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;
  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                default:
  96                        return -EINVAL;
  97        }
  98}
  99
 100static int blkdev_reread_part(struct block_device *bdev)
 101{
 102        struct gendisk *disk = bdev->bd_disk;
 103        int res;
 104
 105        if (!disk_part_scan_enabled(disk) || bdev != bdev->bd_contains)
 106                return -EINVAL;
 107        if (!capable(CAP_SYS_ADMIN))
 108                return -EACCES;
 109        if (!mutex_trylock(&bdev->bd_mutex))
 110                return -EBUSY;
 111        res = rescan_partitions(disk, bdev);
 112        mutex_unlock(&bdev->bd_mutex);
 113        return res;
 114}
 115
 116static int blk_ioctl_discard(struct block_device *bdev, uint64_t start,
 117                             uint64_t len, int secure)
 118{
 119        unsigned long flags = 0;
 120
 121        if (start & 511)
 122                return -EINVAL;
 123        if (len & 511)
 124                return -EINVAL;
 125        start >>= 9;
 126        len >>= 9;
 127
 128        if (start + len > (i_size_read(bdev->bd_inode) >> 9))
 129                return -EINVAL;
 130        if (secure)
 131                flags |= BLKDEV_DISCARD_SECURE;
 132        return blkdev_issue_discard(bdev, start, len, GFP_KERNEL, flags);
 133}
 134
 135static int put_ushort(unsigned long arg, unsigned short val)
 136{
 137        return put_user(val, (unsigned short __user *)arg);
 138}
 139
 140static int put_int(unsigned long arg, int val)
 141{
 142        return put_user(val, (int __user *)arg);
 143}
 144
 145static int put_uint(unsigned long arg, unsigned int val)
 146{
 147        return put_user(val, (unsigned int __user *)arg);
 148}
 149
 150static int put_long(unsigned long arg, long val)
 151{
 152        return put_user(val, (long __user *)arg);
 153}
 154
 155static int put_ulong(unsigned long arg, unsigned long val)
 156{
 157        return put_user(val, (unsigned long __user *)arg);
 158}
 159
 160static int put_u64(unsigned long arg, u64 val)
 161{
 162        return put_user(val, (u64 __user *)arg);
 163}
 164
 165int __blkdev_driver_ioctl(struct block_device *bdev, fmode_t mode,
 166                        unsigned cmd, unsigned long arg)
 167{
 168        struct gendisk *disk = bdev->bd_disk;
 169
 170        if (disk->fops->ioctl)
 171                return disk->fops->ioctl(bdev, mode, cmd, arg);
 172
 173        return -ENOTTY;
 174}
 175/*
 176 * For the record: _GPL here is only because somebody decided to slap it
 177 * on the previous export.  Sheer idiocy, since it wasn't copyrightable
 178 * at all and could be open-coded without any exports by anybody who cares.
 179 */
 180EXPORT_SYMBOL_GPL(__blkdev_driver_ioctl);
 181
 182/*
 183 * Is it an unrecognized ioctl? The correct returns are either
 184 * ENOTTY (final) or ENOIOCTLCMD ("I don't know this one, try a
 185 * fallback"). ENOIOCTLCMD gets turned into ENOTTY by the ioctl
 186 * code before returning.
 187 *
 188 * Confused drivers sometimes return EINVAL, which is wrong. It
 189 * means "I understood the ioctl command, but the parameters to
 190 * it were wrong".
 191 *
 192 * We should aim to just fix the broken drivers, the EINVAL case
 193 * should go away.
 194 */
 195static inline int is_unrecognized_ioctl(int ret)
 196{
 197        return  ret == -EINVAL ||
 198                ret == -ENOTTY ||
 199                ret == -ENOIOCTLCMD;
 200}
 201
 202/*
 203 * always keep this in sync with compat_blkdev_ioctl()
 204 */
 205int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
 206                        unsigned long arg)
 207{
 208        struct gendisk *disk = bdev->bd_disk;
 209        struct backing_dev_info *bdi;
 210        loff_t size;
 211        int ret, n;
 212
 213        switch(cmd) {
 214        case BLKFLSBUF:
 215                if (!capable(CAP_SYS_ADMIN))
 216                        return -EACCES;
 217
 218                ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 219                if (!is_unrecognized_ioctl(ret))
 220                        return ret;
 221
 222                fsync_bdev(bdev);
 223                invalidate_bdev(bdev);
 224                return 0;
 225
 226        case BLKROSET:
 227                ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 228                if (!is_unrecognized_ioctl(ret))
 229                        return ret;
 230                if (!capable(CAP_SYS_ADMIN))
 231                        return -EACCES;
 232                if (get_user(n, (int __user *)(arg)))
 233                        return -EFAULT;
 234                set_device_ro(bdev, n);
 235                return 0;
 236
 237        case BLKDISCARD:
 238        case BLKSECDISCARD: {
 239                uint64_t range[2];
 240
 241                if (!(mode & FMODE_WRITE))
 242                        return -EBADF;
 243
 244                if (copy_from_user(range, (void __user *)arg, sizeof(range)))
 245                        return -EFAULT;
 246
 247                return blk_ioctl_discard(bdev, range[0], range[1],
 248                                         cmd == BLKSECDISCARD);
 249        }
 250
 251        case HDIO_GETGEO: {
 252                struct hd_geometry geo;
 253
 254                if (!arg)
 255                        return -EINVAL;
 256                if (!disk->fops->getgeo)
 257                        return -ENOTTY;
 258
 259                /*
 260                 * We need to set the startsect first, the driver may
 261                 * want to override it.
 262                 */
 263                memset(&geo, 0, sizeof(geo));
 264                geo.start = get_start_sect(bdev);
 265                ret = disk->fops->getgeo(bdev, &geo);
 266                if (ret)
 267                        return ret;
 268                if (copy_to_user((struct hd_geometry __user *)arg, &geo,
 269                                        sizeof(geo)))
 270                        return -EFAULT;
 271                return 0;
 272        }
 273        case BLKRAGET:
 274        case BLKFRAGET:
 275                if (!arg)
 276                        return -EINVAL;
 277                bdi = blk_get_backing_dev_info(bdev);
 278                if (bdi == NULL)
 279                        return -ENOTTY;
 280                return put_long(arg, (bdi->ra_pages * PAGE_CACHE_SIZE) / 512);
 281        case BLKROGET:
 282                return put_int(arg, bdev_read_only(bdev) != 0);
 283        case BLKBSZGET: /* get block device soft block size (cf. BLKSSZGET) */
 284                return put_int(arg, block_size(bdev));
 285        case BLKSSZGET: /* get block device logical block size */
 286                return put_int(arg, bdev_logical_block_size(bdev));
 287        case BLKPBSZGET: /* get block device physical block size */
 288                return put_uint(arg, bdev_physical_block_size(bdev));
 289        case BLKIOMIN:
 290                return put_uint(arg, bdev_io_min(bdev));
 291        case BLKIOOPT:
 292                return put_uint(arg, bdev_io_opt(bdev));
 293        case BLKALIGNOFF:
 294                return put_int(arg, bdev_alignment_offset(bdev));
 295        case BLKDISCARDZEROES:
 296                return put_uint(arg, bdev_discard_zeroes_data(bdev));
 297        case BLKSECTGET:
 298                return put_ushort(arg, queue_max_sectors(bdev_get_queue(bdev)));
 299        case BLKROTATIONAL:
 300                return put_ushort(arg, !blk_queue_nonrot(bdev_get_queue(bdev)));
 301        case BLKRASET:
 302        case BLKFRASET:
 303                if(!capable(CAP_SYS_ADMIN))
 304                        return -EACCES;
 305                bdi = blk_get_backing_dev_info(bdev);
 306                if (bdi == NULL)
 307                        return -ENOTTY;
 308                bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE;
 309                return 0;
 310        case BLKBSZSET:
 311                /* set the logical block size */
 312                if (!capable(CAP_SYS_ADMIN))
 313                        return -EACCES;
 314                if (!arg)
 315                        return -EINVAL;
 316                if (get_user(n, (int __user *) arg))
 317                        return -EFAULT;
 318                if (!(mode & FMODE_EXCL)) {
 319                        bdgrab(bdev);
 320                        if (blkdev_get(bdev, mode | FMODE_EXCL, &bdev) < 0)
 321                                return -EBUSY;
 322                }
 323                ret = set_blocksize(bdev, n);
 324                if (!(mode & FMODE_EXCL))
 325                        blkdev_put(bdev, mode | FMODE_EXCL);
 326                return ret;
 327        case BLKPG:
 328                ret = blkpg_ioctl(bdev, (struct blkpg_ioctl_arg __user *) arg);
 329                break;
 330        case BLKRRPART:
 331                ret = blkdev_reread_part(bdev);
 332                break;
 333        case BLKGETSIZE:
 334                size = i_size_read(bdev->bd_inode);
 335                if ((size >> 9) > ~0UL)
 336                        return -EFBIG;
 337                return put_ulong(arg, size >> 9);
 338        case BLKGETSIZE64:
 339                return put_u64(arg, i_size_read(bdev->bd_inode));
 340        case BLKTRACESTART:
 341        case BLKTRACESTOP:
 342        case BLKTRACESETUP:
 343        case BLKTRACETEARDOWN:
 344                ret = blk_trace_ioctl(bdev, cmd, (char __user *) arg);
 345                break;
 346        default:
 347                ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 348        }
 349        return ret;
 350}
 351EXPORT_SYMBOL_GPL(blkdev_ioctl);
 352
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