tools/kvm/disk/blk.c

   1 #include "kvm/disk-image.h"
   2
   3 /*
   4  * raw image and blk dev are similar, so reuse raw image ops.
   5  */
   6 static struct disk_image_operations blk_dev_ops = {
   7         .read_sector            = raw_image__read_sector,
   8         .write_sector           = raw_image__write_sector,
   9         .close                  = raw_image__close,
  10 };
  11
  12 struct disk_image *blkdev__probe(const char *filename, struct stat *st)
  13 {
  14         u64 size;
  15         int fd;
  16
  17         if (!S_ISBLK(st->st_mode))
  18                 return NULL;
  19
  20         /*
  21          * Be careful! We are opening host block device!
  22          * Open it readonly since we do not want to break user's data on disk.
  23          */
  24         fd                      = open(filename, O_RDONLY);
  25         if (fd < 0)
  26                 return NULL;
  27
  28         if (ioctl(fd, BLKGETSIZE64, &size) < 0) {
  29                 close(fd);
  30                 return NULL;
  31         }
  32
  33         /*
  34          * FIXME: This will not work on 32-bit host because we can not
  35          * mmap large disk. There is not enough virtual address space
  36          * in 32-bit host. However, this works on 64-bit host.
  37          */
  38         return disk_image__new(fd, size, &blk_dev_ops, DISK_IMAGE_MMAP);
  39 }