mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-28 20:02:17 +00:00
![Linus Torvalds](/assets/img/avatar_default.png)
This was entirely automated, using the script by Al: PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>' sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \ $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h) to do the replacement at the end of the merge window. Requested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
368 lines
8.3 KiB
C
368 lines
8.3 KiB
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/major.h>
|
|
#include <linux/blkdev.h>
|
|
#include <linux/backing-dev.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 <linux/mutex.h>
|
|
#include <linux/gfp.h>
|
|
#include <linux/compat.h>
|
|
#include <linux/vmalloc.h>
|
|
|
|
#include <linux/uaccess.h>
|
|
|
|
struct raw_device_data {
|
|
struct block_device *binding;
|
|
int inuse;
|
|
};
|
|
|
|
static struct class *raw_class;
|
|
static struct raw_device_data *raw_devices;
|
|
static DEFINE_MUTEX(raw_mutex);
|
|
static const struct file_operations raw_ctl_fops; /* forward declaration */
|
|
|
|
static int max_raw_minors = MAX_RAW_MINORS;
|
|
|
|
module_param(max_raw_minors, int, 0);
|
|
MODULE_PARM_DESC(max_raw_minors, "Maximum number of raw devices (1-65536)");
|
|
|
|
/*
|
|
* 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;
|
|
}
|
|
|
|
mutex_lock(&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;
|
|
bdgrab(bdev);
|
|
err = blkdev_get(bdev, filp->f_mode | FMODE_EXCL, raw_open);
|
|
if (err)
|
|
goto out;
|
|
err = set_blocksize(bdev, bdev_logical_block_size(bdev));
|
|
if (err)
|
|
goto out1;
|
|
filp->f_flags |= O_DIRECT;
|
|
filp->f_mapping = bdev->bd_inode->i_mapping;
|
|
if (++raw_devices[minor].inuse == 1)
|
|
file_inode(filp)->i_mapping =
|
|
bdev->bd_inode->i_mapping;
|
|
filp->private_data = bdev;
|
|
mutex_unlock(&raw_mutex);
|
|
return 0;
|
|
|
|
out1:
|
|
blkdev_put(bdev, filp->f_mode | FMODE_EXCL);
|
|
out:
|
|
mutex_unlock(&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;
|
|
|
|
mutex_lock(&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;
|
|
mutex_unlock(&raw_mutex);
|
|
|
|
blkdev_put(bdev, filp->f_mode | FMODE_EXCL);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Forward ioctls to the underlying block device.
|
|
*/
|
|
static long
|
|
raw_ioctl(struct file *filp, unsigned int command, unsigned long arg)
|
|
{
|
|
struct block_device *bdev = filp->private_data;
|
|
return blkdev_ioctl(bdev, 0, command, arg);
|
|
}
|
|
|
|
static int bind_set(int number, u64 major, u64 minor)
|
|
{
|
|
dev_t dev = MKDEV(major, minor);
|
|
struct raw_device_data *rawdev;
|
|
int err = 0;
|
|
|
|
if (number <= 0 || number >= max_raw_minors)
|
|
return -EINVAL;
|
|
|
|
if (MAJOR(dev) != major || MINOR(dev) != minor)
|
|
return -EINVAL;
|
|
|
|
rawdev = &raw_devices[number];
|
|
|
|
/*
|
|
* This is like making block devices, so demand the
|
|
* same capability
|
|
*/
|
|
if (!capable(CAP_SYS_ADMIN))
|
|
return -EPERM;
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
|
|
if (MAJOR(dev) == 0 && dev != 0)
|
|
return -EINVAL;
|
|
|
|
mutex_lock(&raw_mutex);
|
|
if (rawdev->inuse) {
|
|
mutex_unlock(&raw_mutex);
|
|
return -EBUSY;
|
|
}
|
|
if (rawdev->binding) {
|
|
bdput(rawdev->binding);
|
|
module_put(THIS_MODULE);
|
|
}
|
|
if (!dev) {
|
|
/* unbind */
|
|
rawdev->binding = NULL;
|
|
device_destroy(raw_class, MKDEV(RAW_MAJOR, number));
|
|
} else {
|
|
rawdev->binding = bdget(dev);
|
|
if (rawdev->binding == NULL) {
|
|
err = -ENOMEM;
|
|
} else {
|
|
dev_t raw = MKDEV(RAW_MAJOR, number);
|
|
__module_get(THIS_MODULE);
|
|
device_destroy(raw_class, raw);
|
|
device_create(raw_class, NULL, raw, NULL,
|
|
"raw%d", number);
|
|
}
|
|
}
|
|
mutex_unlock(&raw_mutex);
|
|
return err;
|
|
}
|
|
|
|
static int bind_get(int number, dev_t *dev)
|
|
{
|
|
struct raw_device_data *rawdev;
|
|
struct block_device *bdev;
|
|
|
|
if (number <= 0 || number >= max_raw_minors)
|
|
return -EINVAL;
|
|
|
|
rawdev = &raw_devices[number];
|
|
|
|
mutex_lock(&raw_mutex);
|
|
bdev = rawdev->binding;
|
|
*dev = bdev ? bdev->bd_dev : 0;
|
|
mutex_unlock(&raw_mutex);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Deal with ioctls against the raw-device control interface, to bind
|
|
* and unbind other raw devices.
|
|
*/
|
|
static long raw_ctl_ioctl(struct file *filp, unsigned int command,
|
|
unsigned long arg)
|
|
{
|
|
struct raw_config_request rq;
|
|
dev_t dev;
|
|
int err;
|
|
|
|
switch (command) {
|
|
case RAW_SETBIND:
|
|
if (copy_from_user(&rq, (void __user *) arg, sizeof(rq)))
|
|
return -EFAULT;
|
|
|
|
return bind_set(rq.raw_minor, rq.block_major, rq.block_minor);
|
|
|
|
case RAW_GETBIND:
|
|
if (copy_from_user(&rq, (void __user *) arg, sizeof(rq)))
|
|
return -EFAULT;
|
|
|
|
err = bind_get(rq.raw_minor, &dev);
|
|
if (err)
|
|
return err;
|
|
|
|
rq.block_major = MAJOR(dev);
|
|
rq.block_minor = MINOR(dev);
|
|
|
|
if (copy_to_user((void __user *)arg, &rq, sizeof(rq)))
|
|
return -EFAULT;
|
|
|
|
return 0;
|
|
}
|
|
|
|
return -EINVAL;
|
|
}
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
struct raw32_config_request {
|
|
compat_int_t raw_minor;
|
|
compat_u64 block_major;
|
|
compat_u64 block_minor;
|
|
};
|
|
|
|
static long raw_ctl_compat_ioctl(struct file *file, unsigned int cmd,
|
|
unsigned long arg)
|
|
{
|
|
struct raw32_config_request __user *user_req = compat_ptr(arg);
|
|
struct raw32_config_request rq;
|
|
dev_t dev;
|
|
int err = 0;
|
|
|
|
switch (cmd) {
|
|
case RAW_SETBIND:
|
|
if (copy_from_user(&rq, user_req, sizeof(rq)))
|
|
return -EFAULT;
|
|
|
|
return bind_set(rq.raw_minor, rq.block_major, rq.block_minor);
|
|
|
|
case RAW_GETBIND:
|
|
if (copy_from_user(&rq, user_req, sizeof(rq)))
|
|
return -EFAULT;
|
|
|
|
err = bind_get(rq.raw_minor, &dev);
|
|
if (err)
|
|
return err;
|
|
|
|
rq.block_major = MAJOR(dev);
|
|
rq.block_minor = MINOR(dev);
|
|
|
|
if (copy_to_user(user_req, &rq, sizeof(rq)))
|
|
return -EFAULT;
|
|
|
|
return 0;
|
|
}
|
|
|
|
return -EINVAL;
|
|
}
|
|
#endif
|
|
|
|
static const struct file_operations raw_fops = {
|
|
.read_iter = blkdev_read_iter,
|
|
.write_iter = blkdev_write_iter,
|
|
.fsync = blkdev_fsync,
|
|
.open = raw_open,
|
|
.release = raw_release,
|
|
.unlocked_ioctl = raw_ioctl,
|
|
.llseek = default_llseek,
|
|
.owner = THIS_MODULE,
|
|
};
|
|
|
|
static const struct file_operations raw_ctl_fops = {
|
|
.unlocked_ioctl = raw_ctl_ioctl,
|
|
#ifdef CONFIG_COMPAT
|
|
.compat_ioctl = raw_ctl_compat_ioctl,
|
|
#endif
|
|
.open = raw_open,
|
|
.owner = THIS_MODULE,
|
|
.llseek = noop_llseek,
|
|
};
|
|
|
|
static struct cdev raw_cdev;
|
|
|
|
static char *raw_devnode(struct device *dev, umode_t *mode)
|
|
{
|
|
return kasprintf(GFP_KERNEL, "raw/%s", dev_name(dev));
|
|
}
|
|
|
|
static int __init raw_init(void)
|
|
{
|
|
dev_t dev = MKDEV(RAW_MAJOR, 0);
|
|
int ret;
|
|
|
|
if (max_raw_minors < 1 || max_raw_minors > 65536) {
|
|
printk(KERN_WARNING "raw: invalid max_raw_minors (must be"
|
|
" between 1 and 65536), using %d\n", MAX_RAW_MINORS);
|
|
max_raw_minors = MAX_RAW_MINORS;
|
|
}
|
|
|
|
raw_devices = vzalloc(sizeof(struct raw_device_data) * max_raw_minors);
|
|
if (!raw_devices) {
|
|
printk(KERN_ERR "Not enough memory for raw device structures\n");
|
|
ret = -ENOMEM;
|
|
goto error;
|
|
}
|
|
|
|
ret = register_chrdev_region(dev, max_raw_minors, "raw");
|
|
if (ret)
|
|
goto error;
|
|
|
|
cdev_init(&raw_cdev, &raw_fops);
|
|
ret = cdev_add(&raw_cdev, dev, max_raw_minors);
|
|
if (ret)
|
|
goto error_region;
|
|
raw_class = class_create(THIS_MODULE, "raw");
|
|
if (IS_ERR(raw_class)) {
|
|
printk(KERN_ERR "Error creating raw class.\n");
|
|
cdev_del(&raw_cdev);
|
|
ret = PTR_ERR(raw_class);
|
|
goto error_region;
|
|
}
|
|
raw_class->devnode = raw_devnode;
|
|
device_create(raw_class, NULL, MKDEV(RAW_MAJOR, 0), NULL, "rawctl");
|
|
|
|
return 0;
|
|
|
|
error_region:
|
|
unregister_chrdev_region(dev, max_raw_minors);
|
|
error:
|
|
vfree(raw_devices);
|
|
return ret;
|
|
}
|
|
|
|
static void __exit raw_exit(void)
|
|
{
|
|
device_destroy(raw_class, MKDEV(RAW_MAJOR, 0));
|
|
class_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");
|