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
40static int hidraw_major;
41static struct cdev hidraw_cdev;
42static struct class *hidraw_class;
43static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES];
44static DEFINE_MUTEX(minors_lock);
45
46static 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 (file->f_flags & O_NONBLOCK) {
61					ret = -EAGAIN;
62					break;
63				}
64				if (signal_pending(current)) {
65					ret = -ERESTARTSYS;
66					break;
67				}
68				if (!list->hidraw->exist) {
69					ret = -EIO;
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 (copy_to_user(buffer, list->buffer[list->tail].value, len)) {
91			ret = -EFAULT;
92			goto out;
93		}
94		ret = len;
95
96		kfree(list->buffer[list->tail].value);
97		list->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1);
98	}
99out:
100	mutex_unlock(&list->read_mutex);
101	return ret;
102}
103
104/* The first byte is expected to be a report number.
105 * This function is to be called with the minors_lock mutex held */
106static ssize_t hidraw_send_report(struct file *file, const char __user *buffer, size_t count, unsigned char report_type)
107{
108	unsigned int minor = iminor(file->f_path.dentry->d_inode);
109	struct hid_device *dev;
110	__u8 *buf;
111	int ret = 0;
112
113	if (!hidraw_table[minor]) {
114		ret = -ENODEV;
115		goto out;
116	}
117
118	dev = hidraw_table[minor]->hid;
119
120	if (!dev->hid_output_raw_report) {
121		ret = -ENODEV;
122		goto out;
123	}
124
125	if (count > HID_MAX_BUFFER_SIZE) {
126		hid_warn(dev, "pid %d passed too large report\n",
127			 task_pid_nr(current));
128		ret = -EINVAL;
129		goto out;
130	}
131
132	if (count < 2) {
133		hid_warn(dev, "pid %d passed too short report\n",
134			 task_pid_nr(current));
135		ret = -EINVAL;
136		goto out;
137	}
138
139	buf = kmalloc(count * sizeof(__u8), GFP_KERNEL);
140	if (!buf) {
141		ret = -ENOMEM;
142		goto out;
143	}
144
145	if (copy_from_user(buf, buffer, count)) {
146		ret = -EFAULT;
147		goto out_free;
148	}
149
150	ret = dev->hid_output_raw_report(dev, buf, count, report_type);
151out_free:
152	kfree(buf);
153out:
154	return ret;
155}
156
157/* the first byte is expected to be a report number */
158static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
159{
160	ssize_t ret;
161	mutex_lock(&minors_lock);
162	ret = hidraw_send_report(file, buffer, count, HID_OUTPUT_REPORT);
163	mutex_unlock(&minors_lock);
164	return ret;
165}
166
167
168/* This function performs a Get_Report transfer over the control endpoint
169 * per section 7.2.1 of the HID specification, version 1.1.  The first byte
170 * of buffer is the report number to request, or 0x0 if the defice does not
171 * use numbered reports. The report_type parameter can be HID_FEATURE_REPORT
172 * or HID_INPUT_REPORT.  This function is to be called with the minors_lock
173 *  mutex held. */
174static ssize_t hidraw_get_report(struct file *file, char __user *buffer, size_t count, unsigned char report_type)
175{
176	unsigned int minor = iminor(file->f_path.dentry->d_inode);
177	struct hid_device *dev;
178	__u8 *buf;
179	int ret = 0, len;
180	unsigned char report_number;
181
182	dev = hidraw_table[minor]->hid;
183
184	if (!dev->hid_get_raw_report) {
185		ret = -ENODEV;
186		goto out;
187	}
188
189	if (count > HID_MAX_BUFFER_SIZE) {
190		printk(KERN_WARNING "hidraw: pid %d passed too large report\n",
191				task_pid_nr(current));
192		ret = -EINVAL;
193		goto out;
194	}
195
196	if (count < 2) {
197		printk(KERN_WARNING "hidraw: pid %d passed too short report\n",
198				task_pid_nr(current));
199		ret = -EINVAL;
200		goto out;
201	}
202
203	buf = kmalloc(count * sizeof(__u8), GFP_KERNEL);
204	if (!buf) {
205		ret = -ENOMEM;
206		goto out;
207	}
208
209	/* Read the first byte from the user. This is the report number,
210	 * which is passed to dev->hid_get_raw_report(). */
211	if (copy_from_user(&report_number, buffer, 1)) {
212		ret = -EFAULT;
213		goto out_free;
214	}
215
216	ret = dev->hid_get_raw_report(dev, report_number, buf, count, report_type);
217
218	if (ret < 0)
219		goto out_free;
220
221	len = (ret < count) ? ret : count;
222
223	if (copy_to_user(buffer, buf, len)) {
224		ret = -EFAULT;
225		goto out_free;
226	}
227
228	ret = len;
229
230out_free:
231	kfree(buf);
232out:
233	return ret;
234}
235
236static unsigned int hidraw_poll(struct file *file, poll_table *wait)
237{
238	struct hidraw_list *list = file->private_data;
239
240	poll_wait(file, &list->hidraw->wait, wait);
241	if (list->head != list->tail)
242		return POLLIN | POLLRDNORM;
243	if (!list->hidraw->exist)
244		return POLLERR | POLLHUP;
245	return 0;
246}
247
248static int hidraw_open(struct inode *inode, struct file *file)
249{
250	unsigned int minor = iminor(inode);
251	struct hidraw *dev;
252	struct hidraw_list *list;
253	int err = 0;
254
255	if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
256		err = -ENOMEM;
257		goto out;
258	}
259
260	mutex_lock(&minors_lock);
261	if (!hidraw_table[minor]) {
262		err = -ENODEV;
263		goto out_unlock;
264	}
265
266	list->hidraw = hidraw_table[minor];
267	mutex_init(&list->read_mutex);
268	list_add_tail(&list->node, &hidraw_table[minor]->list);
269	file->private_data = list;
270
271	dev = hidraw_table[minor];
272	if (!dev->open++) {
273		err = hid_hw_power(dev->hid, PM_HINT_FULLON);
274		if (err < 0) {
275			dev->open--;
276			goto out_unlock;
277		}
278
279		err = hid_hw_open(dev->hid);
280		if (err < 0) {
281			hid_hw_power(dev->hid, PM_HINT_NORMAL);
282			dev->open--;
283		}
284	}
285
286out_unlock:
287	mutex_unlock(&minors_lock);
288out:
289	if (err < 0)
290		kfree(list);
291	return err;
292
293}
294
295static int hidraw_release(struct inode * inode, struct file * file)
296{
297	unsigned int minor = iminor(inode);
298	struct hidraw *dev;
299	struct hidraw_list *list = file->private_data;
300	int ret;
301
302	mutex_lock(&minors_lock);
303	if (!hidraw_table[minor]) {
304		ret = -ENODEV;
305		goto unlock;
306	}
307
308	list_del(&list->node);
309	dev = hidraw_table[minor];
310	if (!--dev->open) {
311		if (list->hidraw->exist) {
312			hid_hw_power(dev->hid, PM_HINT_NORMAL);
313			hid_hw_close(dev->hid);
314		} else {
315			kfree(list->hidraw);
316		}
317	}
318	kfree(list);
319	ret = 0;
320unlock:
321	mutex_unlock(&minors_lock);
322
323	return ret;
324}
325
326static long hidraw_ioctl(struct file *file, unsigned int cmd,
327							unsigned long arg)
328{
329	struct inode *inode = file->f_path.dentry->d_inode;
330	unsigned int minor = iminor(inode);
331	long ret = 0;
332	struct hidraw *dev;
333	void __user *user_arg = (void __user*) arg;
334
335	mutex_lock(&minors_lock);
336	dev = hidraw_table[minor];
337	if (!dev) {
338		ret = -ENODEV;
339		goto out;
340	}
341
342	switch (cmd) {
343		case HIDIOCGRDESCSIZE:
344			if (put_user(dev->hid->rsize, (int __user *)arg))
345				ret = -EFAULT;
346			break;
347
348		case HIDIOCGRDESC:
349			{
350				__u32 len;
351
352				if (get_user(len, (int __user *)arg))
353					ret = -EFAULT;
354				else if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
355					ret = -EINVAL;
356				else if (copy_to_user(user_arg + offsetof(
357					struct hidraw_report_descriptor,
358					value[0]),
359					dev->hid->rdesc,
360					min(dev->hid->rsize, len)))
361					ret = -EFAULT;
362				break;
363			}
364		case HIDIOCGRAWINFO:
365			{
366				struct hidraw_devinfo dinfo;
367
368				dinfo.bustype = dev->hid->bus;
369				dinfo.vendor = dev->hid->vendor;
370				dinfo.product = dev->hid->product;
371				if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
372					ret = -EFAULT;
373				break;
374			}
375		default:
376			{
377				struct hid_device *hid = dev->hid;
378				if (_IOC_TYPE(cmd) != 'H') {
379					ret = -EINVAL;
380					break;
381				}
382
383				if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSFEATURE(0))) {
384					int len = _IOC_SIZE(cmd);
385					ret = hidraw_send_report(file, user_arg, len, HID_FEATURE_REPORT);
386					break;
387				}
388				if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGFEATURE(0))) {
389					int len = _IOC_SIZE(cmd);
390					ret = hidraw_get_report(file, user_arg, len, HID_FEATURE_REPORT);
391					break;
392				}
393
394				/* Begin Read-only ioctls. */
395				if (_IOC_DIR(cmd) != _IOC_READ) {
396					ret = -EINVAL;
397					break;
398				}
399
400				if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) {
401					int len = strlen(hid->name) + 1;
402					if (len > _IOC_SIZE(cmd))
403						len = _IOC_SIZE(cmd);
404					ret = copy_to_user(user_arg, hid->name, len) ?
405						-EFAULT : len;
406					break;
407				}
408
409				if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) {
410					int len = strlen(hid->phys) + 1;
411					if (len > _IOC_SIZE(cmd))
412						len = _IOC_SIZE(cmd);
413					ret = copy_to_user(user_arg, hid->phys, len) ?
414						-EFAULT : len;
415					break;
416				}
417			}
418
419		ret = -ENOTTY;
420	}
421out:
422	mutex_unlock(&minors_lock);
423	return ret;
424}
425
426static const struct file_operations hidraw_ops = {
427	.owner =        THIS_MODULE,
428	.read =         hidraw_read,
429	.write =        hidraw_write,
430	.poll =         hidraw_poll,
431	.open =         hidraw_open,
432	.release =      hidraw_release,
433	.unlocked_ioctl = hidraw_ioctl,
434#ifdef CONFIG_COMPAT
435	.compat_ioctl   = hidraw_ioctl,
436#endif
437	.llseek =	noop_llseek,
438};
439
440void hidraw_report_event(struct hid_device *hid, u8 *data, int len)
441{
442	struct hidraw *dev = hid->hidraw;
443	struct hidraw_list *list;
444
445	list_for_each_entry(list, &dev->list, node) {
446		list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC);
447		list->buffer[list->head].len = len;
448		list->head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
449		kill_fasync(&list->fasync, SIGIO, POLL_IN);
450	}
451
452	wake_up_interruptible(&dev->wait);
453}
454EXPORT_SYMBOL_GPL(hidraw_report_event);
455
456int hidraw_connect(struct hid_device *hid)
457{
458	int minor, result;
459	struct hidraw *dev;
460
461	/* we accept any HID device, no matter the applications */
462
463	dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
464	if (!dev)
465		return -ENOMEM;
466
467	result = -EINVAL;
468
469	mutex_lock(&minors_lock);
470
471	for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
472		if (hidraw_table[minor])
473			continue;
474		hidraw_table[minor] = dev;
475		result = 0;
476		break;
477	}
478
479	if (result) {
480		mutex_unlock(&minors_lock);
481		kfree(dev);
482		goto out;
483	}
484
485	dev->dev = device_create(hidraw_class, &hid->dev, MKDEV(hidraw_major, minor),
486				 NULL, "%s%d", "hidraw", minor);
487
488	if (IS_ERR(dev->dev)) {
489		hidraw_table[minor] = NULL;
490		mutex_unlock(&minors_lock);
491		result = PTR_ERR(dev->dev);
492		kfree(dev);
493		goto out;
494	}
495
496	mutex_unlock(&minors_lock);
497	init_waitqueue_head(&dev->wait);
498	INIT_LIST_HEAD(&dev->list);
499
500	dev->hid = hid;
501	dev->minor = minor;
502
503	dev->exist = 1;
504	hid->hidraw = dev;
505
506out:
507	return result;
508
509}
510EXPORT_SYMBOL_GPL(hidraw_connect);
511
512void hidraw_disconnect(struct hid_device *hid)
513{
514	struct hidraw *hidraw = hid->hidraw;
515
516	mutex_lock(&minors_lock);
517	hidraw->exist = 0;
518
519	device_destroy(hidraw_class, MKDEV(hidraw_major, hidraw->minor));
520
521	hidraw_table[hidraw->minor] = NULL;
522
523	if (hidraw->open) {
524		hid_hw_close(hid);
525		wake_up_interruptible(&hidraw->wait);
526	} else {
527		kfree(hidraw);
528	}
529	mutex_unlock(&minors_lock);
530}
531EXPORT_SYMBOL_GPL(hidraw_disconnect);
532
533int __init hidraw_init(void)
534{
535	int result;
536	dev_t dev_id;
537
538	result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
539			HIDRAW_MAX_DEVICES, "hidraw");
540
541	hidraw_major = MAJOR(dev_id);
542
543	if (result < 0) {
544		pr_warn("can't get major number\n");
545		result = 0;
546		goto out;
547	}
548
549	hidraw_class = class_create(THIS_MODULE, "hidraw");
550	if (IS_ERR(hidraw_class)) {
551		result = PTR_ERR(hidraw_class);
552		unregister_chrdev(hidraw_major, "hidraw");
553		goto out;
554	}
555
556        cdev_init(&hidraw_cdev, &hidraw_ops);
557        cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
558out:
559	return result;
560}
561
562void hidraw_exit(void)
563{
564	dev_t dev_id = MKDEV(hidraw_major, 0);
565
566	cdev_del(&hidraw_cdev);
567	class_destroy(hidraw_class);
568	unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
569
570}
571