mcs/class/corlib/System.Security.Permissions/EnvironmentPermission.cs

   1 //
   2 // System.Security.Permissions.EnvironmentPermission.cs
   3 //
   4 // Authors:
   5 //      Tim Coleman <tim@timcoleman.com>
   6 //      Sebastien Pouliot  <sebastien@ximian.com>
   7 //
   8 // Copyright (C) 2002, Tim Coleman
   9 // Portions Copyright (C) 2003 Motus Technologies (http://www.motus.com)
  10 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
  11 //
  12 // Permission is hereby granted, free of charge, to any person obtaining
  13 // a copy of this software and associated documentation files (the
  14 // "Software"), to deal in the Software without restriction, including
  15 // without limitation the rights to use, copy, modify, merge, publish,
  16 // distribute, sublicense, and/or sell copies of the Software, and to
  17 // permit persons to whom the Software is furnished to do so, subject to
  18 // the following conditions:
  19 //
  20 // The above copyright notice and this permission notice shall be
  21 // included in all copies or substantial portions of the Software.
  22 //
  23 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  27 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  28 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  29 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  30 //
  31
  32 using System.Collections;
  33 using System.Text;
  34
  35 namespace System.Security.Permissions {
  36
  37         [Serializable]
  38         public sealed class EnvironmentPermission : CodeAccessPermission, IUnrestrictedPermission, IBuiltInPermission {
  39
  40                 #region Fields
  41
  42                 private const int version = 1;
  43
  44                 EnvironmentPermissionAccess flags;
  45                 PermissionState _state;
  46                 ArrayList readList;
  47                 ArrayList writeList;
  48
  49                 #endregion // Fields
  50
  51                 #region Constructors
  52
  53                 public EnvironmentPermission (PermissionState state) : base ()
  54                 {
  55                         _state = CheckPermissionState (state, true);
  56                         readList = new ArrayList ();
  57                         writeList = new ArrayList ();
  58                 }
  59
  60                 public EnvironmentPermission (EnvironmentPermissionAccess flag, string pathList) : base ()
  61                 {
  62                         readList = new ArrayList ();
  63                         writeList = new ArrayList ();
  64                         SetPathList (flag, pathList);
  65                 }
  66
  67                 #endregion // Constructors
  68
  69                 #region Methods
  70
  71                 public void AddPathList (EnvironmentPermissionAccess flag, string pathList)
  72                 {
  73                         if (pathList == null)
  74                                 throw new ArgumentNullException ("pathList");
  75
  76                         string[] paths;
  77                         switch (flag) {
  78                                 case EnvironmentPermissionAccess.AllAccess:
  79                                         paths = pathList.Split (';');
  80                                         foreach (string path in paths) {
  81                                                 if (!readList.Contains (path))
  82                                                         readList.Add (path);
  83                                                 if (!writeList.Contains (path))
  84                                                         writeList.Add (path);
  85                                         }
  86                                         break;
  87                                 case EnvironmentPermissionAccess.NoAccess:
  88                                         // ??? unit tests doesn't show removal using NoAccess ???
  89                                         break;
  90                                 case EnvironmentPermissionAccess.Read:
  91                                         paths = pathList.Split (';');
  92                                         foreach (string path in paths) {
  93                                                 if (!readList.Contains (path))
  94                                                         readList.Add (path);
  95                                         }
  96                                         break;
  97                                 case EnvironmentPermissionAccess.Write:
  98                                         paths = pathList.Split (';');
  99                                         foreach (string path in paths) {
 100                                                 if (!writeList.Contains (path))
 101                                                         writeList.Add (path);
 102                                         }
 103                                         break;
 104                                 default:
 105                                         ThrowInvalidFlag (flag, false);
 106                                         break;
 107                         }
 108                 }
 109
 110                 public override IPermission Copy ()
 111                 {
 112                         EnvironmentPermission ep = new EnvironmentPermission (_state);
 113                         string path = GetPathList (EnvironmentPermissionAccess.Read);
 114                         if (path != null)
 115                                 ep.SetPathList (EnvironmentPermissionAccess.Read, path);
 116                         path = GetPathList (EnvironmentPermissionAccess.Write);
 117                         if (path != null)
 118                                 ep.SetPathList (EnvironmentPermissionAccess.Write, path);
 119                         return ep;
 120                 }
 121
 122                 public override void FromXml (SecurityElement esd)
 123                 {
 124                         // General validation in CodeAccessPermission
 125                         CheckSecurityElement (esd, "esd", version, version);
 126                         // Note: we do not (yet) care about the return value
 127                         // as we only accept version 1 (min/max values)
 128
 129                         if (IsUnrestricted (esd))
 130                                 _state = PermissionState.Unrestricted;
 131
 132                         string read = esd.Attribute ("Read");
 133                         if ((read != null) && (read.Length > 0))
 134                                 SetPathList (EnvironmentPermissionAccess.Read, read);
 135
 136                         string write = esd.Attribute ("Write");
 137                         if ((write != null) && (write.Length > 0))
 138                                 SetPathList (EnvironmentPermissionAccess.Write, write);
 139                 }
 140
 141                 public string GetPathList (EnvironmentPermissionAccess flag)
 142                 {
 143                         switch (flag) {
 144                                 case EnvironmentPermissionAccess.AllAccess:
 145                                 case EnvironmentPermissionAccess.NoAccess:
 146                                         ThrowInvalidFlag (flag, true);
 147                                         break;
 148                                 case EnvironmentPermissionAccess.Read:
 149                                         return GetPathList (readList);
 150                                 case EnvironmentPermissionAccess.Write:
 151                                         return GetPathList (writeList);
 152                                 default:
 153                                         ThrowInvalidFlag (flag, false);
 154                                         break;
 155                         }
 156                         return null; // never reached
 157                 }
 158
 159                 public override IPermission Intersect (IPermission target)
 160                 {
 161                         EnvironmentPermission ep = Cast (target);
 162                         if (ep == null)
 163                                 return null;
 164
 165                         if (IsUnrestricted ())
 166                                 return ep.Copy ();
 167                         if (ep.IsUnrestricted ())
 168                                 return Copy ();
 169
 170                         int n = 0;
 171                         EnvironmentPermission result = new EnvironmentPermission (PermissionState.None);
 172                         string readTarget = ep.GetPathList (EnvironmentPermissionAccess.Read);
 173                         if (readTarget != null) {
 174                                 string[] targets = readTarget.Split (';');
 175                                 foreach (string t in targets) {
 176                                         if (readList.Contains (t)) {
 177                                                 result.AddPathList (EnvironmentPermissionAccess.Read, t);
 178                                                 n++;
 179                                         }
 180                                 }
 181                         }
 182
 183                         string writeTarget = ep.GetPathList (EnvironmentPermissionAccess.Write);
 184                         if (writeTarget != null) {
 185                                 string[] targets = writeTarget.Split (';');
 186                                 foreach (string t in targets) {
 187                                         if (writeList.Contains (t)) {
 188                                                 result.AddPathList (EnvironmentPermissionAccess.Write, t);
 189                                                 n++;
 190                                         }
 191                                 }
 192                         }
 193                         return ((n > 0) ? result : null);
 194                 }
 195
 196                 public override bool IsSubsetOf (IPermission target)
 197                 {
 198                         EnvironmentPermission ep = Cast (target);
 199                         if (ep == null)
 200                                 return false;
 201
 202                         if (IsUnrestricted ())
 203                                 return ep.IsUnrestricted ();
 204                         else if (ep.IsUnrestricted ())
 205                                 return true;
 206
 207                         foreach (string s in readList) {
 208                                 if (!ep.readList.Contains (s))
 209                                         return false;
 210                         }
 211
 212                         foreach (string s in writeList) {
 213                                 if (!ep.writeList.Contains (s))
 214                                         return false;
 215                         }
 216
 217                         return true;
 218                 }
 219
 220                 public bool IsUnrestricted ()
 221                 {
 222                         return (_state == PermissionState.Unrestricted);
 223                 }
 224
 225                 public void SetPathList (EnvironmentPermissionAccess flag, string pathList)
 226                 {
 227                         if (pathList == null)
 228                                 throw new ArgumentNullException ("pathList");
 229                         string[] paths;
 230                         switch (flag) {
 231                                 case EnvironmentPermissionAccess.AllAccess:
 232                                         readList.Clear ();
 233                                         writeList.Clear ();
 234                                         paths = pathList.Split (';');
 235                                         foreach (string path in paths) {
 236                                                 readList.Add (path);
 237                                                 writeList.Add (path);
 238                                         }
 239                                         break;
 240                                 case EnvironmentPermissionAccess.NoAccess:
 241                                         // ??? unit tests doesn't show removal using NoAccess ???
 242                                         break;
 243                                 case EnvironmentPermissionAccess.Read:
 244                                         readList.Clear ();
 245                                         paths = pathList.Split (';');
 246                                         foreach (string path in paths) {
 247                                                 readList.Add (path);
 248                                         }
 249                                         break;
 250                                 case EnvironmentPermissionAccess.Write:
 251                                         writeList.Clear ();
 252                                         paths = pathList.Split (';');
 253                                         foreach (string path in paths) {
 254                                                 writeList.Add (path);
 255                                         }
 256                                         break;
 257                                 default:
 258                                         ThrowInvalidFlag (flag, false);
 259                                         break;
 260                         }
 261                 }
 262
 263                 public override SecurityElement ToXml ()
 264                 {
 265                         SecurityElement se = Element (version);
 266
 267                         if (_state == PermissionState.Unrestricted) {
 268                                 se.AddAttribute ("Unrestricted", "true");
 269                         }
 270                         else {
 271                                 string path = GetPathList (EnvironmentPermissionAccess.Read);
 272                                 if (path != null)
 273                                         se.AddAttribute ("Read", path);
 274                                 path = GetPathList (EnvironmentPermissionAccess.Write);
 275                                 if (path != null)
 276                                         se.AddAttribute ("Write", path);
 277                         }
 278                         return se;
 279                 }
 280
 281                 public override IPermission Union (IPermission other)
 282                 {
 283                         EnvironmentPermission ep = Cast (other);
 284                         if (ep == null)
 285                                 return Copy ();
 286
 287                         if (IsUnrestricted () || ep.IsUnrestricted ())
 288                                 return new EnvironmentPermission (PermissionState.Unrestricted);
 289
 290                         if (IsEmpty () && ep.IsEmpty ())
 291                                 return null;
 292
 293                         EnvironmentPermission result = (EnvironmentPermission) Copy ();
 294                         string path = ep.GetPathList (EnvironmentPermissionAccess.Read);
 295                         if (path != null)
 296                                 result.AddPathList (EnvironmentPermissionAccess.Read, path);
 297                         path = ep.GetPathList (EnvironmentPermissionAccess.Write);
 298                         if (path != null)
 299                                 result.AddPathList (EnvironmentPermissionAccess.Write, path);
 300                         return result;
 301                 }
 302
 303                 // IBuiltInPermission
 304                 int IBuiltInPermission.GetTokenIndex ()
 305                 {
 306                         return (int) BuiltInToken.Environment;
 307                 }
 308
 309                 // helpers
 310
 311                 private bool IsEmpty ()
 312                 {
 313                         return ((_state == PermissionState.None) && (readList.Count == 0) && (writeList.Count == 0));
 314                 }
 315
 316                 private EnvironmentPermission Cast (IPermission target)
 317                 {
 318                         if (target == null)
 319                                 return null;
 320
 321                         EnvironmentPermission ep = (target as EnvironmentPermission);
 322                         if (ep == null) {
 323                                 ThrowInvalidPermission (target, typeof (EnvironmentPermission));
 324                         }
 325
 326                         return ep;
 327                 }
 328
 329                 internal void ThrowInvalidFlag (EnvironmentPermissionAccess flag, bool context)
 330                 {
 331                         string msg = null;
 332                         if (context)
 333                                 msg = Locale.GetText ("Unknown flag '{0}'.");
 334                         else
 335                                 msg = Locale.GetText ("Invalid flag '{0}' in this context.");
 336                         throw new ArgumentException (String.Format (msg, flag), "flag");
 337                 }
 338
 339                 private string GetPathList (ArrayList list)
 340                 {
 341                         if (IsUnrestricted ())
 342                                 return String.Empty;
 343 #if NET_2_0
 344                         if (list.Count == 0)
 345                                 return String.Empty;
 346 #else
 347                         if (list.Count == 0)
 348                                 return null;
 349 #endif
 350                         StringBuilder sb = new StringBuilder ();
 351                         foreach (string path in list) {
 352                                 sb.Append (path);
 353                                 sb.Append (";");
 354                         }
 355
 356                         string result = sb.ToString ();
 357                         // remove last ';'
 358                         int n = result.Length;
 359                         if (n > 0)
 360                                 return result.Substring (0, n - 1);
 361 #if NET_2_0
 362                         return String.Empty;
 363 #else
 364                         return ((_state == PermissionState.Unrestricted) ? String.Empty : null);
 365 #endif
 366                 }
 367
 368                 #endregion // Methods
 369         }
 370 }