1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * HID raw devices, giving access to raw HID events.
4 *
5 * In comparison to hiddev, this device does not process the
6 * hid events at all (no parsing, no lookups). This lets applications
7 * to work on raw hid events as they want to, and avoids a need to
8 * use a transport-specific userspace libhid/libusb libraries.
9 *
10 * Copyright (c) 2007-2014 Jiri Kosina
11 */
12
13
14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15
16 #include <linux/fs.h>
17 #include <linux/module.h>
18 #include <linux/errno.h>
19 #include <linux/kernel.h>
20 #include <linux/init.h>
21 #include <linux/cdev.h>
22 #include <linux/poll.h>
23 #include <linux/device.h>
24 #include <linux/major.h>
25 #include <linux/slab.h>
26 #include <linux/hid.h>
27 #include <linux/mutex.h>
28 #include <linux/sched/signal.h>
29 #include <linux/string.h>
30
31 #include <linux/hidraw.h>
32
33 static int hidraw_major;
34 static struct cdev hidraw_cdev;
35 static const struct class hidraw_class = {
36 .name = "hidraw",
37 };
38 static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES];
39 static DECLARE_RWSEM(minors_rwsem);
40
hidraw_read(struct file * file,char __user * buffer,size_t count,loff_t * ppos)41 static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
42 {
43 struct hidraw_list *list = file->private_data;
44 int ret = 0, len;
45 DECLARE_WAITQUEUE(wait, current);
46
47 mutex_lock(&list->read_mutex);
48
49 while (ret == 0) {
50 if (list->head == list->tail) {
51 add_wait_queue(&list->hidraw->wait, &wait);
52 set_current_state(TASK_INTERRUPTIBLE);
53
54 while (list->head == list->tail) {
55 if (signal_pending(current)) {
56 ret = -ERESTARTSYS;
57 break;
58 }
59 if (!list->hidraw->exist) {
60 ret = -EIO;
61 break;
62 }
63 if (file->f_flags & O_NONBLOCK) {
64 ret = -EAGAIN;
65 break;
66 }
67
68 /* allow O_NONBLOCK to work well from other threads */
69 mutex_unlock(&list->read_mutex);
70 schedule();
71 mutex_lock(&list->read_mutex);
72 set_current_state(TASK_INTERRUPTIBLE);
73 }
74
75 set_current_state(TASK_RUNNING);
76 remove_wait_queue(&list->hidraw->wait, &wait);
77 }
78
79 if (ret)
80 goto out;
81
82 len = list->buffer[list->tail].len > count ?
83 count : list->buffer[list->tail].len;
84
85 if (list->buffer[list->tail].value) {
86 if (copy_to_user(buffer, list->buffer[list->tail].value, len)) {
87 ret = -EFAULT;
88 goto out;
89 }
90 ret = len;
91 }
92
93 kfree(list->buffer[list->tail].value);
94 list->buffer[list->tail].value = NULL;
95 list->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1);
96 }
97 out:
98 mutex_unlock(&list->read_mutex);
99 return ret;
100 }
101
102 /*
103 * The first byte of the report buffer is expected to be a report number.
104 */
hidraw_send_report(struct file * file,const char __user * buffer,size_t count,unsigned char report_type)105 static ssize_t hidraw_send_report(struct file *file, const char __user *buffer, size_t count, unsigned char report_type)
106 {
107 unsigned int minor = iminor(file_inode(file));
108 struct hid_device *dev;
109 __u8 *buf;
110 int ret = 0;
111
112 lockdep_assert_held(&minors_rwsem);
113
114 if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
115 ret = -ENODEV;
116 goto out;
117 }
118
119 dev = hidraw_table[minor]->hid;
120
121 if (count > HID_MAX_BUFFER_SIZE) {
122 hid_warn(dev, "pid %d passed too large report\n",
123 task_pid_nr(current));
124 ret = -EINVAL;
125 goto out;
126 }
127
128 if (count < 2) {
129 hid_warn(dev, "pid %d passed too short report\n",
130 task_pid_nr(current));
131 ret = -EINVAL;
132 goto out;
133 }
134
135 buf = memdup_user(buffer, count);
136 if (IS_ERR(buf)) {
137 ret = PTR_ERR(buf);
138 goto out;
139 }
140
141 if ((report_type == HID_OUTPUT_REPORT) &&
142 !(dev->quirks & HID_QUIRK_NO_OUTPUT_REPORTS_ON_INTR_EP)) {
143 ret = hid_hw_output_report(dev, buf, count);
144 /*
145 * compatibility with old implementation of USB-HID and I2C-HID:
146 * if the device does not support receiving output reports,
147 * on an interrupt endpoint, fallback to SET_REPORT HID command.
148 */
149 if (ret != -ENOSYS)
150 goto out_free;
151 }
152
153 ret = hid_hw_raw_request(dev, buf[0], buf, count, report_type,
154 HID_REQ_SET_REPORT);
155
156 out_free:
157 kfree(buf);
158 out:
159 return ret;
160 }
161
hidraw_write(struct file * file,const char __user * buffer,size_t count,loff_t * ppos)162 static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
163 {
164 ssize_t ret;
165 down_read(&minors_rwsem);
166 ret = hidraw_send_report(file, buffer, count, HID_OUTPUT_REPORT);
167 up_read(&minors_rwsem);
168 return ret;
169 }
170
171
172 /*
173 * This function performs a Get_Report transfer over the control endpoint
174 * per section 7.2.1 of the HID specification, version 1.1. The first byte
175 * of buffer is the report number to request, or 0x0 if the device does not
176 * use numbered reports. The report_type parameter can be HID_FEATURE_REPORT
177 * or HID_INPUT_REPORT.
178 */
hidraw_get_report(struct file * file,char __user * buffer,size_t count,unsigned char report_type)179 static ssize_t hidraw_get_report(struct file *file, char __user *buffer, size_t count, unsigned char report_type)
180 {
181 unsigned int minor = iminor(file_inode(file));
182 struct hid_device *dev;
183 __u8 *buf;
184 int ret = 0, len;
185 unsigned char report_number;
186
187 lockdep_assert_held(&minors_rwsem);
188
189 if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
190 ret = -ENODEV;
191 goto out;
192 }
193
194 dev = hidraw_table[minor]->hid;
195
196 if (!dev->ll_driver->raw_request) {
197 ret = -ENODEV;
198 goto out;
199 }
200
201 if (count > HID_MAX_BUFFER_SIZE) {
202 hid_warn(dev, "pid %d passed too large report\n",
203 task_pid_nr(current));
204 ret = -EINVAL;
205 goto out;
206 }
207
208 if (count < 2) {
209 hid_warn(dev, "pid %d passed too short report\n",
210 task_pid_nr(current));
211 ret = -EINVAL;
212 goto out;
213 }
214
215 buf = kmalloc(count, GFP_KERNEL);
216 if (!buf) {
217 ret = -ENOMEM;
218 goto out;
219 }
220
221 /*
222 * Read the first byte from the user. This is the report number,
223 * which is passed to hid_hw_raw_request().
224 */
225 if (copy_from_user(&report_number, buffer, 1)) {
226 ret = -EFAULT;
227 goto out_free;
228 }
229
230 ret = hid_hw_raw_request(dev, report_number, buf, count, report_type,
231 HID_REQ_GET_REPORT);
232
233 if (ret < 0)
234 goto out_free;
235
236 len = (ret < count) ? ret : count;
237
238 if (copy_to_user(buffer, buf, len)) {
239 ret = -EFAULT;
240 goto out_free;
241 }
242
243 ret = len;
244
245 out_free:
246 kfree(buf);
247 out:
248 return ret;
249 }
250
hidraw_poll(struct file * file,poll_table * wait)251 static __poll_t hidraw_poll(struct file *file, poll_table *wait)
252 {
253 struct hidraw_list *list = file->private_data;
254 __poll_t mask = EPOLLOUT | EPOLLWRNORM; /* hidraw is always writable */
255
256 poll_wait(file, &list->hidraw->wait, wait);
257 if (list->head != list->tail)
258 mask |= EPOLLIN | EPOLLRDNORM;
259 if (!list->hidraw->exist)
260 mask |= EPOLLERR | EPOLLHUP;
261 return mask;
262 }
263
hidraw_open(struct inode * inode,struct file * file)264 static int hidraw_open(struct inode *inode, struct file *file)
265 {
266 unsigned int minor = iminor(inode);
267 struct hidraw *dev;
268 struct hidraw_list *list;
269 unsigned long flags;
270 int err = 0;
271
272 if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
273 err = -ENOMEM;
274 goto out;
275 }
276
277 /*
278 * Technically not writing to the hidraw_table but a write lock is
279 * required to protect the device refcount. This is symmetrical to
280 * hidraw_release().
281 */
282 down_write(&minors_rwsem);
283 if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
284 err = -ENODEV;
285 goto out_unlock;
286 }
287
288 dev = hidraw_table[minor];
289 if (!dev->open++) {
290 err = hid_hw_power(dev->hid, PM_HINT_FULLON);
291 if (err < 0) {
292 dev->open--;
293 goto out_unlock;
294 }
295
296 err = hid_hw_open(dev->hid);
297 if (err < 0) {
298 hid_hw_power(dev->hid, PM_HINT_NORMAL);
299 dev->open--;
300 goto out_unlock;
301 }
302 }
303
304 list->hidraw = hidraw_table[minor];
305 mutex_init(&list->read_mutex);
306 spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags);
307 list_add_tail(&list->node, &hidraw_table[minor]->list);
308 spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags);
309 file->private_data = list;
310 out_unlock:
311 up_write(&minors_rwsem);
312 out:
313 if (err < 0)
314 kfree(list);
315 return err;
316
317 }
318
hidraw_fasync(int fd,struct file * file,int on)319 static int hidraw_fasync(int fd, struct file *file, int on)
320 {
321 struct hidraw_list *list = file->private_data;
322
323 return fasync_helper(fd, file, on, &list->fasync);
324 }
325
drop_ref(struct hidraw * hidraw,int exists_bit)326 static void drop_ref(struct hidraw *hidraw, int exists_bit)
327 {
328 if (exists_bit) {
329 hidraw->exist = 0;
330 if (hidraw->open) {
331 hid_hw_close(hidraw->hid);
332 wake_up_interruptible(&hidraw->wait);
333 }
334 device_destroy(&hidraw_class,
335 MKDEV(hidraw_major, hidraw->minor));
336 } else {
337 --hidraw->open;
338 }
339 if (!hidraw->open) {
340 if (!hidraw->exist) {
341 hidraw_table[hidraw->minor] = NULL;
342 kfree(hidraw);
343 } else {
344 /* close device for last reader */
345 hid_hw_close(hidraw->hid);
346 hid_hw_power(hidraw->hid, PM_HINT_NORMAL);
347 }
348 }
349 }
350
hidraw_release(struct inode * inode,struct file * file)351 static int hidraw_release(struct inode * inode, struct file * file)
352 {
353 unsigned int minor = iminor(inode);
354 struct hidraw_list *list = file->private_data;
355 unsigned long flags;
356
357 down_write(&minors_rwsem);
358
359 spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags);
360 for (int i = list->tail; i < list->head; i++)
361 kfree(list->buffer[i].value);
362 list_del(&list->node);
363 spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags);
364 kfree(list);
365
366 drop_ref(hidraw_table[minor], 0);
367
368 up_write(&minors_rwsem);
369 return 0;
370 }
371
hidraw_ioctl(struct file * file,unsigned int cmd,unsigned long arg)372 static long hidraw_ioctl(struct file *file, unsigned int cmd,
373 unsigned long arg)
374 {
375 struct inode *inode = file_inode(file);
376 unsigned int minor = iminor(inode);
377 long ret = 0;
378 struct hidraw *dev;
379 void __user *user_arg = (void __user*) arg;
380
381 down_read(&minors_rwsem);
382 dev = hidraw_table[minor];
383 if (!dev || !dev->exist) {
384 ret = -ENODEV;
385 goto out;
386 }
387
388 switch (cmd) {
389 case HIDIOCGRDESCSIZE:
390 if (put_user(dev->hid->rsize, (int __user *)arg))
391 ret = -EFAULT;
392 break;
393
394 case HIDIOCGRDESC:
395 {
396 __u32 len;
397
398 if (get_user(len, (int __user *)arg))
399 ret = -EFAULT;
400 else if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
401 ret = -EINVAL;
402 else if (copy_to_user(user_arg + offsetof(
403 struct hidraw_report_descriptor,
404 value[0]),
405 dev->hid->rdesc,
406 min(dev->hid->rsize, len)))
407 ret = -EFAULT;
408 break;
409 }
410 case HIDIOCGRAWINFO:
411 {
412 struct hidraw_devinfo dinfo;
413
414 dinfo.bustype = dev->hid->bus;
415 dinfo.vendor = dev->hid->vendor;
416 dinfo.product = dev->hid->product;
417 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
418 ret = -EFAULT;
419 break;
420 }
421 default:
422 {
423 struct hid_device *hid = dev->hid;
424 if (_IOC_TYPE(cmd) != 'H') {
425 ret = -EINVAL;
426 break;
427 }
428
429 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSFEATURE(0))) {
430 int len = _IOC_SIZE(cmd);
431 ret = hidraw_send_report(file, user_arg, len, HID_FEATURE_REPORT);
432 break;
433 }
434 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGFEATURE(0))) {
435 int len = _IOC_SIZE(cmd);
436 ret = hidraw_get_report(file, user_arg, len, HID_FEATURE_REPORT);
437 break;
438 }
439
440 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSINPUT(0))) {
441 int len = _IOC_SIZE(cmd);
442 ret = hidraw_send_report(file, user_arg, len, HID_INPUT_REPORT);
443 break;
444 }
445 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGINPUT(0))) {
446 int len = _IOC_SIZE(cmd);
447 ret = hidraw_get_report(file, user_arg, len, HID_INPUT_REPORT);
448 break;
449 }
450
451 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSOUTPUT(0))) {
452 int len = _IOC_SIZE(cmd);
453 ret = hidraw_send_report(file, user_arg, len, HID_OUTPUT_REPORT);
454 break;
455 }
456 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGOUTPUT(0))) {
457 int len = _IOC_SIZE(cmd);
458 ret = hidraw_get_report(file, user_arg, len, HID_OUTPUT_REPORT);
459 break;
460 }
461
462 /* Begin Read-only ioctls. */
463 if (_IOC_DIR(cmd) != _IOC_READ) {
464 ret = -EINVAL;
465 break;
466 }
467
468 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) {
469 int len = strlen(hid->name) + 1;
470 if (len > _IOC_SIZE(cmd))
471 len = _IOC_SIZE(cmd);
472 ret = copy_to_user(user_arg, hid->name, len) ?
473 -EFAULT : len;
474 break;
475 }
476
477 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) {
478 int len = strlen(hid->phys) + 1;
479 if (len > _IOC_SIZE(cmd))
480 len = _IOC_SIZE(cmd);
481 ret = copy_to_user(user_arg, hid->phys, len) ?
482 -EFAULT : len;
483 break;
484 }
485
486 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWUNIQ(0))) {
487 int len = strlen(hid->uniq) + 1;
488 if (len > _IOC_SIZE(cmd))
489 len = _IOC_SIZE(cmd);
490 ret = copy_to_user(user_arg, hid->uniq, len) ?
491 -EFAULT : len;
492 break;
493 }
494 }
495
496 ret = -ENOTTY;
497 }
498 out:
499 up_read(&minors_rwsem);
500 return ret;
501 }
502
503 static const struct file_operations hidraw_ops = {
504 .owner = THIS_MODULE,
505 .read = hidraw_read,
506 .write = hidraw_write,
507 .poll = hidraw_poll,
508 .open = hidraw_open,
509 .release = hidraw_release,
510 .unlocked_ioctl = hidraw_ioctl,
511 .fasync = hidraw_fasync,
512 .compat_ioctl = compat_ptr_ioctl,
513 .llseek = noop_llseek,
514 };
515
hidraw_report_event(struct hid_device * hid,u8 * data,int len)516 int hidraw_report_event(struct hid_device *hid, u8 *data, int len)
517 {
518 struct hidraw *dev = hid->hidraw;
519 struct hidraw_list *list;
520 int ret = 0;
521 unsigned long flags;
522
523 spin_lock_irqsave(&dev->list_lock, flags);
524 list_for_each_entry(list, &dev->list, node) {
525 int new_head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
526
527 if (new_head == list->tail)
528 continue;
529
530 if (!(list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC))) {
531 ret = -ENOMEM;
532 break;
533 }
534 list->buffer[list->head].len = len;
535 list->head = new_head;
536 kill_fasync(&list->fasync, SIGIO, POLL_IN);
537 }
538 spin_unlock_irqrestore(&dev->list_lock, flags);
539
540 wake_up_interruptible(&dev->wait);
541 return ret;
542 }
543 EXPORT_SYMBOL_GPL(hidraw_report_event);
544
hidraw_connect(struct hid_device * hid)545 int hidraw_connect(struct hid_device *hid)
546 {
547 int minor, result;
548 struct hidraw *dev;
549
550 /* we accept any HID device, all applications */
551
552 dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
553 if (!dev)
554 return -ENOMEM;
555
556 result = -EINVAL;
557
558 down_write(&minors_rwsem);
559
560 for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
561 if (hidraw_table[minor])
562 continue;
563 hidraw_table[minor] = dev;
564 result = 0;
565 break;
566 }
567
568 if (result) {
569 up_write(&minors_rwsem);
570 kfree(dev);
571 goto out;
572 }
573
574 dev->dev = device_create(&hidraw_class, &hid->dev, MKDEV(hidraw_major, minor),
575 NULL, "%s%d", "hidraw", minor);
576
577 if (IS_ERR(dev->dev)) {
578 hidraw_table[minor] = NULL;
579 up_write(&minors_rwsem);
580 result = PTR_ERR(dev->dev);
581 kfree(dev);
582 goto out;
583 }
584
585 init_waitqueue_head(&dev->wait);
586 spin_lock_init(&dev->list_lock);
587 INIT_LIST_HEAD(&dev->list);
588
589 dev->hid = hid;
590 dev->minor = minor;
591
592 dev->exist = 1;
593 hid->hidraw = dev;
594
595 up_write(&minors_rwsem);
596 out:
597 return result;
598
599 }
600 EXPORT_SYMBOL_GPL(hidraw_connect);
601
hidraw_disconnect(struct hid_device * hid)602 void hidraw_disconnect(struct hid_device *hid)
603 {
604 struct hidraw *hidraw = hid->hidraw;
605
606 down_write(&minors_rwsem);
607
608 drop_ref(hidraw, 1);
609
610 up_write(&minors_rwsem);
611 }
612 EXPORT_SYMBOL_GPL(hidraw_disconnect);
613
hidraw_init(void)614 int __init hidraw_init(void)
615 {
616 int result;
617 dev_t dev_id;
618
619 result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
620 HIDRAW_MAX_DEVICES, "hidraw");
621 if (result < 0) {
622 pr_warn("can't get major number\n");
623 goto out;
624 }
625
626 hidraw_major = MAJOR(dev_id);
627
628 result = class_register(&hidraw_class);
629 if (result)
630 goto error_cdev;
631
632 cdev_init(&hidraw_cdev, &hidraw_ops);
633 result = cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
634 if (result < 0)
635 goto error_class;
636
637 pr_info("raw HID events driver (C) Jiri Kosina\n");
638 out:
639 return result;
640
641 error_class:
642 class_unregister(&hidraw_class);
643 error_cdev:
644 unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
645 goto out;
646 }
647
hidraw_exit(void)648 void hidraw_exit(void)
649 {
650 dev_t dev_id = MKDEV(hidraw_major, 0);
651
652 cdev_del(&hidraw_cdev);
653 class_unregister(&hidraw_class);
654 unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
655
656 }
657
