xref: /openbmc/linux/drivers/hid/hidraw.c (revision b04b4f78)
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 #include <linux/fs.h>
23 #include <linux/module.h>
24 #include <linux/errno.h>
25 #include <linux/kernel.h>
26 #include <linux/init.h>
27 #include <linux/cdev.h>
28 #include <linux/poll.h>
29 #include <linux/device.h>
30 #include <linux/major.h>
31 #include <linux/hid.h>
32 #include <linux/mutex.h>
33 #include <linux/smp_lock.h>
34 
35 #include <linux/hidraw.h>
36 
37 static int hidraw_major;
38 static struct cdev hidraw_cdev;
39 static struct class *hidraw_class;
40 static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES];
41 static DEFINE_MUTEX(minors_lock);
42 
43 static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
44 {
45 	struct hidraw_list *list = file->private_data;
46 	int ret = 0, len;
47 	char *report;
48 	DECLARE_WAITQUEUE(wait, current);
49 
50 	while (ret == 0) {
51 
52 		mutex_lock(&list->read_mutex);
53 
54 		if (list->head == list->tail) {
55 			add_wait_queue(&list->hidraw->wait, &wait);
56 			set_current_state(TASK_INTERRUPTIBLE);
57 
58 			while (list->head == list->tail) {
59 				if (file->f_flags & O_NONBLOCK) {
60 					ret = -EAGAIN;
61 					break;
62 				}
63 				if (signal_pending(current)) {
64 					ret = -ERESTARTSYS;
65 					break;
66 				}
67 				if (!list->hidraw->exist) {
68 					ret = -EIO;
69 					break;
70 				}
71 
72 				/* allow O_NONBLOCK to work well from other threads */
73 				mutex_unlock(&list->read_mutex);
74 				schedule();
75 				mutex_lock(&list->read_mutex);
76 				set_current_state(TASK_INTERRUPTIBLE);
77 			}
78 
79 			set_current_state(TASK_RUNNING);
80 			remove_wait_queue(&list->hidraw->wait, &wait);
81 		}
82 
83 		if (ret)
84 			goto out;
85 
86 		report = list->buffer[list->tail].value;
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 	}
99 out:
100 	mutex_unlock(&list->read_mutex);
101 	return ret;
102 }
103 
104 /* the first byte is expected to be a report number */
105 static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
106 {
107 	unsigned int minor = iminor(file->f_path.dentry->d_inode);
108 	/* FIXME: What stops hidraw_table going NULL */
109 	struct hid_device *dev = hidraw_table[minor]->hid;
110 	__u8 *buf;
111 	int ret = 0;
112 
113 	if (!dev->hid_output_raw_report)
114 		return -ENODEV;
115 
116 	if (count > HID_MAX_BUFFER_SIZE) {
117 		printk(KERN_WARNING "hidraw: pid %d passed too large report\n",
118 				task_pid_nr(current));
119 		return -EINVAL;
120 	}
121 
122 	if (count < 2) {
123 		printk(KERN_WARNING "hidraw: pid %d passed too short report\n",
124 				task_pid_nr(current));
125 		return -EINVAL;
126 	}
127 
128 	buf = kmalloc(count * sizeof(__u8), GFP_KERNEL);
129 	if (!buf)
130 		return -ENOMEM;
131 
132 	if (copy_from_user(buf, buffer, count)) {
133 		ret = -EFAULT;
134 		goto out;
135 	}
136 
137 	ret = dev->hid_output_raw_report(dev, buf, count);
138 out:
139 	kfree(buf);
140 	return ret;
141 }
142 
143 static unsigned int hidraw_poll(struct file *file, poll_table *wait)
144 {
145 	struct hidraw_list *list = file->private_data;
146 
147 	poll_wait(file, &list->hidraw->wait, wait);
148 	if (list->head != list->tail)
149 		return POLLIN | POLLRDNORM;
150 	if (!list->hidraw->exist)
151 		return POLLERR | POLLHUP;
152 	return 0;
153 }
154 
155 static int hidraw_open(struct inode *inode, struct file *file)
156 {
157 	unsigned int minor = iminor(inode);
158 	struct hidraw *dev;
159 	struct hidraw_list *list;
160 	int err = 0;
161 
162 	if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
163 		err = -ENOMEM;
164 		goto out;
165 	}
166 
167 	lock_kernel();
168 	mutex_lock(&minors_lock);
169 	if (!hidraw_table[minor]) {
170 		printk(KERN_EMERG "hidraw device with minor %d doesn't exist\n",
171 				minor);
172 		kfree(list);
173 		err = -ENODEV;
174 		goto out_unlock;
175 	}
176 
177 	list->hidraw = hidraw_table[minor];
178 	mutex_init(&list->read_mutex);
179 	list_add_tail(&list->node, &hidraw_table[minor]->list);
180 	file->private_data = list;
181 
182 	dev = hidraw_table[minor];
183 	if (!dev->open++) {
184 		if (dev->hid->ll_driver->power) {
185 			err = dev->hid->ll_driver->power(dev->hid, PM_HINT_FULLON);
186 			if (err < 0)
187 				goto out_unlock;
188 		}
189 		err = dev->hid->ll_driver->open(dev->hid);
190 		if (err < 0) {
191 			if (dev->hid->ll_driver->power)
192 				dev->hid->ll_driver->power(dev->hid, PM_HINT_NORMAL);
193 			dev->open--;
194 		}
195 	}
196 
197 out_unlock:
198 	mutex_unlock(&minors_lock);
199 	unlock_kernel();
200 out:
201 	return err;
202 
203 }
204 
205 static int hidraw_release(struct inode * inode, struct file * file)
206 {
207 	unsigned int minor = iminor(inode);
208 	struct hidraw *dev;
209 	struct hidraw_list *list = file->private_data;
210 
211 	if (!hidraw_table[minor]) {
212 		printk(KERN_EMERG "hidraw device with minor %d doesn't exist\n",
213 				minor);
214 		return -ENODEV;
215 	}
216 
217 	list_del(&list->node);
218 	dev = hidraw_table[minor];
219 	if (!--dev->open) {
220 		if (list->hidraw->exist) {
221 			if (dev->hid->ll_driver->power)
222 				dev->hid->ll_driver->power(dev->hid, PM_HINT_NORMAL);
223 			dev->hid->ll_driver->close(dev->hid);
224 		} else {
225 			kfree(list->hidraw);
226 		}
227 	}
228 
229 	kfree(list);
230 
231 	return 0;
232 }
233 
234 static long hidraw_ioctl(struct file *file, unsigned int cmd,
235 							unsigned long arg)
236 {
237 	struct inode *inode = file->f_path.dentry->d_inode;
238 	unsigned int minor = iminor(inode);
239 	long ret = 0;
240 	/* FIXME: What stops hidraw_table going NULL */
241 	struct hidraw *dev = hidraw_table[minor];
242 	void __user *user_arg = (void __user*) arg;
243 
244 	lock_kernel();
245 	switch (cmd) {
246 		case HIDIOCGRDESCSIZE:
247 			if (put_user(dev->hid->rsize, (int __user *)arg))
248 				ret = -EFAULT;
249 			break;
250 
251 		case HIDIOCGRDESC:
252 			{
253 				__u32 len;
254 
255 				if (get_user(len, (int __user *)arg))
256 					ret = -EFAULT;
257 				else if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
258 					ret = -EINVAL;
259 				else if (copy_to_user(user_arg + offsetof(
260 					struct hidraw_report_descriptor,
261 					value[0]),
262 					dev->hid->rdesc,
263 					min(dev->hid->rsize, len)))
264 					ret = -EFAULT;
265 				break;
266 			}
267 		case HIDIOCGRAWINFO:
268 			{
269 				struct hidraw_devinfo dinfo;
270 
271 				dinfo.bustype = dev->hid->bus;
272 				dinfo.vendor = dev->hid->vendor;
273 				dinfo.product = dev->hid->product;
274 				if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
275 					ret = -EFAULT;
276 				break;
277 			}
278 		default:
279 			{
280 				struct hid_device *hid = dev->hid;
281 				if (_IOC_TYPE(cmd) != 'H' || _IOC_DIR(cmd) != _IOC_READ) {
282 					ret = -EINVAL;
283 					break;
284 				}
285 
286 				if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) {
287 					int len;
288 					if (!hid->name) {
289 						ret = 0;
290 						break;
291 					}
292 					len = strlen(hid->name) + 1;
293 					if (len > _IOC_SIZE(cmd))
294 						len = _IOC_SIZE(cmd);
295 					ret = copy_to_user(user_arg, hid->name, len) ?
296 						-EFAULT : len;
297 					break;
298 				}
299 
300 				if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) {
301 					int len;
302 					if (!hid->phys) {
303 						ret = 0;
304 						break;
305 					}
306 					len = strlen(hid->phys) + 1;
307 					if (len > _IOC_SIZE(cmd))
308 						len = _IOC_SIZE(cmd);
309 					ret = copy_to_user(user_arg, hid->phys, len) ?
310 						-EFAULT : len;
311 					break;
312 				}
313                 }
314 
315 		ret = -ENOTTY;
316 	}
317 	unlock_kernel();
318 	return ret;
319 }
320 
321 static const struct file_operations hidraw_ops = {
322 	.owner =        THIS_MODULE,
323 	.read =         hidraw_read,
324 	.write =        hidraw_write,
325 	.poll =         hidraw_poll,
326 	.open =         hidraw_open,
327 	.release =      hidraw_release,
328 	.unlocked_ioctl = hidraw_ioctl,
329 };
330 
331 void hidraw_report_event(struct hid_device *hid, u8 *data, int len)
332 {
333 	struct hidraw *dev = hid->hidraw;
334 	struct hidraw_list *list;
335 
336 	list_for_each_entry(list, &dev->list, node) {
337 		list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC);
338 		list->buffer[list->head].len = len;
339 		list->head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
340 		kill_fasync(&list->fasync, SIGIO, POLL_IN);
341 	}
342 
343 	wake_up_interruptible(&dev->wait);
344 }
345 EXPORT_SYMBOL_GPL(hidraw_report_event);
346 
347 int hidraw_connect(struct hid_device *hid)
348 {
349 	int minor, result;
350 	struct hidraw *dev;
351 
352 	/* TODO currently we accept any HID device. This should later
353 	 * probably be fixed to accept only those devices which provide
354 	 * non-input applications
355 	 */
356 
357 	dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
358 	if (!dev)
359 		return -ENOMEM;
360 
361 	result = -EINVAL;
362 
363 	mutex_lock(&minors_lock);
364 
365 	for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
366 		if (hidraw_table[minor])
367 			continue;
368 		hidraw_table[minor] = dev;
369 		result = 0;
370 		break;
371 	}
372 
373 	if (result) {
374 		mutex_unlock(&minors_lock);
375 		kfree(dev);
376 		goto out;
377 	}
378 
379 	dev->dev = device_create(hidraw_class, &hid->dev, MKDEV(hidraw_major, minor),
380 				 NULL, "%s%d", "hidraw", minor);
381 
382 	if (IS_ERR(dev->dev)) {
383 		hidraw_table[minor] = NULL;
384 		mutex_unlock(&minors_lock);
385 		result = PTR_ERR(dev->dev);
386 		kfree(dev);
387 		goto out;
388 	}
389 
390 	mutex_unlock(&minors_lock);
391 	init_waitqueue_head(&dev->wait);
392 	INIT_LIST_HEAD(&dev->list);
393 
394 	dev->hid = hid;
395 	dev->minor = minor;
396 
397 	dev->exist = 1;
398 	hid->hidraw = dev;
399 
400 out:
401 	return result;
402 
403 }
404 EXPORT_SYMBOL_GPL(hidraw_connect);
405 
406 void hidraw_disconnect(struct hid_device *hid)
407 {
408 	struct hidraw *hidraw = hid->hidraw;
409 
410 	hidraw->exist = 0;
411 
412 	mutex_lock(&minors_lock);
413 	hidraw_table[hidraw->minor] = NULL;
414 	mutex_unlock(&minors_lock);
415 
416 	device_destroy(hidraw_class, MKDEV(hidraw_major, hidraw->minor));
417 
418 	if (hidraw->open) {
419 		hid->ll_driver->close(hid);
420 		wake_up_interruptible(&hidraw->wait);
421 	} else {
422 		kfree(hidraw);
423 	}
424 }
425 EXPORT_SYMBOL_GPL(hidraw_disconnect);
426 
427 int __init hidraw_init(void)
428 {
429 	int result;
430 	dev_t dev_id;
431 
432 	result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
433 			HIDRAW_MAX_DEVICES, "hidraw");
434 
435 	hidraw_major = MAJOR(dev_id);
436 
437 	if (result < 0) {
438 		printk(KERN_WARNING "hidraw: can't get major number\n");
439 		result = 0;
440 		goto out;
441 	}
442 
443 	hidraw_class = class_create(THIS_MODULE, "hidraw");
444 	if (IS_ERR(hidraw_class)) {
445 		result = PTR_ERR(hidraw_class);
446 		unregister_chrdev(hidraw_major, "hidraw");
447 		goto out;
448 	}
449 
450         cdev_init(&hidraw_cdev, &hidraw_ops);
451         cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
452 out:
453 	return result;
454 }
455 
456 void hidraw_exit(void)
457 {
458 	dev_t dev_id = MKDEV(hidraw_major, 0);
459 
460 	cdev_del(&hidraw_cdev);
461 	class_destroy(hidraw_class);
462 	unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
463 
464 }
465