parse ssh args and command

josebalius · josebalius · commit 8a0f8b6d1c18 · 2021-09-16T10:32:27.000-04:00
diff --git a/internal/codespaces/ssh.go b/internal/codespaces/ssh.go
@@ -12,7 +12,7 @@ import (
 // port-forwarding session. It runs until the shell is terminated
 // (including by cancellation of the context).
 func Shell(ctx context.Context, log logger, sshArgs []string, port int, destination string, usingCustomPort bool) error {
-	cmd, connArgs := newSSHCommand(ctx, port, destination, "")
+	cmd, connArgs := newSSHCommand(ctx, port, destination, sshArgs)
 
 	if usingCustomPort {
 		log.Println("Connection Details: ssh " + destination + " " + strings.Join(connArgs, " "))
@@ -23,23 +23,21 @@ func Shell(ctx context.Context, log logger, sshArgs []string, port int, destinat
 
 // NewRemoteCommand returns an exec.Cmd that will securely run a shell
 // command on the remote machine.
-func NewRemoteCommand(ctx context.Context, tunnelPort int, destination, command string) *exec.Cmd {
-	cmd, _ := newSSHCommand(ctx, tunnelPort, destination, command)
+func NewRemoteCommand(ctx context.Context, tunnelPort int, destination string, sshArgs ...string) *exec.Cmd {
+	cmd, _ := newSSHCommand(ctx, tunnelPort, destination, sshArgs)
 	return cmd
 }
 
 // newSSHCommand populates an exec.Cmd to run a command (or if blank,
 // an interactive shell) over ssh.
-func newSSHCommand(ctx context.Context, port int, dst, command string) (*exec.Cmd, []string) {
+func newSSHCommand(ctx context.Context, port int, dst string, cmdArgs []string) (*exec.Cmd, []string) {
 	connArgs := []string{"-p", strconv.Itoa(port), "-o", "NoHostAuthenticationForLocalhost=yes"}
 
-	cmdArgs := []string{dst, "-C"} // Always use Compression
-	if command == "" {
-		// if we are in a shell send X11 and X11Trust
-		cmdArgs = append(cmdArgs, "-X", "-Y")
-	}
-
+	cmdArgs, command := parseSSHArgs(cmdArgs)
 	cmdArgs = append(cmdArgs, connArgs...)
+	cmdArgs = append(cmdArgs, "-C") // Compression
+	cmdArgs = append(cmdArgs, dst)  // user@host
+
 	if command != "" {
 		cmdArgs = append(cmdArgs, command)
 	}
@@ -51,3 +49,48 @@ func newSSHCommand(ctx context.Context, port int, dst, command string) (*exec.Cm
 
 	return cmd, connArgs
 }
+
+var sshArgumentFlags = map[string]bool{
+	"-b": true,
+	"-c": true,
+	"-D": true,
+	"-e": true,
+	"-F": true,
+	"-I": true,
+	"-i": true,
+	"-L": true,
+	"-l": true,
+	"-m": true,
+	"-O": true,
+	"-o": true,
+	"-p": true,
+	"-R": true,
+	"-S": true,
+	"-W": true,
+	"-w": true,
+}
+
+func parseSSHArgs(sshArgs []string) ([]string, string) {
+	var (
+		cmdArgs      []string
+		command      []string
+		flagArgument bool
+	)
+
+	for _, arg := range sshArgs {
+		switch {
+		case strings.HasPrefix(arg, "-"):
+			cmdArgs = append(cmdArgs, arg)
+			if _, ok := sshArgumentFlags[arg]; ok {
+				flagArgument = true
+			}
+		case flagArgument:
+			cmdArgs = append(cmdArgs, arg)
+			flagArgument = false
+		default:
+			command = append(command, arg)
+		}
+	}
+
+	return cmdArgs, strings.Join(command, " ")
+}
diff --git a/internal/codespaces/ssh_test.go b/internal/codespaces/ssh_test.go
@@ -0,0 +1,64 @@
+package codespaces
+
+import "testing"
+
+func TestParseSSHArgs(t *testing.T) {
+	type testCase struct {
+		Args       []string
+		ParsedArgs []string
+		Command    string
+	}
+
+	testCases := []testCase{
+		{
+			Args:       []string{"-X", "-Y"},
+			ParsedArgs: []string{"-X", "-Y"},
+			Command:    "",
+		},
+		{
+			Args:       []string{"-X", "-Y", "-o", "someoption=test"},
+			ParsedArgs: []string{"-X", "-Y", "-o", "someoption=test"},
+			Command:    "",
+		},
+		{
+			Args:       []string{"-X", "-Y", "-o", "someoption=test", "somecommand"},
+			ParsedArgs: []string{"-X", "-Y", "-o", "someoption=test"},
+			Command:    "somecommand",
+		},
+		{
+			Args:       []string{"-X", "-Y", "-o", "someoption=test", "echo", "test"},
+			ParsedArgs: []string{"-X", "-Y", "-o", "someoption=test"},
+			Command:    "echo test",
+		},
+		{
+			Args:       []string{"somecommand"},
+			ParsedArgs: []string{},
+			Command:    "somecommand",
+		},
+		{
+			Args:       []string{"echo", "test"},
+			ParsedArgs: []string{},
+			Command:    "echo test",
+		},
+		{
+			Args:       []string{"-v", "echo", "hello", "world"},
+			ParsedArgs: []string{"-v"},
+			Command:    "echo hello world",
+		},
+	}
+
+	for _, tcase := range testCases {
+		args, command := parseSSHArgs(tcase.Args)
+		if len(args) != len(tcase.ParsedArgs) {
+			t.Fatalf("args do not match length of expected args. %#v, got '%d', expected: '%d'", tcase, len(args), len(tcase.ParsedArgs))
+		}
+		for i, arg := range args {
+			if arg != tcase.ParsedArgs[i] {
+				t.Fatalf("arg does not match expected parsed arg. %v, got '%s', expected: '%s'", tcase, arg, tcase.ParsedArgs[i])
+			}
+		}
+		if command != tcase.Command {
+			t.Fatalf("command does not match expected command. %v, got: '%s', expected: '%s'", tcase, command, tcase.Command)
+		}
+	}
+}
