gdb/ser-mingw.c

   1 /* Serial interface for local (hardwired) serial ports on Windows systems
   2
   3    Copyright (C) 2006-2020 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21 #include "serial.h"
  22 #include "ser-base.h"
  23 #include "ser-tcp.h"
  24
  25 #include <windows.h>
  26 #include <conio.h>
  27
  28 #include <fcntl.h>
  29 #include <unistd.h>
  30 #include <sys/types.h>
  31
  32 #include "command.h"
  33
  34 struct ser_windows_state
  35 {
  36   int in_progress;
  37   OVERLAPPED ov;
  38   DWORD lastCommMask;
  39   HANDLE except_event;
  40 };
  41
  42 /* CancelIo is not available for Windows 95 OS, so we need to use
  43    LoadLibrary/GetProcAddress to avoid a startup failure.  */
  44 #define CancelIo dyn_CancelIo
  45 typedef BOOL WINAPI (CancelIo_ftype) (HANDLE);
  46 static CancelIo_ftype *CancelIo;
  47
  48 /* Open up a real live device for serial I/O.  */
  49
  50 static int
  51 ser_windows_open (struct serial *scb, const char *name)
  52 {
  53   HANDLE h;
  54   struct ser_windows_state *state;
  55   COMMTIMEOUTS timeouts;
  56
  57   h = CreateFile (name, GENERIC_READ | GENERIC_WRITE, 0, NULL,
  58                   OPEN_EXISTING, FILE_FLAG_OVERLAPPED, NULL);
  59   if (h == INVALID_HANDLE_VALUE)
  60     {
  61       errno = ENOENT;
  62       return -1;
  63     }
  64
  65   scb->fd = _open_osfhandle ((intptr_t) h, O_RDWR);
  66   if (scb->fd < 0)
  67     {
  68       errno = ENOENT;
  69       return -1;
  70     }
  71
  72   if (!SetCommMask (h, EV_RXCHAR))
  73     {
  74       errno = EINVAL;
  75       return -1;
  76     }
  77
  78   timeouts.ReadIntervalTimeout = MAXDWORD;
  79   timeouts.ReadTotalTimeoutConstant = 0;
  80   timeouts.ReadTotalTimeoutMultiplier = 0;
  81   timeouts.WriteTotalTimeoutConstant = 0;
  82   timeouts.WriteTotalTimeoutMultiplier = 0;
  83   if (!SetCommTimeouts (h, &timeouts))
  84     {
  85       errno = EINVAL;
  86       return -1;
  87     }
  88
  89   state = XCNEW (struct ser_windows_state);
  90   scb->state = state;
  91
  92   /* Create a manual reset event to watch the input buffer.  */
  93   state->ov.hEvent = CreateEvent (0, TRUE, FALSE, 0);
  94
  95   /* Create a (currently unused) handle to record exceptions.  */
  96   state->except_event = CreateEvent (0, TRUE, FALSE, 0);
  97
  98   return 0;
  99 }
 100
 101 /* Wait for the output to drain away, as opposed to flushing (discarding)
 102    it.  */
 103
 104 static int
 105 ser_windows_drain_output (struct serial *scb)
 106 {
 107   HANDLE h = (HANDLE) _get_osfhandle (scb->fd);
 108
 109   return (FlushFileBuffers (h) != 0) ? 0 : -1;
 110 }
 111
 112 static int
 113 ser_windows_flush_output (struct serial *scb)
 114 {
 115   HANDLE h = (HANDLE) _get_osfhandle (scb->fd);
 116
 117   return (PurgeComm (h, PURGE_TXCLEAR) != 0) ? 0 : -1;
 118 }
 119
 120 static int
 121 ser_windows_flush_input (struct serial *scb)
 122 {
 123   HANDLE h = (HANDLE) _get_osfhandle (scb->fd);
 124
 125   return (PurgeComm (h, PURGE_RXCLEAR) != 0) ? 0 : -1;
 126 }
 127
 128 static int
 129 ser_windows_send_break (struct serial *scb)
 130 {
 131   HANDLE h = (HANDLE) _get_osfhandle (scb->fd);
 132
 133   if (SetCommBreak (h) == 0)
 134     return -1;
 135
 136   /* Delay for 250 milliseconds.  */
 137   Sleep (250);
 138
 139   if (ClearCommBreak (h))
 140     return -1;
 141
 142   return 0;
 143 }
 144
 145 static void
 146 ser_windows_raw (struct serial *scb)
 147 {
 148   HANDLE h = (HANDLE) _get_osfhandle (scb->fd);
 149   DCB state;
 150
 151   if (GetCommState (h, &state) == 0)
 152     return;
 153
 154   state.fOutxCtsFlow = FALSE;
 155   state.fOutxDsrFlow = FALSE;
 156   state.fDtrControl = DTR_CONTROL_ENABLE;
 157   state.fDsrSensitivity = FALSE;
 158   state.fOutX = FALSE;
 159   state.fInX = FALSE;
 160   state.fNull = FALSE;
 161   state.fAbortOnError = FALSE;
 162   state.ByteSize = 8;
 163
 164   if (SetCommState (h, &state) == 0)
 165     warning (_("SetCommState failed"));
 166 }
 167
 168 static int
 169 ser_windows_setstopbits (struct serial *scb, int num)
 170 {
 171   HANDLE h = (HANDLE) _get_osfhandle (scb->fd);
 172   DCB state;
 173
 174   if (GetCommState (h, &state) == 0)
 175     return -1;
 176
 177   switch (num)
 178     {
 179     case SERIAL_1_STOPBITS:
 180       state.StopBits = ONESTOPBIT;
 181       break;
 182     case SERIAL_1_AND_A_HALF_STOPBITS:
 183       state.StopBits = ONE5STOPBITS;
 184       break;
 185     case SERIAL_2_STOPBITS:
 186       state.StopBits = TWOSTOPBITS;
 187       break;
 188     default:
 189       return 1;
 190     }
 191
 192   return (SetCommState (h, &state) != 0) ? 0 : -1;
 193 }
 194
 195 /* Implement the "setparity" serial_ops callback.  */
 196
 197 static int
 198 ser_windows_setparity (struct serial *scb, int parity)
 199 {
 200   HANDLE h = (HANDLE) _get_osfhandle (scb->fd);
 201   DCB state;
 202
 203   if (GetCommState (h, &state) == 0)
 204     return -1;
 205
 206   switch (parity)
 207     {
 208     case GDBPARITY_NONE:
 209       state.Parity = NOPARITY;
 210       state.fParity = FALSE;
 211       break;
 212     case GDBPARITY_ODD:
 213       state.Parity = ODDPARITY;
 214       state.fParity = TRUE;
 215       break;
 216     case GDBPARITY_EVEN:
 217       state.Parity = EVENPARITY;
 218       state.fParity = TRUE;
 219       break;
 220     default:
 221       internal_warning (__FILE__, __LINE__,
 222                         "Incorrect parity value: %d", parity);
 223       return -1;
 224     }
 225
 226   return (SetCommState (h, &state) != 0) ? 0 : -1;
 227 }
 228
 229 static int
 230 ser_windows_setbaudrate (struct serial *scb, int rate)
 231 {
 232   HANDLE h = (HANDLE) _get_osfhandle (scb->fd);
 233   DCB state;
 234
 235   if (GetCommState (h, &state) == 0)
 236     return -1;
 237
 238   state.BaudRate = rate;
 239
 240   return (SetCommState (h, &state) != 0) ? 0 : -1;
 241 }
 242
 243 static void
 244 ser_windows_close (struct serial *scb)
 245 {
 246   struct ser_windows_state *state;
 247
 248   /* Stop any pending selects.  On Windows 95 OS, CancelIo function does
 249      not exist.  In that case, it can be replaced by a call to CloseHandle,
 250      but this is not necessary here as we do close the Windows handle
 251      by calling close (scb->fd) below.  */
 252   if (CancelIo)
 253     CancelIo ((HANDLE) _get_osfhandle (scb->fd));
 254   state = (struct ser_windows_state *) scb->state;
 255   CloseHandle (state->ov.hEvent);
 256   CloseHandle (state->except_event);
 257
 258   if (scb->fd < 0)
 259     return;
 260
 261   close (scb->fd);
 262   scb->fd = -1;
 263
 264   xfree (scb->state);
 265 }
 266
 267 static void
 268 ser_windows_wait_handle (struct serial *scb, HANDLE *read, HANDLE *except)
 269 {
 270   struct ser_windows_state *state;
 271   COMSTAT status;
 272   DWORD errors;
 273   HANDLE h = (HANDLE) _get_osfhandle (scb->fd);
 274
 275   state = (struct ser_windows_state *) scb->state;
 276
 277   *except = state->except_event;
 278   *read = state->ov.hEvent;
 279
 280   if (state->in_progress)
 281     return;
 282
 283   /* Reset the mask - we are only interested in any characters which
 284      arrive after this point, not characters which might have arrived
 285      and already been read.  */
 286
 287   /* This really, really shouldn't be necessary - just the second one.
 288      But otherwise an internal flag for EV_RXCHAR does not get
 289      cleared, and we get a duplicated event, if the last batch
 290      of characters included at least two arriving close together.  */
 291   if (!SetCommMask (h, 0))
 292     warning (_("ser_windows_wait_handle: reseting mask failed"));
 293
 294   if (!SetCommMask (h, EV_RXCHAR))
 295     warning (_("ser_windows_wait_handle: reseting mask failed (2)"));
 296
 297   /* There's a potential race condition here; we must check cbInQue
 298      and not wait if that's nonzero.  */
 299
 300   ClearCommError (h, &errors, &status);
 301   if (status.cbInQue > 0)
 302     {
 303       SetEvent (state->ov.hEvent);
 304       return;
 305     }
 306
 307   state->in_progress = 1;
 308   ResetEvent (state->ov.hEvent);
 309   state->lastCommMask = -2;
 310   if (WaitCommEvent (h, &state->lastCommMask, &state->ov))
 311     {
 312       gdb_assert (state->lastCommMask & EV_RXCHAR);
 313       SetEvent (state->ov.hEvent);
 314     }
 315   else
 316     gdb_assert (GetLastError () == ERROR_IO_PENDING);
 317 }
 318
 319 static int
 320 ser_windows_read_prim (struct serial *scb, size_t count)
 321 {
 322   struct ser_windows_state *state;
 323   OVERLAPPED ov;
 324   DWORD bytes_read;
 325   HANDLE h;
 326
 327   state = (struct ser_windows_state *) scb->state;
 328   if (state->in_progress)
 329     {
 330       WaitForSingleObject (state->ov.hEvent, INFINITE);
 331       state->in_progress = 0;
 332       ResetEvent (state->ov.hEvent);
 333     }
 334
 335   memset (&ov, 0, sizeof (OVERLAPPED));
 336   ov.hEvent = CreateEvent (0, FALSE, FALSE, 0);
 337   h = (HANDLE) _get_osfhandle (scb->fd);
 338
 339   if (!ReadFile (h, scb->buf, /* count */ 1, &bytes_read, &ov))
 340     {
 341       if (GetLastError () != ERROR_IO_PENDING
 342           || !GetOverlappedResult (h, &ov, &bytes_read, TRUE))
 343         bytes_read = -1;
 344     }
 345
 346   CloseHandle (ov.hEvent);
 347   return bytes_read;
 348 }
 349
 350 static int
 351 ser_windows_write_prim (struct serial *scb, const void *buf, size_t len)
 352 {
 353   OVERLAPPED ov;
 354   DWORD bytes_written;
 355   HANDLE h;
 356
 357   memset (&ov, 0, sizeof (OVERLAPPED));
 358   ov.hEvent = CreateEvent (0, FALSE, FALSE, 0);
 359   h = (HANDLE) _get_osfhandle (scb->fd);
 360   if (!WriteFile (h, buf, len, &bytes_written, &ov))
 361     {
 362       if (GetLastError () != ERROR_IO_PENDING
 363           || !GetOverlappedResult (h, &ov, &bytes_written, TRUE))
 364         bytes_written = -1;
 365     }
 366
 367   CloseHandle (ov.hEvent);
 368   return bytes_written;
 369 }
 370
 371 /* On Windows, gdb_select is implemented using WaitForMulpleObjects.
 372    A "select thread" is created for each file descriptor.  These
 373    threads looks for activity on the corresponding descriptor, using
 374    whatever techniques are appropriate for the descriptor type.  When
 375    that activity occurs, the thread signals an appropriate event,
 376    which wakes up WaitForMultipleObjects.
 377
 378    Each select thread is in one of two states: stopped or started.
 379    Select threads begin in the stopped state.  When gdb_select is
 380    called, threads corresponding to the descriptors of interest are
 381    started by calling a wait_handle function.  Each thread that
 382    notices activity signals the appropriate event and then reenters
 383    the stopped state.  Before gdb_select returns it calls the
 384    wait_handle_done functions, which return the threads to the stopped
 385    state.  */
 386
 387 enum select_thread_state {
 388   STS_STARTED,
 389   STS_STOPPED
 390 };
 391
 392 struct ser_console_state
 393 {
 394   /* Signaled by the select thread to indicate that data is available
 395      on the file descriptor.  */
 396   HANDLE read_event;
 397   /* Signaled by the select thread to indicate that an exception has
 398      occurred on the file descriptor.  */
 399   HANDLE except_event;
 400   /* Signaled by the select thread to indicate that it has entered the
 401      started state.  HAVE_STARTED and HAVE_STOPPED are never signaled
 402      simultaneously.  */
 403   HANDLE have_started;
 404   /* Signaled by the select thread to indicate that it has stopped,
 405      either because data is available (and READ_EVENT is signaled),
 406      because an exception has occurred (and EXCEPT_EVENT is signaled),
 407      or because STOP_SELECT was signaled.  */
 408   HANDLE have_stopped;
 409
 410   /* Signaled by the main program to tell the select thread to enter
 411      the started state.  */
 412   HANDLE start_select;
 413   /* Signaled by the main program to tell the select thread to enter
 414      the stopped state.  */
 415   HANDLE stop_select;
 416   /* Signaled by the main program to tell the select thread to
 417      exit.  */
 418   HANDLE exit_select;
 419
 420   /* The handle for the select thread.  */
 421   HANDLE thread;
 422   /* The state of the select thread.  This field is only accessed in
 423      the main program, never by the select thread itself.  */
 424   enum select_thread_state thread_state;
 425 };
 426
 427 /* Called by a select thread to enter the stopped state.  This
 428    function does not return until the thread has re-entered the
 429    started state.  */
 430 static void
 431 select_thread_wait (struct ser_console_state *state)
 432 {
 433   HANDLE wait_events[2];
 434
 435   /* There are two things that can wake us up: a request that we enter
 436      the started state, or that we exit this thread.  */
 437   wait_events[0] = state->start_select;
 438   wait_events[1] = state->exit_select;
 439   if (WaitForMultipleObjects (2, wait_events, FALSE, INFINITE)
 440       != WAIT_OBJECT_0)
 441     /* Either the EXIT_SELECT event was signaled (requesting that the
 442        thread exit) or an error has occurred.  In either case, we exit
 443        the thread.  */
 444     ExitThread (0);
 445
 446   /* We are now in the started state.  */
 447   SetEvent (state->have_started);
 448 }
 449
 450 typedef DWORD WINAPI (*thread_fn_type)(void *);
 451
 452 /* Create a new select thread for SCB executing THREAD_FN.  The STATE
 453    will be filled in by this function before return.  */
 454 static void
 455 create_select_thread (thread_fn_type thread_fn,
 456                       struct serial *scb,
 457                       struct ser_console_state *state)
 458 {
 459   DWORD threadId;
 460
 461   /* Create all of the events.  These are all auto-reset events.  */
 462   state->read_event = CreateEvent (NULL, FALSE, FALSE, NULL);
 463   state->except_event = CreateEvent (NULL, FALSE, FALSE, NULL);
 464   state->have_started = CreateEvent (NULL, FALSE, FALSE, NULL);
 465   state->have_stopped = CreateEvent (NULL, FALSE, FALSE, NULL);
 466   state->start_select = CreateEvent (NULL, FALSE, FALSE, NULL);
 467   state->stop_select = CreateEvent (NULL, FALSE, FALSE, NULL);
 468   state->exit_select = CreateEvent (NULL, FALSE, FALSE, NULL);
 469
 470   state->thread = CreateThread (NULL, 0, thread_fn, scb, 0, &threadId);
 471   /* The thread begins in the stopped state.  */
 472   state->thread_state = STS_STOPPED;
 473 }
 474
 475 /* Destroy the select thread indicated by STATE.  */
 476 static void
 477 destroy_select_thread (struct ser_console_state *state)
 478 {
 479   /* Ask the thread to exit.  */
 480   SetEvent (state->exit_select);
 481   /* Wait until it does.  */
 482   WaitForSingleObject (state->thread, INFINITE);
 483
 484   /* Destroy the events.  */
 485   CloseHandle (state->read_event);
 486   CloseHandle (state->except_event);
 487   CloseHandle (state->have_started);
 488   CloseHandle (state->have_stopped);
 489   CloseHandle (state->start_select);
 490   CloseHandle (state->stop_select);
 491   CloseHandle (state->exit_select);
 492 }
 493
 494 /* Called by gdb_select to start the select thread indicated by STATE.
 495    This function does not return until the thread has started.  */
 496 static void
 497 start_select_thread (struct ser_console_state *state)
 498 {
 499   /* Ask the thread to start.  */
 500   SetEvent (state->start_select);
 501   /* Wait until it does.  */
 502   WaitForSingleObject (state->have_started, INFINITE);
 503   /* The thread is now started.  */
 504   state->thread_state = STS_STARTED;
 505 }
 506
 507 /* Called by gdb_select to stop the select thread indicated by STATE.
 508    This function does not return until the thread has stopped.  */
 509 static void
 510 stop_select_thread (struct ser_console_state *state)
 511 {
 512   /* If the thread is already in the stopped state, we have nothing to
 513      do.  Some of the wait_handle functions avoid calling
 514      start_select_thread if they notice activity on the relevant file
 515      descriptors.  The wait_handle_done functions still call
 516      stop_select_thread -- but it is already stopped.  */
 517   if (state->thread_state != STS_STARTED)
 518     return;
 519   /* Ask the thread to stop.  */
 520   SetEvent (state->stop_select);
 521   /* Wait until it does.  */
 522   WaitForSingleObject (state->have_stopped, INFINITE);
 523   /* The thread is now stopped.  */
 524   state->thread_state = STS_STOPPED;
 525 }
 526
 527 static DWORD WINAPI
 528 console_select_thread (void *arg)
 529 {
 530   struct serial *scb = (struct serial *) arg;
 531   struct ser_console_state *state;
 532   int event_index;
 533   HANDLE h;
 534
 535   state = (struct ser_console_state *) scb->state;
 536   h = (HANDLE) _get_osfhandle (scb->fd);
 537
 538   while (1)
 539     {
 540       HANDLE wait_events[2];
 541       INPUT_RECORD record;
 542       DWORD n_records;
 543
 544       select_thread_wait (state);
 545
 546       while (1)
 547         {
 548           wait_events[0] = state->stop_select;
 549           wait_events[1] = h;
 550
 551           event_index = WaitForMultipleObjects (2, wait_events,
 552                                                 FALSE, INFINITE);
 553
 554           if (event_index == WAIT_OBJECT_0
 555               || WaitForSingleObject (state->stop_select, 0) == WAIT_OBJECT_0)
 556             break;
 557
 558           if (event_index != WAIT_OBJECT_0 + 1)
 559             {
 560               /* Wait must have failed; assume an error has occured, e.g.
 561                  the handle has been closed.  */
 562               SetEvent (state->except_event);
 563               break;
 564             }
 565
 566           /* We've got a pending event on the console.  See if it's
 567              of interest.  */
 568           if (!PeekConsoleInput (h, &record, 1, &n_records) || n_records != 1)
 569             {
 570               /* Something went wrong.  Maybe the console is gone.  */
 571               SetEvent (state->except_event);
 572               break;
 573             }
 574
 575           if (record.EventType == KEY_EVENT && record.Event.KeyEvent.bKeyDown)
 576             {
 577               WORD keycode = record.Event.KeyEvent.wVirtualKeyCode;
 578
 579               /* Ignore events containing only control keys.  We must
 580                  recognize "enhanced" keys which we are interested in
 581                  reading via getch, if they do not map to ASCII.  But we
 582                  do not want to report input available for e.g. the
 583                  control key alone.  */
 584
 585               if (record.Event.KeyEvent.uChar.AsciiChar != 0
 586                   || keycode == VK_PRIOR
 587                   || keycode == VK_NEXT
 588                   || keycode == VK_END
 589                   || keycode == VK_HOME
 590                   || keycode == VK_LEFT
 591                   || keycode == VK_UP
 592                   || keycode == VK_RIGHT
 593                   || keycode == VK_DOWN
 594                   || keycode == VK_INSERT
 595                   || keycode == VK_DELETE)
 596                 {
 597                   /* This is really a keypress.  */
 598                   SetEvent (state->read_event);
 599                   break;
 600                 }
 601             }
 602
 603           /* Otherwise discard it and wait again.  */
 604           ReadConsoleInput (h, &record, 1, &n_records);
 605         }
 606
 607       SetEvent(state->have_stopped);
 608     }
 609   return 0;
 610 }
 611
 612 static int
 613 fd_is_pipe (int fd)
 614 {
 615   if (PeekNamedPipe ((HANDLE) _get_osfhandle (fd), NULL, 0, NULL, NULL, NULL))
 616     return 1;
 617   else
 618     return 0;
 619 }
 620
 621 static int
 622 fd_is_file (int fd)
 623 {
 624   if (GetFileType ((HANDLE) _get_osfhandle (fd)) == FILE_TYPE_DISK)
 625     return 1;
 626   else
 627     return 0;
 628 }
 629
 630 static DWORD WINAPI
 631 pipe_select_thread (void *arg)
 632 {
 633   struct serial *scb = (struct serial *) arg;
 634   struct ser_console_state *state;
 635   HANDLE h;
 636
 637   state = (struct ser_console_state *) scb->state;
 638   h = (HANDLE) _get_osfhandle (scb->fd);
 639
 640   while (1)
 641     {
 642       DWORD n_avail;
 643
 644       select_thread_wait (state);
 645
 646       /* Wait for something to happen on the pipe.  */
 647       while (1)
 648         {
 649           if (!PeekNamedPipe (h, NULL, 0, NULL, &n_avail, NULL))
 650             {
 651               SetEvent (state->except_event);
 652               break;
 653             }
 654
 655           if (n_avail > 0)
 656             {
 657               SetEvent (state->read_event);
 658               break;
 659             }
 660
 661           /* Delay 10ms before checking again, but allow the stop
 662              event to wake us.  */
 663           if (WaitForSingleObject (state->stop_select, 10) == WAIT_OBJECT_0)
 664             break;
 665         }
 666
 667       SetEvent (state->have_stopped);
 668     }
 669   return 0;
 670 }
 671
 672 static DWORD WINAPI
 673 file_select_thread (void *arg)
 674 {
 675   struct serial *scb = (struct serial *) arg;
 676   struct ser_console_state *state;
 677   HANDLE h;
 678
 679   state = (struct ser_console_state *) scb->state;
 680   h = (HANDLE) _get_osfhandle (scb->fd);
 681
 682   while (1)
 683     {
 684       select_thread_wait (state);
 685
 686       if (SetFilePointer (h, 0, NULL, FILE_CURRENT)
 687           == INVALID_SET_FILE_POINTER)
 688         SetEvent (state->except_event);
 689       else
 690         SetEvent (state->read_event);
 691
 692       SetEvent (state->have_stopped);
 693     }
 694   return 0;
 695 }
 696
 697 static void
 698 ser_console_wait_handle (struct serial *scb, HANDLE *read, HANDLE *except)
 699 {
 700   struct ser_console_state *state = (struct ser_console_state *) scb->state;
 701
 702   if (state == NULL)
 703     {
 704       thread_fn_type thread_fn;
 705       int is_tty;
 706
 707       is_tty = isatty (scb->fd);
 708       if (!is_tty && !fd_is_file (scb->fd) && !fd_is_pipe (scb->fd))
 709         {
 710           *read = NULL;
 711           *except = NULL;
 712           return;
 713         }
 714
 715       state = XCNEW (struct ser_console_state);
 716       scb->state = state;
 717
 718       if (is_tty)
 719         thread_fn = console_select_thread;
 720       else if (fd_is_pipe (scb->fd))
 721         thread_fn = pipe_select_thread;
 722       else
 723         thread_fn = file_select_thread;
 724
 725       create_select_thread (thread_fn, scb, state);
 726     }
 727
 728   *read = state->read_event;
 729   *except = state->except_event;
 730
 731   /* Start from a blank state.  */
 732   ResetEvent (state->read_event);
 733   ResetEvent (state->except_event);
 734   ResetEvent (state->stop_select);
 735
 736   /* First check for a key already in the buffer.  If there is one,
 737      we don't need a thread.  This also catches the second key of
 738      multi-character returns from getch, for instance for arrow
 739      keys.  The second half is in a C library internal buffer,
 740      and PeekConsoleInput will not find it.  */
 741   if (_kbhit ())
 742     {
 743       SetEvent (state->read_event);
 744       return;
 745     }
 746
 747   /* Otherwise, start the select thread.  */
 748   start_select_thread (state);
 749 }
 750
 751 static void
 752 ser_console_done_wait_handle (struct serial *scb)
 753 {
 754   struct ser_console_state *state = (struct ser_console_state *) scb->state;
 755
 756   if (state == NULL)
 757     return;
 758
 759   stop_select_thread (state);
 760 }
 761
 762 static void
 763 ser_console_close (struct serial *scb)
 764 {
 765   struct ser_console_state *state = (struct ser_console_state *) scb->state;
 766
 767   if (scb->state)
 768     {
 769       destroy_select_thread (state);
 770       xfree (scb->state);
 771     }
 772 }
 773
 774 struct ser_console_ttystate
 775 {
 776   int is_a_tty;
 777 };
 778
 779 static serial_ttystate
 780 ser_console_get_tty_state (struct serial *scb)
 781 {
 782   if (isatty (scb->fd))
 783     {
 784       struct ser_console_ttystate *state;
 785
 786       state = XNEW (struct ser_console_ttystate);
 787       state->is_a_tty = 1;
 788       return state;
 789     }
 790   else
 791     return NULL;
 792 }
 793
 794 struct pipe_state
 795 {
 796   /* Since we use the pipe_select_thread for our select emulation,
 797      we need to place the state structure it requires at the front
 798      of our state.  */
 799   struct ser_console_state wait;
 800
 801   /* The pex obj for our (one-stage) pipeline.  */
 802   struct pex_obj *pex;
 803
 804   /* Streams for the pipeline's input and output.  */
 805   FILE *input, *output;
 806 };
 807
 808 static struct pipe_state *
 809 make_pipe_state (void)
 810 {
 811   struct pipe_state *ps = XCNEW (struct pipe_state);
 812
 813   ps->wait.read_event = INVALID_HANDLE_VALUE;
 814   ps->wait.except_event = INVALID_HANDLE_VALUE;
 815   ps->wait.start_select = INVALID_HANDLE_VALUE;
 816   ps->wait.stop_select = INVALID_HANDLE_VALUE;
 817
 818   return ps;
 819 }
 820
 821 static void
 822 free_pipe_state (struct pipe_state *ps)
 823 {
 824   int saved_errno = errno;
 825
 826   if (ps->wait.read_event != INVALID_HANDLE_VALUE)
 827     destroy_select_thread (&ps->wait);
 828
 829   /* Close the pipe to the child.  We must close the pipe before
 830      calling pex_free because pex_free will wait for the child to exit
 831      and the child will not exit until the pipe is closed.  */
 832   if (ps->input)
 833     fclose (ps->input);
 834   if (ps->pex)
 835     {
 836       pex_free (ps->pex);
 837       /* pex_free closes ps->output.  */
 838     }
 839   else if (ps->output)
 840     fclose (ps->output);
 841
 842   xfree (ps);
 843
 844   errno = saved_errno;
 845 }
 846
 847 struct pipe_state_destroyer
 848 {
 849   void operator() (pipe_state *ps) const
 850   {
 851     free_pipe_state (ps);
 852   }
 853 };
 854
 855 typedef std::unique_ptr<pipe_state, pipe_state_destroyer> pipe_state_up;
 856
 857 static int
 858 pipe_windows_open (struct serial *scb, const char *name)
 859 {
 860   FILE *pex_stderr;
 861
 862   if (name == NULL)
 863     error_no_arg (_("child command"));
 864
 865   gdb_argv argv (name);
 866
 867   if (! argv[0] || argv[0][0] == '\0')
 868     error (_("missing child command"));
 869
 870   pipe_state_up ps (make_pipe_state ());
 871
 872   ps->pex = pex_init (PEX_USE_PIPES, "target remote pipe", NULL);
 873   if (! ps->pex)
 874     return -1;
 875   ps->input = pex_input_pipe (ps->pex, 1);
 876   if (! ps->input)
 877     return -1;
 878
 879   {
 880     int err;
 881     const char *err_msg
 882       = pex_run (ps->pex, PEX_SEARCH | PEX_BINARY_INPUT | PEX_BINARY_OUTPUT
 883                  | PEX_STDERR_TO_PIPE,
 884                  argv[0], argv.get (), NULL, NULL,
 885                  &err);
 886
 887     if (err_msg)
 888       {
 889         /* Our caller expects us to return -1, but all they'll do with
 890            it generally is print the message based on errno.  We have
 891            all the same information here, plus err_msg provided by
 892            pex_run, so we just raise the error here.  */
 893         if (err)
 894           error (_("error starting child process '%s': %s: %s"),
 895                  name, err_msg, safe_strerror (err));
 896         else
 897           error (_("error starting child process '%s': %s"),
 898                  name, err_msg);
 899       }
 900   }
 901
 902   ps->output = pex_read_output (ps->pex, 1);
 903   if (! ps->output)
 904     return -1;
 905   scb->fd = fileno (ps->output);
 906
 907   pex_stderr = pex_read_err (ps->pex, 1);
 908   if (! pex_stderr)
 909     return -1;
 910   scb->error_fd = fileno (pex_stderr);
 911
 912   scb->state = ps.release ();
 913
 914   return 0;
 915 }
 916
 917 static int
 918 pipe_windows_fdopen (struct serial *scb, int fd)
 919 {
 920   struct pipe_state *ps;
 921
 922   ps = make_pipe_state ();
 923
 924   ps->input = fdopen (fd, "r+");
 925   if (! ps->input)
 926     goto fail;
 927
 928   ps->output = fdopen (fd, "r+");
 929   if (! ps->output)
 930     goto fail;
 931
 932   scb->fd = fd;
 933   scb->state = (void *) ps;
 934
 935   return 0;
 936
 937  fail:
 938   free_pipe_state (ps);
 939   return -1;
 940 }
 941
 942 static void
 943 pipe_windows_close (struct serial *scb)
 944 {
 945   struct pipe_state *ps = (struct pipe_state *) scb->state;
 946
 947   /* In theory, we should try to kill the subprocess here, but the pex
 948      interface doesn't give us enough information to do that.  Usually
 949      closing the input pipe will get the message across.  */
 950
 951   free_pipe_state (ps);
 952 }
 953
 954
 955 static int
 956 pipe_windows_read (struct serial *scb, size_t count)
 957 {
 958   HANDLE pipeline_out = (HANDLE) _get_osfhandle (scb->fd);
 959   DWORD available;
 960   DWORD bytes_read;
 961
 962   if (pipeline_out == INVALID_HANDLE_VALUE)
 963     return -1;
 964
 965   if (! PeekNamedPipe (pipeline_out, NULL, 0, NULL, &available, NULL))
 966     return -1;
 967
 968   if (count > available)
 969     count = available;
 970
 971   if (! ReadFile (pipeline_out, scb->buf, count, &bytes_read, NULL))
 972     return -1;
 973
 974   return bytes_read;
 975 }
 976
 977
 978 static int
 979 pipe_windows_write (struct serial *scb, const void *buf, size_t count)
 980 {
 981   struct pipe_state *ps = (struct pipe_state *) scb->state;
 982   HANDLE pipeline_in;
 983   DWORD written;
 984
 985   int pipeline_in_fd = fileno (ps->input);
 986   if (pipeline_in_fd < 0)
 987     return -1;
 988
 989   pipeline_in = (HANDLE) _get_osfhandle (pipeline_in_fd);
 990   if (pipeline_in == INVALID_HANDLE_VALUE)
 991     return -1;
 992
 993   if (! WriteFile (pipeline_in, buf, count, &written, NULL))
 994     return -1;
 995
 996   return written;
 997 }
 998
 999
1000 static void
1001 pipe_wait_handle (struct serial *scb, HANDLE *read, HANDLE *except)
1002 {
1003   struct pipe_state *ps = (struct pipe_state *) scb->state;
1004
1005   /* Have we allocated our events yet?  */
1006   if (ps->wait.read_event == INVALID_HANDLE_VALUE)
1007     /* Start the thread.  */
1008     create_select_thread (pipe_select_thread, scb, &ps->wait);
1009
1010   *read = ps->wait.read_event;
1011   *except = ps->wait.except_event;
1012
1013   /* Start from a blank state.  */
1014   ResetEvent (ps->wait.read_event);
1015   ResetEvent (ps->wait.except_event);
1016   ResetEvent (ps->wait.stop_select);
1017
1018   start_select_thread (&ps->wait);
1019 }
1020
1021 static void
1022 pipe_done_wait_handle (struct serial *scb)
1023 {
1024   struct pipe_state *ps = (struct pipe_state *) scb->state;
1025
1026   /* Have we allocated our events yet?  */
1027   if (ps->wait.read_event == INVALID_HANDLE_VALUE)
1028     return;
1029
1030   stop_select_thread (&ps->wait);
1031 }
1032
1033 static int
1034 pipe_avail (struct serial *scb, int fd)
1035 {
1036   HANDLE h = (HANDLE) _get_osfhandle (fd);
1037   DWORD numBytes;
1038   BOOL r = PeekNamedPipe (h, NULL, 0, NULL, &numBytes, NULL);
1039
1040   if (r == FALSE)
1041     numBytes = 0;
1042   return numBytes;
1043 }
1044
1045 int
1046 gdb_pipe (int pdes[2])
1047 {
1048   if (_pipe (pdes, 512, _O_BINARY | _O_NOINHERIT) == -1)
1049     return -1;
1050   return 0;
1051 }
1052
1053 struct net_windows_state
1054 {
1055   struct ser_console_state base;
1056
1057   HANDLE sock_event;
1058 };
1059
1060 /* Check whether the socket has any pending data to be read.  If so,
1061    set the select thread's read event.  On error, set the select
1062    thread's except event.  If any event was set, return true,
1063    otherwise return false.  */
1064
1065 static int
1066 net_windows_socket_check_pending (struct serial *scb)
1067 {
1068   struct net_windows_state *state = (struct net_windows_state *) scb->state;
1069   unsigned long available;
1070
1071   if (ioctlsocket (scb->fd, FIONREAD, &available) != 0)
1072     {
1073       /* The socket closed, or some other error.  */
1074       SetEvent (state->base.except_event);
1075       return 1;
1076     }
1077   else if (available > 0)
1078     {
1079       SetEvent (state->base.read_event);
1080       return 1;
1081     }
1082
1083   return 0;
1084 }
1085
1086 static DWORD WINAPI
1087 net_windows_select_thread (void *arg)
1088 {
1089   struct serial *scb = (struct serial *) arg;
1090   struct net_windows_state *state;
1091   int event_index;
1092
1093   state = (struct net_windows_state *) scb->state;
1094
1095   while (1)
1096     {
1097       HANDLE wait_events[2];
1098       WSANETWORKEVENTS events;
1099
1100       select_thread_wait (&state->base);
1101
1102       wait_events[0] = state->base.stop_select;
1103       wait_events[1] = state->sock_event;
1104
1105       /* Wait for something to happen on the socket.  */
1106       while (1)
1107         {
1108           event_index = WaitForMultipleObjects (2, wait_events, FALSE, INFINITE);
1109
1110           if (event_index == WAIT_OBJECT_0
1111               || WaitForSingleObject (state->base.stop_select, 0) == WAIT_OBJECT_0)
1112             {
1113               /* We have been requested to stop.  */
1114               break;
1115             }
1116
1117           if (event_index != WAIT_OBJECT_0 + 1)
1118             {
1119               /* Some error has occured.  Assume that this is an error
1120                  condition.  */
1121               SetEvent (state->base.except_event);
1122               break;
1123             }
1124
1125           /* Enumerate the internal network events, and reset the
1126              object that signalled us to catch the next event.  */
1127           if (WSAEnumNetworkEvents (scb->fd, state->sock_event, &events) != 0)
1128             {
1129               /* Something went wrong.  Maybe the socket is gone.  */
1130               SetEvent (state->base.except_event);
1131               break;
1132             }
1133
1134           if (events.lNetworkEvents & FD_READ)
1135             {
1136               if (net_windows_socket_check_pending (scb))
1137                 break;
1138
1139               /* Spurious wakeup.  That is, the socket's event was
1140                  signalled before we last called recv.  */
1141             }
1142
1143           if (events.lNetworkEvents & FD_CLOSE)
1144             {
1145               SetEvent (state->base.except_event);
1146               break;
1147             }
1148         }
1149
1150       SetEvent (state->base.have_stopped);
1151     }
1152   return 0;
1153 }
1154
1155 static void
1156 net_windows_wait_handle (struct serial *scb, HANDLE *read, HANDLE *except)
1157 {
1158   struct net_windows_state *state = (struct net_windows_state *) scb->state;
1159
1160   /* Start from a clean slate.  */
1161   ResetEvent (state->base.read_event);
1162   ResetEvent (state->base.except_event);
1163   ResetEvent (state->base.stop_select);
1164
1165   *read = state->base.read_event;
1166   *except = state->base.except_event;
1167
1168   /* Check any pending events.  Otherwise, start the select
1169      thread.  */
1170   if (!net_windows_socket_check_pending (scb))
1171     start_select_thread (&state->base);
1172 }
1173
1174 static void
1175 net_windows_done_wait_handle (struct serial *scb)
1176 {
1177   struct net_windows_state *state = (struct net_windows_state *) scb->state;
1178
1179   stop_select_thread (&state->base);
1180 }
1181
1182 static int
1183 net_windows_open (struct serial *scb, const char *name)
1184 {
1185   struct net_windows_state *state;
1186   int ret;
1187
1188   ret = net_open (scb, name);
1189   if (ret != 0)
1190     return ret;
1191
1192   state = XCNEW (struct net_windows_state);
1193   scb->state = state;
1194
1195   /* Associate an event with the socket.  */
1196   state->sock_event = CreateEvent (0, TRUE, FALSE, 0);
1197   WSAEventSelect (scb->fd, state->sock_event, FD_READ | FD_CLOSE);
1198
1199   /* Start the thread.  */
1200   create_select_thread (net_windows_select_thread, scb, &state->base);
1201
1202   return 0;
1203 }
1204
1205
1206 static void
1207 net_windows_close (struct serial *scb)
1208 {
1209   struct net_windows_state *state = (struct net_windows_state *) scb->state;
1210
1211   destroy_select_thread (&state->base);
1212   CloseHandle (state->sock_event);
1213
1214   xfree (scb->state);
1215
1216   net_close (scb);
1217 }
1218
1219 /* The serial port driver.  */
1220
1221 static const struct serial_ops hardwire_ops =
1222 {
1223   "hardwire",
1224   ser_windows_open,
1225   ser_windows_close,
1226   NULL,
1227   ser_base_readchar,
1228   ser_base_write,
1229   ser_windows_flush_output,
1230   ser_windows_flush_input,
1231   ser_windows_send_break,
1232   ser_windows_raw,
1233   /* These are only used for stdin; we do not need them for serial
1234      ports, so supply the standard dummies.  */
1235   ser_base_get_tty_state,
1236   ser_base_copy_tty_state,
1237   ser_base_set_tty_state,
1238   ser_base_print_tty_state,
1239   ser_windows_setbaudrate,
1240   ser_windows_setstopbits,
1241   ser_windows_setparity,
1242   ser_windows_drain_output,
1243   ser_base_async,
1244   ser_windows_read_prim,
1245   ser_windows_write_prim,
1246   NULL,
1247   ser_windows_wait_handle
1248 };
1249
1250 /* The dummy serial driver used for terminals.  We only provide the
1251    TTY-related methods.  */
1252
1253 static const struct serial_ops tty_ops =
1254 {
1255   "terminal",
1256   NULL,
1257   ser_console_close,
1258   NULL,
1259   NULL,
1260   NULL,
1261   NULL,
1262   NULL,
1263   NULL,
1264   NULL,
1265   ser_console_get_tty_state,
1266   ser_base_copy_tty_state,
1267   ser_base_set_tty_state,
1268   ser_base_print_tty_state,
1269   NULL,
1270   NULL,
1271   NULL,
1272   ser_base_drain_output,
1273   NULL,
1274   NULL,
1275   NULL,
1276   NULL,
1277   ser_console_wait_handle,
1278   ser_console_done_wait_handle
1279 };
1280
1281 /* The pipe interface.  */
1282
1283 static const struct serial_ops pipe_ops =
1284 {
1285   "pipe",
1286   pipe_windows_open,
1287   pipe_windows_close,
1288   pipe_windows_fdopen,
1289   ser_base_readchar,
1290   ser_base_write,
1291   ser_base_flush_output,
1292   ser_base_flush_input,
1293   ser_base_send_break,
1294   ser_base_raw,
1295   ser_base_get_tty_state,
1296   ser_base_copy_tty_state,
1297   ser_base_set_tty_state,
1298   ser_base_print_tty_state,
1299   ser_base_setbaudrate,
1300   ser_base_setstopbits,
1301   ser_base_setparity,
1302   ser_base_drain_output,
1303   ser_base_async,
1304   pipe_windows_read,
1305   pipe_windows_write,
1306   pipe_avail,
1307   pipe_wait_handle,
1308   pipe_done_wait_handle
1309 };
1310
1311 /* The TCP/UDP socket driver.  */
1312
1313 static const struct serial_ops tcp_ops =
1314 {
1315   "tcp",
1316   net_windows_open,
1317   net_windows_close,
1318   NULL,
1319   ser_base_readchar,
1320   ser_base_write,
1321   ser_base_flush_output,
1322   ser_base_flush_input,
1323   ser_tcp_send_break,
1324   ser_base_raw,
1325   ser_base_get_tty_state,
1326   ser_base_copy_tty_state,
1327   ser_base_set_tty_state,
1328   ser_base_print_tty_state,
1329   ser_base_setbaudrate,
1330   ser_base_setstopbits,
1331   ser_base_setparity,
1332   ser_base_drain_output,
1333   ser_base_async,
1334   net_read_prim,
1335   net_write_prim,
1336   NULL,
1337   net_windows_wait_handle,
1338   net_windows_done_wait_handle
1339 };
1340
1341 void _initialize_ser_windows ();
1342 void
1343 _initialize_ser_windows ()
1344 {
1345   WSADATA wsa_data;
1346
1347   HMODULE hm = NULL;
1348
1349   /* First find out if kernel32 exports CancelIo function.  */
1350   hm = LoadLibrary ("kernel32.dll");
1351   if (hm)
1352     {
1353       CancelIo = (CancelIo_ftype *) GetProcAddress (hm, "CancelIo");
1354       FreeLibrary (hm);
1355     }
1356   else
1357     CancelIo = NULL;
1358
1359   serial_add_interface (&hardwire_ops);
1360   serial_add_interface (&tty_ops);
1361   serial_add_interface (&pipe_ops);
1362
1363   /* If WinSock works, register the TCP/UDP socket driver.  */
1364
1365   if (WSAStartup (MAKEWORD (1, 0), &wsa_data) != 0)
1366     /* WinSock is unavailable.  */
1367     return;
1368
1369   serial_add_interface (&tcp_ops);
1370 }