1 files changed, 53 insertions, 0 deletions
diff --git a/libgo/go/cmd/go/internal/base/tool.go b/libgo/go/cmd/go/internal/base/tool.go
new file mode 100644
index 00000000000..c907772c00a
--- /dev/null
+++ b/libgo/go/cmd/go/internal/base/tool.go
@@ -0,0 +1,53 @@
+// 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 (
+	"fmt"
+	"go/build"
+	"os"
+	"path/filepath"
+	"runtime"
+
+	"cmd/go/internal/cfg"
+)
+
+// Configuration for finding tool binaries.
+var (
+	ToolGOOS      = runtime.GOOS
+	ToolGOARCH    = runtime.GOARCH
+	ToolIsWindows = ToolGOOS == "windows"
+	ToolDir       = build.ToolDir
+)
+
+const ToolWindowsExtension = ".exe"
+
+// Tool returns the path to the named tool (for example, "vet").
+// If the tool cannot be found, Tool exits the process.
+func Tool(toolName string) string {
+	toolPath := filepath.Join(ToolDir, toolName)
+	if ToolIsWindows {
+		toolPath += ToolWindowsExtension
+	}
+	if len(cfg.BuildToolexec) > 0 {
+		return toolPath
+	}
+	// Give a nice message if there is no tool with that name.
+	if _, err := os.Stat(toolPath); err != nil {
+		if isInGoToolsRepo(toolName) {
+			fmt.Fprintf(os.Stderr, "go tool: no such tool %q; to install:\n\tgo get golang.org/x/tools/cmd/%s\n", toolName, toolName)
+		} else {
+			fmt.Fprintf(os.Stderr, "go tool: no such tool %q\n", toolName)
+		}
+		SetExitStatus(2)
+		Exit()
+	}
+	return toolPath
+}
+
+// TODO: Delete.
+func isInGoToolsRepo(toolName string) bool {
+	return false
+}