mcs/class/System/System.IO.Ports/WinSerialStream.cs

   1 //
   2 // System.IO.Ports.WinSerialStream.cs
   3 //
   4 // Authors:
   5 //      Carlos Alberto Cortez (calberto.cortez@gmail.com)
   6 //
   7 // (c) Copyright 2006 Novell, Inc. (http://www.novell.com)
   8 //
   9
  10 using System;
  11 using System.Text;
  12 using System.IO;
  13 using System.Runtime.InteropServices;
  14 using System.Threading;
  15 using System.ComponentModel;
  16
  17 namespace System.IO.Ports
  18 {
  19         class WinSerialStream : Stream, ISerialStream, IDisposable
  20         {
  21                 // Windows API Constants
  22                 const uint GenericRead = 0x80000000;
  23                 const uint GenericWrite = 0x40000000;
  24                 const uint OpenExisting = 3;
  25                 const uint FileFlagOverlapped = 0x40000000;
  26                 const uint PurgeRxClear = 0x0008;
  27                 const uint PurgeTxClear = 0x0004;
  28                 const uint WinInfiniteTimeout = 0xFFFFFFFF;
  29                 const uint FileIOPending = 997;
  30
  31                 // Signal constants
  32                 const uint SetRts = 3;
  33                 const uint ClearRts = 4;
  34                 const uint SetDtr = 5;
  35                 const uint ClearDtr = 6;
  36                 const uint SetBreak = 8;
  37                 const uint ClearBreak = 9;
  38                 const uint CtsOn = 0x0010;
  39                 const uint DsrOn = 0x0020;
  40                 const uint RsldOn = 0x0080;
  41
  42                 // Event constants
  43                 const uint EvRxChar = 0x0001;
  44                 const uint EvCts = 0x0008;
  45                 const uint EvDsr = 0x0010;
  46                 const uint EvRlsd = 0x0020;
  47                 const uint EvBreak = 0x0040;
  48                 const uint EvErr = 0x0080;
  49                 const uint EvRing = 0x0100;
  50
  51                 int handle;
  52                 int read_timeout;
  53                 int write_timeout;
  54                 bool disposed;
  55                 IntPtr write_overlapped;
  56                 IntPtr read_overlapped;
  57                 ManualResetEvent read_event;
  58                 ManualResetEvent write_event;
  59                 Timeouts timeouts;
  60
  61                 [DllImport("kernel32", SetLastError = true)]
  62                 static extern int CreateFile(string port_name, uint desired_access,
  63                                 uint share_mode, uint security_attrs, uint creation, uint flags,
  64                                 uint template);
  65
  66                 [DllImport("kernel32", SetLastError = true)]
  67                 static extern bool SetupComm(int handle, int read_buffer_size, int write_buffer_size);
  68
  69                 [DllImport("kernel32", SetLastError = true)]
  70                 static extern bool PurgeComm(int handle, uint flags);
  71
  72                 [DllImport("kernel32", SetLastError = true)]
  73                 static extern bool SetCommTimeouts(int handle, Timeouts timeouts);
  74
  75                 public WinSerialStream (string port_name, int baud_rate, int data_bits, Parity parity, StopBits sb,
  76                                 bool dtr_enable, bool rts_enable, Handshake hs, int read_timeout, int write_timeout,
  77                                 int read_buffer_size, int write_buffer_size)
  78                 {
  79                         handle = CreateFile (port_name != null && !port_name.StartsWith(@"\\.\")
  80                                         ? @"\\.\" + port_name : port_name,
  81                                         GenericRead | GenericWrite, 0, 0, OpenExisting,
  82                                         FileFlagOverlapped, 0);
  83
  84                         if (handle == -1)
  85                                 ReportIOError (port_name);
  86
  87                         // Set port low level attributes
  88                         SetAttributes (baud_rate, parity, data_bits, sb, hs);
  89
  90                         // Clean buffers and set sizes
  91                         if (!PurgeComm (handle, PurgeRxClear | PurgeTxClear) ||
  92                                         !SetupComm (handle, read_buffer_size, write_buffer_size))
  93                                 ReportIOError (null);
  94
  95                         // Set timeouts
  96                         this.read_timeout = read_timeout;
  97                         this.write_timeout = write_timeout;
  98                         timeouts = new Timeouts (read_timeout, write_timeout);
  99                         if (!SetCommTimeouts(handle, timeouts))
 100                                 ReportIOError (null);
 101
 102                         /// Set DTR and RTS
 103                         SetSignal(SerialSignal.Dtr, dtr_enable);
 104
 105                         if (hs != Handshake.RequestToSend &&
 106                                         hs != Handshake.RequestToSendXOnXOff)
 107                                 SetSignal(SerialSignal.Rts, rts_enable);
 108
 109                         // Init overlapped structures
 110                         NativeOverlapped wo = new NativeOverlapped ();
 111                         write_event = new ManualResetEvent (false);
 112                         wo.EventHandle = write_event.Handle;
 113                         write_overlapped = Marshal.AllocHGlobal (Marshal.SizeOf (typeof (NativeOverlapped)));
 114                         Marshal.StructureToPtr (wo, write_overlapped, true);
 115
 116                         NativeOverlapped ro = new NativeOverlapped ();
 117                         read_event = new ManualResetEvent (false);
 118                         ro.EventHandle = read_event.Handle;
 119                         read_overlapped = Marshal.AllocHGlobal (Marshal.SizeOf (typeof (NativeOverlapped)));
 120                         Marshal.StructureToPtr (ro, read_overlapped, true);
 121                 }
 122
 123                 public override bool CanRead {
 124                         get {
 125                                 return true;
 126                         }
 127                 }
 128
 129                 public override bool CanSeek {
 130                         get {
 131                                 return false;
 132                         }
 133                 }
 134
 135                 public override bool CanTimeout {
 136                         get {
 137                                 return true;
 138                         }
 139                 }
 140
 141                 public override bool CanWrite {
 142                         get {
 143                                 return true;
 144                         }
 145                 }
 146
 147                 public override int ReadTimeout {
 148                         get {
 149                                 return read_timeout;
 150                         }
 151                         set {
 152                                 if (value < 0 && value != SerialPort.InfiniteTimeout)
 153                                         throw new ArgumentOutOfRangeException ("value");
 154
 155                                 timeouts.SetValues (value, write_timeout);
 156                                 if (!SetCommTimeouts (handle, timeouts))
 157                                         ReportIOError (null);
 158
 159                                 read_timeout = value;
 160                         }
 161                 }
 162
 163                 public override int WriteTimeout {
 164                         get {
 165                                 return write_timeout;
 166                         }
 167                         set
 168                         {
 169                                 if (value < 0 && value != SerialPort.InfiniteTimeout)
 170                                         throw new ArgumentOutOfRangeException ("value");
 171
 172                                 timeouts.SetValues (read_timeout, value);
 173                                 if (!SetCommTimeouts (handle, timeouts))
 174                                         ReportIOError (null);
 175
 176                                 write_timeout = value;
 177                         }
 178                 }
 179
 180                 public override long Length {
 181                         get {
 182                                 throw new NotSupportedException ();
 183                         }
 184                 }
 185
 186                 public override long Position {
 187                         get {
 188                                 throw new NotSupportedException ();
 189                         }
 190                         set {
 191                                 throw new NotSupportedException ();
 192                         }
 193                 }
 194
 195                 [DllImport("kernel32", SetLastError = true)]
 196                 static extern bool CloseHandle (int handle);
 197
 198                 protected override void Dispose (bool disposing)
 199                 {
 200                         if (disposed)
 201                                 return;
 202
 203                         disposed = true;
 204                         CloseHandle (handle);
 205                         Marshal.FreeHGlobal (write_overlapped);
 206                         Marshal.FreeHGlobal (read_overlapped);
 207                 }
 208
 209                 void IDisposable.Dispose ()
 210                 {
 211                         Dispose (true);
 212                         GC.SuppressFinalize (this);
 213                 }
 214
 215                 public override void Close ()
 216                 {
 217                         ((IDisposable)this).Dispose ();
 218                 }
 219
 220                 ~WinSerialStream ()
 221                 {
 222                         Dispose (false);
 223                 }
 224
 225                 public override void Flush ()
 226                 {
 227                         CheckDisposed ();
 228                         // No dothing by now
 229                 }
 230
 231                 public override long Seek (long offset, SeekOrigin origin)
 232                 {
 233                         throw new NotSupportedException();
 234                 }
 235
 236                 public override void SetLength (long value)
 237                 {
 238                         throw new NotSupportedException();
 239                 }
 240
 241                 [DllImport("kernel32", SetLastError = true)]
 242                         static extern unsafe bool ReadFile (int handle, byte* buffer, int bytes_to_read,
 243                                         out int bytes_read, IntPtr overlapped);
 244
 245                 [DllImport("kernel32", SetLastError = true)]
 246                         static extern unsafe bool GetOverlappedResult (int handle, IntPtr overlapped,
 247                                         ref int bytes_transfered, bool wait);
 248
 249                 public override int Read ([In, Out] byte [] buffer, int offset, int count)
 250                 {
 251                         CheckDisposed ();
 252                         if (buffer == null)
 253                                 throw new ArgumentNullException ("buffer");
 254                         if (offset < 0 || count < 0)
 255                                 throw new ArgumentOutOfRangeException ("offset or count less than zero.");
 256
 257                         if (buffer.Length - offset < count )
 258                                 throw new ArgumentException ("offset+count",
 259                                                               "The size of the buffer is less than offset + count.");
 260
 261                         int bytes_read;
 262
 263                         unsafe {
 264                                 fixed (byte* ptr = buffer) {
 265                                         if (ReadFile (handle, ptr + offset, count, out bytes_read, read_overlapped))
 266                                                 return bytes_read;
 267
 268                                         // Test for overlapped behavior
 269                                         if (Marshal.GetLastWin32Error () != FileIOPending)
 270                                                 ReportIOError (null);
 271
 272                                         if (!GetOverlappedResult (handle, read_overlapped, ref bytes_read, true))
 273                                                 ReportIOError (null);
 274
 275                                 }
 276                         }
 277
 278                         if (bytes_read == 0)
 279                                 throw new TimeoutException (); // We didn't get any byte
 280
 281                         return bytes_read;
 282                 }
 283
 284                 [DllImport("kernel32", SetLastError = true)]
 285                 static extern unsafe bool WriteFile (int handle, byte* buffer, int bytes_to_write,
 286                                 out int bytes_written, IntPtr overlapped);
 287
 288                 public override void Write (byte [] buffer, int offset, int count)
 289                 {
 290                         CheckDisposed ();
 291                         if (buffer == null)
 292                                 throw new ArgumentNullException ("buffer");
 293
 294                         if (offset < 0 || count < 0)
 295                                 throw new ArgumentOutOfRangeException ();
 296
 297                         if (buffer.Length - offset < count)
 298                                 throw new ArgumentException ("offset+count",
 299                                                              "The size of the buffer is less than offset + count.");
 300
 301                         int bytes_written = 0;
 302
 303                         unsafe {
 304                                 fixed (byte* ptr = buffer) {
 305                                         if (WriteFile (handle, ptr + offset, count, out bytes_written, write_overlapped))
 306                                                 return;
 307                                         if (Marshal.GetLastWin32Error() != FileIOPending)
 308                                                 ReportIOError (null);
 309
 310                                         if (!GetOverlappedResult(handle, write_overlapped, ref bytes_written, true))
 311                                                 ReportIOError (null);
 312                                 }
 313                         }
 314
 315                         // If the operation timed out, then
 316                         // we transfered less bytes than the requested ones
 317                         if (bytes_written < count)
 318                                 throw new TimeoutException ();
 319                 }
 320
 321                 [DllImport("kernel32", SetLastError = true)]
 322                 static extern bool GetCommState (int handle, [Out] DCB dcb);
 323
 324                 [DllImport ("kernel32", SetLastError=true)]
 325                 static extern bool SetCommState (int handle, DCB dcb);
 326
 327                 public void SetAttributes (int baud_rate, Parity parity, int data_bits, StopBits bits, Handshake hs)
 328                 {
 329                         DCB dcb = new DCB ();
 330                         if (!GetCommState (handle, dcb))
 331                                 ReportIOError (null);
 332
 333                         dcb.SetValues (baud_rate, parity, data_bits, bits, hs);
 334                         if (!SetCommState (handle, dcb))
 335                                 ReportIOError (null);
 336                 }
 337
 338                 void ReportIOError(string optional_arg)
 339                 {
 340                         int error = Marshal.GetLastWin32Error ();
 341                         string message;
 342                         switch (error) {
 343                                 case 2:
 344                                 case 3:
 345                                         message = "The port `" + optional_arg + "' does not exist.";
 346                                         break;
 347                                 case 87:
 348                                         message = "Parameter is incorrect.";
 349                                         break;
 350                                 default:
 351                                         // As fallback, we show the win32 error
 352                                         message = new Win32Exception ().Message;
 353                                         break;
 354                         }
 355
 356                         throw new IOException (message);
 357                 }
 358
 359                 void CheckDisposed ()
 360                 {
 361                         if (disposed)
 362                                 throw new ObjectDisposedException (GetType ().FullName);
 363                 }
 364
 365                 // ISerialStream members
 366                 public void DiscardInBuffer ()
 367                 {
 368                         if (!PurgeComm (handle, PurgeRxClear))
 369                                 ReportIOError (null);
 370                 }
 371
 372                 public void DiscardOutBuffer ()
 373                 {
 374                         if (!PurgeComm (handle, PurgeTxClear))
 375                                 ReportIOError (null);
 376                 }
 377
 378                 [DllImport ("kernel32", SetLastError=true)]
 379                 static extern bool ClearCommError (int handle, out uint errors, out CommStat stat);
 380
 381                 public int BytesToRead {
 382                         get {
 383                                 uint errors;
 384                                 CommStat stat;
 385                                 if (!ClearCommError (handle, out errors, out stat))
 386                                         ReportIOError (null);
 387
 388                                 return (int)stat.BytesIn;
 389                         }
 390                 }
 391
 392                 public int BytesToWrite {
 393                         get {
 394                                 uint errors;
 395                                 CommStat stat;
 396                                 if (!ClearCommError (handle, out errors, out stat))
 397                                         ReportIOError (null);
 398
 399                                 return (int)stat.BytesOut;
 400                         }
 401                 }
 402
 403                 [DllImport ("kernel32", SetLastError=true)]
 404                 static extern bool GetCommModemStatus (int handle, out uint flags);
 405
 406                 public SerialSignal GetSignals ()
 407                 {
 408                         uint flags;
 409                         if (!GetCommModemStatus (handle, out flags))
 410                                 ReportIOError (null);
 411
 412                         SerialSignal signals = SerialSignal.None;
 413                         if ((flags & RsldOn) != 0)
 414                                 signals |= SerialSignal.Cd;
 415                         if ((flags & CtsOn) != 0)
 416                                 signals |= SerialSignal.Cts;
 417                         if ((flags & DsrOn) != 0)
 418                                 signals |= SerialSignal.Dsr;
 419
 420                         return signals;
 421                 }
 422
 423                 [DllImport ("kernel32", SetLastError=true)]
 424                 static extern bool EscapeCommFunction (int handle, uint flags);
 425
 426                 public void SetSignal (SerialSignal signal, bool value)
 427                 {
 428                         if (signal != SerialSignal.Rts && signal != SerialSignal.Dtr)
 429                                 throw new Exception ("Wrong internal value");
 430
 431                         uint flag;
 432                         if (signal == SerialSignal.Rts)
 433                                 if (value)
 434                                         flag = SetRts;
 435                                 else
 436                                         flag = ClearRts;
 437                         else
 438                                 if (value)
 439                                         flag = SetDtr;
 440                                 else
 441                                         flag = ClearDtr;
 442
 443                         if (!EscapeCommFunction (handle, flag))
 444                                 ReportIOError (null);
 445                 }
 446
 447                 public void SetBreakState (bool value)
 448                 {
 449                         if (!EscapeCommFunction (handle, value ? SetBreak : ClearBreak))
 450                                 ReportIOError (null);
 451                 }
 452
 453         }
 454
 455         [StructLayout (LayoutKind.Sequential)]
 456         class DCB
 457         {
 458                 public int dcb_length;
 459                 public int baud_rate;
 460                 public int flags;
 461                 public short w_reserved;
 462                 public short xon_lim;
 463                 public short xoff_lim;
 464                 public byte byte_size;
 465                 public byte parity;
 466                 public byte stop_bits;
 467                 public byte xon_char;
 468                 public byte xoff_char;
 469                 public byte error_char;
 470                 public byte eof_char;
 471                 public byte evt_char;
 472                 public short w_reserved1;
 473
 474                 // flags:
 475                 //const int fBinary = 0x0001;
 476                 //const int fParity = 0x0002;
 477                 const int fOutxCtsFlow = 0x0004;
 478                 //const int fOutxDsrFlow1 = 0x0008;
 479                 //const int fOutxDsrFlow2 = 0x0010;
 480                 //const int fDtrControl = 0x00020;
 481                 //const int fDsrSensitivity = 0x0040;
 482                 //const int fTXContinueOnXoff = 0x0080;
 483                 const int fOutX = 0x0100;
 484                 const int fInX = 0x0200;
 485                 //const int fErrorChar = 0x0400;
 486                 //const int fNull = 0x0800;
 487                 //const int fRtsControl1 = 0x1000;
 488                 const int fRtsControl2 = 0x2000;
 489                 //const int fAbortOnError = 0x4000;
 490
 491                 public void SetValues (int baud_rate, Parity parity, int byte_size, StopBits sb, Handshake hs)
 492                 {
 493                         switch (sb) {
 494                                 case StopBits.One:
 495                                         stop_bits = 0;
 496                                         break;
 497                                 case StopBits.OnePointFive:
 498                                         stop_bits = 1;
 499                                         break;
 500                                 case StopBits.Two:
 501                                         stop_bits = 2;
 502                                         break;
 503                                 default: // Shouldn't happen
 504                                         break;
 505                         }
 506
 507                         this.baud_rate = baud_rate;
 508                         this.parity = (byte)parity;
 509                         this.byte_size = (byte)byte_size;
 510
 511                         // Clear Handshake flags
 512                         flags &= ~(fOutxCtsFlow | fOutX | fInX | fRtsControl2);
 513
 514                         // Set Handshake flags
 515                         switch (hs)
 516                         {
 517                                 case Handshake.None:
 518                                         break;
 519                                 case Handshake.XOnXOff:
 520                                         flags |= fOutX | fInX;
 521                                         break;
 522                                 case Handshake.RequestToSend:
 523                                         flags |= fOutxCtsFlow | fRtsControl2;
 524                                         break;
 525                                 case Handshake.RequestToSendXOnXOff:
 526                                         flags |= fOutxCtsFlow | fOutX | fInX | fRtsControl2;
 527                                         break;
 528                                 default: // Shouldn't happen
 529                                         break;
 530                         }
 531                 }
 532         }
 533
 534         [StructLayout (LayoutKind.Sequential)]
 535         class Timeouts
 536         {
 537                 public uint ReadIntervalTimeout;
 538                 public uint ReadTotalTimeoutMultiplier;
 539                 public uint ReadTotalTimeoutConstant;
 540                 public uint WriteTotalTimeoutMultiplier;
 541                 public uint WriteTotalTimeoutConstant;
 542
 543                 public const uint MaxDWord = 0xFFFFFFFF;
 544
 545                 public Timeouts (int read_timeout, int write_timeout)
 546                 {
 547                         SetValues (read_timeout, write_timeout);
 548                 }
 549
 550                 public void SetValues (int read_timeout, int write_timeout)
 551                 {
 552                         // FIXME: The windows api docs are not very clear about read timeouts,
 553                         // and we have to simulate infinite with a big value (uint.MaxValue - 1)
 554                         ReadIntervalTimeout = MaxDWord;
 555                         ReadTotalTimeoutMultiplier = MaxDWord;
 556                         ReadTotalTimeoutConstant = (read_timeout == -1 ? MaxDWord - 1 : (uint) read_timeout);
 557
 558                         WriteTotalTimeoutMultiplier = 0;
 559                         WriteTotalTimeoutConstant = (write_timeout == -1 ? MaxDWord : (uint) write_timeout);
 560                 }
 561
 562         }
 563
 564         [StructLayout (LayoutKind.Sequential)]
 565         struct CommStat
 566         {
 567                 public uint flags;
 568                 public uint BytesIn;
 569                 public uint BytesOut;
 570         }
 571 }
 572
 573