1 files changed, 147 insertions, 0 deletions
diff --git a/src/cmd/go/internal/tool/tool.go b/src/cmd/go/internal/tool/tool.go
new file mode 100644
index 0000000..069968b
--- /dev/null
+++ b/src/cmd/go/internal/tool/tool.go
@@ -0,0 +1,147 @@
+// Copyright 2011 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 tool implements the “go tool” command.
+package tool
+
+import (
+	"context"
+	"fmt"
+	"go/build"
+	"os"
+	"os/exec"
+	"os/signal"
+	"sort"
+	"strings"
+
+	"cmd/go/internal/base"
+	"cmd/go/internal/cfg"
+)
+
+var CmdTool = &base.Command{
+	Run:       runTool,
+	UsageLine: "go tool [-n] command [args...]",
+	Short:     "run specified go tool",
+	Long: `
+Tool runs the go tool command identified by the arguments.
+With no arguments it prints the list of known tools.
+
+The -n flag causes tool to print the command that would be
+executed but not execute it.
+
+For more about each tool command, see 'go doc cmd/<command>'.
+`,
+}
+
+var toolN bool
+
+// Return whether tool can be expected in the gccgo tool directory.
+// Other binaries could be in the same directory so don't
+// show those with the 'go tool' command.
+func isGccgoTool(tool string) bool {
+	switch tool {
+	case "cgo", "fix", "cover", "godoc", "vet":
+		return true
+	}
+	return false
+}
+
+func init() {
+	base.AddChdirFlag(&CmdTool.Flag)
+	CmdTool.Flag.BoolVar(&toolN, "n", false, "")
+}
+
+func runTool(ctx context.Context, cmd *base.Command, args []string) {
+	if len(args) == 0 {
+		listTools()
+		return
+	}
+	toolName := args[0]
+	// The tool name must be lower-case letters, numbers or underscores.
+	for _, c := range toolName {
+		switch {
+		case 'a' <= c && c <= 'z', '0' <= c && c <= '9', c == '_':
+		default:
+			fmt.Fprintf(os.Stderr, "go: bad tool name %q\n", toolName)
+			base.SetExitStatus(2)
+			return
+		}
+	}
+	toolPath := base.Tool(toolName)
+	if toolPath == "" {
+		return
+	}
+	if toolN {
+		cmd := toolPath
+		if len(args) > 1 {
+			cmd += " " + strings.Join(args[1:], " ")
+		}
+		fmt.Printf("%s\n", cmd)
+		return
+	}
+	args[0] = toolPath // in case the tool wants to re-exec itself, e.g. cmd/dist
+	toolCmd := &exec.Cmd{
+		Path:   toolPath,
+		Args:   args,
+		Stdin:  os.Stdin,
+		Stdout: os.Stdout,
+		Stderr: os.Stderr,
+	}
+	err := toolCmd.Start()
+	if err == nil {
+		c := make(chan os.Signal, 100)
+		signal.Notify(c)
+		go func() {
+			for sig := range c {
+				toolCmd.Process.Signal(sig)
+			}
+		}()
+		err = toolCmd.Wait()
+		signal.Stop(c)
+		close(c)
+	}
+	if err != nil {
+		// Only print about the exit status if the command
+		// didn't even run (not an ExitError) or it didn't exit cleanly
+		// or we're printing command lines too (-x mode).
+		// Assume if command exited cleanly (even with non-zero status)
+		// it printed any messages it wanted to print.
+		if e, ok := err.(*exec.ExitError); !ok || !e.Exited() || cfg.BuildX {
+			fmt.Fprintf(os.Stderr, "go tool %s: %s\n", toolName, err)
+		}
+		base.SetExitStatus(1)
+		return
+	}
+}
+
+// listTools prints a list of the available tools in the tools directory.
+func listTools() {
+	f, err := os.Open(build.ToolDir)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "go: no tool directory: %s\n", err)
+		base.SetExitStatus(2)
+		return
+	}
+	defer f.Close()
+	names, err := f.Readdirnames(-1)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "go: can't read tool directory: %s\n", err)
+		base.SetExitStatus(2)
+		return
+	}
+
+	sort.Strings(names)
+	for _, name := range names {
+		// Unify presentation by going to lower case.
+		// If it's windows, don't show the .exe suffix.
+		name = strings.TrimSuffix(strings.ToLower(name), cfg.ToolExeSuffix())
+
+		// The tool directory used by gccgo will have other binaries
+		// in addition to go tools. Only display go tools here.
+		if cfg.BuildToolchainName == "gccgo" && !isGccgoTool(name) {
+			continue
+		}
+		fmt.Println(name)
+	}
+}