tile38/vendor/golang.org/x/sys/unix/dev_linux.go
tidwall cfc65a13f6 Refactor repository and build scripts
This commit includes updates that affects the build, testing, and
deployment of Tile38.

- The root level build.sh has been broken up into multiple scripts
  and placed in the "scripts" directory.

- The vendor directory has been updated to follow the Go modules
  rules, thus `make` should work on isolated environments. Also
  some vendored packages may have been updated to a later
  version, if needed.

- The Makefile has been updated to allow for making single
  binaries such as `make tile38-server`. There is some scaffolding
  during the build process, so from now on all binaries should be
  made using make. For example, to run a development version of
  the tile38-cli binary, do this:
     make tile38-cli && ./tile38-cli
  not this:
     go run cmd/tile38-cli/main.go

- Travis.CI docker push script has been updated to address a
  change to Docker's JSON repo meta output, which in turn fixes
  a bug where new Tile38 versions were not being properly pushed
  to Docker
2019-11-18 10:33:15 -07:00

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1.5 KiB
Go

// 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 by the Linux kernel and glibc.
//
// The information below is extracted and adapted from bits/sysmacros.h in the
// glibc sources:
//
// dev_t in glibc is 64-bit, with 32-bit major and minor numbers. glibc's
// default encoding is MMMM Mmmm mmmM MMmm, where M is a hex digit of the major
// number and m is a hex digit of the minor number. This is backward compatible
// with legacy systems where dev_t is 16 bits wide, encoded as MMmm. It is also
// backward compatible with the Linux kernel, which for some architectures uses
// 32-bit dev_t, encoded as mmmM MMmm.
package unix
// Major returns the major component of a Linux device number.
func Major(dev uint64) uint32 {
major := uint32((dev & 0x00000000000fff00) >> 8)
major |= uint32((dev & 0xfffff00000000000) >> 32)
return major
}
// Minor returns the minor component of a Linux device number.
func Minor(dev uint64) uint32 {
minor := uint32((dev & 0x00000000000000ff) >> 0)
minor |= uint32((dev & 0x00000ffffff00000) >> 12)
return minor
}
// Mkdev returns a Linux device number generated from the given major and minor
// components.
func Mkdev(major, minor uint32) uint64 {
dev := (uint64(major) & 0x00000fff) << 8
dev |= (uint64(major) & 0xfffff000) << 32
dev |= (uint64(minor) & 0x000000ff) << 0
dev |= (uint64(minor) & 0xffffff00) << 12
return dev
}