linux/block/ioctl.c
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   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
  12static 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 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
 153static 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
 169static 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
 188static 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);
 202}
 203
 204static int put_ushort(unsigned long arg, unsigned short val)
 205{
 206        return put_user(val, (unsigned short __user *)arg);
 207}
 208
 209static int put_int(unsigned long arg, int val)
 210{
 211        return put_user(val, (int __user *)arg);
 212}
 213
 214static int put_uint(unsigned long arg, unsigned int val)
 215{
 216        return put_user(val, (unsigned int __user *)arg);
 217}
 218
 219static int put_long(unsigned long arg, long val)
 220{
 221        return put_user(val, (long __user *)arg);
 222}
 223
 224static int put_ulong(unsigned long arg, unsigned long val)
 225{
 226        return put_user(val, (unsigned long __user *)arg);
 227}
 228
 229static int put_u64(unsigned long arg, u64 val)
 230{
 231        return put_user(val, (u64 __user *)arg);
 232}
 233
 234int __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 */
 249EXPORT_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 */
 264static 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 */
 274int 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
 282        switch(cmd) {
 283        case BLKFLSBUF:
 284                if (!capable(CAP_SYS_ADMIN))
 285                        return -EACCES;
 286
 287                ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 288                if (!is_unrecognized_ioctl(ret))
 289                        return ret;
 290
 291                fsync_bdev(bdev);
 292                invalidate_bdev(bdev);
 293                return 0;
 294
 295        case BLKROSET:
 296                ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 297                if (!is_unrecognized_ioctl(ret))
 298                        return ret;
 299                if (!capable(CAP_SYS_ADMIN))
 300                        return -EACCES;
 301                if (get_user(n, (int __user *)(arg)))
 302                        return -EFAULT;
 303                set_device_ro(bdev, n);
 304                return 0;
 305
 306        case BLKDISCARD:
 307        case BLKSECDISCARD: {
 308                uint64_t range[2];
 309
 310                if (!(mode & FMODE_WRITE))
 311                        return -EBADF;
 312
 313                if (copy_from_user(range, (void __user *)arg, sizeof(range)))
 314                        return -EFAULT;
 315
 316                return blk_ioctl_discard(bdev, range[0], range[1],
 317                                         cmd == BLKSECDISCARD);
 318        }
 319        case BLKZEROOUT: {
 320                uint64_t range[2];
 321
 322                if (!(mode & FMODE_WRITE))
 323                        return -EBADF;
 324
 325                if (copy_from_user(range, (void __user *)arg, sizeof(range)))
 326                        return -EFAULT;
 327
 328                return blk_ioctl_zeroout(bdev, range[0], range[1]);
 329        }
 330
 331        case HDIO_GETGEO: {
 332                struct hd_geometry geo;
 333
 334                if (!arg)
 335                        return -EINVAL;
 336                if (!disk->fops->getgeo)
 337                        return -ENOTTY;
 338
 339                /*
 340                 * We need to set the startsect first, the driver may
 341                 * want to override it.
 342                 */
 343                memset(&geo, 0, sizeof(geo));
 344                geo.start = get_start_sect(bdev);
 345                ret = disk->fops->getgeo(bdev, &geo);
 346                if (ret)
 347                        return ret;
 348                if (copy_to_user((struct hd_geometry __user *)arg, &geo,
 349                                        sizeof(geo)))
 350                        return -EFAULT;
 351                return 0;
 352        }
 353        case BLKRAGET:
 354        case BLKFRAGET:
 355                if (!arg)
 356                        return -EINVAL;
 357                bdi = blk_get_backing_dev_info(bdev);
 358                if (bdi == NULL)
 359                        return -ENOTTY;
 360                return put_long(arg, (bdi->ra_pages * PAGE_CACHE_SIZE) / 512);
 361        case BLKROGET:
 362                return put_int(arg, bdev_read_only(bdev) != 0);
 363        case BLKBSZGET: /* get block device soft block size (cf. BLKSSZGET) */
 364                return put_int(arg, block_size(bdev));
 365        case BLKSSZGET: /* get block device logical block size */
 366                return put_int(arg, bdev_logical_block_size(bdev));
 367        case BLKPBSZGET: /* get block device physical block size */
 368                return put_uint(arg, bdev_physical_block_size(bdev));
 369        case BLKIOMIN:
 370                return put_uint(arg, bdev_io_min(bdev));
 371        case BLKIOOPT:
 372                return put_uint(arg, bdev_io_opt(bdev));
 373        case BLKALIGNOFF:
 374                return put_int(arg, bdev_alignment_offset(bdev));
 375        case BLKDISCARDZEROES:
 376                return put_uint(arg, bdev_discard_zeroes_data(bdev));
 377        case BLKSECTGET:
 378                return put_ushort(arg, queue_max_sectors(bdev_get_queue(bdev)));
 379        case BLKROTATIONAL:
 380                return put_ushort(arg, !blk_queue_nonrot(bdev_get_queue(bdev)));
 381        case BLKRASET:
 382        case BLKFRASET:
 383                if(!capable(CAP_SYS_ADMIN))
 384                        return -EACCES;
 385                bdi = blk_get_backing_dev_info(bdev);
 386                if (bdi == NULL)
 387                        return -ENOTTY;
 388                bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE;
 389                return 0;
 390        case BLKBSZSET:
 391                /* set the logical block size */
 392                if (!capable(CAP_SYS_ADMIN))
 393                        return -EACCES;
 394                if (!arg)
 395                        return -EINVAL;
 396                if (get_user(n, (int __user *) arg))
 397                        return -EFAULT;
 398                if (!(mode & FMODE_EXCL)) {
 399                        bdgrab(bdev);
 400                        if (blkdev_get(bdev, mode | FMODE_EXCL, &bdev) < 0)
 401                                return -EBUSY;
 402                }
 403                ret = set_blocksize(bdev, n);
 404                if (!(mode & FMODE_EXCL))
 405                        blkdev_put(bdev, mode | FMODE_EXCL);
 406                return ret;
 407        case BLKPG:
 408                ret = blkpg_ioctl(bdev, (struct blkpg_ioctl_arg __user *) arg);
 409                break;
 410        case BLKRRPART:
 411                ret = blkdev_reread_part(bdev);
 412                break;
 413        case BLKGETSIZE:
 414                size = i_size_read(bdev->bd_inode);
 415                if ((size >> 9) > ~0UL)
 416                        return -EFBIG;
 417                return put_ulong(arg, size >> 9);
 418        case BLKGETSIZE64:
 419                return put_u64(arg, i_size_read(bdev->bd_inode));
 420        case BLKTRACESTART:
 421        case BLKTRACESTOP:
 422        case BLKTRACESETUP:
 423        case BLKTRACETEARDOWN:
 424                ret = blk_trace_ioctl(bdev, cmd, (char __user *) arg);
 425                break;
 426        default:
 427                ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 428        }
 429        return ret;
 430}
 431EXPORT_SYMBOL_GPL(blkdev_ioctl);
 432
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