE_DEVICE_TABLE(input, evdev_ids);
1048
1049static struct input_handler evdev_handler = {
1050    .event = evdev_event,
1051    .connect = evdev_connect,
1052    .disconnect = evdev_disconnect,
1053    .fops = &evdev_fops,
1054    .minor = EVDEV_MINOR_BASE,
1055    .name = "evdev",
1056    .id_table = evdev_ids,
1057};
1058
1059static int __init evdev_init(void)
1060{
1061    return input_register_handler(&evdev_handler);
1062}
1063
1064static void __exit evdev_exit(void)
1065{
1066    input_unregister_handler(&evdev_handler);
1067}
1068
1069module_init(evdev_init);
1070module_exit(evdev_exit);
1071
1072MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
1073MODULE_DESCRIPTION("Input driver event char devices");
1074MODULE_LICENSE("GPL");
1075

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