lib: add signal name validator

PR-URL: #27137
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>

lib/internal/validators.js

@@ -5,12 +5,14 @@ const {
   codes: {
     ERR_INVALID_ARG_TYPE,
     ERR_INVALID_ARG_VALUE,
-    ERR_OUT_OF_RANGE
+    ERR_OUT_OF_RANGE,
+    ERR_UNKNOWN_SIGNAL
   }
 } = require('internal/errors');
 const {
   isArrayBufferView
 } = require('internal/util/types');
+const { signals } = internalBinding('constants').os;
 
 function isInt32(value) {
   return value === (value | 0);
@@ -110,6 +112,20 @@ function validateNumber(value, name) {
     throw new ERR_INVALID_ARG_TYPE(name, 'number', value);
 }
 
+function validateSignalName(signal, name = 'signal') {
+  if (typeof signal !== 'string')
+    throw new ERR_INVALID_ARG_TYPE(name, 'string', signal);
+
+  if (signals[signal] === undefined) {
+    if (signals[signal.toUpperCase()] !== undefined) {
+      throw new ERR_UNKNOWN_SIGNAL(signal +
+                                   ' (signals must use all capital letters)');
+    }
+
+    throw new ERR_UNKNOWN_SIGNAL(signal);
+  }
+}
+
 // TODO(BridgeAR): We have multiple validation functions that call
 // `require('internal/utils').toBuf()` before validating for array buffer views.
 // Those should likely also be consolidated in here.
@@ -130,5 +146,6 @@ module.exports = {
   validateInt32,
   validateUint32,
   validateString,
-  validateNumber
+  validateNumber,
+  validateSignalName
 };