// Copyright (c) 2021 Gitpod GmbH. All rights reserved.
// Licensed under the GNU Affero General Public License (AGPL).
// See License.AGPL.txt in the project root for license information.

package iws

import (
	"unsafe"

	"golang.org/x/sys/unix"
)

func syscallOpenTree(dfd int, path string, flags uintptr) (fd uintptr, err error) {
	p1, err := unix.BytePtrFromString(path)
	if err != nil {
		return 0, err
	}
	fd, _, errno := unix.Syscall(unix.SYS_OPEN_TREE, uintptr(dfd), uintptr(unsafe.Pointer(p1)), flags)
	if errno != 0 {
		return 0, errno
	}

	return fd, nil
}

const (
	// FlagOpenTreeClone: https://elixir.bootlin.com/linux/latest/source/include/uapi/linux/mount.h#L62
	flagOpenTreeClone = 1
	// FlagAtRecursive: Apply to the entire subtree: https://elixir.bootlin.com/linux/latest/source/include/uapi/linux/fcntl.h#L112
	flagAtRecursive = 0x8000
)