go-ceph/rbd/snapshot_nautilus.go

// +build !luminous,!mimic
//
// Ceph Nautilus introduced rbd_get_parent() and deprecated rbd_get_parent_info().
// Ceph Nautilus introduced rbd_list_children3() and deprecated rbd_list_children().

package rbd

// #cgo LDFLAGS: -lrbd
// #include <rbd/librbd.h>
// #include <errno.h>
import "C"

import (
	"fmt"
	"unsafe"
)

// GetParentInfo looks for the parent of the image and stores the pool, name
// and snapshot-name in the byte-arrays that are passed as arguments.
//
// Implements:
//   int rbd_get_parent(rbd_image_t image,
//                      rbd_linked_image_spec_t *parent_image,
//                      rbd_snap_spec_t *parent_snap)
func (image *Image) GetParentInfo(pool, name, snapname []byte) error {
	if err := image.validate(imageIsOpen); err != nil {
		return err
	}

	parentImage := C.rbd_linked_image_spec_t{}
	parentSnap := C.rbd_snap_spec_t{}
	ret := C.rbd_get_parent(image.image, &parentImage, &parentSnap)
	if ret != 0 {
		return RBDError(ret)
	}

	defer C.rbd_linked_image_spec_cleanup(&parentImage)
	defer C.rbd_snap_spec_cleanup(&parentSnap)

	strlen := int(C.strlen(parentImage.pool_name))
	if len(pool) < strlen {
		return RBDError(C.ERANGE)
	}
	if copy(pool, C.GoString(parentImage.pool_name)) != strlen {
		return RBDError(C.ERANGE)
	}

	strlen = int(C.strlen(parentImage.image_name))
	if len(name) < strlen {
		return RBDError(C.ERANGE)
	}
	if copy(name, C.GoString(parentImage.image_name)) != strlen {
		return RBDError(C.ERANGE)
	}

	strlen = int(C.strlen(parentSnap.name))
	if len(snapname) < strlen {
		return RBDError(C.ERANGE)
	}
	if copy(snapname, C.GoString(parentSnap.name)) != strlen {
		return RBDError(C.ERANGE)
	}

	return nil
}

// ListChildren returns arrays with the pools and names of the images that are
// children of the given image. The index of the pools and images arrays can be
// used to link the two items together.
//
// Implements:
//   int rbd_list_children3(rbd_image_t image, rbd_linked_image_spec_t *images,
//                          size_t *max_images);
func (image *Image) ListChildren() (pools []string, images []string, err error) {
	if err := image.validate(imageIsOpen); err != nil {
		return nil, nil, err
	}

	size := C.size_t(0)
	ret := C.rbd_list_children3(image.image, nil, &size)
	if ret < 0 && ret != -C.ERANGE {
		return nil, nil, RBDError(ret)
	} else if ret > 0 {
		return nil, nil, fmt.Errorf("rbd_list_children3() returned %d, expected 0", ret)
	} else if ret == 0 && size == 0 {
		return nil, nil, nil
	}

	// expected: ret == -ERANGE, size contains number of image names
	children := make([]C.rbd_linked_image_spec_t, size)
	ret = C.rbd_list_children3(image.image, (*C.rbd_linked_image_spec_t)(unsafe.Pointer(&children[0])), &size)
	if ret < 0 {
		return nil, nil, RBDError(ret)
	}
	defer C.rbd_linked_image_spec_list_cleanup((*C.rbd_linked_image_spec_t)(unsafe.Pointer(&children[0])), size)

	pools = make([]string, size)
	images = make([]string, size)
	for i, child := range children {
		pools[i] = C.GoString(child.pool_name)
		images[i] = C.GoString(child.image_name)
	}
	return pools, images, nil
}