Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Web/Util/PathUtil.cs

@@ -0,0 +1,28 @@
+//------------------------------------------------------------------------------
+// <copyright file="PathUtil.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+//------------------------------------------------------------------------------
+
+namespace System.Web.Util {
+    using System;
+    using System.IO;
+    using System.Security.Permissions;
+
+    internal static class PathUtil {
+
+        private static string _system32Path = GetSystem32Path();
+
+        [FileIOPermission(SecurityAction.Assert, Unrestricted = true)] // we don't leak this path anywhere
+        private static string GetSystem32Path() {
+            return Environment.GetFolderPath(Environment.SpecialFolder.System);
+        }
+
+        // Gets the full path to a file in the SYSTEM32 folder (which is correct for both 32-bit and 64-bit architectures).
+        // Example: "foo.dll" -> "C:\Windows\System32\foo.dll"
+        internal static string GetSystemDllFullPath(string filename) {
+            return Path.Combine(_system32Path, filename);
+        }
+
+    }
+}