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1/*
2 * User-space I/O driver support for HID subsystem
3 * Copyright (c) 2012 David Herrmann
4 */
5
6/*
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License as published by the Free
9 * Software Foundation; either version 2 of the License, or (at your option)
10 * any later version.
11 */
12
13#include <linux/atomic.h>
14#include <linux/compat.h>
15#include <linux/device.h>
16#include <linux/fs.h>
17#include <linux/hid.h>
18#include <linux/input.h>
19#include <linux/miscdevice.h>
20#include <linux/module.h>
21#include <linux/mutex.h>
22#include <linux/poll.h>
23#include <linux/sched.h>
24#include <linux/spinlock.h>
25#include <linux/uhid.h>
26#include <linux/wait.h>
27
28#define UHID_NAME "uhid"
29#define UHID_BUFSIZE 32
30
31struct uhid_device {
32 struct mutex devlock;
33 bool running;
34
35 __u8 *rd_data;
36 uint rd_size;
37
38 struct hid_device *hid;
39 struct uhid_event input_buf;
40
41 wait_queue_head_t waitq;
42 spinlock_t qlock;
43 __u8 head;
44 __u8 tail;
45 struct uhid_event *outq[UHID_BUFSIZE];
46
47 /* blocking GET_REPORT support; state changes protected by qlock */
48 struct mutex report_lock;
49 wait_queue_head_t report_wait;
50 bool report_running;
51 u32 report_id;
52 u32 report_type;
53 struct uhid_event report_buf;
54};
55
56static struct miscdevice uhid_misc;
57
58static void uhid_queue(struct uhid_device *uhid, struct uhid_event *ev)
59{
60 __u8 newhead;
61
62 newhead = (uhid->head + 1) % UHID_BUFSIZE;
63
64 if (newhead != uhid->tail) {
65 uhid->outq[uhid->head] = ev;
66 uhid->head = newhead;
67 wake_up_interruptible(&uhid->waitq);
68 } else {
69 hid_warn(uhid->hid, "Output queue is full\n");
70 kfree(ev);
71 }
72}
73
74static int uhid_queue_event(struct uhid_device *uhid, __u32 event)
75{
76 unsigned long flags;
77 struct uhid_event *ev;
78
79 ev = kzalloc(sizeof(*ev), GFP_KERNEL);
80 if (!ev)
81 return -ENOMEM;
82
83 ev->type = event;
84
85 spin_lock_irqsave(&uhid->qlock, flags);
86 uhid_queue(uhid, ev);
87 spin_unlock_irqrestore(&uhid->qlock, flags);
88
89 return 0;
90}
91
92static int uhid_hid_start(struct hid_device *hid)
93{
94 struct uhid_device *uhid = hid->driver_data;
95 struct uhid_event *ev;
96 unsigned long flags;
97
98 ev = kzalloc(sizeof(*ev), GFP_KERNEL);
99 if (!ev)
100 return -ENOMEM;
101
102 ev->type = UHID_START;
103
104 if (hid->report_enum[HID_FEATURE_REPORT].numbered)
105 ev->u.start.dev_flags |= UHID_DEV_NUMBERED_FEATURE_REPORTS;
106 if (hid->report_enum[HID_OUTPUT_REPORT].numbered)
107 ev->u.start.dev_flags |= UHID_DEV_NUMBERED_OUTPUT_REPORTS;
108 if (hid->report_enum[HID_INPUT_REPORT].numbered)
109 ev->u.start.dev_flags |= UHID_DEV_NUMBERED_INPUT_REPORTS;
110
111 spin_lock_irqsave(&uhid->qlock, flags);
112 uhid_queue(uhid, ev);
113 spin_unlock_irqrestore(&uhid->qlock, flags);
114
115 return 0;
116}
117
118static void uhid_hid_stop(struct hid_device *hid)
119{
120 struct uhid_device *uhid = hid->driver_data;
121
122 hid->claimed = 0;
123 uhid_queue_event(uhid, UHID_STOP);
124}
125
126static int uhid_hid_open(struct hid_device *hid)
127{
128 struct uhid_device *uhid = hid->driver_data;
129
130 return uhid_queue_event(uhid, UHID_OPEN);
131}
132
133static void uhid_hid_close(struct hid_device *hid)
134{
135 struct uhid_device *uhid = hid->driver_data;
136
137 uhid_queue_event(uhid, UHID_CLOSE);
138}
139
140static int uhid_hid_parse(struct hid_device *hid)
141{
142 struct uhid_device *uhid = hid->driver_data;
143
144 return hid_parse_report(hid, uhid->rd_data, uhid->rd_size);
145}
146
147/* must be called with report_lock held */
148static int __uhid_report_queue_and_wait(struct uhid_device *uhid,
149 struct uhid_event *ev,
150 __u32 *report_id)
151{
152 unsigned long flags;
153 int ret;
154
155 spin_lock_irqsave(&uhid->qlock, flags);
156 *report_id = ++uhid->report_id;
157 uhid->report_type = ev->type + 1;
158 uhid->report_running = true;
159 uhid_queue(uhid, ev);
160 spin_unlock_irqrestore(&uhid->qlock, flags);
161
162 ret = wait_event_interruptible_timeout(uhid->report_wait,
163 !uhid->report_running || !uhid->running,
164 5 * HZ);
165 if (!ret || !uhid->running || uhid->report_running)
166 ret = -EIO;
167 else if (ret < 0)
168 ret = -ERESTARTSYS;
169 else
170 ret = 0;
171
172 uhid->report_running = false;
173
174 return ret;
175}
176
177static void uhid_report_wake_up(struct uhid_device *uhid, u32 id,
178 const struct uhid_event *ev)
179{
180 unsigned long flags;
181
182 spin_lock_irqsave(&uhid->qlock, flags);
183
184 /* id for old report; drop it silently */
185 if (uhid->report_type != ev->type || uhid->report_id != id)
186 goto unlock;
187 if (!uhid->report_running)
188 goto unlock;
189
190 memcpy(&uhid->report_buf, ev, sizeof(*ev));
191 uhid->report_running = false;
192 wake_up_interruptible(&uhid->report_wait);
193
194unlock:
195 spin_unlock_irqrestore(&uhid->qlock, flags);
196}
197
198static int uhid_hid_get_report(struct hid_device *hid, unsigned char rnum,
199 u8 *buf, size_t count, u8 rtype)
200{
201 struct uhid_device *uhid = hid->driver_data;
202 struct uhid_get_report_reply_req *req;
203 struct uhid_event *ev;
204 int ret;
205
206 if (!uhid->running)
207 return -EIO;
208
209 ev = kzalloc(sizeof(*ev), GFP_KERNEL);
210 if (!ev)
211 return -ENOMEM;
212
213 ev->type = UHID_GET_REPORT;
214 ev->u.get_report.rnum = rnum;
215 ev->u.get_report.rtype = rtype;
216
217 ret = mutex_lock_interruptible(&uhid->report_lock);
218 if (ret) {
219 kfree(ev);
220 return ret;
221 }
222
223 /* this _always_ takes ownership of @ev */
224 ret = __uhid_report_queue_and_wait(uhid, ev, &ev->u.get_report.id);
225 if (ret)
226 goto unlock;
227
228 req = &uhid->report_buf.u.get_report_reply;
229 if (req->err) {
230 ret = -EIO;
231 } else {
232 ret = min3(count, (size_t)req->size, (size_t)UHID_DATA_MAX);
233 memcpy(buf, req->data, ret);
234 }
235
236unlock:
237 mutex_unlock(&uhid->report_lock);
238 return ret;
239}
240
241static int uhid_hid_set_report(struct hid_device *hid, unsigned char rnum,
242 const u8 *buf, size_t count, u8 rtype)
243{
244 struct uhid_device *uhid = hid->driver_data;
245 struct uhid_event *ev;
246 int ret;
247
248 if (!uhid->running || count > UHID_DATA_MAX)
249 return -EIO;
250
251 ev = kzalloc(sizeof(*ev), GFP_KERNEL);
252 if (!ev)
253 return -ENOMEM;
254
255 ev->type = UHID_SET_REPORT;
256 ev->u.set_report.rnum = rnum;
257 ev->u.set_report.rtype = rtype;
258 ev->u.set_report.size = count;
259 memcpy(ev->u.set_report.data, buf, count);
260
261 ret = mutex_lock_interruptible(&uhid->report_lock);
262 if (ret) {
263 kfree(ev);
264 return ret;
265 }
266
267 /* this _always_ takes ownership of @ev */
268 ret = __uhid_report_queue_and_wait(uhid, ev, &ev->u.set_report.id);
269 if (ret)
270 goto unlock;
271
272 if (uhid->report_buf.u.set_report_reply.err)
273 ret = -EIO;
274 else
275 ret = count;
276
277unlock:
278 mutex_unlock(&uhid->report_lock);
279 return ret;
280}
281
282static int uhid_hid_raw_request(struct hid_device *hid, unsigned char reportnum,
283 __u8 *buf, size_t len, unsigned char rtype,
284 int reqtype)
285{
286 u8 u_rtype;
287
288 switch (rtype) {
289 case HID_FEATURE_REPORT:
290 u_rtype = UHID_FEATURE_REPORT;
291 break;
292 case HID_OUTPUT_REPORT:
293 u_rtype = UHID_OUTPUT_REPORT;
294 break;
295 case HID_INPUT_REPORT:
296 u_rtype = UHID_INPUT_REPORT;
297 break;
298 default:
299 return -EINVAL;
300 }
301
302 switch (reqtype) {
303 case HID_REQ_GET_REPORT:
304 return uhid_hid_get_report(hid, reportnum, buf, len, u_rtype);
305 case HID_REQ_SET_REPORT:
306 return uhid_hid_set_report(hid, reportnum, buf, len, u_rtype);
307 default:
308 return -EIO;
309 }
310}
311
312static int uhid_hid_output_raw(struct hid_device *hid, __u8 *buf, size_t count,
313 unsigned char report_type)
314{
315 struct uhid_device *uhid = hid->driver_data;
316 __u8 rtype;
317 unsigned long flags;
318 struct uhid_event *ev;
319
320 switch (report_type) {
321 case HID_FEATURE_REPORT:
322 rtype = UHID_FEATURE_REPORT;
323 break;
324 case HID_OUTPUT_REPORT:
325 rtype = UHID_OUTPUT_REPORT;
326 break;
327 default:
328 return -EINVAL;
329 }
330
331 if (count < 1 || count > UHID_DATA_MAX)
332 return -EINVAL;
333
334 ev = kzalloc(sizeof(*ev), GFP_KERNEL);
335 if (!ev)
336 return -ENOMEM;
337
338 ev->type = UHID_OUTPUT;
339 ev->u.output.size = count;
340 ev->u.output.rtype = rtype;
341 memcpy(ev->u.output.data, buf, count);
342
343 spin_lock_irqsave(&uhid->qlock, flags);
344 uhid_queue(uhid, ev);
345 spin_unlock_irqrestore(&uhid->qlock, flags);
346
347 return count;
348}
349
350static int uhid_hid_output_report(struct hid_device *hid, __u8 *buf,
351 size_t count)
352{
353 return uhid_hid_output_raw(hid, buf, count, HID_OUTPUT_REPORT);
354}
355
356static struct hid_ll_driver uhid_hid_driver = {
357 .start = uhid_hid_start,
358 .stop = uhid_hid_stop,
359 .open = uhid_hid_open,
360 .close = uhid_hid_close,
361 .parse = uhid_hid_parse,
362 .raw_request = uhid_hid_raw_request,
363 .output_report = uhid_hid_output_report,
364};
365
366#ifdef CONFIG_COMPAT
367
368/* Apparently we haven't stepped on these rakes enough times yet. */
369struct uhid_create_req_compat {
370 __u8 name[128];
371 __u8 phys[64];
372 __u8 uniq[64];
373
374 compat_uptr_t rd_data;
375 __u16 rd_size;
376
377 __u16 bus;
378 __u32 vendor;
379 __u32 product;
380 __u32 version;
381 __u32 country;
382} __attribute__((__packed__));
383
384static int uhid_event_from_user(const char __user *buffer, size_t len,
385 struct uhid_event *event)
386{
387 if (in_compat_syscall()) {
388 u32 type;
389
390 if (get_user(type, buffer))
391 return -EFAULT;
392
393 if (type == UHID_CREATE) {
394 /*
395 * This is our messed up request with compat pointer.
396 * It is largish (more than 256 bytes) so we better
397 * allocate it from the heap.
398 */
399 struct uhid_create_req_compat *compat;
400
401 compat = kzalloc(sizeof(*compat), GFP_KERNEL);
402 if (!compat)
403 return -ENOMEM;
404
405 buffer += sizeof(type);
406 len -= sizeof(type);
407 if (copy_from_user(compat, buffer,
408 min(len, sizeof(*compat)))) {
409 kfree(compat);
410 return -EFAULT;
411 }
412
413 /* Shuffle the data over to proper structure */
414 event->type = type;
415
416 memcpy(event->u.create.name, compat->name,
417 sizeof(compat->name));
418 memcpy(event->u.create.phys, compat->phys,
419 sizeof(compat->phys));
420 memcpy(event->u.create.uniq, compat->uniq,
421 sizeof(compat->uniq));
422
423 event->u.create.rd_data = compat_ptr(compat->rd_data);
424 event->u.create.rd_size = compat->rd_size;
425
426 event->u.create.bus = compat->bus;
427 event->u.create.vendor = compat->vendor;
428 event->u.create.product = compat->product;
429 event->u.create.version = compat->version;
430 event->u.create.country = compat->country;
431
432 kfree(compat);
433 return 0;
434 }
435 /* All others can be copied directly */
436 }
437
438 if (copy_from_user(event, buffer, min(len, sizeof(*event))))
439 return -EFAULT;
440
441 return 0;
442}
443#else
444static int uhid_event_from_user(const char __user *buffer, size_t len,
445 struct uhid_event *event)
446{
447 if (copy_from_user(event, buffer, min(len, sizeof(*event))))
448 return -EFAULT;
449
450 return 0;
451}
452#endif
453
454static int uhid_dev_create2(struct uhid_device *uhid,
455 const struct uhid_event *ev)
456{
457 struct hid_device *hid;
458 size_t rd_size, len;
459 void *rd_data;
460 int ret;
461
462 if (uhid->running)
463 return -EALREADY;
464
465 rd_size = ev->u.create2.rd_size;
466 if (rd_size <= 0 || rd_size > HID_MAX_DESCRIPTOR_SIZE)
467 return -EINVAL;
468
469 rd_data = kmemdup(ev->u.create2.rd_data, rd_size, GFP_KERNEL);
470 if (!rd_data)
471 return -ENOMEM;
472
473 uhid->rd_size = rd_size;
474 uhid->rd_data = rd_data;
475
476 hid = hid_allocate_device();
477 if (IS_ERR(hid)) {
478 ret = PTR_ERR(hid);
479 goto err_free;
480 }
481
482 len = min(sizeof(hid->name), sizeof(ev->u.create2.name)) - 1;
483 strncpy(hid->name, ev->u.create2.name, len);
484 len = min(sizeof(hid->phys), sizeof(ev->u.create2.phys)) - 1;
485 strncpy(hid->phys, ev->u.create2.phys, len);
486 len = min(sizeof(hid->uniq), sizeof(ev->u.create2.uniq)) - 1;
487 strncpy(hid->uniq, ev->u.create2.uniq, len);
488
489 hid->ll_driver = &uhid_hid_driver;
490 hid->bus = ev->u.create2.bus;
491 hid->vendor = ev->u.create2.vendor;
492 hid->product = ev->u.create2.product;
493 hid->version = ev->u.create2.version;
494 hid->country = ev->u.create2.country;
495 hid->driver_data = uhid;
496 hid->dev.parent = uhid_misc.this_device;
497
498 uhid->hid = hid;
499 uhid->running = true;
500
501 ret = hid_add_device(hid);
502 if (ret) {
503 hid_err(hid, "Cannot register HID device\n");
504 goto err_hid;
505 }
506
507 return 0;
508
509err_hid:
510 hid_destroy_device(hid);
511 uhid->hid = NULL;
512 uhid->running = false;
513err_free:
514 kfree(uhid->rd_data);
515 uhid->rd_data = NULL;
516 uhid->rd_size = 0;
517 return ret;
518}
519
520static int uhid_dev_create(struct uhid_device *uhid,
521 struct uhid_event *ev)
522{
523 struct uhid_create_req orig;
524
525 orig = ev->u.create;
526
527 if (orig.rd_size <= 0 || orig.rd_size > HID_MAX_DESCRIPTOR_SIZE)
528 return -EINVAL;
529 if (copy_from_user(&ev->u.create2.rd_data, orig.rd_data, orig.rd_size))
530 return -EFAULT;
531
532 memcpy(ev->u.create2.name, orig.name, sizeof(orig.name));
533 memcpy(ev->u.create2.phys, orig.phys, sizeof(orig.phys));
534 memcpy(ev->u.create2.uniq, orig.uniq, sizeof(orig.uniq));
535 ev->u.create2.rd_size = orig.rd_size;
536 ev->u.create2.bus = orig.bus;
537 ev->u.create2.vendor = orig.vendor;
538 ev->u.create2.product = orig.product;
539 ev->u.create2.version = orig.version;
540 ev->u.create2.country = orig.country;
541
542 return uhid_dev_create2(uhid, ev);
543}
544
545static int uhid_dev_destroy(struct uhid_device *uhid)
546{
547 if (!uhid->running)
548 return -EINVAL;
549
550 uhid->running = false;
551 wake_up_interruptible(&uhid->report_wait);
552
553 hid_destroy_device(uhid->hid);
554 kfree(uhid->rd_data);
555
556 return 0;
557}
558
559static int uhid_dev_input(struct uhid_device *uhid, struct uhid_event *ev)
560{
561 if (!uhid->running)
562 return -EINVAL;
563
564 hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input.data,
565 min_t(size_t, ev->u.input.size, UHID_DATA_MAX), 0);
566
567 return 0;
568}
569
570static int uhid_dev_input2(struct uhid_device *uhid, struct uhid_event *ev)
571{
572 if (!uhid->running)
573 return -EINVAL;
574
575 hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input2.data,
576 min_t(size_t, ev->u.input2.size, UHID_DATA_MAX), 0);
577
578 return 0;
579}
580
581static int uhid_dev_get_report_reply(struct uhid_device *uhid,
582 struct uhid_event *ev)
583{
584 if (!uhid->running)
585 return -EINVAL;
586
587 uhid_report_wake_up(uhid, ev->u.get_report_reply.id, ev);
588 return 0;
589}
590
591static int uhid_dev_set_report_reply(struct uhid_device *uhid,
592 struct uhid_event *ev)
593{
594 if (!uhid->running)
595 return -EINVAL;
596
597 uhid_report_wake_up(uhid, ev->u.set_report_reply.id, ev);
598 return 0;
599}
600
601static int uhid_char_open(struct inode *inode, struct file *file)
602{
603 struct uhid_device *uhid;
604
605 uhid = kzalloc(sizeof(*uhid), GFP_KERNEL);
606 if (!uhid)
607 return -ENOMEM;
608
609 mutex_init(&uhid->devlock);
610 mutex_init(&uhid->report_lock);
611 spin_lock_init(&uhid->qlock);
612 init_waitqueue_head(&uhid->waitq);
613 init_waitqueue_head(&uhid->report_wait);
614 uhid->running = false;
615
616 file->private_data = uhid;
617 nonseekable_open(inode, file);
618
619 return 0;
620}
621
622static int uhid_char_release(struct inode *inode, struct file *file)
623{
624 struct uhid_device *uhid = file->private_data;
625 unsigned int i;
626
627 uhid_dev_destroy(uhid);
628
629 for (i = 0; i < UHID_BUFSIZE; ++i)
630 kfree(uhid->outq[i]);
631
632 kfree(uhid);
633
634 return 0;
635}
636
637static ssize_t uhid_char_read(struct file *file, char __user *buffer,
638 size_t count, loff_t *ppos)
639{
640 struct uhid_device *uhid = file->private_data;
641 int ret;
642 unsigned long flags;
643 size_t len;
644
645 /* they need at least the "type" member of uhid_event */
646 if (count < sizeof(__u32))
647 return -EINVAL;
648
649try_again:
650 if (file->f_flags & O_NONBLOCK) {
651 if (uhid->head == uhid->tail)
652 return -EAGAIN;
653 } else {
654 ret = wait_event_interruptible(uhid->waitq,
655 uhid->head != uhid->tail);
656 if (ret)
657 return ret;
658 }
659
660 ret = mutex_lock_interruptible(&uhid->devlock);
661 if (ret)
662 return ret;
663
664 if (uhid->head == uhid->tail) {
665 mutex_unlock(&uhid->devlock);
666 goto try_again;
667 } else {
668 len = min(count, sizeof(**uhid->outq));
669 if (copy_to_user(buffer, uhid->outq[uhid->tail], len)) {
670 ret = -EFAULT;
671 } else {
672 kfree(uhid->outq[uhid->tail]);
673 uhid->outq[uhid->tail] = NULL;
674
675 spin_lock_irqsave(&uhid->qlock, flags);
676 uhid->tail = (uhid->tail + 1) % UHID_BUFSIZE;
677 spin_unlock_irqrestore(&uhid->qlock, flags);
678 }
679 }
680
681 mutex_unlock(&uhid->devlock);
682 return ret ? ret : len;
683}
684
685static ssize_t uhid_char_write(struct file *file, const char __user *buffer,
686 size_t count, loff_t *ppos)
687{
688 struct uhid_device *uhid = file->private_data;
689 int ret;
690 size_t len;
691
692 /* we need at least the "type" member of uhid_event */
693 if (count < sizeof(__u32))
694 return -EINVAL;
695
696 ret = mutex_lock_interruptible(&uhid->devlock);
697 if (ret)
698 return ret;
699
700 memset(&uhid->input_buf, 0, sizeof(uhid->input_buf));
701 len = min(count, sizeof(uhid->input_buf));
702
703 ret = uhid_event_from_user(buffer, len, &uhid->input_buf);
704 if (ret)
705 goto unlock;
706
707 switch (uhid->input_buf.type) {
708 case UHID_CREATE:
709 ret = uhid_dev_create(uhid, &uhid->input_buf);
710 break;
711 case UHID_CREATE2:
712 ret = uhid_dev_create2(uhid, &uhid->input_buf);
713 break;
714 case UHID_DESTROY:
715 ret = uhid_dev_destroy(uhid);
716 break;
717 case UHID_INPUT:
718 ret = uhid_dev_input(uhid, &uhid->input_buf);
719 break;
720 case UHID_INPUT2:
721 ret = uhid_dev_input2(uhid, &uhid->input_buf);
722 break;
723 case UHID_GET_REPORT_REPLY:
724 ret = uhid_dev_get_report_reply(uhid, &uhid->input_buf);
725 break;
726 case UHID_SET_REPORT_REPLY:
727 ret = uhid_dev_set_report_reply(uhid, &uhid->input_buf);
728 break;
729 default:
730 ret = -EOPNOTSUPP;
731 }
732
733unlock:
734 mutex_unlock(&uhid->devlock);
735
736 /* return "count" not "len" to not confuse the caller */
737 return ret ? ret : count;
738}
739
740static unsigned int uhid_char_poll(struct file *file, poll_table *wait)
741{
742 struct uhid_device *uhid = file->private_data;
743
744 poll_wait(file, &uhid->waitq, wait);
745
746 if (uhid->head != uhid->tail)
747 return POLLIN | POLLRDNORM;
748
749 return 0;
750}
751
752static const struct file_operations uhid_fops = {
753 .owner = THIS_MODULE,
754 .open = uhid_char_open,
755 .release = uhid_char_release,
756 .read = uhid_char_read,
757 .write = uhid_char_write,
758 .poll = uhid_char_poll,
759 .llseek = no_llseek,
760};
761
762static struct miscdevice uhid_misc = {
763 .fops = &uhid_fops,
764 .minor = UHID_MINOR,
765 .name = UHID_NAME,
766};
767
768static int __init uhid_init(void)
769{
770 return misc_register(&uhid_misc);
771}
772
773static void __exit uhid_exit(void)
774{
775 misc_deregister(&uhid_misc);
776}
777
778module_init(uhid_init);
779module_exit(uhid_exit);
780MODULE_LICENSE("GPL");
781MODULE_AUTHOR("David Herrmann <dh.herrmann@gmail.com>");
782MODULE_DESCRIPTION("User-space I/O driver support for HID subsystem");
783MODULE_ALIAS_MISCDEV(UHID_MINOR);
784MODULE_ALIAS("devname:" UHID_NAME);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * User-space I/O driver support for HID subsystem
4 * Copyright (c) 2012 David Herrmann
5 */
6
7/*
8 */
9
10#include <linux/atomic.h>
11#include <linux/compat.h>
12#include <linux/cred.h>
13#include <linux/device.h>
14#include <linux/fs.h>
15#include <linux/hid.h>
16#include <linux/input.h>
17#include <linux/miscdevice.h>
18#include <linux/module.h>
19#include <linux/mutex.h>
20#include <linux/poll.h>
21#include <linux/sched.h>
22#include <linux/spinlock.h>
23#include <linux/uhid.h>
24#include <linux/wait.h>
25
26#define UHID_NAME "uhid"
27#define UHID_BUFSIZE 32
28
29struct uhid_device {
30 struct mutex devlock;
31
32 /* This flag tracks whether the HID device is usable for commands from
33 * userspace. The flag is already set before hid_add_device(), which
34 * runs in workqueue context, to allow hid_add_device() to communicate
35 * with userspace.
36 * However, if hid_add_device() fails, the flag is cleared without
37 * holding devlock.
38 * We guarantee that if @running changes from true to false while you're
39 * holding @devlock, it's still fine to access @hid.
40 */
41 bool running;
42
43 __u8 *rd_data;
44 uint rd_size;
45
46 /* When this is NULL, userspace may use UHID_CREATE/UHID_CREATE2. */
47 struct hid_device *hid;
48 struct uhid_event input_buf;
49
50 wait_queue_head_t waitq;
51 spinlock_t qlock;
52 __u8 head;
53 __u8 tail;
54 struct uhid_event *outq[UHID_BUFSIZE];
55
56 /* blocking GET_REPORT support; state changes protected by qlock */
57 struct mutex report_lock;
58 wait_queue_head_t report_wait;
59 bool report_running;
60 u32 report_id;
61 u32 report_type;
62 struct uhid_event report_buf;
63 struct work_struct worker;
64};
65
66static struct miscdevice uhid_misc;
67
68static void uhid_device_add_worker(struct work_struct *work)
69{
70 struct uhid_device *uhid = container_of(work, struct uhid_device, worker);
71 int ret;
72
73 ret = hid_add_device(uhid->hid);
74 if (ret) {
75 hid_err(uhid->hid, "Cannot register HID device: error %d\n", ret);
76
77 /* We used to call hid_destroy_device() here, but that's really
78 * messy to get right because we have to coordinate with
79 * concurrent writes from userspace that might be in the middle
80 * of using uhid->hid.
81 * Just leave uhid->hid as-is for now, and clean it up when
82 * userspace tries to close or reinitialize the uhid instance.
83 *
84 * However, we do have to clear the ->running flag and do a
85 * wakeup to make sure userspace knows that the device is gone.
86 */
87 WRITE_ONCE(uhid->running, false);
88 wake_up_interruptible(&uhid->report_wait);
89 }
90}
91
92static void uhid_queue(struct uhid_device *uhid, struct uhid_event *ev)
93{
94 __u8 newhead;
95
96 newhead = (uhid->head + 1) % UHID_BUFSIZE;
97
98 if (newhead != uhid->tail) {
99 uhid->outq[uhid->head] = ev;
100 uhid->head = newhead;
101 wake_up_interruptible(&uhid->waitq);
102 } else {
103 hid_warn(uhid->hid, "Output queue is full\n");
104 kfree(ev);
105 }
106}
107
108static int uhid_queue_event(struct uhid_device *uhid, __u32 event)
109{
110 unsigned long flags;
111 struct uhid_event *ev;
112
113 ev = kzalloc(sizeof(*ev), GFP_KERNEL);
114 if (!ev)
115 return -ENOMEM;
116
117 ev->type = event;
118
119 spin_lock_irqsave(&uhid->qlock, flags);
120 uhid_queue(uhid, ev);
121 spin_unlock_irqrestore(&uhid->qlock, flags);
122
123 return 0;
124}
125
126static int uhid_hid_start(struct hid_device *hid)
127{
128 struct uhid_device *uhid = hid->driver_data;
129 struct uhid_event *ev;
130 unsigned long flags;
131
132 ev = kzalloc(sizeof(*ev), GFP_KERNEL);
133 if (!ev)
134 return -ENOMEM;
135
136 ev->type = UHID_START;
137
138 if (hid->report_enum[HID_FEATURE_REPORT].numbered)
139 ev->u.start.dev_flags |= UHID_DEV_NUMBERED_FEATURE_REPORTS;
140 if (hid->report_enum[HID_OUTPUT_REPORT].numbered)
141 ev->u.start.dev_flags |= UHID_DEV_NUMBERED_OUTPUT_REPORTS;
142 if (hid->report_enum[HID_INPUT_REPORT].numbered)
143 ev->u.start.dev_flags |= UHID_DEV_NUMBERED_INPUT_REPORTS;
144
145 spin_lock_irqsave(&uhid->qlock, flags);
146 uhid_queue(uhid, ev);
147 spin_unlock_irqrestore(&uhid->qlock, flags);
148
149 return 0;
150}
151
152static void uhid_hid_stop(struct hid_device *hid)
153{
154 struct uhid_device *uhid = hid->driver_data;
155
156 hid->claimed = 0;
157 uhid_queue_event(uhid, UHID_STOP);
158}
159
160static int uhid_hid_open(struct hid_device *hid)
161{
162 struct uhid_device *uhid = hid->driver_data;
163
164 return uhid_queue_event(uhid, UHID_OPEN);
165}
166
167static void uhid_hid_close(struct hid_device *hid)
168{
169 struct uhid_device *uhid = hid->driver_data;
170
171 uhid_queue_event(uhid, UHID_CLOSE);
172}
173
174static int uhid_hid_parse(struct hid_device *hid)
175{
176 struct uhid_device *uhid = hid->driver_data;
177
178 return hid_parse_report(hid, uhid->rd_data, uhid->rd_size);
179}
180
181/* must be called with report_lock held */
182static int __uhid_report_queue_and_wait(struct uhid_device *uhid,
183 struct uhid_event *ev,
184 __u32 *report_id)
185{
186 unsigned long flags;
187 int ret;
188
189 spin_lock_irqsave(&uhid->qlock, flags);
190 *report_id = ++uhid->report_id;
191 uhid->report_type = ev->type + 1;
192 uhid->report_running = true;
193 uhid_queue(uhid, ev);
194 spin_unlock_irqrestore(&uhid->qlock, flags);
195
196 ret = wait_event_interruptible_timeout(uhid->report_wait,
197 !uhid->report_running || !READ_ONCE(uhid->running),
198 5 * HZ);
199 if (!ret || !READ_ONCE(uhid->running) || uhid->report_running)
200 ret = -EIO;
201 else if (ret < 0)
202 ret = -ERESTARTSYS;
203 else
204 ret = 0;
205
206 uhid->report_running = false;
207
208 return ret;
209}
210
211static void uhid_report_wake_up(struct uhid_device *uhid, u32 id,
212 const struct uhid_event *ev)
213{
214 unsigned long flags;
215
216 spin_lock_irqsave(&uhid->qlock, flags);
217
218 /* id for old report; drop it silently */
219 if (uhid->report_type != ev->type || uhid->report_id != id)
220 goto unlock;
221 if (!uhid->report_running)
222 goto unlock;
223
224 memcpy(&uhid->report_buf, ev, sizeof(*ev));
225 uhid->report_running = false;
226 wake_up_interruptible(&uhid->report_wait);
227
228unlock:
229 spin_unlock_irqrestore(&uhid->qlock, flags);
230}
231
232static int uhid_hid_get_report(struct hid_device *hid, unsigned char rnum,
233 u8 *buf, size_t count, u8 rtype)
234{
235 struct uhid_device *uhid = hid->driver_data;
236 struct uhid_get_report_reply_req *req;
237 struct uhid_event *ev;
238 int ret;
239
240 if (!READ_ONCE(uhid->running))
241 return -EIO;
242
243 ev = kzalloc(sizeof(*ev), GFP_KERNEL);
244 if (!ev)
245 return -ENOMEM;
246
247 ev->type = UHID_GET_REPORT;
248 ev->u.get_report.rnum = rnum;
249 ev->u.get_report.rtype = rtype;
250
251 ret = mutex_lock_interruptible(&uhid->report_lock);
252 if (ret) {
253 kfree(ev);
254 return ret;
255 }
256
257 /* this _always_ takes ownership of @ev */
258 ret = __uhid_report_queue_and_wait(uhid, ev, &ev->u.get_report.id);
259 if (ret)
260 goto unlock;
261
262 req = &uhid->report_buf.u.get_report_reply;
263 if (req->err) {
264 ret = -EIO;
265 } else {
266 ret = min3(count, (size_t)req->size, (size_t)UHID_DATA_MAX);
267 memcpy(buf, req->data, ret);
268 }
269
270unlock:
271 mutex_unlock(&uhid->report_lock);
272 return ret;
273}
274
275static int uhid_hid_set_report(struct hid_device *hid, unsigned char rnum,
276 const u8 *buf, size_t count, u8 rtype)
277{
278 struct uhid_device *uhid = hid->driver_data;
279 struct uhid_event *ev;
280 int ret;
281
282 if (!READ_ONCE(uhid->running) || count > UHID_DATA_MAX)
283 return -EIO;
284
285 ev = kzalloc(sizeof(*ev), GFP_KERNEL);
286 if (!ev)
287 return -ENOMEM;
288
289 ev->type = UHID_SET_REPORT;
290 ev->u.set_report.rnum = rnum;
291 ev->u.set_report.rtype = rtype;
292 ev->u.set_report.size = count;
293 memcpy(ev->u.set_report.data, buf, count);
294
295 ret = mutex_lock_interruptible(&uhid->report_lock);
296 if (ret) {
297 kfree(ev);
298 return ret;
299 }
300
301 /* this _always_ takes ownership of @ev */
302 ret = __uhid_report_queue_and_wait(uhid, ev, &ev->u.set_report.id);
303 if (ret)
304 goto unlock;
305
306 if (uhid->report_buf.u.set_report_reply.err)
307 ret = -EIO;
308 else
309 ret = count;
310
311unlock:
312 mutex_unlock(&uhid->report_lock);
313 return ret;
314}
315
316static int uhid_hid_raw_request(struct hid_device *hid, unsigned char reportnum,
317 __u8 *buf, size_t len, unsigned char rtype,
318 int reqtype)
319{
320 u8 u_rtype;
321
322 switch (rtype) {
323 case HID_FEATURE_REPORT:
324 u_rtype = UHID_FEATURE_REPORT;
325 break;
326 case HID_OUTPUT_REPORT:
327 u_rtype = UHID_OUTPUT_REPORT;
328 break;
329 case HID_INPUT_REPORT:
330 u_rtype = UHID_INPUT_REPORT;
331 break;
332 default:
333 return -EINVAL;
334 }
335
336 switch (reqtype) {
337 case HID_REQ_GET_REPORT:
338 return uhid_hid_get_report(hid, reportnum, buf, len, u_rtype);
339 case HID_REQ_SET_REPORT:
340 return uhid_hid_set_report(hid, reportnum, buf, len, u_rtype);
341 default:
342 return -EIO;
343 }
344}
345
346static int uhid_hid_output_raw(struct hid_device *hid, __u8 *buf, size_t count,
347 unsigned char report_type)
348{
349 struct uhid_device *uhid = hid->driver_data;
350 __u8 rtype;
351 unsigned long flags;
352 struct uhid_event *ev;
353
354 switch (report_type) {
355 case HID_FEATURE_REPORT:
356 rtype = UHID_FEATURE_REPORT;
357 break;
358 case HID_OUTPUT_REPORT:
359 rtype = UHID_OUTPUT_REPORT;
360 break;
361 default:
362 return -EINVAL;
363 }
364
365 if (count < 1 || count > UHID_DATA_MAX)
366 return -EINVAL;
367
368 ev = kzalloc(sizeof(*ev), GFP_KERNEL);
369 if (!ev)
370 return -ENOMEM;
371
372 ev->type = UHID_OUTPUT;
373 ev->u.output.size = count;
374 ev->u.output.rtype = rtype;
375 memcpy(ev->u.output.data, buf, count);
376
377 spin_lock_irqsave(&uhid->qlock, flags);
378 uhid_queue(uhid, ev);
379 spin_unlock_irqrestore(&uhid->qlock, flags);
380
381 return count;
382}
383
384static int uhid_hid_output_report(struct hid_device *hid, __u8 *buf,
385 size_t count)
386{
387 return uhid_hid_output_raw(hid, buf, count, HID_OUTPUT_REPORT);
388}
389
390static const struct hid_ll_driver uhid_hid_driver = {
391 .start = uhid_hid_start,
392 .stop = uhid_hid_stop,
393 .open = uhid_hid_open,
394 .close = uhid_hid_close,
395 .parse = uhid_hid_parse,
396 .raw_request = uhid_hid_raw_request,
397 .output_report = uhid_hid_output_report,
398 .max_buffer_size = UHID_DATA_MAX,
399};
400
401#ifdef CONFIG_COMPAT
402
403/* Apparently we haven't stepped on these rakes enough times yet. */
404struct uhid_create_req_compat {
405 __u8 name[128];
406 __u8 phys[64];
407 __u8 uniq[64];
408
409 compat_uptr_t rd_data;
410 __u16 rd_size;
411
412 __u16 bus;
413 __u32 vendor;
414 __u32 product;
415 __u32 version;
416 __u32 country;
417} __attribute__((__packed__));
418
419static int uhid_event_from_user(const char __user *buffer, size_t len,
420 struct uhid_event *event)
421{
422 if (in_compat_syscall()) {
423 u32 type;
424
425 if (get_user(type, buffer))
426 return -EFAULT;
427
428 if (type == UHID_CREATE) {
429 /*
430 * This is our messed up request with compat pointer.
431 * It is largish (more than 256 bytes) so we better
432 * allocate it from the heap.
433 */
434 struct uhid_create_req_compat *compat;
435
436 compat = kzalloc(sizeof(*compat), GFP_KERNEL);
437 if (!compat)
438 return -ENOMEM;
439
440 buffer += sizeof(type);
441 len -= sizeof(type);
442 if (copy_from_user(compat, buffer,
443 min(len, sizeof(*compat)))) {
444 kfree(compat);
445 return -EFAULT;
446 }
447
448 /* Shuffle the data over to proper structure */
449 event->type = type;
450
451 memcpy(event->u.create.name, compat->name,
452 sizeof(compat->name));
453 memcpy(event->u.create.phys, compat->phys,
454 sizeof(compat->phys));
455 memcpy(event->u.create.uniq, compat->uniq,
456 sizeof(compat->uniq));
457
458 event->u.create.rd_data = compat_ptr(compat->rd_data);
459 event->u.create.rd_size = compat->rd_size;
460
461 event->u.create.bus = compat->bus;
462 event->u.create.vendor = compat->vendor;
463 event->u.create.product = compat->product;
464 event->u.create.version = compat->version;
465 event->u.create.country = compat->country;
466
467 kfree(compat);
468 return 0;
469 }
470 /* All others can be copied directly */
471 }
472
473 if (copy_from_user(event, buffer, min(len, sizeof(*event))))
474 return -EFAULT;
475
476 return 0;
477}
478#else
479static int uhid_event_from_user(const char __user *buffer, size_t len,
480 struct uhid_event *event)
481{
482 if (copy_from_user(event, buffer, min(len, sizeof(*event))))
483 return -EFAULT;
484
485 return 0;
486}
487#endif
488
489static int uhid_dev_create2(struct uhid_device *uhid,
490 const struct uhid_event *ev)
491{
492 struct hid_device *hid;
493 size_t rd_size;
494 void *rd_data;
495 int ret;
496
497 if (uhid->hid)
498 return -EALREADY;
499
500 rd_size = ev->u.create2.rd_size;
501 if (rd_size <= 0 || rd_size > HID_MAX_DESCRIPTOR_SIZE)
502 return -EINVAL;
503
504 rd_data = kmemdup(ev->u.create2.rd_data, rd_size, GFP_KERNEL);
505 if (!rd_data)
506 return -ENOMEM;
507
508 uhid->rd_size = rd_size;
509 uhid->rd_data = rd_data;
510
511 hid = hid_allocate_device();
512 if (IS_ERR(hid)) {
513 ret = PTR_ERR(hid);
514 goto err_free;
515 }
516
517 BUILD_BUG_ON(sizeof(hid->name) != sizeof(ev->u.create2.name));
518 strscpy(hid->name, ev->u.create2.name, sizeof(hid->name));
519 BUILD_BUG_ON(sizeof(hid->phys) != sizeof(ev->u.create2.phys));
520 strscpy(hid->phys, ev->u.create2.phys, sizeof(hid->phys));
521 BUILD_BUG_ON(sizeof(hid->uniq) != sizeof(ev->u.create2.uniq));
522 strscpy(hid->uniq, ev->u.create2.uniq, sizeof(hid->uniq));
523
524 hid->ll_driver = &uhid_hid_driver;
525 hid->bus = ev->u.create2.bus;
526 hid->vendor = ev->u.create2.vendor;
527 hid->product = ev->u.create2.product;
528 hid->version = ev->u.create2.version;
529 hid->country = ev->u.create2.country;
530 hid->driver_data = uhid;
531 hid->dev.parent = uhid_misc.this_device;
532
533 uhid->hid = hid;
534 uhid->running = true;
535
536 /* Adding of a HID device is done through a worker, to allow HID drivers
537 * which use feature requests during .probe to work, without they would
538 * be blocked on devlock, which is held by uhid_char_write.
539 */
540 schedule_work(&uhid->worker);
541
542 return 0;
543
544err_free:
545 kfree(uhid->rd_data);
546 uhid->rd_data = NULL;
547 uhid->rd_size = 0;
548 return ret;
549}
550
551static int uhid_dev_create(struct uhid_device *uhid,
552 struct uhid_event *ev)
553{
554 struct uhid_create_req orig;
555
556 orig = ev->u.create;
557
558 if (orig.rd_size <= 0 || orig.rd_size > HID_MAX_DESCRIPTOR_SIZE)
559 return -EINVAL;
560 if (copy_from_user(&ev->u.create2.rd_data, orig.rd_data, orig.rd_size))
561 return -EFAULT;
562
563 memcpy(ev->u.create2.name, orig.name, sizeof(orig.name));
564 memcpy(ev->u.create2.phys, orig.phys, sizeof(orig.phys));
565 memcpy(ev->u.create2.uniq, orig.uniq, sizeof(orig.uniq));
566 ev->u.create2.rd_size = orig.rd_size;
567 ev->u.create2.bus = orig.bus;
568 ev->u.create2.vendor = orig.vendor;
569 ev->u.create2.product = orig.product;
570 ev->u.create2.version = orig.version;
571 ev->u.create2.country = orig.country;
572
573 return uhid_dev_create2(uhid, ev);
574}
575
576static int uhid_dev_destroy(struct uhid_device *uhid)
577{
578 if (!uhid->hid)
579 return -EINVAL;
580
581 WRITE_ONCE(uhid->running, false);
582 wake_up_interruptible(&uhid->report_wait);
583
584 cancel_work_sync(&uhid->worker);
585
586 hid_destroy_device(uhid->hid);
587 uhid->hid = NULL;
588 kfree(uhid->rd_data);
589
590 return 0;
591}
592
593static int uhid_dev_input(struct uhid_device *uhid, struct uhid_event *ev)
594{
595 if (!READ_ONCE(uhid->running))
596 return -EINVAL;
597
598 hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input.data,
599 min_t(size_t, ev->u.input.size, UHID_DATA_MAX), 0);
600
601 return 0;
602}
603
604static int uhid_dev_input2(struct uhid_device *uhid, struct uhid_event *ev)
605{
606 if (!READ_ONCE(uhid->running))
607 return -EINVAL;
608
609 hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input2.data,
610 min_t(size_t, ev->u.input2.size, UHID_DATA_MAX), 0);
611
612 return 0;
613}
614
615static int uhid_dev_get_report_reply(struct uhid_device *uhid,
616 struct uhid_event *ev)
617{
618 if (!READ_ONCE(uhid->running))
619 return -EINVAL;
620
621 uhid_report_wake_up(uhid, ev->u.get_report_reply.id, ev);
622 return 0;
623}
624
625static int uhid_dev_set_report_reply(struct uhid_device *uhid,
626 struct uhid_event *ev)
627{
628 if (!READ_ONCE(uhid->running))
629 return -EINVAL;
630
631 uhid_report_wake_up(uhid, ev->u.set_report_reply.id, ev);
632 return 0;
633}
634
635static int uhid_char_open(struct inode *inode, struct file *file)
636{
637 struct uhid_device *uhid;
638
639 uhid = kzalloc(sizeof(*uhid), GFP_KERNEL);
640 if (!uhid)
641 return -ENOMEM;
642
643 mutex_init(&uhid->devlock);
644 mutex_init(&uhid->report_lock);
645 spin_lock_init(&uhid->qlock);
646 init_waitqueue_head(&uhid->waitq);
647 init_waitqueue_head(&uhid->report_wait);
648 uhid->running = false;
649 INIT_WORK(&uhid->worker, uhid_device_add_worker);
650
651 file->private_data = uhid;
652 stream_open(inode, file);
653
654 return 0;
655}
656
657static int uhid_char_release(struct inode *inode, struct file *file)
658{
659 struct uhid_device *uhid = file->private_data;
660 unsigned int i;
661
662 uhid_dev_destroy(uhid);
663
664 for (i = 0; i < UHID_BUFSIZE; ++i)
665 kfree(uhid->outq[i]);
666
667 kfree(uhid);
668
669 return 0;
670}
671
672static ssize_t uhid_char_read(struct file *file, char __user *buffer,
673 size_t count, loff_t *ppos)
674{
675 struct uhid_device *uhid = file->private_data;
676 int ret;
677 unsigned long flags;
678 size_t len;
679
680 /* they need at least the "type" member of uhid_event */
681 if (count < sizeof(__u32))
682 return -EINVAL;
683
684try_again:
685 if (file->f_flags & O_NONBLOCK) {
686 if (uhid->head == uhid->tail)
687 return -EAGAIN;
688 } else {
689 ret = wait_event_interruptible(uhid->waitq,
690 uhid->head != uhid->tail);
691 if (ret)
692 return ret;
693 }
694
695 ret = mutex_lock_interruptible(&uhid->devlock);
696 if (ret)
697 return ret;
698
699 if (uhid->head == uhid->tail) {
700 mutex_unlock(&uhid->devlock);
701 goto try_again;
702 } else {
703 len = min(count, sizeof(**uhid->outq));
704 if (copy_to_user(buffer, uhid->outq[uhid->tail], len)) {
705 ret = -EFAULT;
706 } else {
707 kfree(uhid->outq[uhid->tail]);
708 uhid->outq[uhid->tail] = NULL;
709
710 spin_lock_irqsave(&uhid->qlock, flags);
711 uhid->tail = (uhid->tail + 1) % UHID_BUFSIZE;
712 spin_unlock_irqrestore(&uhid->qlock, flags);
713 }
714 }
715
716 mutex_unlock(&uhid->devlock);
717 return ret ? ret : len;
718}
719
720static ssize_t uhid_char_write(struct file *file, const char __user *buffer,
721 size_t count, loff_t *ppos)
722{
723 struct uhid_device *uhid = file->private_data;
724 int ret;
725 size_t len;
726
727 /* we need at least the "type" member of uhid_event */
728 if (count < sizeof(__u32))
729 return -EINVAL;
730
731 ret = mutex_lock_interruptible(&uhid->devlock);
732 if (ret)
733 return ret;
734
735 memset(&uhid->input_buf, 0, sizeof(uhid->input_buf));
736 len = min(count, sizeof(uhid->input_buf));
737
738 ret = uhid_event_from_user(buffer, len, &uhid->input_buf);
739 if (ret)
740 goto unlock;
741
742 switch (uhid->input_buf.type) {
743 case UHID_CREATE:
744 /*
745 * 'struct uhid_create_req' contains a __user pointer which is
746 * copied from, so it's unsafe to allow this with elevated
747 * privileges (e.g. from a setuid binary) or via kernel_write().
748 */
749 if (file->f_cred != current_cred()) {
750 pr_err_once("UHID_CREATE from different security context by process %d (%s), this is not allowed.\n",
751 task_tgid_vnr(current), current->comm);
752 ret = -EACCES;
753 goto unlock;
754 }
755 ret = uhid_dev_create(uhid, &uhid->input_buf);
756 break;
757 case UHID_CREATE2:
758 ret = uhid_dev_create2(uhid, &uhid->input_buf);
759 break;
760 case UHID_DESTROY:
761 ret = uhid_dev_destroy(uhid);
762 break;
763 case UHID_INPUT:
764 ret = uhid_dev_input(uhid, &uhid->input_buf);
765 break;
766 case UHID_INPUT2:
767 ret = uhid_dev_input2(uhid, &uhid->input_buf);
768 break;
769 case UHID_GET_REPORT_REPLY:
770 ret = uhid_dev_get_report_reply(uhid, &uhid->input_buf);
771 break;
772 case UHID_SET_REPORT_REPLY:
773 ret = uhid_dev_set_report_reply(uhid, &uhid->input_buf);
774 break;
775 default:
776 ret = -EOPNOTSUPP;
777 }
778
779unlock:
780 mutex_unlock(&uhid->devlock);
781
782 /* return "count" not "len" to not confuse the caller */
783 return ret ? ret : count;
784}
785
786static __poll_t uhid_char_poll(struct file *file, poll_table *wait)
787{
788 struct uhid_device *uhid = file->private_data;
789 __poll_t mask = EPOLLOUT | EPOLLWRNORM; /* uhid is always writable */
790
791 poll_wait(file, &uhid->waitq, wait);
792
793 if (uhid->head != uhid->tail)
794 mask |= EPOLLIN | EPOLLRDNORM;
795
796 return mask;
797}
798
799static const struct file_operations uhid_fops = {
800 .owner = THIS_MODULE,
801 .open = uhid_char_open,
802 .release = uhid_char_release,
803 .read = uhid_char_read,
804 .write = uhid_char_write,
805 .poll = uhid_char_poll,
806};
807
808static struct miscdevice uhid_misc = {
809 .fops = &uhid_fops,
810 .minor = UHID_MINOR,
811 .name = UHID_NAME,
812};
813module_misc_device(uhid_misc);
814
815MODULE_LICENSE("GPL");
816MODULE_AUTHOR("David Herrmann <dh.herrmann@gmail.com>");
817MODULE_DESCRIPTION("User-space I/O driver support for HID subsystem");
818MODULE_ALIAS_MISCDEV(UHID_MINOR);
819MODULE_ALIAS("devname:" UHID_NAME);