1 // Copyright 2017 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 // Functions to access/create device major and minor numbers matching the 6 // encoding used in OpenBSD's sys/types.h header. 7 8 package unix 9 10 // Major returns the major component of an OpenBSD device number. 11 func Major(dev uint64) uint32 { 12 return uint32((dev & 0x0000ff00) >> 8) 13 } 14 15 // Minor returns the minor component of an OpenBSD device number. 16 func Minor(dev uint64) uint32 { 17 minor := uint32((dev & 0x000000ff) >> 0) 18 minor |= uint32((dev & 0xffff0000) >> 8) 19 return minor 20 } 21 22 // Mkdev returns an OpenBSD device number generated from the given major and minor 23 // components. 24 func Mkdev(major, minor uint32) uint64 { 25 dev := (uint64(major) << 8) & 0x0000ff00 26 dev |= (uint64(minor) << 8) & 0xffff0000 27 dev |= (uint64(minor) << 0) & 0x000000ff 28 return dev 29 } 30