From a5054c7c1385fd50d9394475365355a87a7873ec Mon Sep 17 00:00:00 2001 From: Tobias Klauser Date: Tue, 5 Sep 2017 16:23:55 +0200 Subject: [PATCH] unix: add Major, Minor and Mkdev functions on FreeBSD Add Major, Minor and Mkdev functions for converting devices numbers to their major/minor components and vice versa. The functions follow the behavior of the macros defined in FreeBSD's sys/types.h header. However, the parameter and return types are changed to match the existing implementations of these functions. Because FreeBSD dynamically allocates major/minor device numbers through devfs at runtime, testing the conversion macros against well-known device numbers is not possible. Updates golang/go#8106 Change-Id: I9874e63f388cfc5c0d5cc47d4d0f6ccc489b28f2 Reviewed-on: https://go-review.googlesource.com/61631 Reviewed-by: Ian Lance Taylor Run-TryBot: Ian Lance Taylor TryBot-Result: Gobot Gobot --- unix/dev_freebsd.go | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) create mode 100644 unix/dev_freebsd.go diff --git a/unix/dev_freebsd.go b/unix/dev_freebsd.go new file mode 100644 index 00000000..f793efda --- /dev/null +++ b/unix/dev_freebsd.go @@ -0,0 +1,30 @@ +// Copyright 2017 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// Functions to access/create device major and minor numbers matching the +// encoding used in FreeBSD's sys/types.h header. +// +// The information below is extracted and adapted from sys/types.h: +// +// Minor gives a cookie instead of an index since in order to avoid changing the +// meanings of bits 0-15 or wasting time and space shifting bits 16-31 for +// devices that don't use them. + +package unix + +// Major returns the major component of a FreeBSD device number. +func Major(dev uint64) uint32 { + return uint32((dev >> 8) & 0xff) +} + +// Minor returns the minor component of a FreeBSD device number. +func Minor(dev uint64) uint32 { + return uint32(dev & 0xffff00ff) +} + +// Mkdev returns a FreeBSD device number generated from the given major and +// minor components. +func Mkdev(major, minor uint32) uint64 { + return uint64((major << 8) | minor) +}