xref: /openbmc/linux/drivers/hid/hidraw.c (revision 3b64b188) 
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 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 static void drop_ref(struct hidraw *hid, int exists_bit);
46 
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 (file->f_flags & O_NONBLOCK) {
62 					ret = -EAGAIN;
63 					break;
64 				}
65 				if (signal_pending(current)) {
66 					ret = -ERESTARTSYS;
67 					break;
68 				}
69 				if (!list->hidraw->exist) {
70 					ret = -EIO;
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 /* The first byte is expected to be a report number.
109  * This function is to be called with the minors_lock mutex held */
110 static ssize_t hidraw_send_report(struct file *file, const char __user *buffer, size_t count, unsigned char report_type)
111 {
112 	unsigned int minor = iminor(file->f_path.dentry->d_inode);
113 	struct hid_device *dev;
114 	__u8 *buf;
115 	int ret = 0;
116 
117 	if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
118 		ret = -ENODEV;
119 		goto out;
120 	}
121 
122 	dev = hidraw_table[minor]->hid;
123 
124 	if (!dev->hid_output_raw_report) {
125 		ret = -ENODEV;
126 		goto out;
127 	}
128 
129 	if (count > HID_MAX_BUFFER_SIZE) {
130 		hid_warn(dev, "pid %d passed too large report\n",
131 			 task_pid_nr(current));
132 		ret = -EINVAL;
133 		goto out;
134 	}
135 
136 	if (count < 2) {
137 		hid_warn(dev, "pid %d passed too short report\n",
138 			 task_pid_nr(current));
139 		ret = -EINVAL;
140 		goto out;
141 	}
142 
143 	buf = kmalloc(count * sizeof(__u8), GFP_KERNEL);
144 	if (!buf) {
145 		ret = -ENOMEM;
146 		goto out;
147 	}
148 
149 	if (copy_from_user(buf, buffer, count)) {
150 		ret = -EFAULT;
151 		goto out_free;
152 	}
153 
154 	ret = dev->hid_output_raw_report(dev, buf, count, report_type);
155 out_free:
156 	kfree(buf);
157 out:
158 	return ret;
159 }
160 
161 /* the first byte is expected to be a report number */
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 	mutex_lock(&minors_lock);
166 	ret = hidraw_send_report(file, buffer, count, HID_OUTPUT_REPORT);
167 	mutex_unlock(&minors_lock);
168 	return ret;
169 }
170 
171 
172 /* This function performs a Get_Report transfer over the control endpoint
173  * per section 7.2.1 of the HID specification, version 1.1.  The first byte
174  * of buffer is the report number to request, or 0x0 if the defice does not
175  * use numbered reports. The report_type parameter can be HID_FEATURE_REPORT
176  * or HID_INPUT_REPORT.  This function is to be called with the minors_lock
177  *  mutex held. */
178 static ssize_t hidraw_get_report(struct file *file, char __user *buffer, size_t count, unsigned char report_type)
179 {
180 	unsigned int minor = iminor(file->f_path.dentry->d_inode);
181 	struct hid_device *dev;
182 	__u8 *buf;
183 	int ret = 0, len;
184 	unsigned char report_number;
185 
186 	dev = hidraw_table[minor]->hid;
187 
188 	if (!dev->hid_get_raw_report) {
189 		ret = -ENODEV;
190 		goto out;
191 	}
192 
193 	if (count > HID_MAX_BUFFER_SIZE) {
194 		printk(KERN_WARNING "hidraw: pid %d passed too large report\n",
195 				task_pid_nr(current));
196 		ret = -EINVAL;
197 		goto out;
198 	}
199 
200 	if (count < 2) {
201 		printk(KERN_WARNING "hidraw: pid %d passed too short report\n",
202 				task_pid_nr(current));
203 		ret = -EINVAL;
204 		goto out;
205 	}
206 
207 	buf = kmalloc(count * sizeof(__u8), GFP_KERNEL);
208 	if (!buf) {
209 		ret = -ENOMEM;
210 		goto out;
211 	}
212 
213 	/* Read the first byte from the user. This is the report number,
214 	 * which is passed to dev->hid_get_raw_report(). */
215 	if (copy_from_user(&report_number, buffer, 1)) {
216 		ret = -EFAULT;
217 		goto out_free;
218 	}
219 
220 	ret = dev->hid_get_raw_report(dev, report_number, buf, count, report_type);
221 
222 	if (ret < 0)
223 		goto out_free;
224 
225 	len = (ret < count) ? ret : count;
226 
227 	if (copy_to_user(buffer, buf, len)) {
228 		ret = -EFAULT;
229 		goto out_free;
230 	}
231 
232 	ret = len;
233 
234 out_free:
235 	kfree(buf);
236 out:
237 	return ret;
238 }
239 
240 static unsigned int hidraw_poll(struct file *file, poll_table *wait)
241 {
242 	struct hidraw_list *list = file->private_data;
243 
244 	poll_wait(file, &list->hidraw->wait, wait);
245 	if (list->head != list->tail)
246 		return POLLIN | POLLRDNORM;
247 	if (!list->hidraw->exist)
248 		return POLLERR | POLLHUP;
249 	return 0;
250 }
251 
252 static int hidraw_open(struct inode *inode, struct file *file)
253 {
254 	unsigned int minor = iminor(inode);
255 	struct hidraw *dev;
256 	struct hidraw_list *list;
257 	int err = 0;
258 
259 	if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
260 		err = -ENOMEM;
261 		goto out;
262 	}
263 
264 	mutex_lock(&minors_lock);
265 	if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
266 		err = -ENODEV;
267 		goto out_unlock;
268 	}
269 
270 	list->hidraw = hidraw_table[minor];
271 	mutex_init(&list->read_mutex);
272 	list_add_tail(&list->node, &hidraw_table[minor]->list);
273 	file->private_data = list;
274 
275 	dev = hidraw_table[minor];
276 	if (!dev->open++) {
277 		err = hid_hw_power(dev->hid, PM_HINT_FULLON);
278 		if (err < 0) {
279 			dev->open--;
280 			goto out_unlock;
281 		}
282 
283 		err = hid_hw_open(dev->hid);
284 		if (err < 0) {
285 			hid_hw_power(dev->hid, PM_HINT_NORMAL);
286 			dev->open--;
287 		}
288 	}
289 
290 out_unlock:
291 	mutex_unlock(&minors_lock);
292 out:
293 	if (err < 0)
294 		kfree(list);
295 	return err;
296 
297 }
298 
299 static int hidraw_release(struct inode * inode, struct file * file)
300 {
301 	unsigned int minor = iminor(inode);
302 	struct hidraw_list *list = file->private_data;
303 
304 	drop_ref(hidraw_table[minor], 0);
305 	list_del(&list->node);
306 	kfree(list);
307 	return 0;
308 }
309 
310 static long hidraw_ioctl(struct file *file, unsigned int cmd,
311 							unsigned long arg)
312 {
313 	struct inode *inode = file->f_path.dentry->d_inode;
314 	unsigned int minor = iminor(inode);
315 	long ret = 0;
316 	struct hidraw *dev;
317 	void __user *user_arg = (void __user*) arg;
318 
319 	mutex_lock(&minors_lock);
320 	dev = hidraw_table[minor];
321 	if (!dev) {
322 		ret = -ENODEV;
323 		goto out;
324 	}
325 
326 	switch (cmd) {
327 		case HIDIOCGRDESCSIZE:
328 			if (put_user(dev->hid->rsize, (int __user *)arg))
329 				ret = -EFAULT;
330 			break;
331 
332 		case HIDIOCGRDESC:
333 			{
334 				__u32 len;
335 
336 				if (get_user(len, (int __user *)arg))
337 					ret = -EFAULT;
338 				else if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
339 					ret = -EINVAL;
340 				else if (copy_to_user(user_arg + offsetof(
341 					struct hidraw_report_descriptor,
342 					value[0]),
343 					dev->hid->rdesc,
344 					min(dev->hid->rsize, len)))
345 					ret = -EFAULT;
346 				break;
347 			}
348 		case HIDIOCGRAWINFO:
349 			{
350 				struct hidraw_devinfo dinfo;
351 
352 				dinfo.bustype = dev->hid->bus;
353 				dinfo.vendor = dev->hid->vendor;
354 				dinfo.product = dev->hid->product;
355 				if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
356 					ret = -EFAULT;
357 				break;
358 			}
359 		default:
360 			{
361 				struct hid_device *hid = dev->hid;
362 				if (_IOC_TYPE(cmd) != 'H') {
363 					ret = -EINVAL;
364 					break;
365 				}
366 
367 				if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSFEATURE(0))) {
368 					int len = _IOC_SIZE(cmd);
369 					ret = hidraw_send_report(file, user_arg, len, HID_FEATURE_REPORT);
370 					break;
371 				}
372 				if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGFEATURE(0))) {
373 					int len = _IOC_SIZE(cmd);
374 					ret = hidraw_get_report(file, user_arg, len, HID_FEATURE_REPORT);
375 					break;
376 				}
377 
378 				/* Begin Read-only ioctls. */
379 				if (_IOC_DIR(cmd) != _IOC_READ) {
380 					ret = -EINVAL;
381 					break;
382 				}
383 
384 				if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) {
385 					int len = strlen(hid->name) + 1;
386 					if (len > _IOC_SIZE(cmd))
387 						len = _IOC_SIZE(cmd);
388 					ret = copy_to_user(user_arg, hid->name, len) ?
389 						-EFAULT : len;
390 					break;
391 				}
392 
393 				if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) {
394 					int len = strlen(hid->phys) + 1;
395 					if (len > _IOC_SIZE(cmd))
396 						len = _IOC_SIZE(cmd);
397 					ret = copy_to_user(user_arg, hid->phys, len) ?
398 						-EFAULT : len;
399 					break;
400 				}
401 			}
402 
403 		ret = -ENOTTY;
404 	}
405 out:
406 	mutex_unlock(&minors_lock);
407 	return ret;
408 }
409 
410 static const struct file_operations hidraw_ops = {
411 	.owner =        THIS_MODULE,
412 	.read =         hidraw_read,
413 	.write =        hidraw_write,
414 	.poll =         hidraw_poll,
415 	.open =         hidraw_open,
416 	.release =      hidraw_release,
417 	.unlocked_ioctl = hidraw_ioctl,
418 #ifdef CONFIG_COMPAT
419 	.compat_ioctl   = hidraw_ioctl,
420 #endif
421 	.llseek =	noop_llseek,
422 };
423 
424 int hidraw_report_event(struct hid_device *hid, u8 *data, int len)
425 {
426 	struct hidraw *dev = hid->hidraw;
427 	struct hidraw_list *list;
428 	int ret = 0;
429 
430 	list_for_each_entry(list, &dev->list, node) {
431 		int new_head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
432 
433 		if (new_head == list->tail)
434 			continue;
435 
436 		if (!(list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC))) {
437 			ret = -ENOMEM;
438 			break;
439 		}
440 		list->buffer[list->head].len = len;
441 		list->head = new_head;
442 		kill_fasync(&list->fasync, SIGIO, POLL_IN);
443 	}
444 
445 	wake_up_interruptible(&dev->wait);
446 	return ret;
447 }
448 EXPORT_SYMBOL_GPL(hidraw_report_event);
449 
450 int hidraw_connect(struct hid_device *hid)
451 {
452 	int minor, result;
453 	struct hidraw *dev;
454 
455 	/* we accept any HID device, no matter the applications */
456 
457 	dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
458 	if (!dev)
459 		return -ENOMEM;
460 
461 	result = -EINVAL;
462 
463 	mutex_lock(&minors_lock);
464 
465 	for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
466 		if (hidraw_table[minor])
467 			continue;
468 		hidraw_table[minor] = dev;
469 		result = 0;
470 		break;
471 	}
472 
473 	if (result) {
474 		mutex_unlock(&minors_lock);
475 		kfree(dev);
476 		goto out;
477 	}
478 
479 	dev->dev = device_create(hidraw_class, &hid->dev, MKDEV(hidraw_major, minor),
480 				 NULL, "%s%d", "hidraw", minor);
481 
482 	if (IS_ERR(dev->dev)) {
483 		hidraw_table[minor] = NULL;
484 		mutex_unlock(&minors_lock);
485 		result = PTR_ERR(dev->dev);
486 		kfree(dev);
487 		goto out;
488 	}
489 
490 	mutex_unlock(&minors_lock);
491 	init_waitqueue_head(&dev->wait);
492 	INIT_LIST_HEAD(&dev->list);
493 
494 	dev->hid = hid;
495 	dev->minor = minor;
496 
497 	dev->exist = 1;
498 	hid->hidraw = dev;
499 
500 out:
501 	return result;
502 
503 }
504 EXPORT_SYMBOL_GPL(hidraw_connect);
505 
506 void hidraw_disconnect(struct hid_device *hid)
507 {
508 	struct hidraw *hidraw = hid->hidraw;
509 	drop_ref(hidraw, 1);
510 }
511 EXPORT_SYMBOL_GPL(hidraw_disconnect);
512 
513 int __init hidraw_init(void)
514 {
515 	int result;
516 	dev_t dev_id;
517 
518 	result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
519 			HIDRAW_MAX_DEVICES, "hidraw");
520 
521 	hidraw_major = MAJOR(dev_id);
522 
523 	if (result < 0) {
524 		pr_warn("can't get major number\n");
525 		goto out;
526 	}
527 
528 	hidraw_class = class_create(THIS_MODULE, "hidraw");
529 	if (IS_ERR(hidraw_class)) {
530 		result = PTR_ERR(hidraw_class);
531 		goto error_cdev;
532 	}
533 
534         cdev_init(&hidraw_cdev, &hidraw_ops);
535 	result = cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
536 	if (result < 0)
537 		goto error_class;
538 
539 out:
540 	return result;
541 
542 error_class:
543 	class_destroy(hidraw_class);
544 error_cdev:
545 	unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
546 	goto out;
547 }
548 
549 void hidraw_exit(void)
550 {
551 	dev_t dev_id = MKDEV(hidraw_major, 0);
552 
553 	cdev_del(&hidraw_cdev);
554 	class_destroy(hidraw_class);
555 	unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
556 
557 }
558 
559 static void drop_ref(struct hidraw *hidraw, int exists_bit)
560 {
561 	mutex_lock(&minors_lock);
562 	if (exists_bit) {
563 		hid_hw_close(hidraw->hid);
564 		hidraw->exist = 0;
565 		if (hidraw->open)
566 			wake_up_interruptible(&hidraw->wait);
567 	} else {
568 		--hidraw->open;
569 	}
570 
571 	if (!hidraw->open && !hidraw->exist) {
572 		device_destroy(hidraw_class, MKDEV(hidraw_major, hidraw->minor));
573 		hidraw_table[hidraw->minor] = NULL;
574 		kfree(hidraw);
575 	}
576 	mutex_unlock(&minors_lock);
577 }
578