#include <linux/capability.h>

  #include <linux/blkdev.h>

  #include <linux/export.h>

  #include <linux/gfp.h>

  #include <linux/blkpg.h>

  #include <linux/hdreg.h>

  #include <linux/backing-dev.h>

  #include <linux/fs.h>

  #include <linux/blktrace_api.h>

  #include <linux/pr.h>

  #include <asm/uaccess.h>
  
  static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user *arg)
  {
  	struct block_device *bdevp;
  	struct gendisk *disk;

  	struct hd_struct *part, *lpart;

  	struct blkpg_ioctl_arg a;
  	struct blkpg_partition p;

  	struct disk_part_iter piter;

  	long long start, length;

  	int partno;

  
  	if (!capable(CAP_SYS_ADMIN))
  		return -EACCES;
  	if (copy_from_user(&a, arg, sizeof(struct blkpg_ioctl_arg)))
  		return -EFAULT;
  	if (copy_from_user(&p, a.data, sizeof(struct blkpg_partition)))
  		return -EFAULT;
  	disk = bdev->bd_disk;
  	if (bdev != bdev->bd_contains)
  		return -EINVAL;

  	partno = p.pno;

  	if (partno <= 0)

  		return -EINVAL;
  	switch (a.op) {
  		case BLKPG_ADD_PARTITION:
  			start = p.start >> 9;
  			length = p.length >> 9;

  			/* check for fit in a hd_struct */
  			if (sizeof(sector_t) == sizeof(long) &&

  			    sizeof(long long) > sizeof(long)) {
  				long pstart = start, plength = length;
  				if (pstart != start || plength != length

  				    || pstart < 0 || plength < 0 || partno > 65535)

  					return -EINVAL;
  			}

  			mutex_lock(&bdev->bd_mutex);

  			/* overlap? */

  			disk_part_iter_init(&piter, disk,
  					    DISK_PITER_INCL_EMPTY);
  			while ((part = disk_part_iter_next(&piter))) {
  				if (!(start + length <= part->start_sect ||
  				      start >= part->start_sect + part->nr_sects)) {
  					disk_part_iter_exit(&piter);

  					mutex_unlock(&bdev->bd_mutex);

  					return -EBUSY;
  				}
  			}

  			disk_part_iter_exit(&piter);

  			/* all seems OK */

  			part = add_partition(disk, partno, start, length,

  					     ADDPART_FLAG_NONE, NULL);

  			mutex_unlock(&bdev->bd_mutex);

  			return PTR_ERR_OR_ZERO(part);

  		case BLKPG_DEL_PARTITION:

  			part = disk_get_part(disk, partno);
  			if (!part)

  				return -ENXIO;

  
  			bdevp = bdget(part_devt(part));
  			disk_put_part(part);

  			if (!bdevp)
  				return -ENOMEM;

  			mutex_lock(&bdevp->bd_mutex);

  			if (bdevp->bd_openers) {

  				mutex_unlock(&bdevp->bd_mutex);

  				bdput(bdevp);
  				return -EBUSY;
  			}
  			/* all seems OK */
  			fsync_bdev(bdevp);

  			invalidate_bdev(bdevp);

  			mutex_lock_nested(&bdev->bd_mutex, 1);

  			delete_partition(disk, partno);

  			mutex_unlock(&bdev->bd_mutex);
  			mutex_unlock(&bdevp->bd_mutex);

  			bdput(bdevp);
  
  			return 0;

  		case BLKPG_RESIZE_PARTITION:
  			start = p.start >> 9;
  			/* new length of partition in bytes */
  			length = p.length >> 9;
  			/* check for fit in a hd_struct */
  			if (sizeof(sector_t) == sizeof(long) &&
  			    sizeof(long long) > sizeof(long)) {
  				long pstart = start, plength = length;
  				if (pstart != start || plength != length
  				    || pstart < 0 || plength < 0)
  					return -EINVAL;
  			}
  			part = disk_get_part(disk, partno);
  			if (!part)
  				return -ENXIO;
  			bdevp = bdget(part_devt(part));
  			if (!bdevp) {
  				disk_put_part(part);
  				return -ENOMEM;
  			}
  			mutex_lock(&bdevp->bd_mutex);
  			mutex_lock_nested(&bdev->bd_mutex, 1);
  			if (start != part->start_sect) {
  				mutex_unlock(&bdevp->bd_mutex);
  				mutex_unlock(&bdev->bd_mutex);
  				bdput(bdevp);
  				disk_put_part(part);
  				return -EINVAL;
  			}
  			/* overlap? */
  			disk_part_iter_init(&piter, disk,
  					    DISK_PITER_INCL_EMPTY);
  			while ((lpart = disk_part_iter_next(&piter))) {
  				if (lpart->partno != partno &&
  				   !(start + length <= lpart->start_sect ||
  				   start >= lpart->start_sect + lpart->nr_sects)
  				   ) {
  					disk_part_iter_exit(&piter);
  					mutex_unlock(&bdevp->bd_mutex);
  					mutex_unlock(&bdev->bd_mutex);
  					bdput(bdevp);
  					disk_put_part(part);
  					return -EBUSY;
  				}
  			}
  			disk_part_iter_exit(&piter);
  			part_nr_sects_write(part, (sector_t)length);
  			i_size_write(bdevp->bd_inode, p.length);
  			mutex_unlock(&bdevp->bd_mutex);
  			mutex_unlock(&bdev->bd_mutex);
  			bdput(bdevp);
  			disk_put_part(part);
  			return 0;

  		default:
  			return -EINVAL;
  	}
  }

  /*
   * This is an exported API for the block driver, and will not
   * acquire bd_mutex. This API should be used in case that
   * caller has held bd_mutex already.
   */
  int __blkdev_reread_part(struct block_device *bdev)

  {
  	struct gendisk *disk = bdev->bd_disk;

  	if (!disk_part_scan_enabled(disk) || bdev != bdev->bd_contains)

  		return -EINVAL;
  	if (!capable(CAP_SYS_ADMIN))
  		return -EACCES;

  
  	lockdep_assert_held(&bdev->bd_mutex);
  
  	return rescan_partitions(disk, bdev);
  }
  EXPORT_SYMBOL(__blkdev_reread_part);
  
  /*
   * This is an exported API for the block driver, and will
   * try to acquire bd_mutex. If bd_mutex has been held already
   * in current context, please call __blkdev_reread_part().

   *
   * Make sure the held locks in current context aren't required
   * in open()/close() handler and I/O path for avoiding ABBA deadlock:
   * - bd_mutex is held before calling block driver's open/close
   *   handler
   * - reading partition table may submit I/O to the block device

   */
  int blkdev_reread_part(struct block_device *bdev)
  {
  	int res;

  	mutex_lock(&bdev->bd_mutex);

  	res = __blkdev_reread_part(bdev);

  	mutex_unlock(&bdev->bd_mutex);

  	return res;
  }

  EXPORT_SYMBOL(blkdev_reread_part);

  static int blk_ioctl_discard(struct block_device *bdev, fmode_t mode,
  		unsigned long arg, unsigned long flags)

  {

  	uint64_t range[2];
  	uint64_t start, len;
  
  	if (!(mode & FMODE_WRITE))
  		return -EBADF;
  
  	if (copy_from_user(range, (void __user *)arg, sizeof(range)))
  		return -EFAULT;
  
  	start = range[0];
  	len = range[1];

  	if (start & 511)
  		return -EINVAL;
  	if (len & 511)
  		return -EINVAL;
  	start >>= 9;
  	len >>= 9;

  	if (start + len > (i_size_read(bdev->bd_inode) >> 9))

  		return -EINVAL;

  	return blkdev_issue_discard(bdev, start, len, GFP_KERNEL, flags);

  }

  static int blk_ioctl_zeroout(struct block_device *bdev, fmode_t mode,
  		unsigned long arg)

  {

  	uint64_t range[2];
  	uint64_t start, len;
  
  	if (!(mode & FMODE_WRITE))
  		return -EBADF;
  
  	if (copy_from_user(range, (void __user *)arg, sizeof(range)))
  		return -EFAULT;
  
  	start = range[0];
  	len = range[1];

  	if (start & 511)
  		return -EINVAL;
  	if (len & 511)
  		return -EINVAL;
  	start >>= 9;
  	len >>= 9;
  
  	if (start + len > (i_size_read(bdev->bd_inode) >> 9))
  		return -EINVAL;

  	return blkdev_issue_zeroout(bdev, start, len, GFP_KERNEL, false);

  }

  static int put_ushort(unsigned long arg, unsigned short val)
  {
  	return put_user(val, (unsigned short __user *)arg);
  }
  
  static int put_int(unsigned long arg, int val)
  {
  	return put_user(val, (int __user *)arg);
  }

  static int put_uint(unsigned long arg, unsigned int val)
  {
  	return put_user(val, (unsigned int __user *)arg);
  }

  static int put_long(unsigned long arg, long val)
  {
  	return put_user(val, (long __user *)arg);
  }
  
  static int put_ulong(unsigned long arg, unsigned long val)
  {
  	return put_user(val, (unsigned long __user *)arg);
  }
  
  static int put_u64(unsigned long arg, u64 val)
  {
  	return put_user(val, (u64 __user *)arg);
  }

  int __blkdev_driver_ioctl(struct block_device *bdev, fmode_t mode,
  			unsigned cmd, unsigned long arg)
  {
  	struct gendisk *disk = bdev->bd_disk;

  
  	if (disk->fops->ioctl)
  		return disk->fops->ioctl(bdev, mode, cmd, arg);

  	return -ENOTTY;
  }
  /*
   * For the record: _GPL here is only because somebody decided to slap it
   * on the previous export.  Sheer idiocy, since it wasn't copyrightable
   * at all and could be open-coded without any exports by anybody who cares.
   */
  EXPORT_SYMBOL_GPL(__blkdev_driver_ioctl);

  static int blkdev_pr_register(struct block_device *bdev,
  		struct pr_registration __user *arg)
  {
  	const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
  	struct pr_registration reg;
  
  	if (!capable(CAP_SYS_ADMIN))
  		return -EPERM;
  	if (!ops || !ops->pr_register)
  		return -EOPNOTSUPP;
  	if (copy_from_user(&reg, arg, sizeof(reg)))
  		return -EFAULT;
  
  	if (reg.flags & ~PR_FL_IGNORE_KEY)
  		return -EOPNOTSUPP;
  	return ops->pr_register(bdev, reg.old_key, reg.new_key, reg.flags);
  }
  
  static int blkdev_pr_reserve(struct block_device *bdev,
  		struct pr_reservation __user *arg)
  {
  	const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
  	struct pr_reservation rsv;
  
  	if (!capable(CAP_SYS_ADMIN))
  		return -EPERM;
  	if (!ops || !ops->pr_reserve)
  		return -EOPNOTSUPP;
  	if (copy_from_user(&rsv, arg, sizeof(rsv)))
  		return -EFAULT;
  
  	if (rsv.flags & ~PR_FL_IGNORE_KEY)
  		return -EOPNOTSUPP;
  	return ops->pr_reserve(bdev, rsv.key, rsv.type, rsv.flags);
  }
  
  static int blkdev_pr_release(struct block_device *bdev,
  		struct pr_reservation __user *arg)
  {
  	const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
  	struct pr_reservation rsv;
  
  	if (!capable(CAP_SYS_ADMIN))
  		return -EPERM;
  	if (!ops || !ops->pr_release)
  		return -EOPNOTSUPP;
  	if (copy_from_user(&rsv, arg, sizeof(rsv)))
  		return -EFAULT;
  
  	if (rsv.flags)
  		return -EOPNOTSUPP;
  	return ops->pr_release(bdev, rsv.key, rsv.type);
  }
  
  static int blkdev_pr_preempt(struct block_device *bdev,
  		struct pr_preempt __user *arg, bool abort)
  {
  	const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
  	struct pr_preempt p;
  
  	if (!capable(CAP_SYS_ADMIN))
  		return -EPERM;
  	if (!ops || !ops->pr_preempt)
  		return -EOPNOTSUPP;
  	if (copy_from_user(&p, arg, sizeof(p)))
  		return -EFAULT;
  
  	if (p.flags)
  		return -EOPNOTSUPP;
  	return ops->pr_preempt(bdev, p.old_key, p.new_key, p.type, abort);
  }
  
  static int blkdev_pr_clear(struct block_device *bdev,
  		struct pr_clear __user *arg)
  {
  	const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
  	struct pr_clear c;
  
  	if (!capable(CAP_SYS_ADMIN))
  		return -EPERM;
  	if (!ops || !ops->pr_clear)
  		return -EOPNOTSUPP;
  	if (copy_from_user(&c, arg, sizeof(c)))
  		return -EFAULT;
  
  	if (c.flags)
  		return -EOPNOTSUPP;
  	return ops->pr_clear(bdev, c.key);
  }

  /*

   * Is it an unrecognized ioctl? The correct returns are either
   * ENOTTY (final) or ENOIOCTLCMD ("I don't know this one, try a
   * fallback"). ENOIOCTLCMD gets turned into ENOTTY by the ioctl
   * code before returning.
   *
   * Confused drivers sometimes return EINVAL, which is wrong. It
   * means "I understood the ioctl command, but the parameters to
   * it were wrong".
   *
   * We should aim to just fix the broken drivers, the EINVAL case
   * should go away.
   */
  static inline int is_unrecognized_ioctl(int ret)
  {
  	return	ret == -EINVAL ||
  		ret == -ENOTTY ||
  		ret == -ENOIOCTLCMD;
  }

  static int blkdev_flushbuf(struct block_device *bdev, fmode_t mode,
  		unsigned cmd, unsigned long arg)

  {

  	int ret;

  	if (!capable(CAP_SYS_ADMIN))
  		return -EACCES;

  	ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
  	if (!is_unrecognized_ioctl(ret))
  		return ret;

  	fsync_bdev(bdev);
  	invalidate_bdev(bdev);
  	return 0;
  }

  static int blkdev_roset(struct block_device *bdev, fmode_t mode,
  		unsigned cmd, unsigned long arg)
  {
  	int ret, n;

  	ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
  	if (!is_unrecognized_ioctl(ret))
  		return ret;
  	if (!capable(CAP_SYS_ADMIN))
  		return -EACCES;
  	if (get_user(n, (int __user *)arg))
  		return -EFAULT;
  	set_device_ro(bdev, n);
  	return 0;
  }

  static int blkdev_getgeo(struct block_device *bdev,
  		struct hd_geometry __user *argp)
  {
  	struct gendisk *disk = bdev->bd_disk;
  	struct hd_geometry geo;
  	int ret;

  	if (!argp)
  		return -EINVAL;
  	if (!disk->fops->getgeo)
  		return -ENOTTY;
  
  	/*
  	 * We need to set the startsect first, the driver may
  	 * want to override it.
  	 */
  	memset(&geo, 0, sizeof(geo));
  	geo.start = get_start_sect(bdev);
  	ret = disk->fops->getgeo(bdev, &geo);
  	if (ret)
  		return ret;
  	if (copy_to_user(argp, &geo, sizeof(geo)))
  		return -EFAULT;
  	return 0;
  }

  /* set the logical block size */
  static int blkdev_bszset(struct block_device *bdev, fmode_t mode,
  		int __user *argp)
  {
  	int ret, n;

  	if (!capable(CAP_SYS_ADMIN))
  		return -EACCES;
  	if (!argp)
  		return -EINVAL;
  	if (get_user(n, argp))
  		return -EFAULT;

  	if (!(mode & FMODE_EXCL)) {
  		bdgrab(bdev);
  		if (blkdev_get(bdev, mode | FMODE_EXCL, &bdev) < 0)
  			return -EBUSY;

  	}

  	ret = set_blocksize(bdev, n);
  	if (!(mode & FMODE_EXCL))
  		blkdev_put(bdev, mode | FMODE_EXCL);
  	return ret;
  }

  /*
   * always keep this in sync with compat_blkdev_ioctl()
   */
  int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
  			unsigned long arg)
  {
  	struct backing_dev_info *bdi;
  	void __user *argp = (void __user *)arg;
  	loff_t size;
  	unsigned int max_sectors;
  
  	switch (cmd) {
  	case BLKFLSBUF:
  		return blkdev_flushbuf(bdev, mode, cmd, arg);
  	case BLKROSET:
  		return blkdev_roset(bdev, mode, cmd, arg);
  	case BLKDISCARD:
  		return blk_ioctl_discard(bdev, mode, arg, 0);
  	case BLKSECDISCARD:
  		return blk_ioctl_discard(bdev, mode, arg,
  				BLKDEV_DISCARD_SECURE);
  	case BLKZEROOUT:
  		return blk_ioctl_zeroout(bdev, mode, arg);
  	case HDIO_GETGEO:
  		return blkdev_getgeo(bdev, argp);

  	case BLKRAGET:
  	case BLKFRAGET:
  		if (!arg)
  			return -EINVAL;
  		bdi = blk_get_backing_dev_info(bdev);

  		return put_long(arg, (bdi->ra_pages * PAGE_SIZE) / 512);

  	case BLKROGET:
  		return put_int(arg, bdev_read_only(bdev) != 0);

  	case BLKBSZGET: /* get block device soft block size (cf. BLKSSZGET) */

  		return put_int(arg, block_size(bdev));

  	case BLKSSZGET: /* get block device logical block size */

  		return put_int(arg, bdev_logical_block_size(bdev));

  	case BLKPBSZGET: /* get block device physical block size */
  		return put_uint(arg, bdev_physical_block_size(bdev));
  	case BLKIOMIN:
  		return put_uint(arg, bdev_io_min(bdev));
  	case BLKIOOPT:
  		return put_uint(arg, bdev_io_opt(bdev));
  	case BLKALIGNOFF:
  		return put_int(arg, bdev_alignment_offset(bdev));

  	case BLKDISCARDZEROES:
  		return put_uint(arg, bdev_discard_zeroes_data(bdev));

  	case BLKSECTGET:

  		max_sectors = min_t(unsigned int, USHRT_MAX,
  				    queue_max_sectors(bdev_get_queue(bdev)));
  		return put_ushort(arg, max_sectors);

  	case BLKROTATIONAL:
  		return put_ushort(arg, !blk_queue_nonrot(bdev_get_queue(bdev)));

  	case BLKRASET:
  	case BLKFRASET:
  		if(!capable(CAP_SYS_ADMIN))
  			return -EACCES;
  		bdi = blk_get_backing_dev_info(bdev);

  		bdi->ra_pages = (arg * 512) / PAGE_SIZE;

  		return 0;
  	case BLKBSZSET:

  		return blkdev_bszset(bdev, mode, argp);

  	case BLKPG:

  		return blkpg_ioctl(bdev, argp);

  	case BLKRRPART:

  		return blkdev_reread_part(bdev);

  	case BLKGETSIZE:

  		size = i_size_read(bdev->bd_inode);

  		if ((size >> 9) > ~0UL)
  			return -EFBIG;
  		return put_ulong(arg, size >> 9);
  	case BLKGETSIZE64:

  		return put_u64(arg, i_size_read(bdev->bd_inode));

  	case BLKTRACESTART:
  	case BLKTRACESTOP:
  	case BLKTRACESETUP:
  	case BLKTRACETEARDOWN:

  		return blk_trace_ioctl(bdev, cmd, argp);

  	case IOC_PR_REGISTER:
  		return blkdev_pr_register(bdev, argp);
  	case IOC_PR_RESERVE:
  		return blkdev_pr_reserve(bdev, argp);
  	case IOC_PR_RELEASE:
  		return blkdev_pr_release(bdev, argp);
  	case IOC_PR_PREEMPT:
  		return blkdev_pr_preempt(bdev, argp, false);
  	case IOC_PR_PREEMPT_ABORT:
  		return blkdev_pr_preempt(bdev, argp, true);
  	case IOC_PR_CLEAR:
  		return blkdev_pr_clear(bdev, argp);

  	default:

  		return __blkdev_driver_ioctl(bdev, mode, cmd, arg);

  	}

  }

  EXPORT_SYMBOL_GPL(blkdev_ioctl);