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 || partno > 65535)
  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 PTR_ERR_OR_ZERO(part);
  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 blk_ioctl_zeroout(struct block_device *bdev, uint64_t start,
 189                              uint64_t len)
 190 {
 191         if (start & 511)
 192                 return -EINVAL;
 193         if (len & 511)
 194                 return -EINVAL;
 195         start >>= 9;
 196         len >>= 9;
 197
 198         if (start + len > (i_size_read(bdev->bd_inode) >> 9))
 199                 return -EINVAL;
 200
 201         return blkdev_issue_zeroout(bdev, start, len, GFP_KERNEL, false);
 202 }
 203
 204 static int put_ushort(unsigned long arg, unsigned short val)
 205 {
 206         return put_user(val, (unsigned short __user *)arg);
 207 }
 208
 209 static int put_int(unsigned long arg, int val)
 210 {
 211         return put_user(val, (int __user *)arg);
 212 }
 213
 214 static int put_uint(unsigned long arg, unsigned int val)
 215 {
 216         return put_user(val, (unsigned int __user *)arg);
 217 }
 218
 219 static int put_long(unsigned long arg, long val)
 220 {
 221         return put_user(val, (long __user *)arg);
 222 }
 223
 224 static int put_ulong(unsigned long arg, unsigned long val)
 225 {
 226         return put_user(val, (unsigned long __user *)arg);
 227 }
 228
 229 static int put_u64(unsigned long arg, u64 val)
 230 {
 231         return put_user(val, (u64 __user *)arg);
 232 }
 233
 234 int __blkdev_driver_ioctl(struct block_device *bdev, fmode_t mode,
 235                         unsigned cmd, unsigned long arg)
 236 {
 237         struct gendisk *disk = bdev->bd_disk;
 238
 239         if (disk->fops->ioctl)
 240                 return disk->fops->ioctl(bdev, mode, cmd, arg);
 241
 242         return -ENOTTY;
 243 }
 244 /*
 245  * For the record: _GPL here is only because somebody decided to slap it
 246  * on the previous export.  Sheer idiocy, since it wasn't copyrightable
 247  * at all and could be open-coded without any exports by anybody who cares.
 248  */
 249 EXPORT_SYMBOL_GPL(__blkdev_driver_ioctl);
 250
 251 /*
 252  * Is it an unrecognized ioctl? The correct returns are either
 253  * ENOTTY (final) or ENOIOCTLCMD ("I don't know this one, try a
 254  * fallback"). ENOIOCTLCMD gets turned into ENOTTY by the ioctl
 255  * code before returning.
 256  *
 257  * Confused drivers sometimes return EINVAL, which is wrong. It
 258  * means "I understood the ioctl command, but the parameters to
 259  * it were wrong".
 260  *
 261  * We should aim to just fix the broken drivers, the EINVAL case
 262  * should go away.
 263  */
 264 static inline int is_unrecognized_ioctl(int ret)
 265 {
 266         return  ret == -EINVAL ||
 267                 ret == -ENOTTY ||
 268                 ret == -ENOIOCTLCMD;
 269 }
 270
 271 /*
 272  * always keep this in sync with compat_blkdev_ioctl()
 273  */
 274 int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
 275                         unsigned long arg)
 276 {
 277         struct gendisk *disk = bdev->bd_disk;
 278         struct backing_dev_info *bdi;
 279         loff_t size;
 280         int ret, n;
 281         unsigned int max_sectors;
 282
 283         switch(cmd) {
 284         case BLKFLSBUF:
 285                 if (!capable(CAP_SYS_ADMIN))
 286                         return -EACCES;
 287
 288                 ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 289                 if (!is_unrecognized_ioctl(ret))
 290                         return ret;
 291
 292                 fsync_bdev(bdev);
 293                 invalidate_bdev(bdev);
 294                 return 0;
 295
 296         case BLKROSET:
 297                 ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 298                 if (!is_unrecognized_ioctl(ret))
 299                         return ret;
 300                 if (!capable(CAP_SYS_ADMIN))
 301                         return -EACCES;
 302                 if (get_user(n, (int __user *)(arg)))
 303                         return -EFAULT;
 304                 set_device_ro(bdev, n);
 305                 return 0;
 306
 307         case BLKDISCARD:
 308         case BLKSECDISCARD: {
 309                 uint64_t range[2];
 310
 311                 if (!(mode & FMODE_WRITE))
 312                         return -EBADF;
 313
 314                 if (copy_from_user(range, (void __user *)arg, sizeof(range)))
 315                         return -EFAULT;
 316
 317                 return blk_ioctl_discard(bdev, range[0], range[1],
 318                                          cmd == BLKSECDISCARD);
 319         }
 320         case BLKZEROOUT: {
 321                 uint64_t range[2];
 322
 323                 if (!(mode & FMODE_WRITE))
 324                         return -EBADF;
 325
 326                 if (copy_from_user(range, (void __user *)arg, sizeof(range)))
 327                         return -EFAULT;
 328
 329                 return blk_ioctl_zeroout(bdev, range[0], range[1]);
 330         }
 331
 332         case HDIO_GETGEO: {
 333                 struct hd_geometry geo;
 334
 335                 if (!arg)
 336                         return -EINVAL;
 337                 if (!disk->fops->getgeo)
 338                         return -ENOTTY;
 339
 340                 /*
 341                  * We need to set the startsect first, the driver may
 342                  * want to override it.
 343                  */
 344                 memset(&geo, 0, sizeof(geo));
 345                 geo.start = get_start_sect(bdev);
 346                 ret = disk->fops->getgeo(bdev, &geo);
 347                 if (ret)
 348                         return ret;
 349                 if (copy_to_user((struct hd_geometry __user *)arg, &geo,
 350                                         sizeof(geo)))
 351                         return -EFAULT;
 352                 return 0;
 353         }
 354         case BLKRAGET:
 355         case BLKFRAGET:
 356                 if (!arg)
 357                         return -EINVAL;
 358                 bdi = blk_get_backing_dev_info(bdev);
 359                 return put_long(arg, (bdi->ra_pages * PAGE_CACHE_SIZE) / 512);
 360         case BLKROGET:
 361                 return put_int(arg, bdev_read_only(bdev) != 0);
 362         case BLKBSZGET: /* get block device soft block size (cf. BLKSSZGET) */
 363                 return put_int(arg, block_size(bdev));
 364         case BLKSSZGET: /* get block device logical block size */
 365                 return put_int(arg, bdev_logical_block_size(bdev));
 366         case BLKPBSZGET: /* get block device physical block size */
 367                 return put_uint(arg, bdev_physical_block_size(bdev));
 368         case BLKIOMIN:
 369                 return put_uint(arg, bdev_io_min(bdev));
 370         case BLKIOOPT:
 371                 return put_uint(arg, bdev_io_opt(bdev));
 372         case BLKALIGNOFF:
 373                 return put_int(arg, bdev_alignment_offset(bdev));
 374         case BLKDISCARDZEROES:
 375                 return put_uint(arg, bdev_discard_zeroes_data(bdev));
 376         case BLKSECTGET:
 377                 max_sectors = min_t(unsigned int, USHRT_MAX,
 378                                     queue_max_sectors(bdev_get_queue(bdev)));
 379                 return put_ushort(arg, max_sectors);
 380         case BLKROTATIONAL:
 381                 return put_ushort(arg, !blk_queue_nonrot(bdev_get_queue(bdev)));
 382         case BLKRASET:
 383         case BLKFRASET:
 384                 if(!capable(CAP_SYS_ADMIN))
 385                         return -EACCES;
 386                 bdi = blk_get_backing_dev_info(bdev);
 387                 bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE;
 388                 return 0;
 389         case BLKBSZSET:
 390                 /* set the logical block size */
 391                 if (!capable(CAP_SYS_ADMIN))
 392                         return -EACCES;
 393                 if (!arg)
 394                         return -EINVAL;
 395                 if (get_user(n, (int __user *) arg))
 396                         return -EFAULT;
 397                 if (!(mode & FMODE_EXCL)) {
 398                         bdgrab(bdev);
 399                         if (blkdev_get(bdev, mode | FMODE_EXCL, &bdev) < 0)
 400                                 return -EBUSY;
 401                 }
 402                 ret = set_blocksize(bdev, n);
 403                 if (!(mode & FMODE_EXCL))
 404                         blkdev_put(bdev, mode | FMODE_EXCL);
 405                 return ret;
 406         case BLKPG:
 407                 ret = blkpg_ioctl(bdev, (struct blkpg_ioctl_arg __user *) arg);
 408                 break;
 409         case BLKRRPART:
 410                 ret = blkdev_reread_part(bdev);
 411                 break;
 412         case BLKGETSIZE:
 413                 size = i_size_read(bdev->bd_inode);
 414                 if ((size >> 9) > ~0UL)
 415                         return -EFBIG;
 416                 return put_ulong(arg, size >> 9);
 417         case BLKGETSIZE64:
 418                 return put_u64(arg, i_size_read(bdev->bd_inode));
 419         case BLKTRACESTART:
 420         case BLKTRACESTOP:
 421         case BLKTRACESETUP:
 422         case BLKTRACETEARDOWN:
 423                 ret = blk_trace_ioctl(bdev, cmd, (char __user *) arg);
 424                 break;
 425         default:
 426                 ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 427         }
 428         return ret;
 429 }
 430 EXPORT_SYMBOL_GPL(blkdev_ioctl);