mariadb/vio/viopipe.c

/* Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335  USA */

#include "vio_priv.h"

#ifdef _WIN32

/*
  Disable posting IO completion event to the port.
  In some cases (synchronous timed IO) we want to skip IOCP notifications.
*/
static void disable_iocp_notification(OVERLAPPED *overlapped)
{
  HANDLE *handle = &(overlapped->hEvent);
  *handle = ((HANDLE)((ULONG_PTR) *handle|1));
}

/* Enable posting IO completion event to the port */
static void enable_iocp_notification(OVERLAPPED *overlapped)
{
  HANDLE *handle = &(overlapped->hEvent);
  *handle = (HANDLE)((ULONG_PTR) *handle & ~1);
}

static size_t wait_overlapped_result(Vio *vio, int timeout)
{
  size_t ret= (size_t) -1;
  DWORD transferred, wait_status, timeout_ms;

  timeout_ms= timeout >= 0 ? timeout : INFINITE;

  /* Wait for the overlapped operation to be completed. */
  wait_status= WaitForSingleObject(vio->overlapped.hEvent, timeout_ms);

  /* The operation might have completed, attempt to retrieve the result. */
  if (wait_status == WAIT_OBJECT_0)
  {
    /* If retrieval fails, a error code will have been set. */
    if (GetOverlappedResult(vio->hPipe, &vio->overlapped, &transferred, FALSE))
      ret= transferred;
  }
  else
  {
    /* Error or timeout, cancel the pending I/O operation. */
    CancelIo(vio->hPipe);

    /*
      If the wait timed out, set error code to indicate a
      timeout error. Otherwise, wait_status is WAIT_FAILED
      and extended error information was already set.
    */
    if (wait_status == WAIT_TIMEOUT)
      SetLastError(SOCKET_ETIMEDOUT);
  }

  return ret;
}


size_t vio_read_pipe(Vio *vio, uchar *buf, size_t count)
{
  DWORD transferred;
  size_t ret= (size_t) -1;
  DBUG_ENTER("vio_read_pipe");

  if (vio->shutdown_flag)
      return ret;

  disable_iocp_notification(&vio->overlapped);

  /* Attempt to read from the pipe (overlapped I/O). */
  if (ReadFile(vio->hPipe, buf, (DWORD)count, &transferred, &vio->overlapped))
  {
    /* The operation completed immediately. */
    ret= transferred;
  }
  /* Read operation is pending completion asynchronously? */
  else if (GetLastError() == ERROR_IO_PENDING)
  {
    if (vio->shutdown_flag)
      CancelIo(vio->hPipe);
    ret= wait_overlapped_result(vio, vio->read_timeout);
  }
  enable_iocp_notification(&vio->overlapped);

  DBUG_RETURN(ret);
}


size_t vio_write_pipe(Vio *vio, const uchar *buf, size_t count)
{
  DWORD transferred;
  size_t ret= (size_t) -1;
  DBUG_ENTER("vio_write_pipe");

  if (vio->shutdown_flag == SHUT_RDWR)
    return ret;
  disable_iocp_notification(&vio->overlapped);
  /* Attempt to write to the pipe (overlapped I/O). */
  if (WriteFile(vio->hPipe, buf, (DWORD)count, &transferred, &vio->overlapped))
  {
    /* The operation completed immediately. */
    ret= transferred;
  }
  /* Write operation is pending completion asynchronously? */
  else if (GetLastError() == ERROR_IO_PENDING)
  {
    if (vio->shutdown_flag == SHUT_RDWR)
      CancelIo(vio->hPipe);
    ret= wait_overlapped_result(vio, vio->write_timeout);
  }
  enable_iocp_notification(&vio->overlapped);
  DBUG_RETURN(ret);
}


my_bool vio_is_connected_pipe(Vio *vio)
{
  if (PeekNamedPipe(vio->hPipe, NULL, 0, NULL, NULL, NULL))
    return TRUE;
  else
    return (GetLastError() != ERROR_BROKEN_PIPE);
}


int vio_close_pipe(Vio *vio)
{
  BOOL ret;
  DBUG_ENTER("vio_close_pipe");

  CloseHandle(vio->overlapped.hEvent);
  ret= CloseHandle(vio->hPipe);

  vio->type= VIO_CLOSED;
  vio->hPipe= NULL;
  vio->mysql_socket= MYSQL_INVALID_SOCKET;

  DBUG_RETURN(ret);
}

/* return number of bytes readable from pipe.*/
uint vio_pending_pipe(Vio *vio)
{
  DWORD bytes;
  return PeekNamedPipe(vio->hPipe, NULL, 0, NULL, &bytes, NULL) ? bytes : 0;
}
#endif