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
5package base
6
7import (
8	"cmd/go/internal/cfg"
9	"fmt"
10	"os"
11	"path/filepath"
12	"runtime"
13)
14
15// AppendPWD returns the result of appending PWD=dir to the environment base.
16//
17// The resulting environment makes os.Getwd more efficient for a subprocess
18// running in dir, and also improves the accuracy of paths relative to dir
19// if one or more elements of dir is a symlink.
20func AppendPWD(base []string, dir string) []string {
21	// POSIX requires PWD to be absolute.
22	// Internally we only use absolute paths, so dir should already be absolute.
23	if !filepath.IsAbs(dir) {
24		panic(fmt.Sprintf("AppendPWD with relative path %q", dir))
25	}
26	return append(base, "PWD="+dir)
27}
28
29// AppendPATH returns the result of appending PATH=$GOROOT/bin:$PATH
30// (or the platform equivalent) to the environment base.
31func AppendPATH(base []string) []string {
32	if cfg.GOROOTbin == "" {
33		return base
34	}
35
36	pathVar := "PATH"
37	if runtime.GOOS == "plan9" {
38		pathVar = "path"
39	}
40
41	path := os.Getenv(pathVar)
42	if path == "" {
43		return append(base, pathVar+"="+cfg.GOROOTbin)
44	}
45	return append(base, pathVar+"="+cfg.GOROOTbin+string(os.PathListSeparator)+path)
46}
47