mcs/class/referencesource/System/net/System/Net/HttpSysSettings.cs

   1 using System;
   2 using System.Diagnostics;
   3 using System.Text;
   4 using System.Collections.Generic;
   5 using System.Globalization;
   6 using System.Security.Permissions;
   7 using Microsoft.Win32;
   8 using System.IO;
   9 using System.Security;
  10
  11 namespace System.Net
  12 {
  13     internal static class HttpSysSettings
  14     {
  15         private const string httpSysParametersKey = @"System\CurrentControlSet\Services\HTTP\Parameters";
  16         private const bool enableNonUtf8Default = true;
  17         private const bool favorUtf8Default = true;
  18         private const string enableNonUtf8Name = "EnableNonUtf8";
  19         private const string favorUtf8Name = "FavorUtf8";
  20
  21         private static volatile bool enableNonUtf8;
  22         private static volatile bool favorUtf8;
  23
  24         static HttpSysSettings()
  25         {
  26             enableNonUtf8 = enableNonUtf8Default;
  27             favorUtf8 = favorUtf8Default;
  28             ReadHttpSysRegistrySettings();
  29         }
  30
  31         public static bool EnableNonUtf8
  32         {
  33             get { return enableNonUtf8; }
  34         }
  35
  36         public static bool FavorUtf8
  37         {
  38             get { return favorUtf8; }
  39         }
  40
  41         [RegistryPermission(SecurityAction.Assert, Read = @"HKEY_LOCAL_MACHINE\" + httpSysParametersKey)]
  42         private static void ReadHttpSysRegistrySettings()
  43         {
  44             try
  45             {
  46                 RegistryKey httpSysParameters = Registry.LocalMachine.OpenSubKey(httpSysParametersKey);
  47
  48                 if (httpSysParameters == null)
  49                 {
  50                     LogWarning("ReadHttpSysRegistrySettings", SR.net_log_listener_httpsys_registry_null,
  51                         httpSysParametersKey);
  52                 }
  53                 else
  54                 {
  55                     using (httpSysParameters)
  56                     {
  57                         enableNonUtf8 = ReadRegistryValue(httpSysParameters, enableNonUtf8Name, enableNonUtf8Default);
  58                         favorUtf8 = ReadRegistryValue(httpSysParameters, favorUtf8Name, favorUtf8Default);
  59                     }
  60                 }
  61             }
  62             catch (SecurityException e)
  63             {
  64                 LogRegistryException("ReadHttpSysRegistrySettings", e);
  65             }
  66             catch (ObjectDisposedException e)
  67             {
  68                 LogRegistryException("ReadHttpSysRegistrySettings", e);
  69             }
  70         }
  71
  72         private static bool ReadRegistryValue(RegistryKey key, string valueName, bool defaultValue)
  73         {
  74             Debug.Assert(key != null, "'key' must not be null");
  75
  76             try
  77             {
  78                 // This check will throw an IOException if keyName doesn't exist. That's OK, we return the
  79                 // default value.
  80                 if (key.GetValueKind(valueName) == RegistryValueKind.DWord)
  81                 {
  82                     // At this point we know the Registry value exists and it must be valid (any DWORD value
  83                     // can be converted to a bool).
  84                     return Convert.ToBoolean(key.GetValue(valueName), CultureInfo.InvariantCulture);
  85                 }
  86             }
  87             catch (UnauthorizedAccessException e)
  88             {
  89                 LogRegistryException("ReadRegistryValue", e);
  90             }
  91             catch (IOException e)
  92             {
  93                 LogRegistryException("ReadRegistryValue", e);
  94             }
  95             catch (SecurityException e)
  96             {
  97                 LogRegistryException("ReadRegistryValue", e);
  98             }
  99             catch (ObjectDisposedException e)
 100             {
 101                 LogRegistryException("ReadRegistryValue", e);
 102             }
 103
 104             return defaultValue;
 105         }
 106
 107         private static void LogRegistryException(string methodName, Exception e)
 108         {
 109             LogWarning(methodName, SR.net_log_listener_httpsys_registry_error, httpSysParametersKey, e);
 110         }
 111
 112         private static void LogWarning(string methodName, string message, params object[] args)
 113         {
 114             if (Logging.On)
 115             {
 116                 Logging.PrintWarning(Logging.HttpListener, typeof(HttpSysSettings), methodName,
 117                     SR.GetString(message, args));
 118             }
 119         }
 120     }
 121 }