From d7569863b5bdf17b5b174f1cd3f8b7c22474b5d4 Mon Sep 17 00:00:00 2001
From: Brad Fitzpatrick <bradfitz@tailscale.com>
Date: Sun, 14 Feb 2021 21:11:06 -0800
Subject: [PATCH] cmd/tailscaled: fix up install-system-daemon on darwin, add
 uninstall too

Tangentially related to #987, #177, #594, #925, #505
---
 cmd/tailscaled/debug.go          |  2 ++
 cmd/tailscaled/install_darwin.go | 48 ++++++++++++++++++++++++++++----
 cmd/tailscaled/tailscaled.go     | 27 ++++++++++--------
 3 files changed, 61 insertions(+), 16 deletions(-)

diff --git a/cmd/tailscaled/debug.go b/cmd/tailscaled/debug.go
index 91ccb070a..d852ad893 100644
--- a/cmd/tailscaled/debug.go
+++ b/cmd/tailscaled/debug.go
@@ -33,6 +33,8 @@ var debugArgs struct {
 	derpCheck string
 }
 
+var debugModeFunc = debugMode // so it can be addressable
+
 func debugMode(args []string) error {
 	fs := flag.NewFlagSet("debug", flag.ExitOnError)
 	fs.BoolVar(&debugArgs.monitor, "monitor", false, "If true, run link monitor forever. Precludes all other options.")
diff --git a/cmd/tailscaled/install_darwin.go b/cmd/tailscaled/install_darwin.go
index 34786df93..7c86cd985 100644
--- a/cmd/tailscaled/install_darwin.go
+++ b/cmd/tailscaled/install_darwin.go
@@ -5,6 +5,7 @@
 package main
 
 import (
+	"errors"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -14,6 +15,7 @@ import (
 
 func init() {
 	installSystemDaemon = installSystemDaemonDarwin
+	uninstallSystemDaemon = uninstallSystemDaemonDarwin
 }
 
 // darwinLaunchdPlist is the launchd.plist that's written to
@@ -44,9 +46,46 @@ const darwinLaunchdPlist = `
 
 const sysPlist = "/Library/LaunchDaemons/com.tailscale.tailscaled.plist"
 const targetBin = "/usr/local/bin/tailscaled"
-const service = "system/com.tailscale.tailscaled"
+const service = "com.tailscale.tailscaled"
 
-func installSystemDaemonDarwin() (err error) {
+func uninstallSystemDaemonDarwin(args []string) (ret error) {
+	if len(args) > 0 {
+		return errors.New("uninstall subcommand takes no arguments")
+	}
+
+	plist, err := exec.Command("launchctl", "list", "com.tailscale.tailscaled").Output()
+	_ = plist // parse it? https://github.com/DHowett/go-plist if we need something.
+	running := err == nil
+
+	if running {
+		out, err := exec.Command("launchctl", "stop", "com.tailscale.tailscaled").CombinedOutput()
+		if err != nil {
+			fmt.Printf("launchctl stop com.tailscale.tailscaled: %v, %s\n", err, out)
+			ret = err
+		}
+		out, err = exec.Command("launchctl", "unload", sysPlist).CombinedOutput()
+		if err != nil {
+			fmt.Printf("launchctl unload %s: %v, %s\n", sysPlist, err, out)
+			if ret == nil {
+				ret = err
+			}
+		}
+	}
+
+	err = os.Remove(sysPlist)
+	if os.IsNotExist(err) {
+		err = nil
+		if ret == nil {
+			ret = err
+		}
+	}
+	return ret
+}
+
+func installSystemDaemonDarwin(args []string) (err error) {
+	if len(args) > 0 {
+		return errors.New("install subcommand takes no arguments")
+	}
 	defer func() {
 		if err != nil && os.Getuid() != 0 {
 			err = fmt.Errorf("%w; try running tailscaled with sudo", err)
@@ -84,9 +123,8 @@ func installSystemDaemonDarwin() (err error) {
 		return err
 	}
 
-	// Two best effort commands to stop a previous run.
-	exec.Command("launchctl", "stop", "system/com.tailscale.tailscaled").Run()
-	exec.Command("launchctl", "unload", sysPlist).Run()
+	// Best effort:
+	uninstallSystemDaemonDarwin(nil)
 
 	if err := ioutil.WriteFile(sysPlist, []byte(darwinLaunchdPlist), 0700); err != nil {
 		return err
diff --git a/cmd/tailscaled/tailscaled.go b/cmd/tailscaled/tailscaled.go
index 5782fe3c1..e9691a5dc 100644
--- a/cmd/tailscaled/tailscaled.go
+++ b/cmd/tailscaled/tailscaled.go
@@ -71,7 +71,16 @@ var args struct {
 	verbose    int
 }
 
-var installSystemDaemon func() error // non-nil on some platforms
+var (
+	installSystemDaemon   func([]string) error // non-nil on some platforms
+	uninstallSystemDaemon func([]string) error // non-nil on some platforms
+)
+
+var subCommands = map[string]*func([]string) error{
+	"install-system-daemon":   &installSystemDaemon,
+	"uninstall-system-daemon": &uninstallSystemDaemon,
+	"debug":                   &debugModeFunc,
+}
 
 func main() {
 	// We aren't very performance sensitive, and the parts that are
@@ -94,17 +103,13 @@ func main() {
 	flag.BoolVar(&printVersion, "version", false, "print version information and exit")
 
 	if len(os.Args) > 1 {
-		switch os.Args[1] {
-		case "debug":
-			if err := debugMode(os.Args[2:]); err != nil {
-				log.Fatal(err)
-			}
-			return
-		case "install-system-daemon":
-			if f := installSystemDaemon; f == nil {
+		sub := os.Args[1]
+		if fp, ok := subCommands[sub]; ok {
+			if *fp == nil {
 				log.SetFlags(0)
-				log.Fatalf("install-system-daemon not available on %v", runtime.GOOS)
-			} else if err := f(); err != nil {
+				log.Fatalf("%s not available on %v", sub, runtime.GOOS)
+			}
+			if err := (*fp)(os.Args[2:]); err != nil {
 				log.SetFlags(0)
 				log.Fatal(err)
 			}