block/ioctl.c

   1 #include <linux/sched.h>                /* for capable() */
   2 #include <linux/blkdev.h>
   3 #include <linux/blkpg.h>
   4 #include <linux/backing-dev.h>
   5 #include <linux/buffer_head.h>
   6 #include <linux/smp_lock.h>
   7 #include <asm/uaccess.h>
   8
   9 static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user *arg)
  10 {
  11         struct block_device *bdevp;
  12         struct gendisk *disk;
  13         struct blkpg_ioctl_arg a;
  14         struct blkpg_partition p;
  15         long long start, length;
  16         int part;
  17         int i;
  18
  19         if (!capable(CAP_SYS_ADMIN))
  20                 return -EACCES;
  21         if (copy_from_user(&a, arg, sizeof(struct blkpg_ioctl_arg)))
  22                 return -EFAULT;
  23         if (copy_from_user(&p, a.data, sizeof(struct blkpg_partition)))
  24                 return -EFAULT;
  25         disk = bdev->bd_disk;
  26         if (bdev != bdev->bd_contains)
  27                 return -EINVAL;
  28         part = p.pno;
  29         if (part <= 0 || part >= disk->minors)
  30                 return -EINVAL;
  31         switch (a.op) {
  32                 case BLKPG_ADD_PARTITION:
  33                         start = p.start >> 9;
  34                         length = p.length >> 9;
  35                         /* check for fit in a hd_struct */
  36                         if (sizeof(sector_t) == sizeof(long) &&
  37                             sizeof(long long) > sizeof(long)) {
  38                                 long pstart = start, plength = length;
  39                                 if (pstart != start || plength != length
  40                                     || pstart < 0 || plength < 0)
  41                                         return -EINVAL;
  42                         }
  43                         /* partition number in use? */
  44                         down(&bdev->bd_sem);
  45                         if (disk->part[part - 1]) {
  46                                 up(&bdev->bd_sem);
  47                                 return -EBUSY;
  48                         }
  49                         /* overlap? */
  50                         for (i = 0; i < disk->minors - 1; i++) {
  51                                 struct hd_struct *s = disk->part[i];
  52
  53                                 if (!s)
  54                                         continue;
  55                                 if (!(start+length <= s->start_sect ||
  56                                       start >= s->start_sect + s->nr_sects)) {
  57                                         up(&bdev->bd_sem);
  58                                         return -EBUSY;
  59                                 }
  60                         }
  61                         /* all seems OK */
  62                         add_partition(disk, part, start, length);
  63                         up(&bdev->bd_sem);
  64                         return 0;
  65                 case BLKPG_DEL_PARTITION:
  66                         if (!disk->part[part-1])
  67                                 return -ENXIO;
  68                         if (disk->part[part - 1]->nr_sects == 0)
  69                                 return -ENXIO;
  70                         bdevp = bdget_disk(disk, part);
  71                         if (!bdevp)
  72                                 return -ENOMEM;
  73                         down(&bdevp->bd_sem);
  74                         if (bdevp->bd_openers) {
  75                                 up(&bdevp->bd_sem);
  76                                 bdput(bdevp);
  77                                 return -EBUSY;
  78                         }
  79                         /* all seems OK */
  80                         fsync_bdev(bdevp);
  81                         invalidate_bdev(bdevp, 0);
  82
  83                         down(&bdev->bd_sem);
  84                         delete_partition(disk, part);
  85                         up(&bdev->bd_sem);
  86                         up(&bdevp->bd_sem);
  87                         bdput(bdevp);
  88
  89                         return 0;
  90                 default:
  91                         return -EINVAL;
  92         }
  93 }
  94
  95 static int blkdev_reread_part(struct block_device *bdev)
  96 {
  97         struct gendisk *disk = bdev->bd_disk;
  98         int res;
  99
 100         if (disk->minors == 1 || bdev != bdev->bd_contains)
 101                 return -EINVAL;
 102         if (!capable(CAP_SYS_ADMIN))
 103                 return -EACCES;
 104         if (down_trylock(&bdev->bd_sem))
 105                 return -EBUSY;
 106         res = rescan_partitions(disk, bdev);
 107         up(&bdev->bd_sem);
 108         return res;
 109 }
 110
 111 static int put_ushort(unsigned long arg, unsigned short val)
 112 {
 113         return put_user(val, (unsigned short __user *)arg);
 114 }
 115
 116 static int put_int(unsigned long arg, int val)
 117 {
 118         return put_user(val, (int __user *)arg);
 119 }
 120
 121 static int put_long(unsigned long arg, long val)
 122 {
 123         return put_user(val, (long __user *)arg);
 124 }
 125
 126 static int put_ulong(unsigned long arg, unsigned long val)
 127 {
 128         return put_user(val, (unsigned long __user *)arg);
 129 }
 130
 131 static int put_u64(unsigned long arg, u64 val)
 132 {
 133         return put_user(val, (u64 __user *)arg);
 134 }
 135
 136 static int blkdev_locked_ioctl(struct file *file, struct block_device *bdev,
 137                                 unsigned cmd, unsigned long arg)
 138 {
 139         struct backing_dev_info *bdi;
 140         int ret, n;
 141
 142         switch (cmd) {
 143         case BLKRAGET:
 144         case BLKFRAGET:
 145                 if (!arg)
 146                         return -EINVAL;
 147                 bdi = blk_get_backing_dev_info(bdev);
 148                 if (bdi == NULL)
 149                         return -ENOTTY;
 150                 return put_long(arg, (bdi->ra_pages * PAGE_CACHE_SIZE) / 512);
 151         case BLKROGET:
 152                 return put_int(arg, bdev_read_only(bdev) != 0);
 153         case BLKBSZGET: /* get the logical block size (cf. BLKSSZGET) */
 154                 return put_int(arg, block_size(bdev));
 155         case BLKSSZGET: /* get block device hardware sector size */
 156                 return put_int(arg, bdev_hardsect_size(bdev));
 157         case BLKSECTGET:
 158                 return put_ushort(arg, bdev_get_queue(bdev)->max_sectors);
 159         case BLKRASET:
 160         case BLKFRASET:
 161                 if(!capable(CAP_SYS_ADMIN))
 162                         return -EACCES;
 163                 bdi = blk_get_backing_dev_info(bdev);
 164                 if (bdi == NULL)
 165                         return -ENOTTY;
 166                 bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE;
 167                 return 0;
 168         case BLKBSZSET:
 169                 /* set the logical block size */
 170                 if (!capable(CAP_SYS_ADMIN))
 171                         return -EACCES;
 172                 if (!arg)
 173                         return -EINVAL;
 174                 if (get_user(n, (int __user *) arg))
 175                         return -EFAULT;
 176                 if (bd_claim(bdev, file) < 0)
 177                         return -EBUSY;
 178                 ret = set_blocksize(bdev, n);
 179                 bd_release(bdev);
 180                 return ret;
 181         case BLKPG:
 182                 return blkpg_ioctl(bdev, (struct blkpg_ioctl_arg __user *) arg);
 183         case BLKRRPART:
 184                 return blkdev_reread_part(bdev);
 185         case BLKGETSIZE:
 186                 if ((bdev->bd_inode->i_size >> 9) > ~0UL)
 187                         return -EFBIG;
 188                 return put_ulong(arg, bdev->bd_inode->i_size >> 9);
 189         case BLKGETSIZE64:
 190                 return put_u64(arg, bdev->bd_inode->i_size);
 191         }
 192         return -ENOIOCTLCMD;
 193 }
 194
 195 static int blkdev_driver_ioctl(struct inode *inode, struct file *file,
 196                 struct gendisk *disk, unsigned cmd, unsigned long arg)
 197 {
 198         int ret;
 199         if (disk->fops->unlocked_ioctl)
 200                 return disk->fops->unlocked_ioctl(file, cmd, arg);
 201
 202         if (disk->fops->ioctl) {
 203                 lock_kernel();
 204                 ret = disk->fops->ioctl(inode, file, cmd, arg);
 205                 unlock_kernel();
 206                 return ret;
 207         }
 208
 209         return -ENOTTY;
 210 }
 211
 212 int blkdev_ioctl(struct inode *inode, struct file *file, unsigned cmd,
 213                         unsigned long arg)
 214 {
 215         struct block_device *bdev = inode->i_bdev;
 216         struct gendisk *disk = bdev->bd_disk;
 217         int ret, n;
 218
 219         switch(cmd) {
 220         case BLKFLSBUF:
 221                 if (!capable(CAP_SYS_ADMIN))
 222                         return -EACCES;
 223
 224                 ret = blkdev_driver_ioctl(inode, file, disk, cmd, arg);
 225                 /* -EINVAL to handle old uncorrected drivers */
 226                 if (ret != -EINVAL && ret != -ENOTTY)
 227                         return ret;
 228
 229                 lock_kernel();
 230                 fsync_bdev(bdev);
 231                 invalidate_bdev(bdev, 0);
 232                 unlock_kernel();
 233                 return 0;
 234
 235         case BLKROSET:
 236                 ret = blkdev_driver_ioctl(inode, file, disk, cmd, arg);
 237                 /* -EINVAL to handle old uncorrected drivers */
 238                 if (ret != -EINVAL && ret != -ENOTTY)
 239                         return ret;
 240                 if (!capable(CAP_SYS_ADMIN))
 241                         return -EACCES;
 242                 if (get_user(n, (int __user *)(arg)))
 243                         return -EFAULT;
 244                 lock_kernel();
 245                 set_device_ro(bdev, n);
 246                 unlock_kernel();
 247                 return 0;
 248         }
 249
 250         lock_kernel();
 251         ret = blkdev_locked_ioctl(file, bdev, cmd, arg);
 252         unlock_kernel();
 253         if (ret != -ENOIOCTLCMD)
 254                 return ret;
 255
 256         return blkdev_driver_ioctl(inode, file, disk, cmd, arg);
 257 }
 258
 259 /* Most of the generic ioctls are handled in the normal fallback path.
 260    This assumes the blkdev's low level compat_ioctl always returns
 261    ENOIOCTLCMD for unknown ioctls. */
 262 long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg)
 263 {
 264         struct block_device *bdev = file->f_dentry->d_inode->i_bdev;
 265         struct gendisk *disk = bdev->bd_disk;
 266         int ret = -ENOIOCTLCMD;
 267         if (disk->fops->compat_ioctl) {
 268                 lock_kernel();
 269                 ret = disk->fops->compat_ioctl(file, cmd, arg);
 270                 unlock_kernel();
 271         }
 272         return ret;
 273 }
 274
 275 EXPORT_SYMBOL_GPL(blkdev_ioctl);