Loading...
Note: File does not exist in v3.1.
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 struct mutex report_lock;
48 wait_queue_head_t report_wait;
49 atomic_t report_done;
50 atomic_t report_id;
51 struct uhid_event report_buf;
52};
53
54static struct miscdevice uhid_misc;
55
56static void uhid_queue(struct uhid_device *uhid, struct uhid_event *ev)
57{
58 __u8 newhead;
59
60 newhead = (uhid->head + 1) % UHID_BUFSIZE;
61
62 if (newhead != uhid->tail) {
63 uhid->outq[uhid->head] = ev;
64 uhid->head = newhead;
65 wake_up_interruptible(&uhid->waitq);
66 } else {
67 hid_warn(uhid->hid, "Output queue is full\n");
68 kfree(ev);
69 }
70}
71
72static int uhid_queue_event(struct uhid_device *uhid, __u32 event)
73{
74 unsigned long flags;
75 struct uhid_event *ev;
76
77 ev = kzalloc(sizeof(*ev), GFP_KERNEL);
78 if (!ev)
79 return -ENOMEM;
80
81 ev->type = event;
82
83 spin_lock_irqsave(&uhid->qlock, flags);
84 uhid_queue(uhid, ev);
85 spin_unlock_irqrestore(&uhid->qlock, flags);
86
87 return 0;
88}
89
90static int uhid_hid_start(struct hid_device *hid)
91{
92 struct uhid_device *uhid = hid->driver_data;
93
94 return uhid_queue_event(uhid, UHID_START);
95}
96
97static void uhid_hid_stop(struct hid_device *hid)
98{
99 struct uhid_device *uhid = hid->driver_data;
100
101 hid->claimed = 0;
102 uhid_queue_event(uhid, UHID_STOP);
103}
104
105static int uhid_hid_open(struct hid_device *hid)
106{
107 struct uhid_device *uhid = hid->driver_data;
108
109 return uhid_queue_event(uhid, UHID_OPEN);
110}
111
112static void uhid_hid_close(struct hid_device *hid)
113{
114 struct uhid_device *uhid = hid->driver_data;
115
116 uhid_queue_event(uhid, UHID_CLOSE);
117}
118
119static int uhid_hid_parse(struct hid_device *hid)
120{
121 struct uhid_device *uhid = hid->driver_data;
122
123 return hid_parse_report(hid, uhid->rd_data, uhid->rd_size);
124}
125
126static int uhid_hid_get_raw(struct hid_device *hid, unsigned char rnum,
127 __u8 *buf, size_t count, unsigned char rtype)
128{
129 struct uhid_device *uhid = hid->driver_data;
130 __u8 report_type;
131 struct uhid_event *ev;
132 unsigned long flags;
133 int ret;
134 size_t uninitialized_var(len);
135 struct uhid_feature_answer_req *req;
136
137 if (!uhid->running)
138 return -EIO;
139
140 switch (rtype) {
141 case HID_FEATURE_REPORT:
142 report_type = UHID_FEATURE_REPORT;
143 break;
144 case HID_OUTPUT_REPORT:
145 report_type = UHID_OUTPUT_REPORT;
146 break;
147 case HID_INPUT_REPORT:
148 report_type = UHID_INPUT_REPORT;
149 break;
150 default:
151 return -EINVAL;
152 }
153
154 ret = mutex_lock_interruptible(&uhid->report_lock);
155 if (ret)
156 return ret;
157
158 ev = kzalloc(sizeof(*ev), GFP_KERNEL);
159 if (!ev) {
160 ret = -ENOMEM;
161 goto unlock;
162 }
163
164 spin_lock_irqsave(&uhid->qlock, flags);
165 ev->type = UHID_FEATURE;
166 ev->u.feature.id = atomic_inc_return(&uhid->report_id);
167 ev->u.feature.rnum = rnum;
168 ev->u.feature.rtype = report_type;
169
170 atomic_set(&uhid->report_done, 0);
171 uhid_queue(uhid, ev);
172 spin_unlock_irqrestore(&uhid->qlock, flags);
173
174 ret = wait_event_interruptible_timeout(uhid->report_wait,
175 atomic_read(&uhid->report_done), 5 * HZ);
176
177 /*
178 * Make sure "uhid->running" is cleared on shutdown before
179 * "uhid->report_done" is set.
180 */
181 smp_rmb();
182 if (!ret || !uhid->running) {
183 ret = -EIO;
184 } else if (ret < 0) {
185 ret = -ERESTARTSYS;
186 } else {
187 spin_lock_irqsave(&uhid->qlock, flags);
188 req = &uhid->report_buf.u.feature_answer;
189
190 if (req->err) {
191 ret = -EIO;
192 } else {
193 ret = 0;
194 len = min(count,
195 min_t(size_t, req->size, UHID_DATA_MAX));
196 memcpy(buf, req->data, len);
197 }
198
199 spin_unlock_irqrestore(&uhid->qlock, flags);
200 }
201
202 atomic_set(&uhid->report_done, 1);
203
204unlock:
205 mutex_unlock(&uhid->report_lock);
206 return ret ? ret : len;
207}
208
209static int uhid_hid_output_raw(struct hid_device *hid, __u8 *buf, size_t count,
210 unsigned char report_type)
211{
212 struct uhid_device *uhid = hid->driver_data;
213 __u8 rtype;
214 unsigned long flags;
215 struct uhid_event *ev;
216
217 switch (report_type) {
218 case HID_FEATURE_REPORT:
219 rtype = UHID_FEATURE_REPORT;
220 break;
221 case HID_OUTPUT_REPORT:
222 rtype = UHID_OUTPUT_REPORT;
223 break;
224 default:
225 return -EINVAL;
226 }
227
228 if (count < 1 || count > UHID_DATA_MAX)
229 return -EINVAL;
230
231 ev = kzalloc(sizeof(*ev), GFP_KERNEL);
232 if (!ev)
233 return -ENOMEM;
234
235 ev->type = UHID_OUTPUT;
236 ev->u.output.size = count;
237 ev->u.output.rtype = rtype;
238 memcpy(ev->u.output.data, buf, count);
239
240 spin_lock_irqsave(&uhid->qlock, flags);
241 uhid_queue(uhid, ev);
242 spin_unlock_irqrestore(&uhid->qlock, flags);
243
244 return count;
245}
246
247static int uhid_hid_output_report(struct hid_device *hid, __u8 *buf,
248 size_t count)
249{
250 return uhid_hid_output_raw(hid, buf, count, HID_OUTPUT_REPORT);
251}
252
253static int uhid_raw_request(struct hid_device *hid, unsigned char reportnum,
254 __u8 *buf, size_t len, unsigned char rtype,
255 int reqtype)
256{
257 switch (reqtype) {
258 case HID_REQ_GET_REPORT:
259 return uhid_hid_get_raw(hid, reportnum, buf, len, rtype);
260 case HID_REQ_SET_REPORT:
261 /* TODO: implement proper SET_REPORT functionality */
262 return -ENOSYS;
263 default:
264 return -EIO;
265 }
266}
267
268static struct hid_ll_driver uhid_hid_driver = {
269 .start = uhid_hid_start,
270 .stop = uhid_hid_stop,
271 .open = uhid_hid_open,
272 .close = uhid_hid_close,
273 .parse = uhid_hid_parse,
274 .output_report = uhid_hid_output_report,
275 .raw_request = uhid_raw_request,
276};
277
278#ifdef CONFIG_COMPAT
279
280/* Apparently we haven't stepped on these rakes enough times yet. */
281struct uhid_create_req_compat {
282 __u8 name[128];
283 __u8 phys[64];
284 __u8 uniq[64];
285
286 compat_uptr_t rd_data;
287 __u16 rd_size;
288
289 __u16 bus;
290 __u32 vendor;
291 __u32 product;
292 __u32 version;
293 __u32 country;
294} __attribute__((__packed__));
295
296static int uhid_event_from_user(const char __user *buffer, size_t len,
297 struct uhid_event *event)
298{
299 if (is_compat_task()) {
300 u32 type;
301
302 if (get_user(type, buffer))
303 return -EFAULT;
304
305 if (type == UHID_CREATE) {
306 /*
307 * This is our messed up request with compat pointer.
308 * It is largish (more than 256 bytes) so we better
309 * allocate it from the heap.
310 */
311 struct uhid_create_req_compat *compat;
312
313 compat = kzalloc(sizeof(*compat), GFP_KERNEL);
314 if (!compat)
315 return -ENOMEM;
316
317 buffer += sizeof(type);
318 len -= sizeof(type);
319 if (copy_from_user(compat, buffer,
320 min(len, sizeof(*compat)))) {
321 kfree(compat);
322 return -EFAULT;
323 }
324
325 /* Shuffle the data over to proper structure */
326 event->type = type;
327
328 memcpy(event->u.create.name, compat->name,
329 sizeof(compat->name));
330 memcpy(event->u.create.phys, compat->phys,
331 sizeof(compat->phys));
332 memcpy(event->u.create.uniq, compat->uniq,
333 sizeof(compat->uniq));
334
335 event->u.create.rd_data = compat_ptr(compat->rd_data);
336 event->u.create.rd_size = compat->rd_size;
337
338 event->u.create.bus = compat->bus;
339 event->u.create.vendor = compat->vendor;
340 event->u.create.product = compat->product;
341 event->u.create.version = compat->version;
342 event->u.create.country = compat->country;
343
344 kfree(compat);
345 return 0;
346 }
347 /* All others can be copied directly */
348 }
349
350 if (copy_from_user(event, buffer, min(len, sizeof(*event))))
351 return -EFAULT;
352
353 return 0;
354}
355#else
356static int uhid_event_from_user(const char __user *buffer, size_t len,
357 struct uhid_event *event)
358{
359 if (copy_from_user(event, buffer, min(len, sizeof(*event))))
360 return -EFAULT;
361
362 return 0;
363}
364#endif
365
366static int uhid_dev_create(struct uhid_device *uhid,
367 const struct uhid_event *ev)
368{
369 struct hid_device *hid;
370 int ret;
371
372 if (uhid->running)
373 return -EALREADY;
374
375 uhid->rd_size = ev->u.create.rd_size;
376 if (uhid->rd_size <= 0 || uhid->rd_size > HID_MAX_DESCRIPTOR_SIZE)
377 return -EINVAL;
378
379 uhid->rd_data = kmalloc(uhid->rd_size, GFP_KERNEL);
380 if (!uhid->rd_data)
381 return -ENOMEM;
382
383 if (copy_from_user(uhid->rd_data, ev->u.create.rd_data,
384 uhid->rd_size)) {
385 ret = -EFAULT;
386 goto err_free;
387 }
388
389 hid = hid_allocate_device();
390 if (IS_ERR(hid)) {
391 ret = PTR_ERR(hid);
392 goto err_free;
393 }
394
395 strncpy(hid->name, ev->u.create.name, 127);
396 hid->name[127] = 0;
397 strncpy(hid->phys, ev->u.create.phys, 63);
398 hid->phys[63] = 0;
399 strncpy(hid->uniq, ev->u.create.uniq, 63);
400 hid->uniq[63] = 0;
401
402 hid->ll_driver = &uhid_hid_driver;
403 hid->bus = ev->u.create.bus;
404 hid->vendor = ev->u.create.vendor;
405 hid->product = ev->u.create.product;
406 hid->version = ev->u.create.version;
407 hid->country = ev->u.create.country;
408 hid->driver_data = uhid;
409 hid->dev.parent = uhid_misc.this_device;
410
411 uhid->hid = hid;
412 uhid->running = true;
413
414 ret = hid_add_device(hid);
415 if (ret) {
416 hid_err(hid, "Cannot register HID device\n");
417 goto err_hid;
418 }
419
420 return 0;
421
422err_hid:
423 hid_destroy_device(hid);
424 uhid->hid = NULL;
425 uhid->running = false;
426err_free:
427 kfree(uhid->rd_data);
428 return ret;
429}
430
431static int uhid_dev_create2(struct uhid_device *uhid,
432 const struct uhid_event *ev)
433{
434 struct hid_device *hid;
435 int ret;
436
437 if (uhid->running)
438 return -EALREADY;
439
440 uhid->rd_size = ev->u.create2.rd_size;
441 if (uhid->rd_size <= 0 || uhid->rd_size > HID_MAX_DESCRIPTOR_SIZE)
442 return -EINVAL;
443
444 uhid->rd_data = kmalloc(uhid->rd_size, GFP_KERNEL);
445 if (!uhid->rd_data)
446 return -ENOMEM;
447
448 memcpy(uhid->rd_data, ev->u.create2.rd_data, uhid->rd_size);
449
450 hid = hid_allocate_device();
451 if (IS_ERR(hid)) {
452 ret = PTR_ERR(hid);
453 goto err_free;
454 }
455
456 strncpy(hid->name, ev->u.create2.name, 127);
457 hid->name[127] = 0;
458 strncpy(hid->phys, ev->u.create2.phys, 63);
459 hid->phys[63] = 0;
460 strncpy(hid->uniq, ev->u.create2.uniq, 63);
461 hid->uniq[63] = 0;
462
463 hid->ll_driver = &uhid_hid_driver;
464 hid->bus = ev->u.create2.bus;
465 hid->vendor = ev->u.create2.vendor;
466 hid->product = ev->u.create2.product;
467 hid->version = ev->u.create2.version;
468 hid->country = ev->u.create2.country;
469 hid->driver_data = uhid;
470 hid->dev.parent = uhid_misc.this_device;
471
472 uhid->hid = hid;
473 uhid->running = true;
474
475 ret = hid_add_device(hid);
476 if (ret) {
477 hid_err(hid, "Cannot register HID device\n");
478 goto err_hid;
479 }
480
481 return 0;
482
483err_hid:
484 hid_destroy_device(hid);
485 uhid->hid = NULL;
486 uhid->running = false;
487err_free:
488 kfree(uhid->rd_data);
489 return ret;
490}
491
492static int uhid_dev_destroy(struct uhid_device *uhid)
493{
494 if (!uhid->running)
495 return -EINVAL;
496
497 /* clear "running" before setting "report_done" */
498 uhid->running = false;
499 smp_wmb();
500 atomic_set(&uhid->report_done, 1);
501 wake_up_interruptible(&uhid->report_wait);
502
503 hid_destroy_device(uhid->hid);
504 kfree(uhid->rd_data);
505
506 return 0;
507}
508
509static int uhid_dev_input(struct uhid_device *uhid, struct uhid_event *ev)
510{
511 if (!uhid->running)
512 return -EINVAL;
513
514 hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input.data,
515 min_t(size_t, ev->u.input.size, UHID_DATA_MAX), 0);
516
517 return 0;
518}
519
520static int uhid_dev_input2(struct uhid_device *uhid, struct uhid_event *ev)
521{
522 if (!uhid->running)
523 return -EINVAL;
524
525 hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input2.data,
526 min_t(size_t, ev->u.input2.size, UHID_DATA_MAX), 0);
527
528 return 0;
529}
530
531static int uhid_dev_feature_answer(struct uhid_device *uhid,
532 struct uhid_event *ev)
533{
534 unsigned long flags;
535
536 if (!uhid->running)
537 return -EINVAL;
538
539 spin_lock_irqsave(&uhid->qlock, flags);
540
541 /* id for old report; drop it silently */
542 if (atomic_read(&uhid->report_id) != ev->u.feature_answer.id)
543 goto unlock;
544 if (atomic_read(&uhid->report_done))
545 goto unlock;
546
547 memcpy(&uhid->report_buf, ev, sizeof(*ev));
548 atomic_set(&uhid->report_done, 1);
549 wake_up_interruptible(&uhid->report_wait);
550
551unlock:
552 spin_unlock_irqrestore(&uhid->qlock, flags);
553 return 0;
554}
555
556static int uhid_char_open(struct inode *inode, struct file *file)
557{
558 struct uhid_device *uhid;
559
560 uhid = kzalloc(sizeof(*uhid), GFP_KERNEL);
561 if (!uhid)
562 return -ENOMEM;
563
564 mutex_init(&uhid->devlock);
565 mutex_init(&uhid->report_lock);
566 spin_lock_init(&uhid->qlock);
567 init_waitqueue_head(&uhid->waitq);
568 init_waitqueue_head(&uhid->report_wait);
569 uhid->running = false;
570 atomic_set(&uhid->report_done, 1);
571
572 file->private_data = uhid;
573 nonseekable_open(inode, file);
574
575 return 0;
576}
577
578static int uhid_char_release(struct inode *inode, struct file *file)
579{
580 struct uhid_device *uhid = file->private_data;
581 unsigned int i;
582
583 uhid_dev_destroy(uhid);
584
585 for (i = 0; i < UHID_BUFSIZE; ++i)
586 kfree(uhid->outq[i]);
587
588 kfree(uhid);
589
590 return 0;
591}
592
593static ssize_t uhid_char_read(struct file *file, char __user *buffer,
594 size_t count, loff_t *ppos)
595{
596 struct uhid_device *uhid = file->private_data;
597 int ret;
598 unsigned long flags;
599 size_t len;
600
601 /* they need at least the "type" member of uhid_event */
602 if (count < sizeof(__u32))
603 return -EINVAL;
604
605try_again:
606 if (file->f_flags & O_NONBLOCK) {
607 if (uhid->head == uhid->tail)
608 return -EAGAIN;
609 } else {
610 ret = wait_event_interruptible(uhid->waitq,
611 uhid->head != uhid->tail);
612 if (ret)
613 return ret;
614 }
615
616 ret = mutex_lock_interruptible(&uhid->devlock);
617 if (ret)
618 return ret;
619
620 if (uhid->head == uhid->tail) {
621 mutex_unlock(&uhid->devlock);
622 goto try_again;
623 } else {
624 len = min(count, sizeof(**uhid->outq));
625 if (copy_to_user(buffer, uhid->outq[uhid->tail], len)) {
626 ret = -EFAULT;
627 } else {
628 kfree(uhid->outq[uhid->tail]);
629 uhid->outq[uhid->tail] = NULL;
630
631 spin_lock_irqsave(&uhid->qlock, flags);
632 uhid->tail = (uhid->tail + 1) % UHID_BUFSIZE;
633 spin_unlock_irqrestore(&uhid->qlock, flags);
634 }
635 }
636
637 mutex_unlock(&uhid->devlock);
638 return ret ? ret : len;
639}
640
641static ssize_t uhid_char_write(struct file *file, const char __user *buffer,
642 size_t count, loff_t *ppos)
643{
644 struct uhid_device *uhid = file->private_data;
645 int ret;
646 size_t len;
647
648 /* we need at least the "type" member of uhid_event */
649 if (count < sizeof(__u32))
650 return -EINVAL;
651
652 ret = mutex_lock_interruptible(&uhid->devlock);
653 if (ret)
654 return ret;
655
656 memset(&uhid->input_buf, 0, sizeof(uhid->input_buf));
657 len = min(count, sizeof(uhid->input_buf));
658
659 ret = uhid_event_from_user(buffer, len, &uhid->input_buf);
660 if (ret)
661 goto unlock;
662
663 switch (uhid->input_buf.type) {
664 case UHID_CREATE:
665 ret = uhid_dev_create(uhid, &uhid->input_buf);
666 break;
667 case UHID_CREATE2:
668 ret = uhid_dev_create2(uhid, &uhid->input_buf);
669 break;
670 case UHID_DESTROY:
671 ret = uhid_dev_destroy(uhid);
672 break;
673 case UHID_INPUT:
674 ret = uhid_dev_input(uhid, &uhid->input_buf);
675 break;
676 case UHID_INPUT2:
677 ret = uhid_dev_input2(uhid, &uhid->input_buf);
678 break;
679 case UHID_FEATURE_ANSWER:
680 ret = uhid_dev_feature_answer(uhid, &uhid->input_buf);
681 break;
682 default:
683 ret = -EOPNOTSUPP;
684 }
685
686unlock:
687 mutex_unlock(&uhid->devlock);
688
689 /* return "count" not "len" to not confuse the caller */
690 return ret ? ret : count;
691}
692
693static unsigned int uhid_char_poll(struct file *file, poll_table *wait)
694{
695 struct uhid_device *uhid = file->private_data;
696
697 poll_wait(file, &uhid->waitq, wait);
698
699 if (uhid->head != uhid->tail)
700 return POLLIN | POLLRDNORM;
701
702 return 0;
703}
704
705static const struct file_operations uhid_fops = {
706 .owner = THIS_MODULE,
707 .open = uhid_char_open,
708 .release = uhid_char_release,
709 .read = uhid_char_read,
710 .write = uhid_char_write,
711 .poll = uhid_char_poll,
712 .llseek = no_llseek,
713};
714
715static struct miscdevice uhid_misc = {
716 .fops = &uhid_fops,
717 .minor = UHID_MINOR,
718 .name = UHID_NAME,
719};
720
721static int __init uhid_init(void)
722{
723 return misc_register(&uhid_misc);
724}
725
726static void __exit uhid_exit(void)
727{
728 misc_deregister(&uhid_misc);
729}
730
731module_init(uhid_init);
732module_exit(uhid_exit);
733MODULE_LICENSE("GPL");
734MODULE_AUTHOR("David Herrmann <dh.herrmann@gmail.com>");
735MODULE_DESCRIPTION("User-space I/O driver support for HID subsystem");
736MODULE_ALIAS_MISCDEV(UHID_MINOR);
737MODULE_ALIAS("devname:" UHID_NAME);