block/ioctl.c

   1 #include <linux/sched.h>                /* for capable() */
   2 #include <linux/blkdev.h>
   3 #include <linux/blkpg.h>
   4 #include <linux/hdreg.h>
   5 #include <linux/backing-dev.h>
   6 #include <linux/buffer_head.h>
   7 #include <linux/smp_lock.h>
   8 #include <asm/uaccess.h>
   9
  10 static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user *arg)
  11 {
  12         struct block_device *bdevp;
  13         struct gendisk *disk;
  14         struct blkpg_ioctl_arg a;
  15         struct blkpg_partition p;
  16         long long start, length;
  17         int part;
  18         int i;
  19
  20         if (!capable(CAP_SYS_ADMIN))
  21                 return -EACCES;
  22         if (copy_from_user(&a, arg, sizeof(struct blkpg_ioctl_arg)))
  23                 return -EFAULT;
  24         if (copy_from_user(&p, a.data, sizeof(struct blkpg_partition)))
  25                 return -EFAULT;
  26         disk = bdev->bd_disk;
  27         if (bdev != bdev->bd_contains)
  28                 return -EINVAL;
  29         part = p.pno;
  30         if (part <= 0 || part >= disk->minors)
  31                 return -EINVAL;
  32         switch (a.op) {
  33                 case BLKPG_ADD_PARTITION:
  34                         start = p.start >> 9;
  35                         length = p.length >> 9;
  36                         /* check for fit in a hd_struct */
  37                         if (sizeof(sector_t) == sizeof(long) &&
  38                             sizeof(long long) > sizeof(long)) {
  39                                 long pstart = start, plength = length;
  40                                 if (pstart != start || plength != length
  41                                     || pstart < 0 || plength < 0)
  42                                         return -EINVAL;
  43                         }
  44                         /* partition number in use? */
  45                         down(&bdev->bd_sem);
  46                         if (disk->part[part - 1]) {
  47                                 up(&bdev->bd_sem);
  48                                 return -EBUSY;
  49                         }
  50                         /* overlap? */
  51                         for (i = 0; i < disk->minors - 1; i++) {
  52                                 struct hd_struct *s = disk->part[i];
  53
  54                                 if (!s)
  55                                         continue;
  56                                 if (!(start+length <= s->start_sect ||
  57                                       start >= s->start_sect + s->nr_sects)) {
  58                                         up(&bdev->bd_sem);
  59                                         return -EBUSY;
  60                                 }
  61                         }
  62                         /* all seems OK */
  63                         add_partition(disk, part, start, length);
  64                         up(&bdev->bd_sem);
  65                         return 0;
  66                 case BLKPG_DEL_PARTITION:
  67                         if (!disk->part[part-1])
  68                                 return -ENXIO;
  69                         if (disk->part[part - 1]->nr_sects == 0)
  70                                 return -ENXIO;
  71                         bdevp = bdget_disk(disk, part);
  72                         if (!bdevp)
  73                                 return -ENOMEM;
  74                         down(&bdevp->bd_sem);
  75                         if (bdevp->bd_openers) {
  76                                 up(&bdevp->bd_sem);
  77                                 bdput(bdevp);
  78                                 return -EBUSY;
  79                         }
  80                         /* all seems OK */
  81                         fsync_bdev(bdevp);
  82                         invalidate_bdev(bdevp, 0);
  83
  84                         down(&bdev->bd_sem);
  85                         delete_partition(disk, part);
  86                         up(&bdev->bd_sem);
  87                         up(&bdevp->bd_sem);
  88                         bdput(bdevp);
  89
  90                         return 0;
  91                 default:
  92                         return -EINVAL;
  93         }
  94 }
  95
  96 static int blkdev_reread_part(struct block_device *bdev)
  97 {
  98         struct gendisk *disk = bdev->bd_disk;
  99         int res;
 100
 101         if (disk->minors == 1 || bdev != bdev->bd_contains)
 102                 return -EINVAL;
 103         if (!capable(CAP_SYS_ADMIN))
 104                 return -EACCES;
 105         if (down_trylock(&bdev->bd_sem))
 106                 return -EBUSY;
 107         res = rescan_partitions(disk, bdev);
 108         up(&bdev->bd_sem);
 109         return res;
 110 }
 111
 112 static int put_ushort(unsigned long arg, unsigned short val)
 113 {
 114         return put_user(val, (unsigned short __user *)arg);
 115 }
 116
 117 static int put_int(unsigned long arg, int val)
 118 {
 119         return put_user(val, (int __user *)arg);
 120 }
 121
 122 static int put_long(unsigned long arg, long val)
 123 {
 124         return put_user(val, (long __user *)arg);
 125 }
 126
 127 static int put_ulong(unsigned long arg, unsigned long val)
 128 {
 129         return put_user(val, (unsigned long __user *)arg);
 130 }
 131
 132 static int put_u64(unsigned long arg, u64 val)
 133 {
 134         return put_user(val, (u64 __user *)arg);
 135 }
 136
 137 static int blkdev_locked_ioctl(struct file *file, struct block_device *bdev,
 138                                 unsigned cmd, unsigned long arg)
 139 {
 140         struct backing_dev_info *bdi;
 141         int ret, n;
 142
 143         switch (cmd) {
 144         case BLKRAGET:
 145         case BLKFRAGET:
 146                 if (!arg)
 147                         return -EINVAL;
 148                 bdi = blk_get_backing_dev_info(bdev);
 149                 if (bdi == NULL)
 150                         return -ENOTTY;
 151                 return put_long(arg, (bdi->ra_pages * PAGE_CACHE_SIZE) / 512);
 152         case BLKROGET:
 153                 return put_int(arg, bdev_read_only(bdev) != 0);
 154         case BLKBSZGET: /* get the logical block size (cf. BLKSSZGET) */
 155                 return put_int(arg, block_size(bdev));
 156         case BLKSSZGET: /* get block device hardware sector size */
 157                 return put_int(arg, bdev_hardsect_size(bdev));
 158         case BLKSECTGET:
 159                 return put_ushort(arg, bdev_get_queue(bdev)->max_sectors);
 160         case BLKRASET:
 161         case BLKFRASET:
 162                 if(!capable(CAP_SYS_ADMIN))
 163                         return -EACCES;
 164                 bdi = blk_get_backing_dev_info(bdev);
 165                 if (bdi == NULL)
 166                         return -ENOTTY;
 167                 bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE;
 168                 return 0;
 169         case BLKBSZSET:
 170                 /* set the logical block size */
 171                 if (!capable(CAP_SYS_ADMIN))
 172                         return -EACCES;
 173                 if (!arg)
 174                         return -EINVAL;
 175                 if (get_user(n, (int __user *) arg))
 176                         return -EFAULT;
 177                 if (bd_claim(bdev, file) < 0)
 178                         return -EBUSY;
 179                 ret = set_blocksize(bdev, n);
 180                 bd_release(bdev);
 181                 return ret;
 182         case BLKPG:
 183                 return blkpg_ioctl(bdev, (struct blkpg_ioctl_arg __user *) arg);
 184         case BLKRRPART:
 185                 return blkdev_reread_part(bdev);
 186         case BLKGETSIZE:
 187                 if ((bdev->bd_inode->i_size >> 9) > ~0UL)
 188                         return -EFBIG;
 189                 return put_ulong(arg, bdev->bd_inode->i_size >> 9);
 190         case BLKGETSIZE64:
 191                 return put_u64(arg, bdev->bd_inode->i_size);
 192         }
 193         return -ENOIOCTLCMD;
 194 }
 195
 196 static int blkdev_driver_ioctl(struct inode *inode, struct file *file,
 197                 struct gendisk *disk, unsigned cmd, unsigned long arg)
 198 {
 199         int ret;
 200         if (disk->fops->unlocked_ioctl)
 201                 return disk->fops->unlocked_ioctl(file, cmd, arg);
 202
 203         if (disk->fops->ioctl) {
 204                 lock_kernel();
 205                 ret = disk->fops->ioctl(inode, file, cmd, arg);
 206                 unlock_kernel();
 207                 return ret;
 208         }
 209
 210         return -ENOTTY;
 211 }
 212
 213 int blkdev_ioctl(struct inode *inode, struct file *file, unsigned cmd,
 214                         unsigned long arg)
 215 {
 216         struct block_device *bdev = inode->i_bdev;
 217         struct gendisk *disk = bdev->bd_disk;
 218         int ret, n;
 219
 220         switch(cmd) {
 221         case BLKFLSBUF:
 222                 if (!capable(CAP_SYS_ADMIN))
 223                         return -EACCES;
 224
 225                 ret = blkdev_driver_ioctl(inode, file, disk, cmd, arg);
 226                 /* -EINVAL to handle old uncorrected drivers */
 227                 if (ret != -EINVAL && ret != -ENOTTY)
 228                         return ret;
 229
 230                 lock_kernel();
 231                 fsync_bdev(bdev);
 232                 invalidate_bdev(bdev, 0);
 233                 unlock_kernel();
 234                 return 0;
 235
 236         case BLKROSET:
 237                 ret = blkdev_driver_ioctl(inode, file, disk, cmd, arg);
 238                 /* -EINVAL to handle old uncorrected drivers */
 239                 if (ret != -EINVAL && ret != -ENOTTY)
 240                         return ret;
 241                 if (!capable(CAP_SYS_ADMIN))
 242                         return -EACCES;
 243                 if (get_user(n, (int __user *)(arg)))
 244                         return -EFAULT;
 245                 lock_kernel();
 246                 set_device_ro(bdev, n);
 247                 unlock_kernel();
 248                 return 0;
 249         case HDIO_GETGEO: {
 250                 struct hd_geometry geo;
 251
 252                 if (!arg)
 253                         return -EINVAL;
 254                 if (!disk->fops->getgeo)
 255                         return -ENOTTY;
 256
 257                 /*
 258                  * We need to set the startsect first, the driver may
 259                  * want to override it.
 260                  */
 261                 geo.start = get_start_sect(bdev);
 262                 ret = disk->fops->getgeo(bdev, &geo);
 263                 if (ret)
 264                         return ret;
 265                 if (copy_to_user((struct hd_geometry __user *)arg, &geo,
 266                                         sizeof(geo)))
 267                         return -EFAULT;
 268                 return 0;
 269         }
 270         }
 271
 272         lock_kernel();
 273         ret = blkdev_locked_ioctl(file, bdev, cmd, arg);
 274         unlock_kernel();
 275         if (ret != -ENOIOCTLCMD)
 276                 return ret;
 277
 278         return blkdev_driver_ioctl(inode, file, disk, cmd, arg);
 279 }
 280
 281 /* Most of the generic ioctls are handled in the normal fallback path.
 282    This assumes the blkdev's low level compat_ioctl always returns
 283    ENOIOCTLCMD for unknown ioctls. */
 284 long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg)
 285 {
 286         struct block_device *bdev = file->f_dentry->d_inode->i_bdev;
 287         struct gendisk *disk = bdev->bd_disk;
 288         int ret = -ENOIOCTLCMD;
 289         if (disk->fops->compat_ioctl) {
 290                 lock_kernel();
 291                 ret = disk->fops->compat_ioctl(file, cmd, arg);
 292                 unlock_kernel();
 293         }
 294         return ret;
 295 }
 296
 297 EXPORT_SYMBOL_GPL(blkdev_ioctl);