+++ /dev/null
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- * 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 {
- dev_t binding;
- struct block_device *bdev;
- 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 = CONFIG_MAX_RAW_DEVS;
-
-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;
- }
-
- pr_warn_ratelimited(
- "process %s (pid %d) is using the deprecated raw device\n"
- "support will be removed in Linux 5.14.\n",
- current->comm, current->pid);
-
- mutex_lock(&raw_mutex);
-
- /*
- * All we need to do on open is check that the device is bound.
- */
- err = -ENODEV;
- if (!raw_devices[minor].binding)
- goto out;
- bdev = blkdev_get_by_dev(raw_devices[minor].binding,
- filp->f_mode | FMODE_EXCL, raw_open);
- if (IS_ERR(bdev)) {
- err = PTR_ERR(bdev);
- 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;
- raw_devices[minor].bdev = 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].bdev;
- 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);
- dev_t raw = MKDEV(RAW_MAJOR, number);
- 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)
- module_put(THIS_MODULE);
-
- rawdev->binding = dev;
- if (!dev) {
- /* unbind */
- device_destroy(raw_class, raw);
- } else {
- __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)
-{
- if (number <= 0 || number >= max_raw_minors)
- return -EINVAL;
- *dev = raw_devices[number].binding;
- 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) {
- pr_warn("raw: invalid max_raw_minors (must be between 1 and 65536), using %d\n",
- CONFIG_MAX_RAW_DEVS);
- max_raw_minors = CONFIG_MAX_RAW_DEVS;
- }
-
- raw_devices = vzalloc(array_size(max_raw_minors,
- sizeof(struct raw_device_data)));
- 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");
projects / linux-2.6-microblaze.git / commitdiff