1 files changed, 276 insertions, 0 deletions
diff --git a/cmd/tailscaled/cli/cli.go b/cmd/tailscaled/cli/cli.go
new file mode 100644
index 000000000..ab58eb4a3
--- /dev/null
+++ b/cmd/tailscaled/cli/cli.go
@@ -0,0 +1,276 @@
+// Copyright (c) 2020 Tailscale Inc & 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 cli contains the cmd/tailscale CLI code in a package that can be included
+// in other wrapper binaries such as the Mac and Windows clients.
+package cli
+
+import (
+	"context"
+	"errors"
+	"flag"
+	"fmt"
+	"io"
+	"log"
+	"net"
+	"os"
+	"os/signal"
+	"runtime"
+	"strconv"
+	"strings"
+	"syscall"
+	"text/tabwriter"
+
+	"github.com/peterbourgon/ff/v2/ffcli"
+	"tailscale.com/client/tailscale"
+	"tailscale.com/ipn"
+	"tailscale.com/paths"
+	"tailscale.com/safesocket"
+	"tailscale.com/syncs"
+)
+
+// ActLikeCLI reports whether a GUI application should act like the
+// CLI based on os.Args, GOOS, the context the process is running in
+// (pty, parent PID), etc.
+func ActLikeCLI() bool {
+	// This function is only used on macOS.
+	if runtime.GOOS != "darwin" {
+		return false
+	}
+
+	// Escape hatch to let people force running the macOS
+	// GUI Tailscale binary as the CLI.
+	if v, _ := strconv.ParseBool(os.Getenv("TAILSCALE_BE_CLI")); v {
+		return true
+	}
+
+	// If our parent is launchd, we're definitely not
+	// being run as a CLI.
+	if os.Getppid() == 1 {
+		return false
+	}
+
+	// Xcode adds the -NSDocumentRevisionsDebugMode flag on execution.
+	// If present, we are almost certainly being run as a GUI.
+	for _, arg := range os.Args {
+		if arg == "-NSDocumentRevisionsDebugMode" {
+			return false
+		}
+	}
+
+	// Looking at the environment of the GUI Tailscale app (ps eww
+	// $PID), empirically none of these environment variables are
+	// present. But all or some of these should be present with
+	// Terminal.all and bash or zsh.
+	for _, e := range []string{
+		"SHLVL",
+		"TERM",
+		"TERM_PROGRAM",
+		"PS1",
+	} {
+		if os.Getenv(e) != "" {
+			return true
+		}
+	}
+	return false
+}
+
+// Run runs the CLI. The args do not include the binary name.
+func Run(args []string) error {
+	if len(args) == 1 && (args[0] == "-V" || args[0] == "--version") {
+		args = []string{"version"}
+	}
+
+	rootfs := flag.NewFlagSet("tailscale", flag.ExitOnError)
+	rootfs.StringVar(&rootArgs.socket, "socket", paths.DefaultTailscaledSocket(), "path to tailscaled's unix socket")
+
+	rootCmd := &ffcli.Command{
+		Name:       "tailscale",
+		ShortUsage: "tailscale [flags] <subcommand> [command flags]",
+		ShortHelp:  "The easiest, most secure way to use WireGuard.",
+		LongHelp: strings.TrimSpace(`
+For help on subcommands, add --help after: "tailscale status --help".
+
+This CLI is still under active development. Commands and flags will
+change in the future.
+`),
+		Subcommands: []*ffcli.Command{
+			upCmd,
+			downCmd,
+			logoutCmd,
+			netcheckCmd,
+			ipCmd,
+			statusCmd,
+			pingCmd,
+			versionCmd,
+			webCmd,
+			fileCmd,
+			bugReportCmd,
+		},
+		FlagSet:   rootfs,
+		Exec:      func(context.Context, []string) error { return flag.ErrHelp },
+		UsageFunc: usageFunc,
+	}
+	for _, c := range rootCmd.Subcommands {
+		c.UsageFunc = usageFunc
+	}
+
+	// Don't advertise the debug command, but it exists.
+	if strSliceContains(args, "debug") {
+		rootCmd.Subcommands = append(rootCmd.Subcommands, debugCmd)
+	}
+
+	if err := rootCmd.Parse(args); err != nil {
+		return err
+	}
+
+	tailscale.TailscaledSocket = rootArgs.socket
+
+	err := rootCmd.Run(context.Background())
+	if err == flag.ErrHelp {
+		return nil
+	}
+	return err
+}
+
+func fatalf(format string, a ...interface{}) {
+	log.SetFlags(0)
+	log.Fatalf(format, a...)
+}
+
+var rootArgs struct {
+	socket string
+}
+
+var gotSignal syncs.AtomicBool
+
+func connect(ctx context.Context) (net.Conn, *ipn.BackendClient, context.Context, context.CancelFunc) {
+	c, err := safesocket.Connect(rootArgs.socket, 41112)
+	if err != nil {
+		if runtime.GOOS != "windows" && rootArgs.socket == "" {
+			fatalf("--socket cannot be empty")
+		}
+		fatalf("Failed to connect to tailscaled. (safesocket.Connect: %v)\n", err)
+	}
+	clientToServer := func(b []byte) {
+		ipn.WriteMsg(c, b)
+	}
+
+	ctx, cancel := context.WithCancel(ctx)
+
+	go func() {
+		interrupt := make(chan os.Signal, 1)
+		signal.Notify(interrupt, syscall.SIGINT, syscall.SIGTERM)
+		select {
+		case <-interrupt:
+		case <-ctx.Done():
+			// Context canceled elsewhere.
+			signal.Reset(syscall.SIGINT, syscall.SIGTERM)
+			return
+		}
+		gotSignal.Set(true)
+		c.Close()
+		cancel()
+	}()
+
+	bc := ipn.NewBackendClient(log.Printf, clientToServer)
+	return c, bc, ctx, cancel
+}
+
+// pump receives backend messages on conn and pushes them into bc.
+func pump(ctx context.Context, bc *ipn.BackendClient, conn net.Conn) error {
+	defer conn.Close()
+	for ctx.Err() == nil {
+		msg, err := ipn.ReadMsg(conn)
+		if err != nil {
+			if ctx.Err() != nil {
+				return ctx.Err()
+			}
+			if errors.Is(err, io.EOF) || errors.Is(err, net.ErrClosed) {
+				return fmt.Errorf("%w (tailscaled stopped running?)", err)
+			}
+			return err
+		}
+		bc.GotNotifyMsg(msg)
+	}
+	return ctx.Err()
+}
+
+func strSliceContains(ss []string, s string) bool {
+	for _, v := range ss {
+		if v == s {
+			return true
+		}
+	}
+	return false
+}
+
+func usageFunc(c *ffcli.Command) string {
+	var b strings.Builder
+
+	fmt.Fprintf(&b, "USAGE\n")
+	if c.ShortUsage != "" {
+		fmt.Fprintf(&b, "  %s\n", c.ShortUsage)
+	} else {
+		fmt.Fprintf(&b, "  %s\n", c.Name)
+	}
+	fmt.Fprintf(&b, "\n")
+
+	if c.LongHelp != "" {
+		fmt.Fprintf(&b, "%s\n\n", c.LongHelp)
+	}
+
+	if len(c.Subcommands) > 0 {
+		fmt.Fprintf(&b, "SUBCOMMANDS\n")
+		tw := tabwriter.NewWriter(&b, 0, 2, 2, ' ', 0)
+		for _, subcommand := range c.Subcommands {
+			fmt.Fprintf(tw, "  %s\t%s\n", subcommand.Name, subcommand.ShortHelp)
+		}
+		tw.Flush()
+		fmt.Fprintf(&b, "\n")
+	}
+
+	if countFlags(c.FlagSet) > 0 {
+		fmt.Fprintf(&b, "FLAGS\n")
+		tw := tabwriter.NewWriter(&b, 0, 2, 2, ' ', 0)
+		c.FlagSet.VisitAll(func(f *flag.Flag) {
+			var s string
+			name, usage := flag.UnquoteUsage(f)
+			if isBoolFlag(f) {
+				s = fmt.Sprintf("  --%s, --%s=false", f.Name, f.Name)
+			} else {
+				s = fmt.Sprintf("  --%s", f.Name) // Two spaces before --; see next two comments.
+				if len(name) > 0 {
+					s += " " + name
+				}
+			}
+			// Four spaces before the tab triggers good alignment
+			// for both 4- and 8-space tab stops.
+			s += "\n    \t"
+			s += strings.ReplaceAll(usage, "\n", "\n    \t")
+
+			if f.DefValue != "" {
+				s += fmt.Sprintf(" (default %s)", f.DefValue)
+			}
+
+			fmt.Fprintln(&b, s)
+		})
+		tw.Flush()
+		fmt.Fprintf(&b, "\n")
+	}
+
+	return strings.TrimSpace(b.String())
+}
+
+func isBoolFlag(f *flag.Flag) bool {
+	bf, ok := f.Value.(interface {
+		IsBoolFlag() bool
+	})
+	return ok && bf.IsBoolFlag()
+}
+
+func countFlags(fs *flag.FlagSet) (n int) {
+	fs.VisitAll(func(*flag.Flag) { n++ })
+	return n
+}