1 #ifndef KVM__DISK_IMAGE_H 2 #define KVM__DISK_IMAGE_H 3 4 #include <linux/types.h> 5 #include <stdbool.h> 6 #include <sys/uio.h> 7 #include <unistd.h> 8 9 #define SECTOR_SHIFT 9 10 #define SECTOR_SIZE (1UL << SECTOR_SHIFT) 11 12 struct disk_image; 13 14 struct disk_image_operations { 15 int (*read_sector)(struct disk_image *disk, u64 sector, void *dst, u32 dst_len); 16 int (*write_sector)(struct disk_image *disk, u64 sector, void *src, u32 src_len); 17 ssize_t (*read_sector_iov)(struct disk_image *disk, u64 sector, const struct iovec *iov, int iovcount); 18 ssize_t (*write_sector_iov)(struct disk_image *disk, u64 sector, const struct iovec *iov, int iovcount); 19 int (*flush)(struct disk_image *disk); 20 void (*close)(struct disk_image *disk); 21 }; 22 23 struct disk_image { 24 int fd; 25 u64 size; 26 struct disk_image_operations *ops; 27 void *priv; 28 }; 29 30 struct disk_image *disk_image__open(const char *filename, bool readonly); 31 struct disk_image *disk_image__new(int fd, u64 size, struct disk_image_operations *ops); 32 struct disk_image *disk_image__new_readonly(int fd, u64 size, struct disk_image_operations *ops); 33 void disk_image__close(struct disk_image *disk); 34 35 static inline int disk_image__read_sector(struct disk_image *disk, u64 sector, void *dst, u32 dst_len) 36 { 37 return disk->ops->read_sector(disk, sector, dst, dst_len); 38 } 39 40 static inline int disk_image__write_sector(struct disk_image *disk, u64 sector, void *src, u32 src_len) 41 { 42 return disk->ops->write_sector(disk, sector, src, src_len); 43 } 44 45 static inline ssize_t disk_image__read_sector_iov(struct disk_image *disk, u64 sector, const struct iovec *iov, int iovcount) 46 { 47 if (disk->ops->read_sector_iov) 48 return disk->ops->read_sector_iov(disk, sector, iov, iovcount); 49 50 while (iovcount--) { 51 if (disk->ops->read_sector(disk, sector, iov->iov_base, iov->iov_len) < 0) 52 return -1; 53 54 sector += iov->iov_len >> SECTOR_SHIFT; 55 iov++; 56 } 57 58 return sector << SECTOR_SHIFT; 59 } 60 61 static inline ssize_t disk_image__write_sector_iov(struct disk_image *disk, u64 sector, const struct iovec *iov, int iovcount) 62 { 63 if (disk->ops->write_sector_iov) 64 return disk->ops->write_sector_iov(disk, sector, iov, iovcount); 65 66 while (iovcount--) { 67 if (disk->ops->write_sector(disk, sector, iov->iov_base, iov->iov_len) < 0) 68 return -1; 69 70 sector += iov->iov_len >> SECTOR_SHIFT; 71 iov++; 72 } 73 74 return sector << SECTOR_SHIFT; 75 } 76 77 static inline int disk_image__flush(struct disk_image *disk) 78 { 79 if (disk->ops->flush) 80 return disk->ops->flush(disk); 81 return fsync(disk->fd); 82 } 83 84 #endif /* KVM__DISK_IMAGE_H */ 85