Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
This commit is contained in:
Linus Torvalds
342
drivers/char/raw.c
Normal file
342
drivers/char/raw.c
Normal file
@@ -0,0 +1,342 @@
|
||||
/*
|
||||
* 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 ioctl_by_bdev(bdev, 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");
|
||||
Reference in New Issue
Block a user