| // +build linux |
| |
| package loopback // import "github.com/docker/docker/pkg/loopback" |
| |
| import ( |
| "unsafe" |
| |
| "golang.org/x/sys/unix" |
| ) |
| |
| func ioctlLoopCtlGetFree(fd uintptr) (int, error) { |
| // The ioctl interface for /dev/loop-control (since Linux 3.1) is a bit |
| // off compared to what you'd expect: instead of writing an integer to a |
| // parameter pointer like unix.IoctlGetInt() expects, it returns the first |
| // available loop device index directly. |
| ioctlReturn, _, err := unix.Syscall(unix.SYS_IOCTL, fd, LoopCtlGetFree, 0) |
| if err != 0 { |
| return 0, err |
| } |
| return int(ioctlReturn), nil |
| } |
| |
| func ioctlLoopSetFd(loopFd, sparseFd uintptr) error { |
| return unix.IoctlSetInt(int(loopFd), unix.LOOP_SET_FD, int(sparseFd)) |
| } |
| |
| func ioctlLoopSetStatus64(loopFd uintptr, loopInfo *unix.LoopInfo64) error { |
| if _, _, err := unix.Syscall(unix.SYS_IOCTL, loopFd, unix.LOOP_SET_STATUS64, uintptr(unsafe.Pointer(loopInfo))); err != 0 { |
| return err |
| } |
| return nil |
| } |
| |
| func ioctlLoopClrFd(loopFd uintptr) error { |
| if _, _, err := unix.Syscall(unix.SYS_IOCTL, loopFd, unix.LOOP_CLR_FD, 0); err != 0 { |
| return err |
| } |
| return nil |
| } |
| |
| func ioctlLoopGetStatus64(loopFd uintptr) (*unix.LoopInfo64, error) { |
| loopInfo := &unix.LoopInfo64{} |
| |
| if _, _, err := unix.Syscall(unix.SYS_IOCTL, loopFd, unix.LOOP_GET_STATUS64, uintptr(unsafe.Pointer(loopInfo))); err != 0 { |
| return nil, err |
| } |
| return loopInfo, nil |
| } |
| |
| func ioctlLoopSetCapacity(loopFd uintptr, value int) error { |
| return unix.IoctlSetInt(int(loopFd), unix.LOOP_SET_CAPACITY, value) |
| } |