tools/kvm/disk/raw.c

   1 #include "kvm/disk-image.h"
   2
   3 ssize_t raw_image__read_sector_iov(struct disk_image *disk, u64 sector, const struct iovec *iov, int iovcount)
   4 {
   5         u64 offset = sector << SECTOR_SHIFT;
   6
   7         return preadv_in_full(disk->fd, iov, iovcount, offset);
   8 }
   9
  10 ssize_t raw_image__write_sector_iov(struct disk_image *disk, u64 sector, const struct iovec *iov, int iovcount)
  11 {
  12         u64 offset = sector << SECTOR_SHIFT;
  13
  14         return pwritev_in_full(disk->fd, iov, iovcount, offset);
  15 }
  16
  17 ssize_t raw_image__read_sector(struct disk_image *disk, u64 sector, void *dst, u32 dst_len)
  18 {
  19         u64 offset = sector << SECTOR_SHIFT;
  20
  21         if (offset + dst_len > disk->size)
  22                 return -1;
  23
  24         memcpy(dst, disk->priv + offset, dst_len);
  25
  26         return dst_len;
  27 }
  28
  29 ssize_t raw_image__write_sector(struct disk_image *disk, u64 sector, void *src, u32 src_len)
  30 {
  31         u64 offset = sector << SECTOR_SHIFT;
  32
  33         if (offset + src_len > disk->size)
  34                 return -1;
  35
  36         memcpy(disk->priv + offset, src, src_len);
  37
  38         return src_len;
  39 }
  40
  41 int raw_image__close(struct disk_image *disk)
  42 {
  43         int ret = 0;
  44
  45         if (disk->priv != MAP_FAILED)
  46                 ret = munmap(disk->priv, disk->size);
  47
  48         return ret;
  49 }
  50
  51 /*
  52  * multiple buffer based disk image operations
  53  */
  54 static struct disk_image_operations raw_image_iov_ops = {
  55         .read_sector_iov        = raw_image__read_sector_iov,
  56         .write_sector_iov       = raw_image__write_sector_iov,
  57 };
  58
  59 /*
  60  * single buffer based disk image operations
  61  */
  62 static struct disk_image_operations raw_image_ops = {
  63         .read_sector            = raw_image__read_sector,
  64         .write_sector           = raw_image__write_sector,
  65         .close                  = raw_image__close,
  66 };
  67
  68 struct disk_image *raw_image__probe(int fd, struct stat *st, bool readonly)
  69 {
  70
  71         if (readonly)
  72                 /*
  73                  * Use mmap's MAP_PRIVATE to implement non-persistent write
  74                  * FIXME: This does not work on 32-bit host.
  75                  */
  76                 return disk_image__new(fd, st->st_size, &raw_image_ops, DISK_IMAGE_MMAP);
  77         else
  78                 /*
  79                  * Use read/write instead of mmap
  80                  */
  81                 return disk_image__new(fd, st->st_size, &raw_image_iov_ops, DISK_IMAGE_NOMMAP);
  82 }