| Don Newton | 98fd881 | 2019-09-23 15:15:02 -0400 | [diff] [blame] | 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 | } |