[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / char / raw.c

/*
 * linux/drivers/char/raw.c
 *
 * Front-end raw character devices.  These can be bound to any block
 * devices to provide genuine Unix raw character device semantics.
 *
 * We reserve minor number 0 for a control interface.  ioctl()s on this
 * device are used to bind the other minor numbers to block devices.
 */

#include <linux/init.h>
#include <linux/fs.h>
#include <linux/devfs_fs_kernel.h>
#include <linux/major.h>
#include <linux/blkdev.h>
#include <linux/module.h>
#include <linux/raw.h>
#include <linux/capability.h>
#include <linux/uio.h>
#include <linux/cdev.h>
#include <linux/device.h>

#include <asm/uaccess.h>

struct raw_device_data {
	struct block_device *binding;
	int inuse;
};

static struct class_simple *raw_class;
static struct raw_device_data raw_devices[MAX_RAW_MINORS];
static DECLARE_MUTEX(raw_mutex);
static struct file_operations raw_ctl_fops;	     /* forward declaration */

/*
 * Open/close code for raw IO.
 *
 * We just rewrite the i_mapping for the /dev/raw/rawN file descriptor to
 * point at the blockdev's address_space and set the file handle to use
 * O_DIRECT.
 *
 * Set the device's soft blocksize to the minimum possible.  This gives the
 * finest possible alignment and has no adverse impact on performance.
 */
static int raw_open(struct inode *inode, struct file *filp)
{
	const int minor = iminor(inode);
	struct block_device *bdev;
	int err;

	if (minor == 0) {	/* It is the control device */
		filp->f_op = &raw_ctl_fops;
		return 0;
	}

	down(&raw_mutex);

	/*
	 * All we need to do on open is check that the device is bound.
	 */
	bdev = raw_devices[minor].binding;
	err = -ENODEV;
	if (!bdev)
		goto out;
	igrab(bdev->bd_inode);
	err = blkdev_get(bdev, filp->f_mode, 0);
	if (err)
		goto out;
	err = bd_claim(bdev, raw_open);
	if (err)
		goto out1;
	err = set_blocksize(bdev, bdev_hardsect_size(bdev));
	if (err)
		goto out2;
	filp->f_flags |= O_DIRECT;
	filp->f_mapping = bdev->bd_inode->i_mapping;
	if (++raw_devices[minor].inuse == 1)
		filp->f_dentry->d_inode->i_mapping =
			bdev->bd_inode->i_mapping;
	filp->private_data = bdev;
	up(&raw_mutex);
	return 0;

out2:
	bd_release(bdev);
out1:
	blkdev_put(bdev);
out:
	up(&raw_mutex);
	return err;
}

/*
 * When the final fd which refers to this character-special node is closed, we
 * make its ->mapping point back at its own i_data.
 */
static int raw_release(struct inode *inode, struct file *filp)
{
	const int minor= iminor(inode);
	struct block_device *bdev;

	down(&raw_mutex);
	bdev = raw_devices[minor].binding;
	if (--raw_devices[minor].inuse == 0) {
		/* Here  inode->i_mapping == bdev->bd_inode->i_mapping  */
		inode->i_mapping = &inode->i_data;
		inode->i_mapping->backing_dev_info = &default_backing_dev_info;
	}
	up(&raw_mutex);

	bd_release(bdev);
	blkdev_put(bdev);
	return 0;
}

/*
 * Forward ioctls to the underlying block device.
 */
static int
raw_ioctl(struct inode *inode, struct file *filp,
		  unsigned int command, unsigned long arg)
{
	struct block_device *bdev = filp->private_data;

	return blkdev_ioctl(bdev->bd_inode, NULL, command, arg);
}

static void bind_device(struct raw_config_request *rq)
{
	class_simple_device_remove(MKDEV(RAW_MAJOR, rq->raw_minor));
	class_simple_device_add(raw_class, MKDEV(RAW_MAJOR, rq->raw_minor),
				      NULL, "raw%d", rq->raw_minor);
}

/*
 * Deal with ioctls against the raw-device control interface, to bind
 * and unbind other raw devices.
 */
static int raw_ctl_ioctl(struct inode *inode, struct file *filp,
			unsigned int command, unsigned long arg)
{
	struct raw_config_request rq;
	struct raw_device_data *rawdev;
	int err = 0;

	switch (command) {
	case RAW_SETBIND:
	case RAW_GETBIND:

		/* First, find out which raw minor we want */

		if (copy_from_user(&rq, (void __user *) arg, sizeof(rq))) {
			err = -EFAULT;
			goto out;
		}

		if (rq.raw_minor < 0 || rq.raw_minor >= MAX_RAW_MINORS) {
			err = -EINVAL;
			goto out;
		}
		rawdev = &raw_devices[rq.raw_minor];

		if (command == RAW_SETBIND) {
			dev_t dev;

			/*
			 * This is like making block devices, so demand the
			 * same capability
			 */
			if (!capable(CAP_SYS_ADMIN)) {
				err = -EPERM;
				goto out;
			}

			/*
			 * For now, we don't need to check that the underlying
			 * block device is present or not: we can do that when
			 * the raw device is opened.  Just check that the
			 * major/minor numbers make sense.
			 */

			dev = MKDEV(rq.block_major, rq.block_minor);
			if ((rq.block_major == 0 && rq.block_minor != 0) ||
					MAJOR(dev) != rq.block_major ||
					MINOR(dev) != rq.block_minor) {
				err = -EINVAL;
				goto out;
			}

			down(&raw_mutex);
			if (rawdev->inuse) {
				up(&raw_mutex);
				err = -EBUSY;
				goto out;
			}
			if (rawdev->binding) {
				bdput(rawdev->binding);
				module_put(THIS_MODULE);
			}
			if (rq.block_major == 0 && rq.block_minor == 0) {
				/* unbind */
				rawdev->binding = NULL;
				class_simple_device_remove(MKDEV(RAW_MAJOR,
								rq.raw_minor));
			} else {
				rawdev->binding = bdget(dev);
				if (rawdev->binding == NULL)
					err = -ENOMEM;
				else {
					__module_get(THIS_MODULE);
					bind_device(&rq);
				}
			}
			up(&raw_mutex);
		} else {
			struct block_device *bdev;

			down(&raw_mutex);
			bdev = rawdev->binding;
			if (bdev) {
				rq.block_major = MAJOR(bdev->bd_dev);
				rq.block_minor = MINOR(bdev->bd_dev);
			} else {
				rq.block_major = rq.block_minor = 0;
			}
			up(&raw_mutex);
			if (copy_to_user((void __user *)arg, &rq, sizeof(rq))) {
				err = -EFAULT;
				goto out;
			}
		}
		break;
	default:
		err = -EINVAL;
		break;
	}
out:
	return err;
}

static ssize_t raw_file_write(struct file *file, const char __user *buf,
				   size_t count, loff_t *ppos)
{
	struct iovec local_iov = {
		.iov_base = (char __user *)buf,
		.iov_len = count
	};

	return generic_file_write_nolock(file, &local_iov, 1, ppos);
}

static ssize_t raw_file_aio_write(struct kiocb *iocb, const char __user *buf,
					size_t count, loff_t pos)
{
	struct iovec local_iov = {
		.iov_base = (char __user *)buf,
		.iov_len = count
	};

	return generic_file_aio_write_nolock(iocb, &local_iov, 1, &iocb->ki_pos);
}


static struct file_operations raw_fops = {
	.read	=	generic_file_read,
	.aio_read = 	generic_file_aio_read,
	.write	=	raw_file_write,
	.aio_write = 	raw_file_aio_write,
	.open	=	raw_open,
	.release=	raw_release,
	.ioctl	=	raw_ioctl,
	.readv	= 	generic_file_readv,
	.writev	= 	generic_file_writev,
	.owner	=	THIS_MODULE,
};

static struct file_operations raw_ctl_fops = {
	.ioctl	=	raw_ctl_ioctl,
	.open	=	raw_open,
	.owner	=	THIS_MODULE,
};

static struct cdev raw_cdev = {
	.kobj	=	{.name = "raw", },
	.owner	=	THIS_MODULE,
};

static int __init raw_init(void)
{
	int i;
	dev_t dev = MKDEV(RAW_MAJOR, 0);

	if (register_chrdev_region(dev, MAX_RAW_MINORS, "raw"))
		goto error;

	cdev_init(&raw_cdev, &raw_fops);
	if (cdev_add(&raw_cdev, dev, MAX_RAW_MINORS)) {
		kobject_put(&raw_cdev.kobj);
		unregister_chrdev_region(dev, MAX_RAW_MINORS);
		goto error;
	}

	raw_class = class_simple_create(THIS_MODULE, "raw");
	if (IS_ERR(raw_class)) {
		printk(KERN_ERR "Error creating raw class.\n");
		cdev_del(&raw_cdev);
		unregister_chrdev_region(dev, MAX_RAW_MINORS);
		goto error;
	}
	class_simple_device_add(raw_class, MKDEV(RAW_MAJOR, 0), NULL, "rawctl");

	devfs_mk_cdev(MKDEV(RAW_MAJOR, 0),
		      S_IFCHR | S_IRUGO | S_IWUGO,
		      "raw/rawctl");
	for (i = 1; i < MAX_RAW_MINORS; i++)
		devfs_mk_cdev(MKDEV(RAW_MAJOR, i),
			      S_IFCHR | S_IRUGO | S_IWUGO,
			      "raw/raw%d", i);
	return 0;

error:
	printk(KERN_ERR "error register raw device\n");
	return 1;
}

static void __exit raw_exit(void)
{
	int i;

	for (i = 1; i < MAX_RAW_MINORS; i++)
		devfs_remove("raw/raw%d", i);
	devfs_remove("raw/rawctl");
	devfs_remove("raw");
	class_simple_device_remove(MKDEV(RAW_MAJOR, 0));
	class_simple_destroy(raw_class);
	cdev_del(&raw_cdev);
	unregister_chrdev_region(MKDEV(RAW_MAJOR, 0), MAX_RAW_MINORS);
}

module_init(raw_init);
module_exit(raw_exit);
MODULE_LICENSE("GPL");
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/drivers/char/raw.c
	3	*
	4	* Front-end raw character devices. These can be bound to any block
	5	* devices to provide genuine Unix raw character device semantics.
	6	*
	7	* We reserve minor number 0 for a control interface. ioctl()s on this
	8	* device are used to bind the other minor numbers to block devices.
	9	*/
	10
	11	#include <linux/init.h>
	12	#include <linux/fs.h>
	13	#include <linux/devfs_fs_kernel.h>
	14	#include <linux/major.h>
	15	#include <linux/blkdev.h>
	16	#include <linux/module.h>
	17	#include <linux/raw.h>
	18	#include <linux/capability.h>
	19	#include <linux/uio.h>
	20	#include <linux/cdev.h>
	21	#include <linux/device.h>
	22
	23	#include <asm/uaccess.h>
	24
	25	struct raw_device_data {
	26	struct block_device *binding;
	27	int inuse;
	28	};
	29
	30	static struct class_simple *raw_class;
	31	static struct raw_device_data raw_devices[MAX_RAW_MINORS];
	32	static DECLARE_MUTEX(raw_mutex);
	33	static struct file_operations raw_ctl_fops; /* forward declaration */
	34
	35	/*
	36	* Open/close code for raw IO.
	37	*
	38	* We just rewrite the i_mapping for the /dev/raw/rawN file descriptor to
	39	* point at the blockdev's address_space and set the file handle to use
	40	* O_DIRECT.
	41	*
	42	* Set the device's soft blocksize to the minimum possible. This gives the
	43	* finest possible alignment and has no adverse impact on performance.
	44	*/
	45	static int raw_open(struct inode inode, struct file filp)
	46	{
	47	const int minor = iminor(inode);
	48	struct block_device *bdev;
	49	int err;
	50
	51	if (minor == 0) { /* It is the control device */
	52	filp->f_op = &raw_ctl_fops;
	53	return 0;
	54	}
	55
	56	down(&raw_mutex);
	57
	58	/*
	59	* All we need to do on open is check that the device is bound.
	60	*/
	61	bdev = raw_devices[minor].binding;
	62	err = -ENODEV;
	63	if (!bdev)
	64	goto out;
65	igrab(bdev->bd_inode);
66	err = blkdev_get(bdev, filp->f_mode, 0);
67	if (err)
68	goto out;
69	err = bd_claim(bdev, raw_open);
70	if (err)
71	goto out1;
72	err = set_blocksize(bdev, bdev_hardsect_size(bdev));
73	if (err)
74	goto out2;
75	filp->f_flags \|= O_DIRECT;
76	filp->f_mapping = bdev->bd_inode->i_mapping;
77	if (++raw_devices[minor].inuse == 1)
78	filp->f_dentry->d_inode->i_mapping =
79	bdev->bd_inode->i_mapping;
80	filp->private_data = bdev;
81	up(&raw_mutex);
82	return 0;
83
84	out2:
85	bd_release(bdev);
86	out1:
87	blkdev_put(bdev);
88	out:
89	up(&raw_mutex);
90	return err;
91	}
92
93	/*
94	* When the final fd which refers to this character-special node is closed, we
95	* make its ->mapping point back at its own i_data.
96	*/
97	static int raw_release(struct inode inode, struct file filp)
98	{
99	const int minor= iminor(inode);
100	struct block_device *bdev;
101
102	down(&raw_mutex);
103	bdev = raw_devices[minor].binding;
104	if (--raw_devices[minor].inuse == 0) {
105	/* Here inode->i_mapping == bdev->bd_inode->i_mapping */
106	inode->i_mapping = &inode->i_data;
107	inode->i_mapping->backing_dev_info = &default_backing_dev_info;
108	}
109	up(&raw_mutex);
110
111	bd_release(bdev);
112	blkdev_put(bdev);
113	return 0;
114	}
115
116	/*
117	* Forward ioctls to the underlying block device.
118	*/
119	static int
120	raw_ioctl(struct inode inode, struct file filp,
121	unsigned int command, unsigned long arg)
122	{
123	struct block_device *bdev = filp->private_data;
124
e72022e1	125	return blkdev_ioctl(bdev->bd_inode, NULL, command, arg);
1da177e4 LT	126	}
	127
	128	static void bind_device(struct raw_config_request *rq)
	129	{
	130	class_simple_device_remove(MKDEV(RAW_MAJOR, rq->raw_minor));
	131	class_simple_device_add(raw_class, MKDEV(RAW_MAJOR, rq->raw_minor),
	132	NULL, "raw%d", rq->raw_minor);
	133	}
	134
	135	/*
	136	* Deal with ioctls against the raw-device control interface, to bind
	137	* and unbind other raw devices.
	138	*/
	139	static int raw_ctl_ioctl(struct inode inode, struct file filp,
	140	unsigned int command, unsigned long arg)
	141	{
	142	struct raw_config_request rq;
	143	struct raw_device_data *rawdev;
	144	int err = 0;
	145
	146	switch (command) {
	147	case RAW_SETBIND:
	148	case RAW_GETBIND:
	149
	150	/* First, find out which raw minor we want */
	151
	152	if (copy_from_user(&rq, (void __user *) arg, sizeof(rq))) {
	153	err = -EFAULT;
	154	goto out;
	155	}
	156
	157	if (rq.raw_minor < 0 \|\| rq.raw_minor >= MAX_RAW_MINORS) {
	158	err = -EINVAL;
	159	goto out;
	160	}
	161	rawdev = &raw_devices[rq.raw_minor];
	162
	163	if (command == RAW_SETBIND) {
	164	dev_t dev;
	165
	166	/*
	167	* This is like making block devices, so demand the
	168	* same capability
	169	*/
	170	if (!capable(CAP_SYS_ADMIN)) {
	171	err = -EPERM;
	172	goto out;
	173	}
	174
	175	/*
	176	* For now, we don't need to check that the underlying
	177	* block device is present or not: we can do that when
	178	* the raw device is opened. Just check that the
	179	* major/minor numbers make sense.
	180	*/
	181
	182	dev = MKDEV(rq.block_major, rq.block_minor);
	183	if ((rq.block_major == 0 && rq.block_minor != 0) \|\|
	184	MAJOR(dev) != rq.block_major \|\|
	185	MINOR(dev) != rq.block_minor) {
	186	err = -EINVAL;
	187	goto out;
	188	}
	189
190	down(&raw_mutex);
191	if (rawdev->inuse) {
192	up(&raw_mutex);
193	err = -EBUSY;
194	goto out;
195	}
196	if (rawdev->binding) {
197	bdput(rawdev->binding);
198	module_put(THIS_MODULE);
199	}
200	if (rq.block_major == 0 && rq.block_minor == 0) {
201	/* unbind */
202	rawdev->binding = NULL;
203	class_simple_device_remove(MKDEV(RAW_MAJOR,
204	rq.raw_minor));
205	} else {
206	rawdev->binding = bdget(dev);
207	if (rawdev->binding == NULL)
208	err = -ENOMEM;
209	else {
210	__module_get(THIS_MODULE);
211	bind_device(&rq);
212	}
213	}
214	up(&raw_mutex);
215	} else {
216	struct block_device *bdev;
217
218	down(&raw_mutex);
219	bdev = rawdev->binding;
220	if (bdev) {
221	rq.block_major = MAJOR(bdev->bd_dev);
222	rq.block_minor = MINOR(bdev->bd_dev);
223	} else {
224	rq.block_major = rq.block_minor = 0;
225	}
226	up(&raw_mutex);
227	if (copy_to_user((void __user *)arg, &rq, sizeof(rq))) {
228	err = -EFAULT;
229	goto out;
230	}
231	}
232	break;
233	default:
234	err = -EINVAL;
235	break;
236	}
237	out:
238	return err;
239	}
240
241	static ssize_t raw_file_write(struct file file, const char __user buf,
242	size_t count, loff_t *ppos)
243	{
244	struct iovec local_iov = {
245	.iov_base = (char __user *)buf,
246	.iov_len = count
247	};
248
249	return generic_file_write_nolock(file, &local_iov, 1, ppos);
250	}
251
252	static ssize_t raw_file_aio_write(struct kiocb iocb, const char __user buf,
253	size_t count, loff_t pos)
254	{
255	struct iovec local_iov = {
256	.iov_base = (char __user *)buf,
257	.iov_len = count
258	};
259
260	return generic_file_aio_write_nolock(iocb, &local_iov, 1, &iocb->ki_pos);
261	}
262
263
264	static struct file_operations raw_fops = {
265	.read = generic_file_read,
266	.aio_read = generic_file_aio_read,
267	.write = raw_file_write,
268	.aio_write = raw_file_aio_write,
269	.open = raw_open,
270	.release= raw_release,
271	.ioctl = raw_ioctl,
272	.readv = generic_file_readv,
273	.writev = generic_file_writev,
274	.owner = THIS_MODULE,
275	};
276
277	static struct file_operations raw_ctl_fops = {
278	.ioctl = raw_ctl_ioctl,
279	.open = raw_open,
280	.owner = THIS_MODULE,
281	};
282
283	static struct cdev raw_cdev = {
284	.kobj = {.name = "raw", },
285	.owner = THIS_MODULE,
286	};
287
288	static int __init raw_init(void)
289	{
290	int i;
291	dev_t dev = MKDEV(RAW_MAJOR, 0);
292
293	if (register_chrdev_region(dev, MAX_RAW_MINORS, "raw"))
294	goto error;
295
296	cdev_init(&raw_cdev, &raw_fops);
297	if (cdev_add(&raw_cdev, dev, MAX_RAW_MINORS)) {
298	kobject_put(&raw_cdev.kobj);
299	unregister_chrdev_region(dev, MAX_RAW_MINORS);
300	goto error;
301	}
302
303	raw_class = class_simple_create(THIS_MODULE, "raw");
304	if (IS_ERR(raw_class)) {
305	printk(KERN_ERR "Error creating raw class.\n");
306	cdev_del(&raw_cdev);
307	unregister_chrdev_region(dev, MAX_RAW_MINORS);
308	goto error;
309	}
310	class_simple_device_add(raw_class, MKDEV(RAW_MAJOR, 0), NULL, "rawctl");
311
312	devfs_mk_cdev(MKDEV(RAW_MAJOR, 0),
313	S_IFCHR \| S_IRUGO \| S_IWUGO,
314	"raw/rawctl");
315	for (i = 1; i < MAX_RAW_MINORS; i++)
316	devfs_mk_cdev(MKDEV(RAW_MAJOR, i),
317	S_IFCHR \| S_IRUGO \| S_IWUGO,
318	"raw/raw%d", i);
319	return 0;
320
321	error:
322	printk(KERN_ERR "error register raw device\n");
323	return 1;
324	}
325
326	static void __exit raw_exit(void)
327	{
328	int i;
329
330	for (i = 1; i < MAX_RAW_MINORS; i++)
331	devfs_remove("raw/raw%d", i);
332	devfs_remove("raw/rawctl");
333	devfs_remove("raw");
334	class_simple_device_remove(MKDEV(RAW_MAJOR, 0));
335	class_simple_destroy(raw_class);
336	cdev_del(&raw_cdev);
337	unregister_chrdev_region(MKDEV(RAW_MAJOR, 0), MAX_RAW_MINORS);
338	}
339
340	module_init(raw_init);
341	module_exit(raw_exit);
342	MODULE_LICENSE("GPL");