block/ioctl.c

   1 #include <linux/capability.h>
   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 <linux/blktrace_api.h>
   9 #include <asm/uaccess.h>
  10
  11 static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user *arg)
  12 {
  13         struct block_device *bdevp;
  14         struct gendisk *disk;
  15         struct blkpg_ioctl_arg a;
  16         struct blkpg_partition p;
  17         long long start, length;
  18         int part;
  19         int i;
  20
  21         if (!capable(CAP_SYS_ADMIN))
  22                 return -EACCES;
  23         if (copy_from_user(&a, arg, sizeof(struct blkpg_ioctl_arg)))
  24                 return -EFAULT;
  25         if (copy_from_user(&p, a.data, sizeof(struct blkpg_partition)))
  26                 return -EFAULT;
  27         disk = bdev->bd_disk;
  28         if (bdev != bdev->bd_contains)
  29                 return -EINVAL;
  30         part = p.pno;
  31         if (part <= 0 || part >= disk->minors)
  32                 return -EINVAL;
  33         switch (a.op) {
  34                 case BLKPG_ADD_PARTITION:
  35                         start = p.start >> 9;
  36                         length = p.length >> 9;
  37                         /* check for fit in a hd_struct */
  38                         if (sizeof(sector_t) == sizeof(long) &&
  39                             sizeof(long long) > sizeof(long)) {
  40                                 long pstart = start, plength = length;
  41                                 if (pstart != start || plength != length
  42                                     || pstart < 0 || plength < 0)
  43                                         return -EINVAL;
  44                         }
  45                         /* partition number in use? */
  46                         mutex_lock(&bdev->bd_mutex);
  47                         if (disk->part[part - 1]) {
  48                                 mutex_unlock(&bdev->bd_mutex);
  49                                 return -EBUSY;
  50                         }
  51                         /* overlap? */
  52                         for (i = 0; i < disk->minors - 1; i++) {
  53                                 struct hd_struct *s = disk->part[i];
  54
  55                                 if (!s)
  56                                         continue;
  57                                 if (!(start+length <= s->start_sect ||
  58                                       start >= s->start_sect + s->nr_sects)) {
  59                                         mutex_unlock(&bdev->bd_mutex);
  60                                         return -EBUSY;
  61                                 }
  62                         }
  63                         /* all seems OK */
  64                         add_partition(disk, part, start, length);
  65                         mutex_unlock(&bdev->bd_mutex);
  66                         return 0;
  67                 case BLKPG_DEL_PARTITION:
  68                         if (!disk->part[part-1])
  69                                 return -ENXIO;
  70                         if (disk->part[part - 1]->nr_sects == 0)
  71                                 return -ENXIO;
  72                         bdevp = bdget_disk(disk, part);
  73                         if (!bdevp)
  74                                 return -ENOMEM;
  75                         mutex_lock(&bdevp->bd_mutex);
  76                         if (bdevp->bd_openers) {
  77                                 mutex_unlock(&bdevp->bd_mutex);
  78                                 bdput(bdevp);
  79                                 return -EBUSY;
  80                         }
  81                         /* all seems OK */
  82                         fsync_bdev(bdevp);
  83                         invalidate_bdev(bdevp, 0);
  84
  85                         mutex_lock(&bdev->bd_mutex);
  86                         delete_partition(disk, part);
  87                         mutex_unlock(&bdev->bd_mutex);
  88                         mutex_unlock(&bdevp->bd_mutex);
  89                         bdput(bdevp);
  90
  91                         return 0;
  92                 default:
  93                         return -EINVAL;
  94         }
  95 }
  96
  97 static int blkdev_reread_part(struct block_device *bdev)
  98 {
  99         struct gendisk *disk = bdev->bd_disk;
 100         int res;
 101
 102         if (disk->minors == 1 || bdev != bdev->bd_contains)
 103                 return -EINVAL;
 104         if (!capable(CAP_SYS_ADMIN))
 105                 return -EACCES;
 106         if (!mutex_trylock(&bdev->bd_mutex))
 107                 return -EBUSY;
 108         res = rescan_partitions(disk, bdev);
 109         mutex_unlock(&bdev->bd_mutex);
 110         return res;
 111 }
 112
 113 static int put_ushort(unsigned long arg, unsigned short val)
 114 {
 115         return put_user(val, (unsigned short __user *)arg);
 116 }
 117
 118 static int put_int(unsigned long arg, int val)
 119 {
 120         return put_user(val, (int __user *)arg);
 121 }
 122
 123 static int put_long(unsigned long arg, long val)
 124 {
 125         return put_user(val, (long __user *)arg);
 126 }
 127
 128 static int put_ulong(unsigned long arg, unsigned long val)
 129 {
 130         return put_user(val, (unsigned long __user *)arg);
 131 }
 132
 133 static int put_u64(unsigned long arg, u64 val)
 134 {
 135         return put_user(val, (u64 __user *)arg);
 136 }
 137
 138 static int blkdev_locked_ioctl(struct file *file, struct block_device *bdev,
 139                                 unsigned cmd, unsigned long arg)
 140 {
 141         struct backing_dev_info *bdi;
 142         int ret, n;
 143
 144         switch (cmd) {
 145         case BLKRAGET:
 146         case BLKFRAGET:
 147                 if (!arg)
 148                         return -EINVAL;
 149                 bdi = blk_get_backing_dev_info(bdev);
 150                 if (bdi == NULL)
 151                         return -ENOTTY;
 152                 return put_long(arg, (bdi->ra_pages * PAGE_CACHE_SIZE) / 512);
 153         case BLKROGET:
 154                 return put_int(arg, bdev_read_only(bdev) != 0);
 155         case BLKBSZGET: /* get the logical block size (cf. BLKSSZGET) */
 156                 return put_int(arg, block_size(bdev));
 157         case BLKSSZGET: /* get block device hardware sector size */
 158                 return put_int(arg, bdev_hardsect_size(bdev));
 159         case BLKSECTGET:
 160                 return put_ushort(arg, bdev_get_queue(bdev)->max_sectors);
 161         case BLKRASET:
 162         case BLKFRASET:
 163                 if(!capable(CAP_SYS_ADMIN))
 164                         return -EACCES;
 165                 bdi = blk_get_backing_dev_info(bdev);
 166                 if (bdi == NULL)
 167                         return -ENOTTY;
 168                 bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE;
 169                 return 0;
 170         case BLKBSZSET:
 171                 /* set the logical block size */
 172                 if (!capable(CAP_SYS_ADMIN))
 173                         return -EACCES;
 174                 if (!arg)
 175                         return -EINVAL;
 176                 if (get_user(n, (int __user *) arg))
 177                         return -EFAULT;
 178                 if (bd_claim(bdev, file) < 0)
 179                         return -EBUSY;
 180                 ret = set_blocksize(bdev, n);
 181                 bd_release(bdev);
 182                 return ret;
 183         case BLKPG:
 184                 return blkpg_ioctl(bdev, (struct blkpg_ioctl_arg __user *) arg);
 185         case BLKRRPART:
 186                 return blkdev_reread_part(bdev);
 187         case BLKGETSIZE:
 188                 if ((bdev->bd_inode->i_size >> 9) > ~0UL)
 189                         return -EFBIG;
 190                 return put_ulong(arg, bdev->bd_inode->i_size >> 9);
 191         case BLKGETSIZE64:
 192                 return put_u64(arg, bdev->bd_inode->i_size);
 193         case BLKTRACESTART:
 194         case BLKTRACESTOP:
 195         case BLKTRACESETUP:
 196         case BLKTRACETEARDOWN:
 197                 return blk_trace_ioctl(bdev, cmd, (char __user *) arg);
 198         }
 199         return -ENOIOCTLCMD;
 200 }
 201
 202 static int blkdev_driver_ioctl(struct inode *inode, struct file *file,
 203                 struct gendisk *disk, unsigned cmd, unsigned long arg)
 204 {
 205         int ret;
 206         if (disk->fops->unlocked_ioctl)
 207                 return disk->fops->unlocked_ioctl(file, cmd, arg);
 208
 209         if (disk->fops->ioctl) {
 210                 lock_kernel();
 211                 ret = disk->fops->ioctl(inode, file, cmd, arg);
 212                 unlock_kernel();
 213                 return ret;
 214         }
 215
 216         return -ENOTTY;
 217 }
 218
 219 int blkdev_ioctl(struct inode *inode, struct file *file, unsigned cmd,
 220                         unsigned long arg)
 221 {
 222         struct block_device *bdev = inode->i_bdev;
 223         struct gendisk *disk = bdev->bd_disk;
 224         int ret, n;
 225
 226         switch(cmd) {
 227         case BLKFLSBUF:
 228                 if (!capable(CAP_SYS_ADMIN))
 229                         return -EACCES;
 230
 231                 ret = blkdev_driver_ioctl(inode, file, disk, cmd, arg);
 232                 /* -EINVAL to handle old uncorrected drivers */
 233                 if (ret != -EINVAL && ret != -ENOTTY)
 234                         return ret;
 235
 236                 lock_kernel();
 237                 fsync_bdev(bdev);
 238                 invalidate_bdev(bdev, 0);
 239                 unlock_kernel();
 240                 return 0;
 241
 242         case BLKROSET:
 243                 ret = blkdev_driver_ioctl(inode, file, disk, cmd, arg);
 244                 /* -EINVAL to handle old uncorrected drivers */
 245                 if (ret != -EINVAL && ret != -ENOTTY)
 246                         return ret;
 247                 if (!capable(CAP_SYS_ADMIN))
 248                         return -EACCES;
 249                 if (get_user(n, (int __user *)(arg)))
 250                         return -EFAULT;
 251                 lock_kernel();
 252                 set_device_ro(bdev, n);
 253                 unlock_kernel();
 254                 return 0;
 255         case HDIO_GETGEO: {
 256                 struct hd_geometry geo;
 257
 258                 if (!arg)
 259                         return -EINVAL;
 260                 if (!disk->fops->getgeo)
 261                         return -ENOTTY;
 262
 263                 /*
 264                  * We need to set the startsect first, the driver may
 265                  * want to override it.
 266                  */
 267                 geo.start = get_start_sect(bdev);
 268                 ret = disk->fops->getgeo(bdev, &geo);
 269                 if (ret)
 270                         return ret;
 271                 if (copy_to_user((struct hd_geometry __user *)arg, &geo,
 272                                         sizeof(geo)))
 273                         return -EFAULT;
 274                 return 0;
 275         }
 276         }
 277
 278         lock_kernel();
 279         ret = blkdev_locked_ioctl(file, bdev, cmd, arg);
 280         unlock_kernel();
 281         if (ret != -ENOIOCTLCMD)
 282                 return ret;
 283
 284         return blkdev_driver_ioctl(inode, file, disk, cmd, arg);
 285 }
 286
 287 /* Most of the generic ioctls are handled in the normal fallback path.
 288    This assumes the blkdev's low level compat_ioctl always returns
 289    ENOIOCTLCMD for unknown ioctls. */
 290 long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg)
 291 {
 292         struct block_device *bdev = file->f_dentry->d_inode->i_bdev;
 293         struct gendisk *disk = bdev->bd_disk;
 294         int ret = -ENOIOCTLCMD;
 295         if (disk->fops->compat_ioctl) {
 296                 lock_kernel();
 297                 ret = disk->fops->compat_ioctl(file, cmd, arg);
 298                 unlock_kernel();
 299         }
 300         return ret;
 301 }
 302
 303 EXPORT_SYMBOL_GPL(blkdev_ioctl);