feat: quote Windows supervisor arguments

internal/client/supervisor/windows/commandline.go

@@ -0,0 +1,54 @@
+package windows
+
+import (
+	"errors"
+	"strings"
+	"unicode/utf8"
+)
+
+var ErrInvalidCommandLineArgument = errors.New("Windows command-line argument contains NUL or invalid UTF-8")
+
+// BuildCommandLine constructs the lpCommandLine string for an explicit
+// lpApplicationName. It implements the CommandLineToArgvW-compatible escaping
+// convention: quotes are escaped by a preceding run of backslashes and trailing
+// backslashes inside a quoted argument are doubled.
+func BuildCommandLine(arguments []string) (string, error) {
+	if len(arguments) == 0 {
+		return "", nil
+	}
+	quoted := make([]string, len(arguments))
+	for index, argument := range arguments {
+		if strings.IndexByte(argument, 0) >= 0 || !utf8.ValidString(argument) {
+			return "", ErrInvalidCommandLineArgument
+		}
+		quoted[index] = quoteArgument(argument)
+	}
+	return strings.Join(quoted, " "), nil
+}
+
+func quoteArgument(argument string) string {
+	if argument != "" && !strings.ContainsAny(argument, " \t\n\v\"") {
+		return argument
+	}
+	var output strings.Builder
+	output.Grow(len(argument) + 2)
+	output.WriteByte('"')
+	backslashes := 0
+	for _, character := range argument {
+		switch character {
+		case '\\':
+			backslashes++
+		case '"':
+			output.WriteString(strings.Repeat("\\", backslashes*2+1))
+			output.WriteRune(character)
+			backslashes = 0
+		default:
+			output.WriteString(strings.Repeat("\\", backslashes))
+			output.WriteRune(character)
+			backslashes = 0
+		}
+	}
+	output.WriteString(strings.Repeat("\\", backslashes*2))
+	output.WriteByte('"')
+	return output.String()
+}

internal/client/supervisor/windows/commandline_test.go

@@ -0,0 +1,42 @@
+package windows
+
+import (
+	"errors"
+	"testing"
+)
+
+func TestBuildCommandLine_HP_CMD_01(t *testing.T) {
+	t.Parallel()
+	cases := []struct {
+		name      string
+		arguments []string
+		want      string
+	}{
+		{"empty vector", nil, ""},
+		{"ordinary", []string{"-File", `C:\ProgramData\RVBox\work\run.ps1`}, `-File C:\ProgramData\RVBox\work\run.ps1`},
+		{"empty argument", []string{"-Command", ""}, `-Command ""`},
+		{"spaces", []string{"-File", `C:\path with spaces\run.ps1`}, `-File "C:\path with spaces\run.ps1"`},
+		{"embedded quote", []string{`say "hello"`}, `"say \"hello\""`},
+		{"trailing slash", []string{`C:\path with spaces\`}, `"C:\path with spaces\\"`},
+		{"unicode", []string{"-File", `C:\工作\脚本.ps1`}, `-File C:\工作\脚本.ps1`},
+	}
+	for _, test := range cases {
+		t.Run(test.name, func(t *testing.T) {
+			t.Parallel()
+			got, err := BuildCommandLine(test.arguments)
+			if err != nil || got != test.want {
+				t.Fatalf("BuildCommandLine(%q) = (%q, %v), want %q", test.arguments, got, err, test.want)
+			}
+		})
+	}
+}
+
+func TestBuildCommandLineRejectsNUL_BH_CMD_01(t *testing.T) {
+	t.Parallel()
+	if _, err := BuildCommandLine([]string{"safe", "bad\x00argument"}); !errors.Is(err, ErrInvalidCommandLineArgument) {
+		t.Fatalf("NUL argument error = %v", err)
+	}
+	if _, err := BuildCommandLine([]string{string([]byte{0xff})}); !errors.Is(err, ErrInvalidCommandLineArgument) {
+		t.Fatalf("invalid UTF-8 argument error = %v", err)
+	}
+}