hidraw.c 13.9 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628
/*
 * HID raw devices, giving access to raw HID events.
 *
 * In comparison to hiddev, this device does not process the
 * hid events at all (no parsing, no lookups). This lets applications
 * to work on raw hid events as they want to, and avoids a need to
 * use a transport-specific userspace libhid/libusb libraries.
 *
 *  Copyright (c) 2007-2014 Jiri Kosina
 */

/*
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/fs.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/cdev.h>
#include <linux/poll.h>
#include <linux/device.h>
#include <linux/major.h>
#include <linux/slab.h>
#include <linux/hid.h>
#include <linux/mutex.h>
#include <linux/sched.h>

#include <linux/hidraw.h>

static int hidraw_major;
static struct cdev hidraw_cdev;
static struct class *hidraw_class;
static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES];
static DEFINE_MUTEX(minors_lock);

static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
{
	struct hidraw_list *list = file->private_data;
	int ret = 0, len;
	DECLARE_WAITQUEUE(wait, current);

	mutex_lock(&list->read_mutex);

	while (ret == 0) {
		if (list->head == list->tail) {
			add_wait_queue(&list->hidraw->wait, &wait);
			set_current_state(TASK_INTERRUPTIBLE);

			while (list->head == list->tail) {
				if (signal_pending(current)) {
					ret = -ERESTARTSYS;
					break;
				}
				if (!list->hidraw->exist) {
					ret = -EIO;
					break;
				}
				if (file->f_flags & O_NONBLOCK) {
					ret = -EAGAIN;
					break;
				}

				/* allow O_NONBLOCK to work well from other threads */
				mutex_unlock(&list->read_mutex);
				schedule();
				mutex_lock(&list->read_mutex);
				set_current_state(TASK_INTERRUPTIBLE);
			}

			set_current_state(TASK_RUNNING);
			remove_wait_queue(&list->hidraw->wait, &wait);
		}

		if (ret)
			goto out;

		len = list->buffer[list->tail].len > count ?
			count : list->buffer[list->tail].len;

		if (list->buffer[list->tail].value) {
			if (copy_to_user(buffer, list->buffer[list->tail].value, len)) {
				ret = -EFAULT;
				goto out;
			}
			ret = len;
		}

		kfree(list->buffer[list->tail].value);
		list->buffer[list->tail].value = NULL;
		list->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1);
	}
out:
	mutex_unlock(&list->read_mutex);
	return ret;
}

/*
 * The first byte of the report buffer is expected to be a report number.
 *
 * This function is to be called with the minors_lock mutex held.
 */
static ssize_t hidraw_send_report(struct file *file, const char __user *buffer, size_t count, unsigned char report_type)
{
	unsigned int minor = iminor(file_inode(file));
	struct hid_device *dev;
	__u8 *buf;
	int ret = 0;

	if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
		ret = -ENODEV;
		goto out;
	}

	dev = hidraw_table[minor]->hid;


	if (count > HID_MAX_BUFFER_SIZE) {
		hid_warn(dev, "pid %d passed too large report\n",
			 task_pid_nr(current));
		ret = -EINVAL;
		goto out;
	}

	if (count < 2) {
		hid_warn(dev, "pid %d passed too short report\n",
			 task_pid_nr(current));
		ret = -EINVAL;
		goto out;
	}

	buf = kmalloc(count * sizeof(__u8), GFP_KERNEL);
	if (!buf) {
		ret = -ENOMEM;
		goto out;
	}

	if (copy_from_user(buf, buffer, count)) {
		ret = -EFAULT;
		goto out_free;
	}

	if ((report_type == HID_OUTPUT_REPORT) &&
	    !(dev->quirks & HID_QUIRK_NO_OUTPUT_REPORTS_ON_INTR_EP)) {
		ret = hid_hw_output_report(dev, buf, count);
		/*
		 * compatibility with old implementation of USB-HID and I2C-HID:
		 * if the device does not support receiving output reports,
		 * on an interrupt endpoint, fallback to SET_REPORT HID command.
		 */
		if (ret != -ENOSYS)
			goto out_free;
	}

	ret = hid_hw_raw_request(dev, buf[0], buf, count, report_type,
				HID_REQ_SET_REPORT);

out_free:
	kfree(buf);
out:
	return ret;
}

static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
{
	ssize_t ret;
	mutex_lock(&minors_lock);
	ret = hidraw_send_report(file, buffer, count, HID_OUTPUT_REPORT);
	mutex_unlock(&minors_lock);
	return ret;
}


/*
 * This function performs a Get_Report transfer over the control endpoint
 * per section 7.2.1 of the HID specification, version 1.1.  The first byte
 * of buffer is the report number to request, or 0x0 if the defice does not
 * use numbered reports. The report_type parameter can be HID_FEATURE_REPORT
 * or HID_INPUT_REPORT.
 *
 * This function is to be called with the minors_lock mutex held.
 */
static ssize_t hidraw_get_report(struct file *file, char __user *buffer, size_t count, unsigned char report_type)
{
	unsigned int minor = iminor(file_inode(file));
	struct hid_device *dev;
	__u8 *buf;
	int ret = 0, len;
	unsigned char report_number;

	dev = hidraw_table[minor]->hid;

	if (!dev->ll_driver->raw_request) {
		ret = -ENODEV;
		goto out;
	}

	if (count > HID_MAX_BUFFER_SIZE) {
		printk(KERN_WARNING "hidraw: pid %d passed too large report\n",
				task_pid_nr(current));
		ret = -EINVAL;
		goto out;
	}

	if (count < 2) {
		printk(KERN_WARNING "hidraw: pid %d passed too short report\n",
				task_pid_nr(current));
		ret = -EINVAL;
		goto out;
	}

	buf = kmalloc(count * sizeof(__u8), GFP_KERNEL);
	if (!buf) {
		ret = -ENOMEM;
		goto out;
	}

	/*
	 * Read the first byte from the user. This is the report number,
	 * which is passed to hid_hw_raw_request().
	 */
	if (copy_from_user(&report_number, buffer, 1)) {
		ret = -EFAULT;
		goto out_free;
	}

	ret = hid_hw_raw_request(dev, report_number, buf, count, report_type,
				 HID_REQ_GET_REPORT);

	if (ret < 0)
		goto out_free;

	len = (ret < count) ? ret : count;

	if (copy_to_user(buffer, buf, len)) {
		ret = -EFAULT;
		goto out_free;
	}

	ret = len;

out_free:
	kfree(buf);
out:
	return ret;
}

static unsigned int hidraw_poll(struct file *file, poll_table *wait)
{
	struct hidraw_list *list = file->private_data;

	poll_wait(file, &list->hidraw->wait, wait);
	if (list->head != list->tail)
		return POLLIN | POLLRDNORM;
	if (!list->hidraw->exist)
		return POLLERR | POLLHUP;
	return 0;
}

static int hidraw_open(struct inode *inode, struct file *file)
{
	unsigned int minor = iminor(inode);
	struct hidraw *dev;
	struct hidraw_list *list;
	unsigned long flags;
	int err = 0;

	if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
		err = -ENOMEM;
		goto out;
	}

	mutex_lock(&minors_lock);
	if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
		err = -ENODEV;
		goto out_unlock;
	}

	dev = hidraw_table[minor];
	if (!dev->open++) {
		err = hid_hw_power(dev->hid, PM_HINT_FULLON);
		if (err < 0) {
			dev->open--;
			goto out_unlock;
		}

		err = hid_hw_open(dev->hid);
		if (err < 0) {
			hid_hw_power(dev->hid, PM_HINT_NORMAL);
			dev->open--;
			goto out_unlock;
		}
	}

	list->hidraw = hidraw_table[minor];
	mutex_init(&list->read_mutex);
	spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags);
	list_add_tail(&list->node, &hidraw_table[minor]->list);
	spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags);
	file->private_data = list;
out_unlock:
	mutex_unlock(&minors_lock);
out:
	if (err < 0)
		kfree(list);
	return err;

}

static int hidraw_fasync(int fd, struct file *file, int on)
{
	struct hidraw_list *list = file->private_data;

	return fasync_helper(fd, file, on, &list->fasync);
}

static void drop_ref(struct hidraw *hidraw, int exists_bit)
{
	if (exists_bit) {
		hidraw->exist = 0;
		if (hidraw->open) {
			hid_hw_close(hidraw->hid);
			wake_up_interruptible(&hidraw->wait);
		}
		device_destroy(hidraw_class,
			       MKDEV(hidraw_major, hidraw->minor));
	} else {
		--hidraw->open;
	}
	if (!hidraw->open) {
		if (!hidraw->exist) {
			hidraw_table[hidraw->minor] = NULL;
			kfree(hidraw);
		} else {
			/* close device for last reader */
			hid_hw_power(hidraw->hid, PM_HINT_NORMAL);
			hid_hw_close(hidraw->hid);
		}
	}
}

static int hidraw_release(struct inode * inode, struct file * file)
{
	unsigned int minor = iminor(inode);
	struct hidraw_list *list = file->private_data;
	unsigned long flags;

	mutex_lock(&minors_lock);

	spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags);
	list_del(&list->node);
	spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags);
	kfree(list);

	drop_ref(hidraw_table[minor], 0);

	mutex_unlock(&minors_lock);
	return 0;
}

static long hidraw_ioctl(struct file *file, unsigned int cmd,
							unsigned long arg)
{
	struct inode *inode = file_inode(file);
	unsigned int minor = iminor(inode);
	long ret = 0;
	struct hidraw *dev;
	void __user *user_arg = (void __user*) arg;

	mutex_lock(&minors_lock);
	dev = hidraw_table[minor];
	if (!dev) {
		ret = -ENODEV;
		goto out;
	}

	switch (cmd) {
		case HIDIOCGRDESCSIZE:
			if (put_user(dev->hid->rsize, (int __user *)arg))
				ret = -EFAULT;
			break;

		case HIDIOCGRDESC:
			{
				__u32 len;

				if (get_user(len, (int __user *)arg))
					ret = -EFAULT;
				else if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
					ret = -EINVAL;
				else if (copy_to_user(user_arg + offsetof(
					struct hidraw_report_descriptor,
					value[0]),
					dev->hid->rdesc,
					min(dev->hid->rsize, len)))
					ret = -EFAULT;
				break;
			}
		case HIDIOCGRAWINFO:
			{
				struct hidraw_devinfo dinfo;

				dinfo.bustype = dev->hid->bus;
				dinfo.vendor = dev->hid->vendor;
				dinfo.product = dev->hid->product;
				if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
					ret = -EFAULT;
				break;
			}
		default:
			{
				struct hid_device *hid = dev->hid;
				if (_IOC_TYPE(cmd) != 'H') {
					ret = -EINVAL;
					break;
				}

				if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSFEATURE(0))) {
					int len = _IOC_SIZE(cmd);
					ret = hidraw_send_report(file, user_arg, len, HID_FEATURE_REPORT);
					break;
				}
				if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGFEATURE(0))) {
					int len = _IOC_SIZE(cmd);
					ret = hidraw_get_report(file, user_arg, len, HID_FEATURE_REPORT);
					break;
				}

				/* Begin Read-only ioctls. */
				if (_IOC_DIR(cmd) != _IOC_READ) {
					ret = -EINVAL;
					break;
				}

				if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) {
					int len = strlen(hid->name) + 1;
					if (len > _IOC_SIZE(cmd))
						len = _IOC_SIZE(cmd);
					ret = copy_to_user(user_arg, hid->name, len) ?
						-EFAULT : len;
					break;
				}

				if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) {
					int len = strlen(hid->phys) + 1;
					if (len > _IOC_SIZE(cmd))
						len = _IOC_SIZE(cmd);
					ret = copy_to_user(user_arg, hid->phys, len) ?
						-EFAULT : len;
					break;
				}
			}

		ret = -ENOTTY;
	}
out:
	mutex_unlock(&minors_lock);
	return ret;
}

static const struct file_operations hidraw_ops = {
	.owner =        THIS_MODULE,
	.read =         hidraw_read,
	.write =        hidraw_write,
	.poll =         hidraw_poll,
	.open =         hidraw_open,
	.release =      hidraw_release,
	.unlocked_ioctl = hidraw_ioctl,
	.fasync =	hidraw_fasync,
#ifdef CONFIG_COMPAT
	.compat_ioctl   = hidraw_ioctl,
#endif
	.llseek =	noop_llseek,
};

int hidraw_report_event(struct hid_device *hid, u8 *data, int len)
{
	struct hidraw *dev = hid->hidraw;
	struct hidraw_list *list;
	int ret = 0;
	unsigned long flags;

	spin_lock_irqsave(&dev->list_lock, flags);
	list_for_each_entry(list, &dev->list, node) {
		int new_head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);

		if (new_head == list->tail)
			continue;

		if (!(list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC))) {
			ret = -ENOMEM;
			break;
		}
		list->buffer[list->head].len = len;
		list->head = new_head;
		kill_fasync(&list->fasync, SIGIO, POLL_IN);
	}
	spin_unlock_irqrestore(&dev->list_lock, flags);

	wake_up_interruptible(&dev->wait);
	return ret;
}
EXPORT_SYMBOL_GPL(hidraw_report_event);

int hidraw_connect(struct hid_device *hid)
{
	int minor, result;
	struct hidraw *dev;

	/* we accept any HID device, all applications */

	dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
	if (!dev)
		return -ENOMEM;

	result = -EINVAL;

	mutex_lock(&minors_lock);

	for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
		if (hidraw_table[minor])
			continue;
		hidraw_table[minor] = dev;
		result = 0;
		break;
	}

	if (result) {
		mutex_unlock(&minors_lock);
		kfree(dev);
		goto out;
	}

	dev->dev = device_create(hidraw_class, &hid->dev, MKDEV(hidraw_major, minor),
				 NULL, "%s%d", "hidraw", minor);

	if (IS_ERR(dev->dev)) {
		hidraw_table[minor] = NULL;
		mutex_unlock(&minors_lock);
		result = PTR_ERR(dev->dev);
		kfree(dev);
		goto out;
	}

	init_waitqueue_head(&dev->wait);
	spin_lock_init(&dev->list_lock);
	INIT_LIST_HEAD(&dev->list);

	dev->hid = hid;
	dev->minor = minor;

	dev->exist = 1;
	hid->hidraw = dev;

	mutex_unlock(&minors_lock);
out:
	return result;

}
EXPORT_SYMBOL_GPL(hidraw_connect);

void hidraw_disconnect(struct hid_device *hid)
{
	struct hidraw *hidraw = hid->hidraw;

	mutex_lock(&minors_lock);

	drop_ref(hidraw, 1);

	mutex_unlock(&minors_lock);
}
EXPORT_SYMBOL_GPL(hidraw_disconnect);

int __init hidraw_init(void)
{
	int result;
	dev_t dev_id;

	result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
			HIDRAW_MAX_DEVICES, "hidraw");

	hidraw_major = MAJOR(dev_id);

	if (result < 0) {
		pr_warn("can't get major number\n");
		goto out;
	}

	hidraw_class = class_create(THIS_MODULE, "hidraw");
	if (IS_ERR(hidraw_class)) {
		result = PTR_ERR(hidraw_class);
		goto error_cdev;
	}

        cdev_init(&hidraw_cdev, &hidraw_ops);
	result = cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
	if (result < 0)
		goto error_class;

	printk(KERN_INFO "hidraw: raw HID events driver (C) Jiri Kosina\n");
out:
	return result;

error_class:
	class_destroy(hidraw_class);
error_cdev:
	unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
	goto out;
}

void hidraw_exit(void)
{
	dev_t dev_id = MKDEV(hidraw_major, 0);

	cdev_del(&hidraw_cdev);
	class_destroy(hidraw_class);
	unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);

}