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