log: improve prefix handling (#5489)

pkg/config/v1/validation/name.go

@@ -0,0 +1,48 @@
+// Copyright 2026 The frp Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package validation
+
+import (
+	"fmt"
+	"unicode"
+	"unicode/utf8"
+)
+
+const (
+	// MaxRunIDLength is the maximum number of bytes accepted for a control run ID.
+	MaxRunIDLength = 64
+)
+
+func validateIdentifier(value, kind string, maxLength int) error {
+	if value == "" {
+		return fmt.Errorf("%s cannot be empty", kind)
+	}
+	if len(value) > maxLength {
+		return fmt.Errorf("%s is too long: length %d exceeds maximum %d", kind, len(value), maxLength)
+	}
+	if !utf8.ValidString(value) {
+		return fmt.Errorf("%s must be valid UTF-8", kind)
+	}
+	for _, r := range value {
+		if !unicode.IsPrint(r) {
+			return fmt.Errorf("%s contains non-printable character", kind)
+		}
+	}
+	return nil
+}
+
+func ValidateRunID(runID string) error {
+	return validateIdentifier(runID, "run id", MaxRunIDLength)
+}

pkg/config/v1/validation/name_test.go

@@ -0,0 +1,48 @@
+// Copyright 2026 The frp Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package validation
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestValidateIdentifiers(t *testing.T) {
+	tests := []struct {
+		name      string
+		validate  func(string) error
+		value     string
+		wantError string
+	}{
+		{name: "run id accepts printable values", validate: ValidateRunID, value: "run-%1000s-中文"},
+		{name: "run id rejects empty", validate: ValidateRunID, wantError: "cannot be empty"},
+		{name: "run id rejects control character", validate: ValidateRunID, value: "run\nforged", wantError: "non-printable"},
+		{name: "run id rejects invalid utf8", validate: ValidateRunID, value: string([]byte{0xff}), wantError: "valid UTF-8"},
+		{name: "run id rejects excessive length", validate: ValidateRunID, value: strings.Repeat("a", MaxRunIDLength+1), wantError: "too long"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := tt.validate(tt.value)
+			if tt.wantError == "" {
+				require.NoError(t, err)
+				return
+			}
+			require.ErrorContains(t, err, tt.wantError)
+		})
+	}
+}