block/ioctl.c

   1 #include <linux/capability.h>
   2 #include <linux/blkdev.h>
   3 #include <linux/export.h>
   4 #include <linux/gfp.h>
   5 #include <linux/blkpg.h>
   6 #include <linux/hdreg.h>
   7 #include <linux/backing-dev.h>
   8 #include <linux/fs.h>
   9 #include <linux/blktrace_api.h>
  10 #include <asm/uaccess.h>
  11
  12 static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user *arg)
  13 {
  14         struct block_device *bdevp;
  15         struct gendisk *disk;
  16         struct hd_struct *part, *lpart;
  17         struct blkpg_ioctl_arg a;
  18         struct blkpg_partition p;
  19         struct disk_part_iter piter;
  20         long long start, length;
  21         int partno;
  22
  23         if (!capable(CAP_SYS_ADMIN))
  24                 return -EACCES;
  25         if (copy_from_user(&a, arg, sizeof(struct blkpg_ioctl_arg)))
  26                 return -EFAULT;
  27         if (copy_from_user(&p, a.data, sizeof(struct blkpg_partition)))
  28                 return -EFAULT;
  29         disk = bdev->bd_disk;
  30         if (bdev != bdev->bd_contains)
  31                 return -EINVAL;
  32         partno = p.pno;
  33         if (partno <= 0)
  34                 return -EINVAL;
  35         switch (a.op) {
  36                 case BLKPG_ADD_PARTITION:
  37                         start = p.start >> 9;
  38                         length = p.length >> 9;
  39                         /* check for fit in a hd_struct */
  40                         if (sizeof(sector_t) == sizeof(long) &&
  41                             sizeof(long long) > sizeof(long)) {
  42                                 long pstart = start, plength = length;
  43                                 if (pstart != start || plength != length
  44                                     || pstart < 0 || plength < 0)
  45                                         return -EINVAL;
  46                         }
  47
  48                         mutex_lock(&bdev->bd_mutex);
  49
  50                         /* overlap? */
  51                         disk_part_iter_init(&piter, disk,
  52                                             DISK_PITER_INCL_EMPTY);
  53                         while ((part = disk_part_iter_next(&piter))) {
  54                                 if (!(start + length <= part->start_sect ||
  55                                       start >= part->start_sect + part->nr_sects)) {
  56                                         disk_part_iter_exit(&piter);
  57                                         mutex_unlock(&bdev->bd_mutex);
  58                                         return -EBUSY;
  59                                 }
  60                         }
  61                         disk_part_iter_exit(&piter);
  62
  63                         /* all seems OK */
  64                         part = add_partition(disk, partno, start, length,
  65                                              ADDPART_FLAG_NONE, NULL);
  66                         mutex_unlock(&bdev->bd_mutex);
  67                         return IS_ERR(part) ? PTR_ERR(part) : 0;
  68                 case BLKPG_DEL_PARTITION:
  69                         part = disk_get_part(disk, partno);
  70                         if (!part)
  71                                 return -ENXIO;
  72
  73                         bdevp = bdget(part_devt(part));
  74                         disk_put_part(part);
  75                         if (!bdevp)
  76                                 return -ENOMEM;
  77
  78                         mutex_lock(&bdevp->bd_mutex);
  79                         if (bdevp->bd_openers) {
  80                                 mutex_unlock(&bdevp->bd_mutex);
  81                                 bdput(bdevp);
  82                                 return -EBUSY;
  83                         }
  84                         /* all seems OK */
  85                         fsync_bdev(bdevp);
  86                         invalidate_bdev(bdevp);
  87
  88                         mutex_lock_nested(&bdev->bd_mutex, 1);
  89                         delete_partition(disk, partno);
  90                         mutex_unlock(&bdev->bd_mutex);
  91                         mutex_unlock(&bdevp->bd_mutex);
  92                         bdput(bdevp);
  93
  94                         return 0;
  95                 case BLKPG_RESIZE_PARTITION:
  96                         start = p.start >> 9;
  97                         /* new length of partition in bytes */
  98                         length = p.length >> 9;
  99                         /* check for fit in a hd_struct */
 100                         if (sizeof(sector_t) == sizeof(long) &&
 101                             sizeof(long long) > sizeof(long)) {
 102                                 long pstart = start, plength = length;
 103                                 if (pstart != start || plength != length
 104                                     || pstart < 0 || plength < 0)
 105                                         return -EINVAL;
 106                         }
 107                         part = disk_get_part(disk, partno);
 108                         if (!part)
 109                                 return -ENXIO;
 110                         bdevp = bdget(part_devt(part));
 111                         if (!bdevp) {
 112                                 disk_put_part(part);
 113                                 return -ENOMEM;
 114                         }
 115                         mutex_lock(&bdevp->bd_mutex);
 116                         mutex_lock_nested(&bdev->bd_mutex, 1);
 117                         if (start != part->start_sect) {
 118                                 mutex_unlock(&bdevp->bd_mutex);
 119                                 mutex_unlock(&bdev->bd_mutex);
 120                                 bdput(bdevp);
 121                                 disk_put_part(part);
 122                                 return -EINVAL;
 123                         }
 124                         /* overlap? */
 125                         disk_part_iter_init(&piter, disk,
 126                                             DISK_PITER_INCL_EMPTY);
 127                         while ((lpart = disk_part_iter_next(&piter))) {
 128                                 if (lpart->partno != partno &&
 129                                    !(start + length <= lpart->start_sect ||
 130                                    start >= lpart->start_sect + lpart->nr_sects)
 131                                    ) {
 132                                         disk_part_iter_exit(&piter);
 133                                         mutex_unlock(&bdevp->bd_mutex);
 134                                         mutex_unlock(&bdev->bd_mutex);
 135                                         bdput(bdevp);
 136                                         disk_put_part(part);
 137                                         return -EBUSY;
 138                                 }
 139                         }
 140                         disk_part_iter_exit(&piter);
 141                         part_nr_sects_write(part, (sector_t)length);
 142                         i_size_write(bdevp->bd_inode, p.length);
 143                         mutex_unlock(&bdevp->bd_mutex);
 144                         mutex_unlock(&bdev->bd_mutex);
 145                         bdput(bdevp);
 146                         disk_put_part(part);
 147                         return 0;
 148                 default:
 149                         return -EINVAL;
 150         }
 151 }
 152
 153 static int blkdev_reread_part(struct block_device *bdev)
 154 {
 155         struct gendisk *disk = bdev->bd_disk;
 156         int res;
 157
 158         if (!disk_part_scan_enabled(disk) || bdev != bdev->bd_contains)
 159                 return -EINVAL;
 160         if (!capable(CAP_SYS_ADMIN))
 161                 return -EACCES;
 162         if (!mutex_trylock(&bdev->bd_mutex))
 163                 return -EBUSY;
 164         res = rescan_partitions(disk, bdev);
 165         mutex_unlock(&bdev->bd_mutex);
 166         return res;
 167 }
 168
 169 static int blk_ioctl_discard(struct block_device *bdev, uint64_t start,
 170                              uint64_t len, int secure)
 171 {
 172         unsigned long flags = 0;
 173
 174         if (start & 511)
 175                 return -EINVAL;
 176         if (len & 511)
 177                 return -EINVAL;
 178         start >>= 9;
 179         len >>= 9;
 180
 181         if (start + len > (i_size_read(bdev->bd_inode) >> 9))
 182                 return -EINVAL;
 183         if (secure)
 184                 flags |= BLKDEV_DISCARD_SECURE;
 185         return blkdev_issue_discard(bdev, start, len, GFP_KERNEL, flags);
 186 }
 187
 188 static int put_ushort(unsigned long arg, unsigned short val)
 189 {
 190         return put_user(val, (unsigned short __user *)arg);
 191 }
 192
 193 static int put_int(unsigned long arg, int val)
 194 {
 195         return put_user(val, (int __user *)arg);
 196 }
 197
 198 static int put_uint(unsigned long arg, unsigned int val)
 199 {
 200         return put_user(val, (unsigned int __user *)arg);
 201 }
 202
 203 static int put_long(unsigned long arg, long val)
 204 {
 205         return put_user(val, (long __user *)arg);
 206 }
 207
 208 static int put_ulong(unsigned long arg, unsigned long val)
 209 {
 210         return put_user(val, (unsigned long __user *)arg);
 211 }
 212
 213 static int put_u64(unsigned long arg, u64 val)
 214 {
 215         return put_user(val, (u64 __user *)arg);
 216 }
 217
 218 int __blkdev_driver_ioctl(struct block_device *bdev, fmode_t mode,
 219                         unsigned cmd, unsigned long arg)
 220 {
 221         struct gendisk *disk = bdev->bd_disk;
 222
 223         if (disk->fops->ioctl)
 224                 return disk->fops->ioctl(bdev, mode, cmd, arg);
 225
 226         return -ENOTTY;
 227 }
 228 /*
 229  * For the record: _GPL here is only because somebody decided to slap it
 230  * on the previous export.  Sheer idiocy, since it wasn't copyrightable
 231  * at all and could be open-coded without any exports by anybody who cares.
 232  */
 233 EXPORT_SYMBOL_GPL(__blkdev_driver_ioctl);
 234
 235 /*
 236  * Is it an unrecognized ioctl? The correct returns are either
 237  * ENOTTY (final) or ENOIOCTLCMD ("I don't know this one, try a
 238  * fallback"). ENOIOCTLCMD gets turned into ENOTTY by the ioctl
 239  * code before returning.
 240  *
 241  * Confused drivers sometimes return EINVAL, which is wrong. It
 242  * means "I understood the ioctl command, but the parameters to
 243  * it were wrong".
 244  *
 245  * We should aim to just fix the broken drivers, the EINVAL case
 246  * should go away.
 247  */
 248 static inline int is_unrecognized_ioctl(int ret)
 249 {
 250         return  ret == -EINVAL ||
 251                 ret == -ENOTTY ||
 252                 ret == -ENOIOCTLCMD;
 253 }
 254
 255 /*
 256  * always keep this in sync with compat_blkdev_ioctl()
 257  */
 258 int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
 259                         unsigned long arg)
 260 {
 261         struct gendisk *disk = bdev->bd_disk;
 262         struct backing_dev_info *bdi;
 263         loff_t size;
 264         int ret, n;
 265
 266         switch(cmd) {
 267         case BLKFLSBUF:
 268                 if (!capable(CAP_SYS_ADMIN))
 269                         return -EACCES;
 270
 271                 ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 272                 if (!is_unrecognized_ioctl(ret))
 273                         return ret;
 274
 275                 fsync_bdev(bdev);
 276                 invalidate_bdev(bdev);
 277                 return 0;
 278
 279         case BLKROSET:
 280                 ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 281                 if (!is_unrecognized_ioctl(ret))
 282                         return ret;
 283                 if (!capable(CAP_SYS_ADMIN))
 284                         return -EACCES;
 285                 if (get_user(n, (int __user *)(arg)))
 286                         return -EFAULT;
 287                 set_device_ro(bdev, n);
 288                 return 0;
 289
 290         case BLKDISCARD:
 291         case BLKSECDISCARD: {
 292                 uint64_t range[2];
 293
 294                 if (!(mode & FMODE_WRITE))
 295                         return -EBADF;
 296
 297                 if (copy_from_user(range, (void __user *)arg, sizeof(range)))
 298                         return -EFAULT;
 299
 300                 return blk_ioctl_discard(bdev, range[0], range[1],
 301                                          cmd == BLKSECDISCARD);
 302         }
 303
 304         case HDIO_GETGEO: {
 305                 struct hd_geometry geo;
 306
 307                 if (!arg)
 308                         return -EINVAL;
 309                 if (!disk->fops->getgeo)
 310                         return -ENOTTY;
 311
 312                 /*
 313                  * We need to set the startsect first, the driver may
 314                  * want to override it.
 315                  */
 316                 memset(&geo, 0, sizeof(geo));
 317                 geo.start = get_start_sect(bdev);
 318                 ret = disk->fops->getgeo(bdev, &geo);
 319                 if (ret)
 320                         return ret;
 321                 if (copy_to_user((struct hd_geometry __user *)arg, &geo,
 322                                         sizeof(geo)))
 323                         return -EFAULT;
 324                 return 0;
 325         }
 326         case BLKRAGET:
 327         case BLKFRAGET:
 328                 if (!arg)
 329                         return -EINVAL;
 330                 bdi = blk_get_backing_dev_info(bdev);
 331                 if (bdi == NULL)
 332                         return -ENOTTY;
 333                 return put_long(arg, (bdi->ra_pages * PAGE_CACHE_SIZE) / 512);
 334         case BLKROGET:
 335                 return put_int(arg, bdev_read_only(bdev) != 0);
 336         case BLKBSZGET: /* get block device soft block size (cf. BLKSSZGET) */
 337                 return put_int(arg, block_size(bdev));
 338         case BLKSSZGET: /* get block device logical block size */
 339                 return put_int(arg, bdev_logical_block_size(bdev));
 340         case BLKPBSZGET: /* get block device physical block size */
 341                 return put_uint(arg, bdev_physical_block_size(bdev));
 342         case BLKIOMIN:
 343                 return put_uint(arg, bdev_io_min(bdev));
 344         case BLKIOOPT:
 345                 return put_uint(arg, bdev_io_opt(bdev));
 346         case BLKALIGNOFF:
 347                 return put_int(arg, bdev_alignment_offset(bdev));
 348         case BLKDISCARDZEROES:
 349                 return put_uint(arg, bdev_discard_zeroes_data(bdev));
 350         case BLKSECTGET:
 351                 return put_ushort(arg, queue_max_sectors(bdev_get_queue(bdev)));
 352         case BLKROTATIONAL:
 353                 return put_ushort(arg, !blk_queue_nonrot(bdev_get_queue(bdev)));
 354         case BLKRASET:
 355         case BLKFRASET:
 356                 if(!capable(CAP_SYS_ADMIN))
 357                         return -EACCES;
 358                 bdi = blk_get_backing_dev_info(bdev);
 359                 if (bdi == NULL)
 360                         return -ENOTTY;
 361                 bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE;
 362                 return 0;
 363         case BLKBSZSET:
 364                 /* set the logical block size */
 365                 if (!capable(CAP_SYS_ADMIN))
 366                         return -EACCES;
 367                 if (!arg)
 368                         return -EINVAL;
 369                 if (get_user(n, (int __user *) arg))
 370                         return -EFAULT;
 371                 if (!(mode & FMODE_EXCL)) {
 372                         bdgrab(bdev);
 373                         if (blkdev_get(bdev, mode | FMODE_EXCL, &bdev) < 0)
 374                                 return -EBUSY;
 375                 }
 376                 ret = set_blocksize(bdev, n);
 377                 if (!(mode & FMODE_EXCL))
 378                         blkdev_put(bdev, mode | FMODE_EXCL);
 379                 return ret;
 380         case BLKPG:
 381                 ret = blkpg_ioctl(bdev, (struct blkpg_ioctl_arg __user *) arg);
 382                 break;
 383         case BLKRRPART:
 384                 ret = blkdev_reread_part(bdev);
 385                 break;
 386         case BLKGETSIZE:
 387                 size = i_size_read(bdev->bd_inode);
 388                 if ((size >> 9) > ~0UL)
 389                         return -EFBIG;
 390                 return put_ulong(arg, size >> 9);
 391         case BLKGETSIZE64:
 392                 return put_u64(arg, i_size_read(bdev->bd_inode));
 393         case BLKTRACESTART:
 394         case BLKTRACESTOP:
 395         case BLKTRACESETUP:
 396         case BLKTRACETEARDOWN:
 397                 ret = blk_trace_ioctl(bdev, cmd, (char __user *) arg);
 398                 break;
 399         default:
 400                 ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 401         }
 402         return ret;
 403 }
 404 EXPORT_SYMBOL_GPL(blkdev_ioctl);