1/*
2 * HID raw devices, giving access to raw HID events.
3 *
4 * In comparison to hiddev, this device does not process the
5 * hid events at all (no parsing, no lookups). This lets applications
6 * to work on raw hid events as they want to, and avoids a need to
7 * use a transport-specific userspace libhid/libusb libraries.
8 *
9 * Copyright (c) 2007-2014 Jiri Kosina
10 */
11
12/*
13 * This program is free software; you can redistribute it and/or modify it
14 * under the terms and conditions of the GNU General Public License,
15 * version 2, as published by the Free Software Foundation.
16 *
17 * You should have received a copy of the GNU General Public License along with
18 * this program; if not, write to the Free Software Foundation, Inc.,
19 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
20 */
21
22#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
23
24#include <linux/fs.h>
25#include <linux/module.h>
26#include <linux/errno.h>
27#include <linux/kernel.h>
28#include <linux/init.h>
29#include <linux/cdev.h>
30#include <linux/poll.h>
31#include <linux/device.h>
32#include <linux/major.h>
33#include <linux/slab.h>
34#include <linux/hid.h>
35#include <linux/mutex.h>
36#include <linux/sched/signal.h>
37#include <linux/string.h>
38
39#include <linux/hidraw.h>
40
41static int hidraw_major;
42static struct cdev hidraw_cdev;
43static struct class *hidraw_class;
44static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES];
45static DEFINE_MUTEX(minors_lock);
46
47static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
48{
49 struct hidraw_list *list = file->private_data;
50 int ret = 0, len;
51 DECLARE_WAITQUEUE(wait, current);
52
53 mutex_lock(&list->read_mutex);
54
55 while (ret == 0) {
56 if (list->head == list->tail) {
57 add_wait_queue(&list->hidraw->wait, &wait);
58 set_current_state(TASK_INTERRUPTIBLE);
59
60 while (list->head == list->tail) {
61 if (signal_pending(current)) {
62 ret = -ERESTARTSYS;
63 break;
64 }
65 if (!list->hidraw->exist) {
66 ret = -EIO;
67 break;
68 }
69 if (file->f_flags & O_NONBLOCK) {
70 ret = -EAGAIN;
71 break;
72 }
73
74 /* allow O_NONBLOCK to work well from other threads */
75 mutex_unlock(&list->read_mutex);
76 schedule();
77 mutex_lock(&list->read_mutex);
78 set_current_state(TASK_INTERRUPTIBLE);
79 }
80
81 set_current_state(TASK_RUNNING);
82 remove_wait_queue(&list->hidraw->wait, &wait);
83 }
84
85 if (ret)
86 goto out;
87
88 len = list->buffer[list->tail].len > count ?
89 count : list->buffer[list->tail].len;
90
91 if (list->buffer[list->tail].value) {
92 if (copy_to_user(buffer, list->buffer[list->tail].value, len)) {
93 ret = -EFAULT;
94 goto out;
95 }
96 ret = len;
97 }
98
99 kfree(list->buffer[list->tail].value);
100 list->buffer[list->tail].value = NULL;
101 list->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1);
102 }
103out:
104 mutex_unlock(&list->read_mutex);
105 return ret;
106}
107
108/*
109 * The first byte of the report buffer is expected to be a report number.
110 */
111static ssize_t hidraw_send_report(struct file *file, const char __user *buffer, size_t count, unsigned char report_type)
112{
113 unsigned int minor = iminor(file_inode(file));
114 struct hid_device *dev;
115 __u8 *buf;
116 int ret = 0;
117
118 lockdep_assert_held(&minors_lock);
119
120 if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
121 ret = -ENODEV;
122 goto out;
123 }
124
125 dev = hidraw_table[minor]->hid;
126
127 if (count > HID_MAX_BUFFER_SIZE) {
128 hid_warn(dev, "pid %d passed too large report\n",
129 task_pid_nr(current));
130 ret = -EINVAL;
131 goto out;
132 }
133
134 if (count < 2) {
135 hid_warn(dev, "pid %d passed too short report\n",
136 task_pid_nr(current));
137 ret = -EINVAL;
138 goto out;
139 }
140
141 buf = memdup_user(buffer, count);
142 if (IS_ERR(buf)) {
143 ret = PTR_ERR(buf);
144 goto out;
145 }
146
147 if ((report_type == HID_OUTPUT_REPORT) &&
148 !(dev->quirks & HID_QUIRK_NO_OUTPUT_REPORTS_ON_INTR_EP)) {
149 ret = hid_hw_output_report(dev, buf, count);
150 /*
151 * compatibility with old implementation of USB-HID and I2C-HID:
152 * if the device does not support receiving output reports,
153 * on an interrupt endpoint, fallback to SET_REPORT HID command.
154 */
155 if (ret != -ENOSYS)
156 goto out_free;
157 }
158
159 ret = hid_hw_raw_request(dev, buf[0], buf, count, report_type,
160 HID_REQ_SET_REPORT);
161
162out_free:
163 kfree(buf);
164out:
165 return ret;
166}
167
168static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
169{
170 ssize_t ret;
171 mutex_lock(&minors_lock);
172 ret = hidraw_send_report(file, buffer, count, HID_OUTPUT_REPORT);
173 mutex_unlock(&minors_lock);
174 return ret;
175}
176
177
178/*
179 * This function performs a Get_Report transfer over the control endpoint
180 * per section 7.2.1 of the HID specification, version 1.1. The first byte
181 * of buffer is the report number to request, or 0x0 if the defice does not
182 * use numbered reports. The report_type parameter can be HID_FEATURE_REPORT
183 * or HID_INPUT_REPORT.
184 */
185static ssize_t hidraw_get_report(struct file *file, char __user *buffer, size_t count, unsigned char report_type)
186{
187 unsigned int minor = iminor(file_inode(file));
188 struct hid_device *dev;
189 __u8 *buf;
190 int ret = 0, len;
191 unsigned char report_number;
192
193 lockdep_assert_held(&minors_lock);
194
195 if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
196 ret = -ENODEV;
197 goto out;
198 }
199
200 dev = hidraw_table[minor]->hid;
201
202 if (!dev->ll_driver->raw_request) {
203 ret = -ENODEV;
204 goto out;
205 }
206
207 if (count > HID_MAX_BUFFER_SIZE) {
208 printk(KERN_WARNING "hidraw: pid %d passed too large report\n",
209 task_pid_nr(current));
210 ret = -EINVAL;
211 goto out;
212 }
213
214 if (count < 2) {
215 printk(KERN_WARNING "hidraw: pid %d passed too short report\n",
216 task_pid_nr(current));
217 ret = -EINVAL;
218 goto out;
219 }
220
221 buf = kmalloc(count, GFP_KERNEL);
222 if (!buf) {
223 ret = -ENOMEM;
224 goto out;
225 }
226
227 /*
228 * Read the first byte from the user. This is the report number,
229 * which is passed to hid_hw_raw_request().
230 */
231 if (copy_from_user(&report_number, buffer, 1)) {
232 ret = -EFAULT;
233 goto out_free;
234 }
235
236 ret = hid_hw_raw_request(dev, report_number, buf, count, report_type,
237 HID_REQ_GET_REPORT);
238
239 if (ret < 0)
240 goto out_free;
241
242 len = (ret < count) ? ret : count;
243
244 if (copy_to_user(buffer, buf, len)) {
245 ret = -EFAULT;
246 goto out_free;
247 }
248
249 ret = len;
250
251out_free:
252 kfree(buf);
253out:
254 return ret;
255}
256
257static __poll_t hidraw_poll(struct file *file, poll_table *wait)
258{
259 struct hidraw_list *list = file->private_data;
260
261 poll_wait(file, &list->hidraw->wait, wait);
262 if (list->head != list->tail)
263 return EPOLLIN | EPOLLRDNORM;
264 if (!list->hidraw->exist)
265 return EPOLLERR | EPOLLHUP;
266 return 0;
267}
268
269static int hidraw_open(struct inode *inode, struct file *file)
270{
271 unsigned int minor = iminor(inode);
272 struct hidraw *dev;
273 struct hidraw_list *list;
274 unsigned long flags;
275 int err = 0;
276
277 if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
278 err = -ENOMEM;
279 goto out;
280 }
281
282 mutex_lock(&minors_lock);
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;
310out_unlock:
311 mutex_unlock(&minors_lock);
312out:
313 if (err < 0)
314 kfree(list);
315 return err;
316
317}
318
319static 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
326static 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
351static 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 mutex_lock(&minors_lock);
358
359 spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags);
360 list_del(&list->node);
361 spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags);
362 kfree(list);
363
364 drop_ref(hidraw_table[minor], 0);
365
366 mutex_unlock(&minors_lock);
367 return 0;
368}
369
370static long hidraw_ioctl(struct file *file, unsigned int cmd,
371 unsigned long arg)
372{
373 struct inode *inode = file_inode(file);
374 unsigned int minor = iminor(inode);
375 long ret = 0;
376 struct hidraw *dev;
377 void __user *user_arg = (void __user*) arg;
378
379 mutex_lock(&minors_lock);
380 dev = hidraw_table[minor];
381 if (!dev) {
382 ret = -ENODEV;
383 goto out;
384 }
385
386 switch (cmd) {
387 case HIDIOCGRDESCSIZE:
388 if (put_user(dev->hid->rsize, (int __user *)arg))
389 ret = -EFAULT;
390 break;
391
392 case HIDIOCGRDESC:
393 {
394 __u32 len;
395
396 if (get_user(len, (int __user *)arg))
397 ret = -EFAULT;
398 else if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
399 ret = -EINVAL;
400 else if (copy_to_user(user_arg + offsetof(
401 struct hidraw_report_descriptor,
402 value[0]),
403 dev->hid->rdesc,
404 min(dev->hid->rsize, len)))
405 ret = -EFAULT;
406 break;
407 }
408 case HIDIOCGRAWINFO:
409 {
410 struct hidraw_devinfo dinfo;
411
412 dinfo.bustype = dev->hid->bus;
413 dinfo.vendor = dev->hid->vendor;
414 dinfo.product = dev->hid->product;
415 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
416 ret = -EFAULT;
417 break;
418 }
419 default:
420 {
421 struct hid_device *hid = dev->hid;
422 if (_IOC_TYPE(cmd) != 'H') {
423 ret = -EINVAL;
424 break;
425 }
426
427 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSFEATURE(0))) {
428 int len = _IOC_SIZE(cmd);
429 ret = hidraw_send_report(file, user_arg, len, HID_FEATURE_REPORT);
430 break;
431 }
432 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGFEATURE(0))) {
433 int len = _IOC_SIZE(cmd);
434 ret = hidraw_get_report(file, user_arg, len, HID_FEATURE_REPORT);
435 break;
436 }
437
438 /* Begin Read-only ioctls. */
439 if (_IOC_DIR(cmd) != _IOC_READ) {
440 ret = -EINVAL;
441 break;
442 }
443
444 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) {
445 int len = strlen(hid->name) + 1;
446 if (len > _IOC_SIZE(cmd))
447 len = _IOC_SIZE(cmd);
448 ret = copy_to_user(user_arg, hid->name, len) ?
449 -EFAULT : len;
450 break;
451 }
452
453 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) {
454 int len = strlen(hid->phys) + 1;
455 if (len > _IOC_SIZE(cmd))
456 len = _IOC_SIZE(cmd);
457 ret = copy_to_user(user_arg, hid->phys, len) ?
458 -EFAULT : len;
459 break;
460 }
461 }
462
463 ret = -ENOTTY;
464 }
465out:
466 mutex_unlock(&minors_lock);
467 return ret;
468}
469
470static const struct file_operations hidraw_ops = {
471 .owner = THIS_MODULE,
472 .read = hidraw_read,
473 .write = hidraw_write,
474 .poll = hidraw_poll,
475 .open = hidraw_open,
476 .release = hidraw_release,
477 .unlocked_ioctl = hidraw_ioctl,
478 .fasync = hidraw_fasync,
479#ifdef CONFIG_COMPAT
480 .compat_ioctl = hidraw_ioctl,
481#endif
482 .llseek = noop_llseek,
483};
484
485int hidraw_report_event(struct hid_device *hid, u8 *data, int len)
486{
487 struct hidraw *dev = hid->hidraw;
488 struct hidraw_list *list;
489 int ret = 0;
490 unsigned long flags;
491
492 spin_lock_irqsave(&dev->list_lock, flags);
493 list_for_each_entry(list, &dev->list, node) {
494 int new_head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
495
496 if (new_head == list->tail)
497 continue;
498
499 if (!(list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC))) {
500 ret = -ENOMEM;
501 break;
502 }
503 list->buffer[list->head].len = len;
504 list->head = new_head;
505 kill_fasync(&list->fasync, SIGIO, POLL_IN);
506 }
507 spin_unlock_irqrestore(&dev->list_lock, flags);
508
509 wake_up_interruptible(&dev->wait);
510 return ret;
511}
512EXPORT_SYMBOL_GPL(hidraw_report_event);
513
514int hidraw_connect(struct hid_device *hid)
515{
516 int minor, result;
517 struct hidraw *dev;
518
519 /* we accept any HID device, all applications */
520
521 dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
522 if (!dev)
523 return -ENOMEM;
524
525 result = -EINVAL;
526
527 mutex_lock(&minors_lock);
528
529 for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
530 if (hidraw_table[minor])
531 continue;
532 hidraw_table[minor] = dev;
533 result = 0;
534 break;
535 }
536
537 if (result) {
538 mutex_unlock(&minors_lock);
539 kfree(dev);
540 goto out;
541 }
542
543 dev->dev = device_create(hidraw_class, &hid->dev, MKDEV(hidraw_major, minor),
544 NULL, "%s%d", "hidraw", minor);
545
546 if (IS_ERR(dev->dev)) {
547 hidraw_table[minor] = NULL;
548 mutex_unlock(&minors_lock);
549 result = PTR_ERR(dev->dev);
550 kfree(dev);
551 goto out;
552 }
553
554 init_waitqueue_head(&dev->wait);
555 spin_lock_init(&dev->list_lock);
556 INIT_LIST_HEAD(&dev->list);
557
558 dev->hid = hid;
559 dev->minor = minor;
560
561 dev->exist = 1;
562 hid->hidraw = dev;
563
564 mutex_unlock(&minors_lock);
565out:
566 return result;
567
568}
569EXPORT_SYMBOL_GPL(hidraw_connect);
570
571void hidraw_disconnect(struct hid_device *hid)
572{
573 struct hidraw *hidraw = hid->hidraw;
574
575 mutex_lock(&minors_lock);
576
577 drop_ref(hidraw, 1);
578
579 mutex_unlock(&minors_lock);
580}
581EXPORT_SYMBOL_GPL(hidraw_disconnect);
582
583int __init hidraw_init(void)
584{
585 int result;
586 dev_t dev_id;
587
588 result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
589 HIDRAW_MAX_DEVICES, "hidraw");
590 if (result < 0) {
591 pr_warn("can't get major number\n");
592 goto out;
593 }
594
595 hidraw_major = MAJOR(dev_id);
596
597 hidraw_class = class_create(THIS_MODULE, "hidraw");
598 if (IS_ERR(hidraw_class)) {
599 result = PTR_ERR(hidraw_class);
600 goto error_cdev;
601 }
602
603 cdev_init(&hidraw_cdev, &hidraw_ops);
604 result = cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
605 if (result < 0)
606 goto error_class;
607
608 printk(KERN_INFO "hidraw: raw HID events driver (C) Jiri Kosina\n");
609out:
610 return result;
611
612error_class:
613 class_destroy(hidraw_class);
614error_cdev:
615 unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
616 goto out;
617}
618
619void hidraw_exit(void)
620{
621 dev_t dev_id = MKDEV(hidraw_major, 0);
622
623 cdev_del(&hidraw_cdev);
624 class_destroy(hidraw_class);
625 unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
626
627}
628