ioctl.c 8.58 KB
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#include <linux/capability.h>
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#include <linux/blkdev.h>
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#include <linux/export.h>
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#include <linux/gfp.h>
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#include <linux/blkpg.h>
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#include <linux/hdreg.h>
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#include <linux/backing-dev.h>
#include <linux/buffer_head.h>
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#include <linux/blktrace_api.h>
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#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;
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	struct hd_struct *part;
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	struct blkpg_ioctl_arg a;
	struct blkpg_partition p;
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	struct disk_part_iter piter;
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	long long start, length;
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	int partno;
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	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;
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	partno = p.pno;
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	if (partno <= 0)
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		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)
					return -EINVAL;
			}
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			mutex_lock(&bdev->bd_mutex);
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			/* overlap? */
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			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);
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					mutex_unlock(&bdev->bd_mutex);
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					return -EBUSY;
				}
			}
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			disk_part_iter_exit(&piter);

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			/* all seems OK */
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			part = add_partition(disk, partno, start, length,
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					     ADDPART_FLAG_NONE, NULL);
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			mutex_unlock(&bdev->bd_mutex);
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			return IS_ERR(part) ? PTR_ERR(part) : 0;
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		case BLKPG_DEL_PARTITION:
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			part = disk_get_part(disk, partno);
			if (!part)
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				return -ENXIO;
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			bdevp = bdget(part_devt(part));
			disk_put_part(part);
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			if (!bdevp)
				return -ENOMEM;
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			mutex_lock(&bdevp->bd_mutex);
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			if (bdevp->bd_openers) {
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				mutex_unlock(&bdevp->bd_mutex);
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				bdput(bdevp);
				return -EBUSY;
			}
			/* all seems OK */
			fsync_bdev(bdevp);
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			invalidate_bdev(bdevp);
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			mutex_lock_nested(&bdev->bd_mutex, 1);
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			delete_partition(disk, partno);
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			mutex_unlock(&bdev->bd_mutex);
			mutex_unlock(&bdevp->bd_mutex);
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			bdput(bdevp);

			return 0;
		default:
			return -EINVAL;
	}
}

static int blkdev_reread_part(struct block_device *bdev)
{
	struct gendisk *disk = bdev->bd_disk;
	int res;

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	if (!disk_part_scan_enabled(disk) || bdev != bdev->bd_contains)
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		return -EINVAL;
	if (!capable(CAP_SYS_ADMIN))
		return -EACCES;
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	if (!mutex_trylock(&bdev->bd_mutex))
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		return -EBUSY;
	res = rescan_partitions(disk, bdev);
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	mutex_unlock(&bdev->bd_mutex);
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	return res;
}

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static int blk_ioctl_discard(struct block_device *bdev, uint64_t start,
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			     uint64_t len, int secure)
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{
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	unsigned long flags = 0;
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	if (start & 511)
		return -EINVAL;
	if (len & 511)
		return -EINVAL;
	start >>= 9;
	len >>= 9;

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	if (start + len > (i_size_read(bdev->bd_inode) >> 9))
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		return -EINVAL;
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	if (secure)
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		flags |= BLKDEV_DISCARD_SECURE;
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	return blkdev_issue_discard(bdev, start, len, GFP_KERNEL, flags);
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}

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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);
}

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

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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);
}

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

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/*
 * 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;
}

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/*
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 * always keep this in sync with compat_blkdev_ioctl()
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 */
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int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
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			unsigned long arg)
{
	struct gendisk *disk = bdev->bd_disk;
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	struct backing_dev_info *bdi;
	loff_t size;
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	int ret, n;

	switch(cmd) {
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	case BLKFLSBUF:
		if (!capable(CAP_SYS_ADMIN))
			return -EACCES;
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		ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
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		if (!is_unrecognized_ioctl(ret))
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			return ret;

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		fsync_bdev(bdev);
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		invalidate_bdev(bdev);
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		return 0;
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	case BLKROSET:
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		ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
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		if (!is_unrecognized_ioctl(ret))
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			return ret;
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		if (!capable(CAP_SYS_ADMIN))
			return -EACCES;
		if (get_user(n, (int __user *)(arg)))
			return -EFAULT;
		set_device_ro(bdev, n);
		return 0;
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	case BLKDISCARD:
	case BLKSECDISCARD: {
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		uint64_t range[2];

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		if (!(mode & FMODE_WRITE))
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			return -EBADF;

		if (copy_from_user(range, (void __user *)arg, sizeof(range)))
			return -EFAULT;

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		return blk_ioctl_discard(bdev, range[0], range[1],
					 cmd == BLKSECDISCARD);
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	}

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	case HDIO_GETGEO: {
		struct hd_geometry geo;

		if (!arg)
			return -EINVAL;
		if (!disk->fops->getgeo)
			return -ENOTTY;

		/*
		 * We need to set the startsect first, the driver may
		 * want to override it.
		 */
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		memset(&geo, 0, sizeof(geo));
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		geo.start = get_start_sect(bdev);
		ret = disk->fops->getgeo(bdev, &geo);
		if (ret)
			return ret;
		if (copy_to_user((struct hd_geometry __user *)arg, &geo,
					sizeof(geo)))
			return -EFAULT;
		return 0;
	}
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	case BLKRAGET:
	case BLKFRAGET:
		if (!arg)
			return -EINVAL;
		bdi = blk_get_backing_dev_info(bdev);
		if (bdi == NULL)
			return -ENOTTY;
		return put_long(arg, (bdi->ra_pages * PAGE_CACHE_SIZE) / 512);
	case BLKROGET:
		return put_int(arg, bdev_read_only(bdev) != 0);
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	case BLKBSZGET: /* get block device soft block size (cf. BLKSSZGET) */
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		return put_int(arg, block_size(bdev));
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	case BLKSSZGET: /* get block device logical block size */
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		return put_int(arg, bdev_logical_block_size(bdev));
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	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));
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	case BLKDISCARDZEROES:
		return put_uint(arg, bdev_discard_zeroes_data(bdev));
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	case BLKSECTGET:
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		return put_ushort(arg, queue_max_sectors(bdev_get_queue(bdev)));
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	case BLKRASET:
	case BLKFRASET:
		if(!capable(CAP_SYS_ADMIN))
			return -EACCES;
		bdi = blk_get_backing_dev_info(bdev);
		if (bdi == NULL)
			return -ENOTTY;
		bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE;
		return 0;
	case BLKBSZSET:
		/* set the logical block size */
		if (!capable(CAP_SYS_ADMIN))
			return -EACCES;
		if (!arg)
			return -EINVAL;
		if (get_user(n, (int __user *) arg))
			return -EFAULT;
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		if (!(mode & FMODE_EXCL)) {
			bdgrab(bdev);
			if (blkdev_get(bdev, mode | FMODE_EXCL, &bdev) < 0)
				return -EBUSY;
		}
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		ret = set_blocksize(bdev, n);
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		if (!(mode & FMODE_EXCL))
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			blkdev_put(bdev, mode | FMODE_EXCL);
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		return ret;
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	case BLKPG:
		ret = blkpg_ioctl(bdev, (struct blkpg_ioctl_arg __user *) arg);
		break;
	case BLKRRPART:
		ret = blkdev_reread_part(bdev);
		break;
	case BLKGETSIZE:
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		size = i_size_read(bdev->bd_inode);
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		if ((size >> 9) > ~0UL)
			return -EFBIG;
		return put_ulong(arg, size >> 9);
	case BLKGETSIZE64:
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		return put_u64(arg, i_size_read(bdev->bd_inode));
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	case BLKTRACESTART:
	case BLKTRACESTOP:
	case BLKTRACESETUP:
	case BLKTRACETEARDOWN:
		ret = blk_trace_ioctl(bdev, cmd, (char __user *) arg);
		break;
	default:
		ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
	}
	return ret;
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}
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EXPORT_SYMBOL_GPL(blkdev_ioctl);