class/System.Core/System.IO.MemoryMappedFiles/MemoryMappedFile.cs

   1 //
   2 // MemoryMappedFile.cs
   3 //
   4 // Authors:
   5 //      Zoltan Varga (vargaz@gmail.com)
   6 //
   7 // Copyright (C) 2009, Novell, Inc (http://www.novell.com)
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining
  10 // a copy of this software and associated documentation files (the
  11 // "Software"), to deal in the Software without restriction, including
  12 // without limitation the rights to use, copy, modify, merge, publish,
  13 // distribute, sublicense, and/or sell copies of the Software, and to
  14 // permit persons to whom the Software is furnished to do so, subject to
  15 // the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be
  18 // included in all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27 //
  28
  29 #if NET_4_0
  30
  31 using System;
  32 using System.IO;
  33 using System.Collections.Generic;
  34 using Microsoft.Win32.SafeHandles;
  35 using Mono.Unix.Native;
  36 using Mono.Unix;
  37 using System.Runtime.InteropServices;
  38
  39 namespace System.IO.MemoryMappedFiles
  40 {
  41         public class MemoryMappedFile : IDisposable {
  42                 MemoryMappedFileAccess fileAccess;
  43                 string name;
  44                 long fileCapacity;
  45
  46                 //
  47                 // We allow the use of either the FileStream/keepOpen combo
  48                 // or a Unix file descriptor.  This way we avoid the dependency on
  49                 // Mono's io-layer having the Unix file descriptors mapped to
  50                 // the same io-layer handle
  51                 //
  52                 FileStream stream;
  53                 bool keepOpen;
  54                 int unix_fd;
  55
  56                 public static MemoryMappedFile CreateFromFile (string path)
  57                 {
  58                         return CreateFromFile (path, FileMode.Open, null, 0, MemoryMappedFileAccess.ReadWrite);
  59                 }
  60
  61                 public static MemoryMappedFile CreateFromFile (string path, FileMode mode)
  62                 {
  63                         return CreateFromFile (path, mode, null, 0, MemoryMappedFileAccess.ReadWrite);
  64                 }
  65
  66                 public static MemoryMappedFile CreateFromFile (string path, FileMode mode, string mapName)
  67                 {
  68                         return CreateFromFile (path, mode, mapName, 0, MemoryMappedFileAccess.ReadWrite);
  69                 }
  70
  71                 public static MemoryMappedFile CreateFromFile (string path, FileMode mode, string mapName, long capacity)
  72                 {
  73                         return CreateFromFile (path, mode, mapName, capacity, MemoryMappedFileAccess.ReadWrite);
  74                 }
  75
  76                 //
  77                 // Turns the FileMode into the first half of open(2) flags
  78                 //
  79                 static OpenFlags ToUnixMode (FileMode mode)
  80                 {
  81                         switch (mode){
  82                         case FileMode.CreateNew:
  83                                 return OpenFlags.O_CREAT | OpenFlags.O_EXCL;
  84
  85                         case FileMode.Create:
  86                                 return OpenFlags.O_CREAT | OpenFlags.O_TRUNC;
  87
  88                         case FileMode.OpenOrCreate:
  89                                 return OpenFlags.O_CREAT;
  90
  91                         case FileMode.Truncate:
  92                                 return OpenFlags.O_TRUNC;
  93
  94                         case FileMode.Append:
  95                                 return OpenFlags.O_APPEND;
  96                         default:
  97                         case FileMode.Open:
  98                                 return 0;
  99                         }
 100                 }
 101
 102                 //
 103                 // Turns the MemoryMappedFileAccess into the second half of open(2) flags
 104                 //
 105                 static OpenFlags ToUnixMode (MemoryMappedFileAccess access)
 106                 {
 107                         switch (access){
 108                         case MemoryMappedFileAccess.CopyOnWrite:
 109                         case MemoryMappedFileAccess.ReadWriteExecute:
 110                         case MemoryMappedFileAccess.ReadWrite:
 111                                 return OpenFlags.O_RDWR;
 112
 113                         case MemoryMappedFileAccess.Write:
 114                                 return OpenFlags.O_WRONLY;
 115
 116                         case MemoryMappedFileAccess.ReadExecute:
 117                         case MemoryMappedFileAccess.Read:
 118                         default:
 119                                 return OpenFlags.O_RDONLY;
 120                         }
 121                 }
 122
 123                 public static MemoryMappedFile CreateFromFile (string path, FileMode mode, string mapName, long capacity, MemoryMappedFileAccess access)
 124                 {
 125                         if (path == null)
 126                                 throw new ArgumentNullException ("path");
 127                         if (path.Length == 0)
 128                                 throw new ArgumentException ("path");
 129                         if (mapName != null && mapName.Length == 0)
 130                                 throw new ArgumentException ("mapName");
 131
 132                         int fd;
 133                         if (MonoUtil.IsUnix){
 134                                 Stat buf;
 135                                 if (Syscall.stat (path, out buf) == -1)
 136                                         UnixMarshal.ThrowExceptionForLastError ();
 137
 138                                 if ((capacity == 0 && buf.st_size == 0) || (capacity > buf.st_size))
 139                                         throw new ArgumentException ("capacity");
 140
 141                                 fd = Syscall.open (path, ToUnixMode (mode) | ToUnixMode (access), FilePermissions.DEFFILEMODE);
 142
 143                                 if (fd == -1)
 144                                         UnixMarshal.ThrowExceptionForLastError ();
 145                         } else
 146                                 throw new NotImplementedException ();
 147
 148                         return new MemoryMappedFile () {
 149                                 unix_fd = fd,
 150                                 fileAccess = access,
 151                                 name = mapName,
 152                                 fileCapacity = capacity
 153                         };
 154                 }
 155
 156                 static void ConfigureUnixFD (IntPtr handle, HandleInheritability h)
 157                 {
 158                         // TODO: Mono.Posix is lacking O_CLOEXEC definitions for fcntl.
 159                 }
 160
 161
 162                 [DllImport("kernel32.dll", SetLastError = true)]
 163                 static extern bool SetHandleInformation (IntPtr hObject, int dwMask, int dwFlags);
 164                 static void ConfigureWindowsFD (IntPtr handle, HandleInheritability h)
 165                 {
 166                         SetHandleInformation (handle, 1 /* FLAG_INHERIT */, h == HandleInheritability.None ? 0 : 1);
 167                 }
 168
 169                 [MonoLimitation ("memoryMappedFileSecurity is currently ignored")]
 170                 public static MemoryMappedFile CreateFromFile (FileStream fileStream, string mapName, long capacity, MemoryMappedFileAccess access,
 171                                                                MemoryMappedFileSecurity memoryMappedFileSecurity, HandleInheritability inheritability,
 172                                                                bool leaveOpen)
 173                 {
 174                         if (fileStream == null)
 175                                 throw new ArgumentNullException ("fileStream");
 176                         if (mapName != null && mapName.Length == 0)
 177                                 throw new ArgumentException ("mapName");
 178                         if ((capacity == 0 && fileStream.Length == 0) || (capacity > fileStream.Length))
 179                                 throw new ArgumentException ("capacity");
 180
 181                         if (MonoUtil.IsUnix)
 182                                 ConfigureUnixFD (fileStream.Handle, inheritability);
 183                         else
 184                                 ConfigureWindowsFD (fileStream.Handle, inheritability);
 185
 186                         return new MemoryMappedFile () {
 187                                 stream = fileStream,
 188                                 fileAccess = access,
 189                                 name = mapName,
 190                                 fileCapacity = capacity,
 191                                 keepOpen = leaveOpen
 192                         };
 193                 }
 194
 195                 [MonoLimitation ("CreateNew requires that mapName be a file name on Unix")]
 196                 public static MemoryMappedFile CreateNew (string mapName, long capacity)
 197                 {
 198                         return CreateNew (mapName, capacity, MemoryMappedFileAccess.ReadWrite, MemoryMappedFileOptions.DelayAllocatePages, null, 0);
 199                 }
 200
 201                 [MonoLimitation ("CreateNew requires that mapName be a file name on Unix")]
 202                 public static MemoryMappedFile CreateNew (string mapName, long capacity, MemoryMappedFileAccess access)
 203                 {
 204                         return CreateNew (mapName, capacity, access, MemoryMappedFileOptions.DelayAllocatePages, null, 0);
 205                 }
 206
 207                 [MonoLimitation ("CreateNew requires that mapName be a file name on Unix; options and memoryMappedFileSecurity are ignored")]
 208                 public static MemoryMappedFile CreateNew (string mapName, long capacity, MemoryMappedFileAccess access,
 209                                                           MemoryMappedFileOptions options, MemoryMappedFileSecurity memoryMappedFileSecurity,
 210                                                           HandleInheritability handleInheritability)
 211                 {
 212                         return CreateFromFile (mapName, FileMode.CreateNew, mapName, capacity, access);
 213                 }
 214
 215                 [MonoLimitation ("CreateOrOpen requires that mapName be a file name on Unix")]
 216                 public static MemoryMappedFile CreateOrOpen (string mapName, long capacity)
 217                 {
 218                         return CreateOrOpen (mapName, capacity, MemoryMappedFileAccess.ReadWrite);
 219                 }
 220
 221                 [MonoLimitation ("CreateOrOpen requires that mapName be a file name on Unix")]
 222                 public static MemoryMappedFile CreateOrOpen (string mapName, long capacity, MemoryMappedFileAccess access)
 223                 {
 224                         return CreateFromFile (mapName, FileMode.OpenOrCreate, mapName, capacity, access);
 225                 }
 226
 227                 [MonoTODO]
 228                 public static MemoryMappedFile CreateOrOpen (string mapName, long capacity, MemoryMappedFileAccess access, MemoryMappedFileOptions options, MemoryMappedFileSecurity memoryMappedFileSecurity, HandleInheritability handleInheritability)
 229                 {
 230                         throw new NotImplementedException ();
 231                 }
 232
 233                 [MonoTODO]
 234                 public static MemoryMappedFile OpenExisting (string mapName)
 235                 {
 236                         throw new NotImplementedException ();
 237                 }
 238
 239                 [MonoTODO]
 240                 public static MemoryMappedFile OpenExisting (string mapName, MemoryMappedFileRights desiredAccessRights)
 241                 {
 242                         throw new NotImplementedException ();
 243                 }
 244
 245                 [MonoTODO]
 246                 public static MemoryMappedFile OpenExisting (string mapName, MemoryMappedFileRights desiredAccessRights, HandleInheritability inheritability)
 247                 {
 248                         throw new NotImplementedException ();
 249                 }
 250
 251                 public MemoryMappedViewStream CreateViewStream ()
 252                 {
 253                         return CreateViewStream (0, 0);
 254                 }
 255
 256                 public MemoryMappedViewStream CreateViewStream (long offset, long size)
 257                 {
 258                         return CreateViewStream (offset, size, MemoryMappedFileAccess.ReadWrite);
 259                 }
 260
 261                 public MemoryMappedViewStream CreateViewStream (long offset, long size, MemoryMappedFileAccess access)
 262                 {
 263                         return new MemoryMappedViewStream (stream != null ? (int)stream.Handle : unix_fd, offset, size, access);
 264                 }
 265
 266                 public MemoryMappedViewAccessor CreateViewAccessor ()
 267                 {
 268                         return CreateViewAccessor (0, 0);
 269                 }
 270
 271                 public MemoryMappedViewAccessor CreateViewAccessor (long offset, long size)
 272                 {
 273                         return CreateViewAccessor (offset, size, MemoryMappedFileAccess.ReadWrite);
 274                 }
 275
 276                 public MemoryMappedViewAccessor CreateViewAccessor (long offset, long size, MemoryMappedFileAccess access)
 277                 {
 278                         int file_handle = stream != null ? (int) stream.Handle : unix_fd;
 279
 280                         return new MemoryMappedViewAccessor (file_handle, offset, size, access);
 281                 }
 282
 283                 MemoryMappedFile ()
 284                 {
 285                 }
 286
 287                 public void Dispose ()
 288                 {
 289                         Dispose (true);
 290                 }
 291
 292                 protected virtual void Dispose (bool disposing)
 293                 {
 294                         if (disposing){
 295                                 if (stream != null){
 296                                         if (keepOpen == false)
 297                                                 stream.Close ();
 298                                         unix_fd = -1;
 299                                 }
 300                                 if (unix_fd != -1)
 301                                         Syscall.close (unix_fd);
 302                                 unix_fd = -1;
 303                                 stream = null;
 304                         }
 305                 }
 306
 307                 [MonoTODO]
 308                 public MemoryMappedFileSecurity GetAccessControl ()
 309                 {
 310                         throw new NotImplementedException ();
 311                 }
 312
 313                 [MonoTODO]
 314                 public void SetAccessControl (MemoryMappedFileSecurity memoryMappedFileSecurity)
 315                 {
 316                         throw new NotImplementedException ();
 317                 }
 318
 319                 [MonoTODO]
 320                 public SafeMemoryMappedFileHandle SafeMemoryMappedFileHandle {
 321                         get {
 322                                 throw new NotImplementedException ();
 323                         }
 324                 }
 325
 326                 static int pagesize;
 327
 328                 static MmapProts ToUnixProts (MemoryMappedFileAccess access)
 329                 {
 330                         MmapProts prots;
 331
 332                         switch (access){
 333                         case MemoryMappedFileAccess.ReadWrite:
 334                                 return MmapProts.PROT_WRITE | MmapProts.PROT_READ;
 335                                 break;
 336
 337                         case MemoryMappedFileAccess.Write:
 338                                 return MmapProts.PROT_WRITE;
 339
 340                         case MemoryMappedFileAccess.CopyOnWrite:
 341                                 return MmapProts.PROT_WRITE | MmapProts.PROT_READ;
 342
 343                         case MemoryMappedFileAccess.ReadExecute:
 344                                 return MmapProts.PROT_EXEC;
 345
 346                         case MemoryMappedFileAccess.ReadWriteExecute:
 347                                 return MmapProts.PROT_WRITE | MmapProts.PROT_READ | MmapProts.PROT_EXEC;
 348
 349                         case MemoryMappedFileAccess.Read:
 350                         default:
 351                                 return MmapProts.PROT_READ;
 352                         }
 353                 }
 354
 355                 internal static unsafe void MapPosix (int file_handle, long offset, ref long size, MemoryMappedFileAccess access, out IntPtr map_addr, out int offset_diff)
 356                 {
 357                         if (pagesize == 0)
 358                                 pagesize = Syscall.getpagesize ();
 359
 360                         Stat buf;
 361                         Syscall.fstat (file_handle, out buf);
 362                         long fsize = buf.st_size;
 363
 364                         if (size == 0 || size > fsize)
 365                                 size = fsize;
 366
 367                         // Align offset
 368                         long real_offset = offset & ~(pagesize - 1);
 369
 370                         offset_diff = (int)(offset - real_offset);
 371
 372                         // FIXME: Need to determine the unix fd for the file, Handle is only
 373                         // equal to it by accident
 374                         //
 375                         // The new API no longer uses FileStream everywhere, but exposes instead
 376                         // the filename (with one exception), we could move this API to use
 377                         // file descriptors instead of the FileStream plus its Handle.
 378                         //
 379                         map_addr = Syscall.mmap (IntPtr.Zero, (ulong) size,
 380                                                  ToUnixProts (access),
 381                                                  access == MemoryMappedFileAccess.CopyOnWrite ? MmapFlags.MAP_PRIVATE : MmapFlags.MAP_SHARED,
 382                                                  file_handle, real_offset);
 383
 384                         if (map_addr == (IntPtr)(-1))
 385                                 throw new IOException ("mmap failed for fd#" + file_handle + "(" + offset + ", " + size + ")");
 386                 }
 387
 388                 internal static bool UnmapPosix (IntPtr map_addr, ulong map_size)
 389                 {
 390                         return Syscall.munmap (map_addr, map_size) == 0;
 391                 }
 392
 393         }
 394 }
 395
 396 #endif