AllowRoot setting to control if a cli is allowed to run as root

cli/app.go

@@ -25,6 +25,7 @@ type App struct {
 	OnExit         OnExit
 	ContextConfig  func(Context, context.Context) context.Context
 	ContextOptions []ContextOption
+	AllowRoot      bool
 }
 
 type Option func(*App)
@@ -33,9 +34,10 @@ type ContextOption func(*Context)
 
 func NewApp(opts ...Option) *App {
 	app := &App{
-		Stdout: os.Stdout,
-		Stderr: os.Stderr,
-		OnExit: newOnExit(),
+		Stdout:    os.Stdout,
+		Stderr:    os.Stderr,
+		OnExit:    newOnExit(),
+		AllowRoot: false,
 	}
 	for _, opt := range opts {
 		opt(app)

cli/cliviper/cliviper_test.go

@@ -22,6 +22,7 @@ func TestCLIViperApp(t *testing.T) {
 
 	// set cliviper.App() option
 	app := cli.NewApp(cliviper.App())
+	app.AllowRoot = true
 	app.Flags = []flag.Flag{
 		flag.StringFlag{Name: msgFlag},
 	}

cli/debugapp_test.go

@@ -50,6 +50,7 @@ func TestNewDebugApp(t *testing.T) {
 		{err: testExitCoder{error: fmt.Errorf("foo"), exitCode: 2}, wantExitCode: 2, errorStringer: testErrorStringer, wantDebugFalse: "^foo\n$", wantDebugTrue: "^error-stringer\n$"},
 	} {
 		app := cli.NewApp(cli.DebugHandler(currCase.errorStringer))
+		app.AllowRoot = true
 		app.Action = func(ctx cli.Context) error {
 			return currCase.err
 		}

cli/exitcode_test.go

@@ -28,6 +28,7 @@ import (
 
 func main() {
 	app := cli.NewApp()
+	app.AllowRoot = true
 	app.Action = func(ctx cli.Context) error {
 		%v
 	}

cli/flagvalue_test.go

@@ -52,6 +52,7 @@ func TestBindFlagValues(t *testing.T) {
 		},
 	} {
 		app := cli.NewApp()
+		app.AllowRoot = true
 		app.Command = cli.Command{
 			Name: "foo",
 			Flags: []flag.Flag{
@@ -111,6 +112,7 @@ func TestBindFlagValuesStringParam(t *testing.T) {
 		},
 	} {
 		app := cli.NewApp()
+		app.AllowRoot = true
 		app.Command = cli.Command{
 			Name: "foo",
 			Flags: []flag.Flag{

cli/parse_test.go

@@ -294,6 +294,7 @@ func TestParseFlags(t *testing.T) {
 		t.Run(currCase.name, func(t *testing.T) {
 			app := cli.NewApp()
 			app.Name = "test"
+			app.AllowRoot = true
 
 			output := &bytes.Buffer{}
 			app.Subcommands = []cli.Command{

cli/run.go

@@ -37,6 +37,13 @@ func (app *App) Run(args []string) (exitStatus int) {
 		return 0
 	}
 
+	if !app.AllowRoot {
+		if syscall.Getuid() == 0 {
+			ctx.Errorf("%v\n", "Root is not allowed to run this program.")
+			return 1
+		}
+	}
+
 	baseContext := context.Background()
 	if app.ContextConfig != nil {
 		baseContext = app.ContextConfig(ctx, baseContext)

cli/run_test.go

@@ -34,6 +34,7 @@ func TestRunErrorOutput(t *testing.T) {
 
 	for i, currCase := range cases {
 		app := cli.NewApp()
+		app.AllowRoot = true
 		app.Action = func(ctx cli.Context) error {
 			return currCase.err
 		}
@@ -79,6 +80,7 @@ func TestRunErrorHandler(t *testing.T) {
 
 	for i, currCase := range cases {
 		app := cli.NewApp()
+		app.AllowRoot = true
 		app.ErrorHandler = currCase.handler
 		app.Action = func(ctx cli.Context) error {
 			return currCase.err
@@ -118,6 +120,7 @@ func TestRunContext(t *testing.T) {
 			name: "check that context is propagated to app action",
 			check: func(t *testing.T) {
 				app := cli.NewApp()
+				app.AllowRoot = true
 
 				app.Command.Flags = []flag.Flag{
 					flag.StringFlag{
@@ -136,6 +139,7 @@ func TestRunContext(t *testing.T) {
 			name: "check that context is propagated to app error handler",
 			check: func(t *testing.T) {
 				app := cli.NewApp()
+				app.AllowRoot = true
 
 				app.Command.Flags = []flag.Flag{
 					flag.StringFlag{
@@ -162,6 +166,7 @@ func TestRunContext(t *testing.T) {
 			name: "check that context is propagated to app subcommand",
 			check: func(t *testing.T) {
 				app := cli.NewApp()
+				app.AllowRoot = true
 
 				app.Command.Flags = []flag.Flag{
 					flag.StringFlag{