cmd/tailscale/cli: don't ExitOnError on js/wasm

An os.Exit brings down the whole wasm module.

Updates #3157

Change-Id: I3daa97fd854715b901f3dbb04b57d841576b60b1
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

cmd/tailscale/cli/cert.go

@@ -29,7 +29,7 @@
 	ShortHelp:  "get TLS certs",
 	ShortUsage: "cert [flags] <domain>",
 	FlagSet: (func() *flag.FlagSet {
-		fs := flag.NewFlagSet("cert", flag.ExitOnError)
+		fs := newFlagSet("cert")
 		fs.StringVar(&certArgs.certFile, "cert-file", "", "output cert file or \"-\" for stdout; defaults to DOMAIN.crt if --cert-file and --key-file are both unset")
 		fs.StringVar(&certArgs.keyFile, "key-file", "", "output cert file or \"-\" for stdout; defaults to DOMAIN.key if --cert-file and --key-file are both unset")
 		fs.BoolVar(&certArgs.serve, "serve-demo", false, "if true, serve on port :443 using the cert as a demo, instead of writing out the files to disk")

cmd/tailscale/cli/cli.go

@@ -77,6 +77,14 @@ func ActLikeCLI() bool {
 	return false
 }
 
+func newFlagSet(name string) *flag.FlagSet {
+	onError := flag.ExitOnError
+	if runtime.GOOS == "js" {
+		onError = flag.ContinueOnError
+	}
+	return flag.NewFlagSet(name, onError)
+}
+
 // 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") {
@@ -90,7 +98,7 @@ func Run(args []string) error {
 		})
 	})
 
-	rootfs := flag.NewFlagSet("tailscale", flag.ExitOnError)
+	rootfs := newFlagSet("tailscale")
 	rootfs.StringVar(&rootArgs.socket, "socket", paths.DefaultTailscaledSocket(), "path to tailscaled's unix socket")
 
 	rootCmd := &ffcli.Command{

cmd/tailscale/cli/debug.go

@@ -27,7 +27,7 @@
 	Name: "debug",
 	Exec: runDebug,
 	FlagSet: (func() *flag.FlagSet {
-		fs := flag.NewFlagSet("debug", flag.ExitOnError)
+		fs := newFlagSet("debug")
 		fs.BoolVar(&debugArgs.goroutines, "daemon-goroutines", false, "If true, dump the tailscaled daemon's goroutines")
 		fs.BoolVar(&debugArgs.ipn, "ipn", false, "If true, subscribe to IPN notifications")
 		fs.BoolVar(&debugArgs.prefs, "prefs", false, "If true, dump active prefs")

cmd/tailscale/cli/file.go

@@ -55,7 +55,7 @@
 	ShortHelp:  "Copy file(s) to a host",
 	Exec:       runCp,
 	FlagSet: (func() *flag.FlagSet {
-		fs := flag.NewFlagSet("cp", flag.ExitOnError)
+		fs := newFlagSet("cp")
 		fs.StringVar(&cpArgs.name, "name", "", "alternate filename to use, especially useful when <file> is \"-\" (stdin)")
 		fs.BoolVar(&cpArgs.verbose, "verbose", false, "verbose output")
 		fs.BoolVar(&cpArgs.targets, "targets", false, "list possible file cp targets")
@@ -304,7 +304,7 @@ func runCpTargets(ctx context.Context, args []string) error {
 	ShortHelp:  "Move files out of the Tailscale file inbox",
 	Exec:       runFileGet,
 	FlagSet: (func() *flag.FlagSet {
-		fs := flag.NewFlagSet("get", flag.ExitOnError)
+		fs := newFlagSet("get")
 		fs.BoolVar(&getArgs.wait, "wait", false, "wait for a file to arrive if inbox is empty")
 		fs.BoolVar(&getArgs.verbose, "verbose", false, "verbose output")
 		return fs

cmd/tailscale/cli/ip.go

@@ -23,7 +23,7 @@
 	LongHelp:   "Shows the Tailscale IP address of the current machine without an argument. With an argument, it shows the IP of a named peer.",
 	Exec:       runIP,
 	FlagSet: (func() *flag.FlagSet {
-		fs := flag.NewFlagSet("ip", flag.ExitOnError)
+		fs := newFlagSet("ip")
 		fs.BoolVar(&ipArgs.want4, "4", false, "only print IPv4 address")
 		fs.BoolVar(&ipArgs.want6, "6", false, "only print IPv6 address")
 		return fs

cmd/tailscale/cli/netcheck.go

@@ -33,7 +33,7 @@
 	ShortHelp:  "Print an analysis of local network conditions",
 	Exec:       runNetcheck,
 	FlagSet: (func() *flag.FlagSet {
-		fs := flag.NewFlagSet("netcheck", flag.ExitOnError)
+		fs := newFlagSet("netcheck")
 		fs.StringVar(&netcheckArgs.format, "format", "", `output format; empty (for human-readable), "json" or "json-line"`)
 		fs.DurationVar(&netcheckArgs.every, "every", 0, "if non-zero, do an incremental report with the given frequency")
 		fs.BoolVar(&netcheckArgs.verbose, "verbose", false, "verbose logs")

cmd/tailscale/cli/ping.go

@@ -45,7 +45,7 @@
 `),
 	Exec: runPing,
 	FlagSet: (func() *flag.FlagSet {
-		fs := flag.NewFlagSet("ping", flag.ExitOnError)
+		fs := newFlagSet("ping")
 		fs.BoolVar(&pingArgs.verbose, "verbose", false, "verbose output")
 		fs.BoolVar(&pingArgs.untilDirect, "until-direct", true, "stop once a direct path is established")
 		fs.BoolVar(&pingArgs.tsmp, "tsmp", false, "do a TSMP-level ping (through IP + wireguard, but not involving host OS stack)")

cmd/tailscale/cli/status.go

@@ -31,7 +31,7 @@
 	ShortHelp:  "Show state of tailscaled and its connections",
 	Exec:       runStatus,
 	FlagSet: (func() *flag.FlagSet {
-		fs := flag.NewFlagSet("status", flag.ExitOnError)
+		fs := newFlagSet("status")
 		fs.BoolVar(&statusArgs.json, "json", false, "output in JSON format (WARNING: format subject to change)")
 		fs.BoolVar(&statusArgs.web, "web", false, "run webserver with HTML showing status")
 		fs.BoolVar(&statusArgs.active, "active", false, "filter output to only peers with active sessions (not applicable to web mode)")

cmd/tailscale/cli/up.go

@@ -63,7 +63,7 @@ func effectiveGOOS() string {
 var upFlagSet = newUpFlagSet(effectiveGOOS(), &upArgs)
 
 func newUpFlagSet(goos string, upArgs *upArgsT) *flag.FlagSet {
-	upf := flag.NewFlagSet("up", flag.ExitOnError)
+	upf := newFlagSet("up")
 
 	upf.BoolVar(&upArgs.qr, "qr", false, "show QR code for login URLs")
 	upf.BoolVar(&upArgs.forceReauth, "force-reauth", false, "force reauthentication")

cmd/tailscale/cli/version.go

@@ -20,7 +20,7 @@
 	ShortUsage: "version [flags]",
 	ShortHelp:  "Print Tailscale version",
 	FlagSet: (func() *flag.FlagSet {
-		fs := flag.NewFlagSet("version", flag.ExitOnError)
+		fs := newFlagSet("version")
 		fs.BoolVar(&versionArgs.daemon, "daemon", false, "also print local node's daemon version")
 		return fs
 	})(),

cmd/tailscale/cli/web.go

@@ -76,7 +76,7 @@ type tmplData struct {
 `),
 
 	FlagSet: (func() *flag.FlagSet {
-		webf := flag.NewFlagSet("web", flag.ExitOnError)
+		webf := newFlagSet("web")
 		webf.StringVar(&webArgs.listen, "listen", "localhost:8088", "listen address; use port 0 for automatic")
 		webf.BoolVar(&webArgs.cgi, "cgi", false, "run as CGI script")
 		return webf