1 files changed, 46 insertions, 0 deletions
diff --git a/src/cmd/go/internal/base/env.go b/src/cmd/go/internal/base/env.go
new file mode 100644
index 0000000..20ae06d
--- /dev/null
+++ b/src/cmd/go/internal/base/env.go
@@ -0,0 +1,46 @@
+// 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.
+
+package base
+
+import (
+	"cmd/go/internal/cfg"
+	"fmt"
+	"os"
+	"path/filepath"
+	"runtime"
+)
+
+// AppendPWD returns the result of appending PWD=dir to the environment base.
+//
+// The resulting environment makes os.Getwd more efficient for a subprocess
+// running in dir, and also improves the accuracy of paths relative to dir
+// if one or more elements of dir is a symlink.
+func AppendPWD(base []string, dir string) []string {
+	// POSIX requires PWD to be absolute.
+	// Internally we only use absolute paths, so dir should already be absolute.
+	if !filepath.IsAbs(dir) {
+		panic(fmt.Sprintf("AppendPWD with relative path %q", dir))
+	}
+	return append(base, "PWD="+dir)
+}
+
+// AppendPATH returns the result of appending PATH=$GOROOT/bin:$PATH
+// (or the platform equivalent) to the environment base.
+func AppendPATH(base []string) []string {
+	if cfg.GOROOTbin == "" {
+		return base
+	}
+
+	pathVar := "PATH"
+	if runtime.GOOS == "plan9" {
+		pathVar = "path"
+	}
+
+	path := os.Getenv(pathVar)
+	if path == "" {
+		return append(base, pathVar+"="+cfg.GOROOTbin)
+	}
+	return append(base, pathVar+"="+cfg.GOROOTbin+string(os.PathListSeparator)+path)
+}