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
41 static int hidraw_major;
42 static struct cdev hidraw_cdev;
43 static struct class *hidraw_class;
44 static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES];
45 static DEFINE_MUTEX(minors_lock);
46
hidraw_read(struct file * file,char __user * buffer,size_t count,loff_t * ppos)47 static 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 }
103 out:
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 *
111 * This function is to be called with the minors_lock mutex held.
112 */
hidraw_send_report(struct file * file,const char __user * buffer,size_t count,unsigned char report_type)113 static ssize_t hidraw_send_report(struct file *file, const char __user *buffer, size_t count, unsigned char report_type)
114 {
115 unsigned int minor = iminor(file_inode(file));
116 struct hid_device *dev;
117 __u8 *buf;
118 int ret = 0;
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
162 out_free:
163 kfree(buf);
164 out:
165 return ret;
166 }
167
hidraw_write(struct file * file,const char __user * buffer,size_t count,loff_t * ppos)168 static 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 *
185 * This function is to be called with the minors_lock mutex held.
186 */
hidraw_get_report(struct file * file,char __user * buffer,size_t count,unsigned char report_type)187 static ssize_t hidraw_get_report(struct file *file, char __user *buffer, size_t count, unsigned char report_type)
188 {
189 unsigned int minor = iminor(file_inode(file));
190 struct hid_device *dev;
191 __u8 *buf;
192 int ret = 0, len;
193 unsigned char report_number;
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
251 out_free:
252 kfree(buf);
253 out:
254 return ret;
255 }
256
hidraw_poll(struct file * file,poll_table * wait)257 static __poll_t hidraw_poll(struct file *file, poll_table *wait)
258 {
259 struct hidraw_list *list = file->private_data;
260 __poll_t mask = EPOLLOUT | EPOLLWRNORM; /* hidraw is always writable */
261
262 poll_wait(file, &list->hidraw->wait, wait);
263 if (list->head != list->tail)
264 mask |= EPOLLIN | EPOLLRDNORM;
265 if (!list->hidraw->exist)
266 mask |= EPOLLERR | EPOLLHUP;
267 return mask;
268 }
269
hidraw_open(struct inode * inode,struct file * file)270 static int hidraw_open(struct inode *inode, struct file *file)
271 {
272 unsigned int minor = iminor(inode);
273 struct hidraw *dev;
274 struct hidraw_list *list;
275 unsigned long flags;
276 int err = 0;
277
278 if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
279 err = -ENOMEM;
280 goto out;
281 }
282
283 mutex_lock(&minors_lock);
284 if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
285 err = -ENODEV;
286 goto out_unlock;
287 }
288
289 dev = hidraw_table[minor];
290 if (!dev->open++) {
291 err = hid_hw_power(dev->hid, PM_HINT_FULLON);
292 if (err < 0) {
293 dev->open--;
294 goto out_unlock;
295 }
296
297 err = hid_hw_open(dev->hid);
298 if (err < 0) {
299 hid_hw_power(dev->hid, PM_HINT_NORMAL);
300 dev->open--;
301 goto out_unlock;
302 }
303 }
304
305 list->hidraw = hidraw_table[minor];
306 mutex_init(&list->read_mutex);
307 spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags);
308 list_add_tail(&list->node, &hidraw_table[minor]->list);
309 spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags);
310 file->private_data = list;
311 out_unlock:
312 mutex_unlock(&minors_lock);
313 out:
314 if (err < 0)
315 kfree(list);
316 return err;
317
318 }
319
hidraw_fasync(int fd,struct file * file,int on)320 static int hidraw_fasync(int fd, struct file *file, int on)
321 {
322 struct hidraw_list *list = file->private_data;
323
324 return fasync_helper(fd, file, on, &list->fasync);
325 }
326
drop_ref(struct hidraw * hidraw,int exists_bit)327 static void drop_ref(struct hidraw *hidraw, int exists_bit)
328 {
329 if (exists_bit) {
330 hidraw->exist = 0;
331 if (hidraw->open) {
332 hid_hw_close(hidraw->hid);
333 wake_up_interruptible(&hidraw->wait);
334 }
335 device_destroy(hidraw_class,
336 MKDEV(hidraw_major, hidraw->minor));
337 } else {
338 --hidraw->open;
339 }
340 if (!hidraw->open) {
341 if (!hidraw->exist) {
342 hidraw_table[hidraw->minor] = NULL;
343 kfree(hidraw);
344 } else {
345 /* close device for last reader */
346 hid_hw_close(hidraw->hid);
347 hid_hw_power(hidraw->hid, PM_HINT_NORMAL);
348 }
349 }
350 }
351
hidraw_release(struct inode * inode,struct file * file)352 static int hidraw_release(struct inode * inode, struct file * file)
353 {
354 unsigned int minor = iminor(inode);
355 struct hidraw_list *list = file->private_data;
356 unsigned long flags;
357 int i;
358
359 mutex_lock(&minors_lock);
360
361 spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags);
362 for (i = list->tail; i < list->head; i++)
363 kfree(list->buffer[i].value);
364 list_del(&list->node);
365 spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags);
366 kfree(list);
367
368 drop_ref(hidraw_table[minor], 0);
369
370 mutex_unlock(&minors_lock);
371 return 0;
372 }
373
hidraw_ioctl(struct file * file,unsigned int cmd,unsigned long arg)374 static long hidraw_ioctl(struct file *file, unsigned int cmd,
375 unsigned long arg)
376 {
377 struct inode *inode = file_inode(file);
378 unsigned int minor = iminor(inode);
379 long ret = 0;
380 struct hidraw *dev;
381 void __user *user_arg = (void __user*) arg;
382
383 mutex_lock(&minors_lock);
384 dev = hidraw_table[minor];
385 if (!dev || !dev->exist) {
386 ret = -ENODEV;
387 goto out;
388 }
389
390 switch (cmd) {
391 case HIDIOCGRDESCSIZE:
392 if (put_user(dev->hid->rsize, (int __user *)arg))
393 ret = -EFAULT;
394 break;
395
396 case HIDIOCGRDESC:
397 {
398 __u32 len;
399
400 if (get_user(len, (int __user *)arg))
401 ret = -EFAULT;
402 else if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
403 ret = -EINVAL;
404 else if (copy_to_user(user_arg + offsetof(
405 struct hidraw_report_descriptor,
406 value[0]),
407 dev->hid->rdesc,
408 min(dev->hid->rsize, len)))
409 ret = -EFAULT;
410 break;
411 }
412 case HIDIOCGRAWINFO:
413 {
414 struct hidraw_devinfo dinfo;
415
416 dinfo.bustype = dev->hid->bus;
417 dinfo.vendor = dev->hid->vendor;
418 dinfo.product = dev->hid->product;
419 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
420 ret = -EFAULT;
421 break;
422 }
423 default:
424 {
425 struct hid_device *hid = dev->hid;
426 if (_IOC_TYPE(cmd) != 'H') {
427 ret = -EINVAL;
428 break;
429 }
430
431 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSFEATURE(0))) {
432 int len = _IOC_SIZE(cmd);
433 ret = hidraw_send_report(file, user_arg, len, HID_FEATURE_REPORT);
434 break;
435 }
436 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGFEATURE(0))) {
437 int len = _IOC_SIZE(cmd);
438 ret = hidraw_get_report(file, user_arg, len, HID_FEATURE_REPORT);
439 break;
440 }
441
442 /* Begin Read-only ioctls. */
443 if (_IOC_DIR(cmd) != _IOC_READ) {
444 ret = -EINVAL;
445 break;
446 }
447
448 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) {
449 int len = strlen(hid->name) + 1;
450 if (len > _IOC_SIZE(cmd))
451 len = _IOC_SIZE(cmd);
452 ret = copy_to_user(user_arg, hid->name, len) ?
453 -EFAULT : len;
454 break;
455 }
456
457 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) {
458 int len = strlen(hid->phys) + 1;
459 if (len > _IOC_SIZE(cmd))
460 len = _IOC_SIZE(cmd);
461 ret = copy_to_user(user_arg, hid->phys, len) ?
462 -EFAULT : len;
463 break;
464 }
465 }
466
467 ret = -ENOTTY;
468 }
469 out:
470 mutex_unlock(&minors_lock);
471 return ret;
472 }
473
474 static const struct file_operations hidraw_ops = {
475 .owner = THIS_MODULE,
476 .read = hidraw_read,
477 .write = hidraw_write,
478 .poll = hidraw_poll,
479 .open = hidraw_open,
480 .release = hidraw_release,
481 .unlocked_ioctl = hidraw_ioctl,
482 .fasync = hidraw_fasync,
483 #ifdef CONFIG_COMPAT
484 .compat_ioctl = hidraw_ioctl,
485 #endif
486 .llseek = noop_llseek,
487 };
488
hidraw_report_event(struct hid_device * hid,u8 * data,int len)489 int hidraw_report_event(struct hid_device *hid, u8 *data, int len)
490 {
491 struct hidraw *dev = hid->hidraw;
492 struct hidraw_list *list;
493 int ret = 0;
494 unsigned long flags;
495
496 spin_lock_irqsave(&dev->list_lock, flags);
497 list_for_each_entry(list, &dev->list, node) {
498 int new_head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
499
500 if (new_head == list->tail)
501 continue;
502
503 if (!(list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC))) {
504 ret = -ENOMEM;
505 break;
506 }
507 list->buffer[list->head].len = len;
508 list->head = new_head;
509 kill_fasync(&list->fasync, SIGIO, POLL_IN);
510 }
511 spin_unlock_irqrestore(&dev->list_lock, flags);
512
513 wake_up_interruptible(&dev->wait);
514 return ret;
515 }
516 EXPORT_SYMBOL_GPL(hidraw_report_event);
517
hidraw_connect(struct hid_device * hid)518 int hidraw_connect(struct hid_device *hid)
519 {
520 int minor, result;
521 struct hidraw *dev;
522
523 /* we accept any HID device, all applications */
524
525 dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
526 if (!dev)
527 return -ENOMEM;
528
529 result = -EINVAL;
530
531 mutex_lock(&minors_lock);
532
533 for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
534 if (hidraw_table[minor])
535 continue;
536 hidraw_table[minor] = dev;
537 result = 0;
538 break;
539 }
540
541 if (result) {
542 mutex_unlock(&minors_lock);
543 kfree(dev);
544 goto out;
545 }
546
547 dev->dev = device_create(hidraw_class, &hid->dev, MKDEV(hidraw_major, minor),
548 NULL, "%s%d", "hidraw", minor);
549
550 if (IS_ERR(dev->dev)) {
551 hidraw_table[minor] = NULL;
552 mutex_unlock(&minors_lock);
553 result = PTR_ERR(dev->dev);
554 kfree(dev);
555 goto out;
556 }
557
558 init_waitqueue_head(&dev->wait);
559 spin_lock_init(&dev->list_lock);
560 INIT_LIST_HEAD(&dev->list);
561
562 dev->hid = hid;
563 dev->minor = minor;
564
565 dev->exist = 1;
566 hid->hidraw = dev;
567
568 mutex_unlock(&minors_lock);
569 out:
570 return result;
571
572 }
573 EXPORT_SYMBOL_GPL(hidraw_connect);
574
hidraw_disconnect(struct hid_device * hid)575 void hidraw_disconnect(struct hid_device *hid)
576 {
577 struct hidraw *hidraw = hid->hidraw;
578
579 mutex_lock(&minors_lock);
580
581 drop_ref(hidraw, 1);
582
583 mutex_unlock(&minors_lock);
584 }
585 EXPORT_SYMBOL_GPL(hidraw_disconnect);
586
hidraw_init(void)587 int __init hidraw_init(void)
588 {
589 int result;
590 dev_t dev_id;
591
592 result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
593 HIDRAW_MAX_DEVICES, "hidraw");
594 if (result < 0) {
595 pr_warn("can't get major number\n");
596 goto out;
597 }
598
599 hidraw_major = MAJOR(dev_id);
600
601 hidraw_class = class_create(THIS_MODULE, "hidraw");
602 if (IS_ERR(hidraw_class)) {
603 result = PTR_ERR(hidraw_class);
604 goto error_cdev;
605 }
606
607 cdev_init(&hidraw_cdev, &hidraw_ops);
608 result = cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
609 if (result < 0)
610 goto error_class;
611
612 printk(KERN_INFO "hidraw: raw HID events driver (C) Jiri Kosina\n");
613 out:
614 return result;
615
616 error_class:
617 class_destroy(hidraw_class);
618 error_cdev:
619 unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
620 goto out;
621 }
622
hidraw_exit(void)623 void hidraw_exit(void)
624 {
625 dev_t dev_id = MKDEV(hidraw_major, 0);
626
627 cdev_del(&hidraw_cdev);
628 class_destroy(hidraw_class);
629 unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
630
631 }
632