3 files changed, 19 insertions, 3 deletions
diff --git a/kvmd/validators/__init__.py b/kvmd/validators/__init__.py
index 9a372002..d6caa835 100644
--- a/kvmd/validators/__init__.py
+++ b/kvmd/validators/__init__.py
@@ -26,6 +26,7 @@ from typing import List
 from typing import Mapping
 from typing import Sequence
 from typing import Callable
+from typing import TypeVar
 from typing import NoReturn
 from typing import Union
 from typing import Any
@@ -37,6 +38,10 @@ class ValidatorError(ValueError):
 
 
 # =====
+_RetvalSeqT = TypeVar("_RetvalSeqT", bound=Sequence)
+
+
+# =====
 def raise_error(arg: Any, name: str, hide: bool=False) -> NoReturn:
     arg_str = " "
     if not hide:
@@ -77,6 +82,12 @@ def check_re_match(arg: Any, name: str, pattern: str, strip: bool=True, hide: bo
     return arg
 
 
+def check_len(arg: _RetvalSeqT, name: str, limit: int) -> _RetvalSeqT:
+    if len(arg) > limit:
+        raise_error(arg, name)
+    return arg
+
+
 def check_any(arg: Any, name: str, validators: List[Callable[[Any], Any]]) -> Any:
     for validator in validators:
         try:
diff --git a/kvmd/validators/hw.py b/kvmd/validators/hw.py
index 82d1221a..59a0363d 100644
--- a/kvmd/validators/hw.py
+++ b/kvmd/validators/hw.py
@@ -24,6 +24,7 @@ from typing import Any
 
 from . import check_in_list
 from . import check_re_match
+from . import check_len
 
 from .basic import valid_number
 
@@ -44,7 +45,8 @@ def valid_gpio_pin_optional(arg: Any) -> int:
 
 
 def valid_otg_gadget(arg: Any) -> str:
-    return check_re_match(arg, "OTG gadget name", r"^[a-z_][a-z0-9_-]*$")[:255]
+    name = "OTG gadget name"
+    return check_len(check_re_match(arg, name, r"^[a-z_][a-z0-9_-]*$"), name, 255)
 
 
 def valid_otg_id(arg: Any) -> int:
diff --git a/kvmd/validators/kvm.py b/kvmd/validators/kvm.py
index fe9a8a8e..17895c47 100644
--- a/kvmd/validators/kvm.py
+++ b/kvmd/validators/kvm.py
@@ -28,6 +28,7 @@ from ..keyboard.mappings import KEYMAP
 from . import raise_error
 from . import check_string_in_list
 from . import check_re_match
+from . import check_len
 
 from .basic import valid_stripped_string_not_empty
 from .basic import valid_number
@@ -92,7 +93,8 @@ def valid_hid_mouse_wheel(arg: Any) -> int:
 
 # =====
 def valid_ugpio_driver(arg: Any) -> str:
-    return check_re_match(arg, "GPIO driver", r"^[a-zA-Z_][a-zA-Z0-9_-]*$")[:255]
+    name = "GPIO driver"
+    return check_len(check_re_match(arg, name, r"^[a-zA-Z_][a-zA-Z0-9_-]*$"), name, 255)
 
 
 def valid_ugpio_mode(arg: Any) -> str:
@@ -100,7 +102,8 @@ def valid_ugpio_mode(arg: Any) -> str:
 
 
 def valid_ugpio_channel(arg: Any) -> str:
-    return check_re_match(arg, "GPIO channel", r"^[a-zA-Z_][a-zA-Z0-9_-]*$")[:255]
+    name = "GPIO channel"
+    return check_len(check_re_match(arg, name, r"^[a-zA-Z_][a-zA-Z0-9_-]*$"), name, 255)
 
 
 def valid_ugpio_view_table(arg: Any) -> List[List[str]]: