// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
// SPDX-License-Identifier: MIT

//go:build darwin

package nfsfs

import "syscall"

// mknod creates a device node. It needs the superuser on darwin, and a
// failure of permission is reported as such rather than as an io error.
// The kind is picked before the single call: a second mknod over an
// existing node fails EEXIST and leaves the wrong kind behind.
func mknod(path string, spec CreateSpec, perm uint32) error {
	dev := makedev(spec.Major, spec.Minor)
	kind := uint32(syscall.S_IFCHR)
	if spec.Kind == KindBlk {
		kind = syscall.S_IFBLK
	}
	return syscall.Mknod(path, perm|kind, int(dev))
}

// makedev assembles a device number the way the kernel expects it: the
// encoding of makedev in bsd/sys/types.h of xnu, where the major number
// sits at bits twenty-four through thirty-one and the minor number keeps
// bits zero through twenty-three.
func makedev(major, minor uint32) uint64 {
	return uint64(major&0xff)<<24 | uint64(minor&0xffffff)
}