/src/FreeRDP/winpr/libwinpr/comm/comm_serial_sys.c

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/**
 * WinPR: Windows Portable Runtime
 * Serial Communication API
 *
 * Copyright 2011 O.S. Systems Software Ltda.
 * Copyright 2011 Eduardo Fiss Beloni <beloni@ossystems.com.br>
 * Copyright 2014 Marc-Andre Moreau <marcandre.moreau@gmail.com>
 * Copyright 2014 Hewlett-Packard Development Company, L.P.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <winpr/assert.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <termios.h>
#include <unistd.h>

#include "comm_serial_sys.h"
#include "comm.h"

#include <winpr/crt.h>
#include <winpr/wlog.h>

/* Undocumented flag, not supported everywhere.
 * Provide a sensible fallback to avoid compilation problems. */
#ifndef CMSPAR
#define CMSPAR 010000000000
#endif

/* hard-coded in N_TTY */
#define TTY_THRESHOLD_THROTTLE 128 /* now based on remaining room */
#define TTY_THRESHOLD_UNTHROTTLE 128
#define N_TTY_BUF_SIZE 4096

#define BAUD_TABLE_END 0010020 /* __MAX_BAUD + 1 */

/* 0: B* (Linux termios)
 * 1: CBR_* or actual baud rate
 * 2: BAUD_* (identical to SERIAL_BAUD_*)
 */
static const speed_t BAUD_TABLE[][3] = {
#ifdef B0
  { B0, 0, 0 }, /* hang up */
#endif
#ifdef B50
  { B50, 50, 0 },
#endif
#ifdef B75
  { B75, 75, BAUD_075 },
#endif
#ifdef B110
  { B110, CBR_110, BAUD_110 },
#endif
#ifdef B134
  { B134, 134, 0 /*BAUD_134_5*/ },
#endif
#ifdef B150
  { B150, 150, BAUD_150 },
#endif
#ifdef B200
  { B200, 200, 0 },
#endif
#ifdef B300
  { B300, CBR_300, BAUD_300 },
#endif
#ifdef B600
  { B600, CBR_600, BAUD_600 },
#endif
#ifdef B1200
  { B1200, CBR_1200, BAUD_1200 },
#endif
#ifdef B1800
  { B1800, 1800, BAUD_1800 },
#endif
#ifdef B2400
  { B2400, CBR_2400, BAUD_2400 },
#endif
#ifdef B4800
  { B4800, CBR_4800, BAUD_4800 },
#endif
/* {, ,BAUD_7200} */
#ifdef B9600
  { B9600, CBR_9600, BAUD_9600 },
#endif
/* {, CBR_14400, BAUD_14400}, /\* unsupported on Linux *\/ */
#ifdef B19200
  { B19200, CBR_19200, BAUD_19200 },
#endif
#ifdef B38400
  { B38400, CBR_38400, BAUD_38400 },
#endif
/* {, CBR_56000, BAUD_56K}, /\* unsupported on Linux *\/ */
#ifdef B57600
  { B57600, CBR_57600, BAUD_57600 },
#endif
#ifdef B115200
  { B115200, CBR_115200, BAUD_115200 },
#endif
/* {, CBR_128000, BAUD_128K}, /\* unsupported on Linux *\/ */
/* {, CBR_256000, BAUD_USER}, /\* unsupported on Linux *\/ */
#ifdef B230400
  { B230400, 230400, BAUD_USER },
#endif
#ifdef B460800
  { B460800, 460800, BAUD_USER },
#endif
#ifdef B500000
  { B500000, 500000, BAUD_USER },
#endif
#ifdef B576000
  { B576000, 576000, BAUD_USER },
#endif
#ifdef B921600
  { B921600, 921600, BAUD_USER },
#endif
#ifdef B1000000
  { B1000000, 1000000, BAUD_USER },
#endif
#ifdef B1152000
  { B1152000, 1152000, BAUD_USER },
#endif
#ifdef B1500000
  { B1500000, 1500000, BAUD_USER },
#endif
#ifdef B2000000
  { B2000000, 2000000, BAUD_USER },
#endif
#ifdef B2500000
  { B2500000, 2500000, BAUD_USER },
#endif
#ifdef B3000000
  { B3000000, 3000000, BAUD_USER },
#endif
#ifdef B3500000
  { B3500000, 3500000, BAUD_USER },
#endif
#ifdef B4000000
  { B4000000, 4000000, BAUD_USER }, /* __MAX_BAUD */
#endif
  { BAUD_TABLE_END, 0, 0 }
};

static const char* get_modem_flag_str(int flag)
{
  if (flag & TIOCM_LE)
    return "DSR";
  if (flag & TIOCM_DTR)
    return "DTR";
  if (flag & TIOCM_RTS)
    return "RTS";
  if (flag & TIOCM_ST)
    return "Secondary TXD";
  if (flag & TIOCM_SR)
    return "Secondary RXD";
  if (flag & TIOCM_CTS)
    return "CTS";
  if (flag & TIOCM_CAR)
    return "DCD";
  if (flag & TIOCM_CD)
    return "CD";
  if (flag & TIOCM_RNG)
    return "RNG";
  if (flag & TIOCM_RI)
    return "RI";
  if (flag & TIOCM_DSR)
    return "DSR";
  return "UNKNOWN";
}

static const char* get_modem_status_str(int status, char* buffer, size_t size)
{
  const int flags[] = { TIOCM_LE,  TIOCM_DTR, TIOCM_RTS, TIOCM_ST, TIOCM_SR, TIOCM_CTS,
                      TIOCM_CAR, TIOCM_CD,  TIOCM_RNG, TIOCM_RI, TIOCM_DSR };
  winpr_str_append("{", buffer, size, "");

  const char* sep = "";
  for (size_t x = 0; x < ARRAYSIZE(flags); x++)
  {
    const int flag = flags[x];
    if (status & flag)
    {
      winpr_str_append(get_modem_flag_str(flag), buffer, size, sep);
      sep = "|";
    }
  }

  char number[32] = { 0 };
  (void)_snprintf(number, sizeof(number), "}[0x%08x]", (unsigned)status);
  winpr_str_append(number, buffer, size, "");
  return buffer;
}

static BOOL get_properties(WINPR_ATTR_UNUSED WINPR_COMM* pComm, COMMPROP* pProperties)
{
  WINPR_ASSERT(pComm);
  /* http://msdn.microsoft.com/en-us/library/windows/hardware/jj680684%28v=vs.85%29.aspx
   * http://msdn.microsoft.com/en-us/library/windows/desktop/aa363189%28v=vs.85%29.aspx
   */

  /* FIXME: properties should be better probed. The current
   * implementation just relies on the Linux' implementation.
   */
  WINPR_ASSERT(pProperties);
  if (pProperties->dwProvSpec1 != COMMPROP_INITIALIZED)
  {
    ZeroMemory(pProperties, sizeof(COMMPROP));
    pProperties->wPacketLength = sizeof(COMMPROP);
  }

  pProperties->wPacketVersion = 2;

  pProperties->dwServiceMask = SERIAL_SP_SERIALCOMM;

  /* pProperties->Reserved1; not used */

  /* FIXME: could be implemented on top of N_TTY */
  pProperties->dwMaxTxQueue = N_TTY_BUF_SIZE;
  pProperties->dwMaxRxQueue = N_TTY_BUF_SIZE;

  /* FIXME: to be probe on the device? */
  pProperties->dwMaxBaud = BAUD_USER;

  /* FIXME: what about PST_RS232? see also: serial_struct */
  pProperties->dwProvSubType = PST_UNSPECIFIED;

  /* TODO: to be finalized */
  pProperties->dwProvCapabilities =
      /*PCF_16BITMODE |*/ PCF_DTRDSR | PCF_INTTIMEOUTS | PCF_PARITY_CHECK | /*PCF_RLSD |*/
      PCF_RTSCTS | PCF_SETXCHAR | /*PCF_SPECIALCHARS |*/ PCF_TOTALTIMEOUTS | PCF_XONXOFF;

  /* TODO: double check SP_RLSD */
  pProperties->dwSettableParams = SP_BAUD | SP_DATABITS | SP_HANDSHAKING | SP_PARITY |
                                  SP_PARITY_CHECK | /*SP_RLSD |*/ SP_STOPBITS;

  pProperties->dwSettableBaud = 0;
  for (int i = 0; BAUD_TABLE[i][0] < BAUD_TABLE_END; i++)
  {
    pProperties->dwSettableBaud |= BAUD_TABLE[i][2];
  }

  pProperties->wSettableData =
      DATABITS_5 | DATABITS_6 | DATABITS_7 | DATABITS_8 /*| DATABITS_16 | DATABITS_16X*/;

  pProperties->wSettableStopParity = STOPBITS_10 | /*STOPBITS_15 |*/ STOPBITS_20 | PARITY_NONE |
                                     PARITY_ODD | PARITY_EVEN | PARITY_MARK | PARITY_SPACE;

  /* FIXME: additional input and output buffers could be implemented on top of N_TTY */
  pProperties->dwCurrentTxQueue = N_TTY_BUF_SIZE;
  pProperties->dwCurrentRxQueue = N_TTY_BUF_SIZE;

  /* pProperties->ProvSpec1; see above */
  /* pProperties->ProvSpec2; ignored */
  /* pProperties->ProvChar[1]; ignored */

  return TRUE;
}

static BOOL set_baud_rate(WINPR_COMM* pComm, const SERIAL_BAUD_RATE* pBaudRate)
{
  speed_t newSpeed = 0;
  struct termios futureState = { 0 };

  WINPR_ASSERT(pComm);
  WINPR_ASSERT(pBaudRate);

  if (tcgetattr(pComm->fd, &futureState) <
      0) /* NB: preserves current settings not directly handled by the Communication Functions */
  {
    SetLastError(ERROR_IO_DEVICE);
    return FALSE;
  }

  for (int i = 0; BAUD_TABLE[i][0] < BAUD_TABLE_END; i++)
  {
    if (BAUD_TABLE[i][1] == pBaudRate->BaudRate)
    {
      newSpeed = BAUD_TABLE[i][0];
      if (cfsetspeed(&futureState, newSpeed) < 0)
      {
        CommLog_Print(WLOG_WARN, "failed to set speed 0x%x (%" PRIu32 ")", newSpeed,
                      pBaudRate->BaudRate);
        return FALSE;
      }

      WINPR_ASSERT(cfgetispeed(&futureState) == newSpeed);

      if (comm_ioctl_tcsetattr(pComm->fd, TCSANOW, &futureState) < 0)
      {
        CommLog_Print(WLOG_WARN, "comm_ioctl_tcsetattr failure: last-error: 0x%" PRIX32 "",
                      GetLastError());
        return FALSE;
      }

      return TRUE;
    }
  }

  CommLog_Print(WLOG_WARN, "could not find a matching speed for the baud rate %" PRIu32 "",
                pBaudRate->BaudRate);
  SetLastError(ERROR_INVALID_DATA);
  return FALSE;
}

static BOOL get_baud_rate(WINPR_COMM* pComm, SERIAL_BAUD_RATE* pBaudRate)
{
  speed_t currentSpeed = 0;
  struct termios currentState = { 0 };

  WINPR_ASSERT(pComm);
  WINPR_ASSERT(pBaudRate);

  if (tcgetattr(pComm->fd, &currentState) < 0)
  {
    SetLastError(ERROR_IO_DEVICE);
    return FALSE;
  }

  currentSpeed = cfgetispeed(&currentState);

  for (int i = 0; BAUD_TABLE[i][0] < BAUD_TABLE_END; i++)
  {
    if (BAUD_TABLE[i][0] == currentSpeed)
    {
      pBaudRate->BaudRate = BAUD_TABLE[i][1];
      return TRUE;
    }
  }

  CommLog_Print(WLOG_WARN, "could not find a matching baud rate for the speed 0x%x",
                currentSpeed);
  SetLastError(ERROR_INVALID_DATA);
  return FALSE;
}

/**
 * NOTE: Only XonChar and XoffChar are plenty supported with the Linux
 *       N_TTY line discipline.
 *
 * ERRORS:
 *   ERROR_IO_DEVICE
 *   ERROR_INVALID_PARAMETER when Xon and Xoff chars are the same;
 *   ERROR_NOT_SUPPORTED
 */
static BOOL set_serial_chars(WINPR_COMM* pComm, const SERIAL_CHARS* pSerialChars)
{
  BOOL result = TRUE;
  struct termios upcomingTermios = { 0 };

  WINPR_ASSERT(pComm);
  WINPR_ASSERT(pSerialChars);

  if (tcgetattr(pComm->fd, &upcomingTermios) < 0)
  {
    SetLastError(ERROR_IO_DEVICE);
    return FALSE;
  }

  /* termios(3): (..) above symbolic subscript values are all
   * different, except that VTIME, VMIN may have the same value
   * as VEOL, VEOF, respectively. In noncanonical mode the
   * special character meaning is replaced by the timeout
   * meaning.
   *
   * EofChar and c_cc[VEOF] are not quite the same, prefer to
   * don't use c_cc[VEOF] at all.
   *
   * FIXME: might be implemented during read/write I/O
   */
  if (pSerialChars->EofChar != '\0')
  {
    CommLog_Print(WLOG_WARN, "EofChar %02" PRIX8 " cannot be set\n", pSerialChars->EofChar);
    SetLastError(ERROR_NOT_SUPPORTED);
    result = FALSE; /* but keep on */
  }

  /* According the Linux's n_tty discipline, characters with a
   * parity error can only be let unchanged, replaced by \0 or
   * get the prefix the prefix \377 \0
   */

  /* FIXME: see also: set_handflow() */
  if (pSerialChars->ErrorChar != '\0')
  {
    CommLog_Print(WLOG_WARN, "ErrorChar 0x%02" PRIX8 " ('%c') cannot be set (unsupported).\n",
                  pSerialChars->ErrorChar, (char)pSerialChars->ErrorChar);
    SetLastError(ERROR_NOT_SUPPORTED);
    result = FALSE; /* but keep on */
  }

  /* FIXME: see also: set_handflow() */
  if (pSerialChars->BreakChar != '\0')
  {
    CommLog_Print(WLOG_WARN, "BreakChar 0x%02" PRIX8 " ('%c') cannot be set (unsupported).\n",
                  pSerialChars->BreakChar, (char)pSerialChars->BreakChar);
    SetLastError(ERROR_NOT_SUPPORTED);
    result = FALSE; /* but keep on */
  }

  if (pSerialChars->EventChar != '\0')
  {
    pComm->eventChar = pSerialChars->EventChar;
  }

  upcomingTermios.c_cc[VSTART] = pSerialChars->XonChar;

  upcomingTermios.c_cc[VSTOP] = pSerialChars->XoffChar;

  if (comm_ioctl_tcsetattr(pComm->fd, TCSANOW, &upcomingTermios) < 0)
  {
    CommLog_Print(WLOG_WARN, "comm_ioctl_tcsetattr failure: last-error: 0x%08" PRIX32 "",
                  GetLastError());
    return FALSE;
  }

  return result;
}

static BOOL get_serial_chars(WINPR_COMM* pComm, SERIAL_CHARS* pSerialChars)
{
  struct termios currentTermios = { 0 };

  WINPR_ASSERT(pComm);
  WINPR_ASSERT(pSerialChars);

  if (tcgetattr(pComm->fd, &currentTermios) < 0)
  {
    SetLastError(ERROR_IO_DEVICE);
    return FALSE;
  }

  ZeroMemory(pSerialChars, sizeof(SERIAL_CHARS));

  /* EofChar unsupported */

  /* ErrorChar unsupported */

  /* BreakChar unsupported */

  /* FIXME: see also: set_serial_chars() */
  /* EventChar */

  pSerialChars->XonChar = currentTermios.c_cc[VSTART];

  pSerialChars->XoffChar = currentTermios.c_cc[VSTOP];

  return TRUE;
}

static BOOL set_line_control(WINPR_COMM* pComm, const SERIAL_LINE_CONTROL* pLineControl)
{
  BOOL result = TRUE;
  struct termios upcomingTermios = { 0 };

  WINPR_ASSERT(pComm);
  WINPR_ASSERT(pLineControl);

  /* http://msdn.microsoft.com/en-us/library/windows/desktop/aa363214%28v=vs.85%29.aspx
   *
   * The use of 5 data bits with 2 stop bits is an invalid
   * combination, as is 6, 7, or 8 data bits with 1.5 stop bits.
   *
   * FIXME: preferred to let the underlying driver to deal with
   * this issue. At least produce a warning message?
   */

  if (tcgetattr(pComm->fd, &upcomingTermios) < 0)
  {
    SetLastError(ERROR_IO_DEVICE);
    return FALSE;
  }

  /* FIXME: use of a COMMPROP to validate new settings? */

  switch (pLineControl->StopBits)
  {
    case STOP_BIT_1:
      upcomingTermios.c_cflag &= (uint32_t)~CSTOPB;
      break;

    case STOP_BITS_1_5:
      CommLog_Print(WLOG_WARN, "Unsupported one and a half stop bits.");
      break;

    case STOP_BITS_2:
      upcomingTermios.c_cflag |= CSTOPB;
      break;

    default:
      CommLog_Print(WLOG_WARN, "unexpected number of stop bits: %" PRIu8 "\n",
                    pLineControl->StopBits);
      result = FALSE; /* but keep on */
      break;
  }

  switch (pLineControl->Parity)
  {
    case NO_PARITY:
      upcomingTermios.c_cflag &= (uint32_t)~(PARENB | PARODD | CMSPAR);
      break;

    case ODD_PARITY:
      upcomingTermios.c_cflag &= (uint32_t)~CMSPAR;
      upcomingTermios.c_cflag |= PARENB | PARODD;
      break;

    case EVEN_PARITY:
      upcomingTermios.c_cflag &= (uint32_t)~(PARODD | CMSPAR);
      upcomingTermios.c_cflag |= PARENB;
      break;

    case MARK_PARITY:
      upcomingTermios.c_cflag |= PARENB | PARODD | CMSPAR;
      break;

    case SPACE_PARITY:
      upcomingTermios.c_cflag &= (uint32_t)~PARODD;
      upcomingTermios.c_cflag |= PARENB | CMSPAR;
      break;

    default:
      CommLog_Print(WLOG_WARN, "unexpected type of parity: %" PRIu8 "\n",
                    pLineControl->Parity);
      result = FALSE; /* but keep on */
      break;
  }

  switch (pLineControl->WordLength)
  {
    case 5:
      upcomingTermios.c_cflag &= (uint32_t)~CSIZE;
      upcomingTermios.c_cflag |= CS5;
      break;

    case 6:
      upcomingTermios.c_cflag &= (uint32_t)~CSIZE;
      upcomingTermios.c_cflag |= CS6;
      break;

    case 7:
      upcomingTermios.c_cflag &= (uint32_t)~CSIZE;
      upcomingTermios.c_cflag |= CS7;
      break;

    case 8:
      upcomingTermios.c_cflag &= (uint32_t)~CSIZE;
      upcomingTermios.c_cflag |= CS8;
      break;

    default:
      CommLog_Print(WLOG_WARN, "unexpected number od data bits per character: %" PRIu8 "\n",
                    pLineControl->WordLength);
      result = FALSE; /* but keep on */
      break;
  }

  if (comm_ioctl_tcsetattr(pComm->fd, TCSANOW, &upcomingTermios) < 0)
  {
    CommLog_Print(WLOG_WARN, "comm_ioctl_tcsetattr failure: last-error: 0x%08" PRIX32 "",
                  GetLastError());
    return FALSE;
  }

  return result;
}

static BOOL get_line_control(WINPR_COMM* pComm, SERIAL_LINE_CONTROL* pLineControl)
{
  struct termios currentTermios = { 0 };

  WINPR_ASSERT(pComm);
  WINPR_ASSERT(pLineControl);

  if (tcgetattr(pComm->fd, &currentTermios) < 0)
  {
    SetLastError(ERROR_IO_DEVICE);
    return FALSE;
  }

  pLineControl->StopBits = (currentTermios.c_cflag & CSTOPB) ? STOP_BITS_2 : STOP_BIT_1;

  if (!(currentTermios.c_cflag & PARENB))
  {
    pLineControl->Parity = NO_PARITY;
  }
  else if (currentTermios.c_cflag & CMSPAR)
  {
    pLineControl->Parity = (currentTermios.c_cflag & PARODD) ? MARK_PARITY : SPACE_PARITY;
  }
  else
  {
    /* PARENB is set */
    pLineControl->Parity = (currentTermios.c_cflag & PARODD) ? ODD_PARITY : EVEN_PARITY;
  }

  switch (currentTermios.c_cflag & CSIZE)
  {
    case CS5:
      pLineControl->WordLength = 5;
      break;
    case CS6:
      pLineControl->WordLength = 6;
      break;
    case CS7:
      pLineControl->WordLength = 7;
      break;
    default:
      pLineControl->WordLength = 8;
      break;
  }

  return TRUE;
}

static BOOL set_handflow(WINPR_COMM* pComm, const SERIAL_HANDFLOW* pHandflow)
{
  BOOL result = TRUE;
  struct termios upcomingTermios = { 0 };

  WINPR_ASSERT(pComm);
  WINPR_ASSERT(pHandflow);

  if (tcgetattr(pComm->fd, &upcomingTermios) < 0)
  {
    SetLastError(ERROR_IO_DEVICE);
    return FALSE;
  }

  /* HUPCL */

  /* logical XOR */
  if ((!(pHandflow->ControlHandShake & SERIAL_DTR_CONTROL) &&
       (pHandflow->FlowReplace & SERIAL_RTS_CONTROL)) ||
      ((pHandflow->ControlHandShake & SERIAL_DTR_CONTROL) &&
       !(pHandflow->FlowReplace & SERIAL_RTS_CONTROL)))
  {
    CommLog_Print(WLOG_WARN,
                  "SERIAL_DTR_CONTROL:%s and SERIAL_RTS_CONTROL:%s cannot be different, HUPCL "
                  "will be set since it is claimed for one of the both lines.",
                  (pHandflow->ControlHandShake & SERIAL_DTR_CONTROL) ? "ON" : "OFF",
                  (pHandflow->FlowReplace & SERIAL_RTS_CONTROL) ? "ON" : "OFF");
  }

  if ((pHandflow->ControlHandShake & SERIAL_DTR_CONTROL) ||
      (pHandflow->FlowReplace & SERIAL_RTS_CONTROL))
  {
    upcomingTermios.c_cflag |= HUPCL;
  }
  else
  {
    upcomingTermios.c_cflag &= (uint32_t)~HUPCL;

    /* FIXME: is the DTR line also needs to be forced to a disable state according
     * SERIAL_DTR_CONTROL? */
    /* FIXME: is the RTS line also needs to be forced to a disable state according
     * SERIAL_RTS_CONTROL? */
  }

  /* CRTSCTS */

  /* logical XOR */
  if ((!(pHandflow->ControlHandShake & SERIAL_CTS_HANDSHAKE) &&
       (pHandflow->FlowReplace & SERIAL_RTS_HANDSHAKE)) ||
      ((pHandflow->ControlHandShake & SERIAL_CTS_HANDSHAKE) &&
       !(pHandflow->FlowReplace & SERIAL_RTS_HANDSHAKE)))
  {
    CommLog_Print(WLOG_WARN,
                  "SERIAL_CTS_HANDSHAKE:%s and SERIAL_RTS_HANDSHAKE:%s cannot be different, "
                  "CRTSCTS will be set since it is claimed for one of the both lines.",
                  (pHandflow->ControlHandShake & SERIAL_CTS_HANDSHAKE) ? "ON" : "OFF",
                  (pHandflow->FlowReplace & SERIAL_RTS_HANDSHAKE) ? "ON" : "OFF");
  }

  if ((pHandflow->ControlHandShake & SERIAL_CTS_HANDSHAKE) ||
      (pHandflow->FlowReplace & SERIAL_RTS_HANDSHAKE))
  {
    upcomingTermios.c_cflag |= CRTSCTS;
  }
  else
  {
    upcomingTermios.c_cflag &= ~CRTSCTS;
  }

  /* ControlHandShake */

  if (pHandflow->ControlHandShake & SERIAL_DTR_HANDSHAKE)
  {
    /* DTR/DSR flow control not supported on Linux */
    CommLog_Print(WLOG_WARN, "Attempt to use the unsupported SERIAL_DTR_HANDSHAKE feature.");
    SetLastError(ERROR_NOT_SUPPORTED);
    result = FALSE; /* but keep on */
  }

  if (pHandflow->ControlHandShake & SERIAL_DSR_HANDSHAKE)
  {
    /* DTR/DSR flow control not supported on Linux */
    CommLog_Print(WLOG_WARN, "Attempt to use the unsupported SERIAL_DSR_HANDSHAKE feature.");
    SetLastError(ERROR_NOT_SUPPORTED);
    result = FALSE; /* but keep on */
  }

  if (pHandflow->ControlHandShake & SERIAL_DCD_HANDSHAKE)
  {
    /* DCD flow control not supported on Linux */
    CommLog_Print(WLOG_WARN, "Attempt to use the unsupported SERIAL_DCD_HANDSHAKE feature.");
    SetLastError(ERROR_NOT_SUPPORTED);
    result = FALSE; /* but keep on */
  }

  // FIXME: could be implemented during read/write I/O
  if (pHandflow->ControlHandShake & SERIAL_DSR_SENSITIVITY)
  {
    /* DSR line control not supported on Linux */
    CommLog_Print(WLOG_WARN, "Attempt to use the unsupported SERIAL_DSR_SENSITIVITY feature.");
    SetLastError(ERROR_NOT_SUPPORTED);
    result = FALSE; /* but keep on */
  }

  // FIXME: could be implemented during read/write I/O
  if (pHandflow->ControlHandShake & SERIAL_ERROR_ABORT)
  {
    /* Aborting operations on error not supported on Linux */
    CommLog_Print(WLOG_WARN, "Attempt to use the unsupported SERIAL_ERROR_ABORT feature.");
    SetLastError(ERROR_NOT_SUPPORTED);
    result = FALSE; /* but keep on */
  }

  /* FlowReplace */

  if (pHandflow->FlowReplace & SERIAL_AUTO_TRANSMIT)
  {
    upcomingTermios.c_iflag |= IXON;
  }
  else
  {
    upcomingTermios.c_iflag &= (uint32_t)~IXON;
  }

  if (pHandflow->FlowReplace & SERIAL_AUTO_RECEIVE)
  {
    upcomingTermios.c_iflag |= IXOFF;
  }
  else
  {
    upcomingTermios.c_iflag &= (uint32_t)~IXOFF;
  }

  // FIXME: could be implemented during read/write I/O, as of today ErrorChar is necessary '\0'
  if (pHandflow->FlowReplace & SERIAL_ERROR_CHAR)
  {
    /* errors will be replaced by the character '\0'. */
    upcomingTermios.c_iflag &= (uint32_t)~IGNPAR;
  }
  else
  {
    upcomingTermios.c_iflag |= IGNPAR;
  }

  if (pHandflow->FlowReplace & SERIAL_NULL_STRIPPING)
  {
    upcomingTermios.c_iflag |= IGNBRK;
  }
  else
  {
    upcomingTermios.c_iflag &= (uint32_t)~IGNBRK;
  }

  // FIXME: could be implemented during read/write I/O
  if (pHandflow->FlowReplace & SERIAL_BREAK_CHAR)
  {
    CommLog_Print(WLOG_WARN, "Attempt to use the unsupported SERIAL_BREAK_CHAR feature.");
    SetLastError(ERROR_NOT_SUPPORTED);
    result = FALSE; /* but keep on */
  }

  // FIXME: could be implemented during read/write I/O
  if (pHandflow->FlowReplace & SERIAL_XOFF_CONTINUE)
  {
    /* not supported on Linux */
    CommLog_Print(WLOG_WARN, "Attempt to use the unsupported SERIAL_XOFF_CONTINUE feature.");
    SetLastError(ERROR_NOT_SUPPORTED);
    result = FALSE; /* but keep on */
  }

  /* XonLimit */

  pComm->XOffLimit = pHandflow->XoffLimit;
  pComm->XOnLimit = pHandflow->XonLimit;

  if (comm_ioctl_tcsetattr(pComm->fd, TCSANOW, &upcomingTermios) < 0)
  {
    CommLog_Print(WLOG_WARN, "comm_ioctl_tcsetattr failure: last-error: 0x%" PRIX32 "",
                  GetLastError());
    return FALSE;
  }

  return result;
}

static BOOL get_handflow(WINPR_COMM* pComm, SERIAL_HANDFLOW* pHandflow)
{
  struct termios currentTermios = { 0 };

  WINPR_ASSERT(pComm);
  WINPR_ASSERT(pHandflow);

  if (tcgetattr(pComm->fd, &currentTermios) < 0)
  {
    SetLastError(ERROR_IO_DEVICE);
    return FALSE;
  }

  /* ControlHandShake */

  pHandflow->ControlHandShake = 0;

  if (currentTermios.c_cflag & HUPCL)
    pHandflow->ControlHandShake |= SERIAL_DTR_CONTROL;

  /* SERIAL_DTR_HANDSHAKE unsupported */

  if (currentTermios.c_cflag & CRTSCTS)
    pHandflow->ControlHandShake |= SERIAL_CTS_HANDSHAKE;

  /* SERIAL_DSR_HANDSHAKE unsupported */

  /* SERIAL_DCD_HANDSHAKE unsupported */

  /* SERIAL_DSR_SENSITIVITY unsupported */

  /* SERIAL_ERROR_ABORT unsupported */

  /* FlowReplace */

  pHandflow->FlowReplace = 0;

  if (currentTermios.c_iflag & IXON)
    pHandflow->FlowReplace |= SERIAL_AUTO_TRANSMIT;

  if (currentTermios.c_iflag & IXOFF)
    pHandflow->FlowReplace |= SERIAL_AUTO_RECEIVE;

  if (!(currentTermios.c_iflag & IGNPAR))
    pHandflow->FlowReplace |= SERIAL_ERROR_CHAR;

  if (currentTermios.c_iflag & IGNBRK)
    pHandflow->FlowReplace |= SERIAL_NULL_STRIPPING;

  /* SERIAL_BREAK_CHAR unsupported */

  if (currentTermios.c_cflag & HUPCL)
    pHandflow->FlowReplace |= SERIAL_RTS_CONTROL;

  if (currentTermios.c_cflag & CRTSCTS)
    pHandflow->FlowReplace |= SERIAL_RTS_HANDSHAKE;

  /* SERIAL_XOFF_CONTINUE unsupported */

  pHandflow->XonLimit = pComm->XOnLimit;
  pHandflow->XoffLimit = pComm->XOffLimit;

  return TRUE;
}

static BOOL set_timeouts(WINPR_COMM* pComm, const SERIAL_TIMEOUTS* pTimeouts)
{
  WINPR_ASSERT(pComm);
  WINPR_ASSERT(pTimeouts);

  /* NB: timeouts are applied on system during read/write I/O */

  /* http://msdn.microsoft.com/en-us/library/windows/hardware/hh439614%28v=vs.85%29.aspx */
  if ((pTimeouts->ReadIntervalTimeout == MAXULONG) &&
      (pTimeouts->ReadTotalTimeoutConstant == MAXULONG))
  {
    CommLog_Print(
        WLOG_WARN,
        "ReadIntervalTimeout and ReadTotalTimeoutConstant cannot be both set to MAXULONG");
    SetLastError(ERROR_INVALID_PARAMETER);
    return FALSE;
  }

  pComm->timeouts.ReadIntervalTimeout = pTimeouts->ReadIntervalTimeout;
  pComm->timeouts.ReadTotalTimeoutMultiplier = pTimeouts->ReadTotalTimeoutMultiplier;
  pComm->timeouts.ReadTotalTimeoutConstant = pTimeouts->ReadTotalTimeoutConstant;
  pComm->timeouts.WriteTotalTimeoutMultiplier = pTimeouts->WriteTotalTimeoutMultiplier;
  pComm->timeouts.WriteTotalTimeoutConstant = pTimeouts->WriteTotalTimeoutConstant;

  CommLog_Print(WLOG_DEBUG, "ReadIntervalTimeout %" PRIu32 "",
                pComm->timeouts.ReadIntervalTimeout);
  CommLog_Print(WLOG_DEBUG, "ReadTotalTimeoutMultiplier %" PRIu32 "",
                pComm->timeouts.ReadTotalTimeoutMultiplier);
  CommLog_Print(WLOG_DEBUG, "ReadTotalTimeoutConstant %" PRIu32 "",
                pComm->timeouts.ReadTotalTimeoutConstant);
  CommLog_Print(WLOG_DEBUG, "WriteTotalTimeoutMultiplier %" PRIu32 "",
                pComm->timeouts.WriteTotalTimeoutMultiplier);
  CommLog_Print(WLOG_DEBUG, "WriteTotalTimeoutConstant %" PRIu32 "",
                pComm->timeouts.WriteTotalTimeoutConstant);

  return TRUE;
}

static BOOL get_timeouts(WINPR_COMM* pComm, SERIAL_TIMEOUTS* pTimeouts)
{
  WINPR_ASSERT(pComm);
  WINPR_ASSERT(pTimeouts);

  pTimeouts->ReadIntervalTimeout = pComm->timeouts.ReadIntervalTimeout;
  pTimeouts->ReadTotalTimeoutMultiplier = pComm->timeouts.ReadTotalTimeoutMultiplier;
  pTimeouts->ReadTotalTimeoutConstant = pComm->timeouts.ReadTotalTimeoutConstant;
  pTimeouts->WriteTotalTimeoutMultiplier = pComm->timeouts.WriteTotalTimeoutMultiplier;
  pTimeouts->WriteTotalTimeoutConstant = pComm->timeouts.WriteTotalTimeoutConstant;

  return TRUE;
}

static BOOL set_lines(WINPR_COMM* pComm, UINT32 lines)
{
  WINPR_ASSERT(pComm);

  return CommIoCtl(pComm, TIOCMBIS, &lines);
}

static BOOL clear_lines(WINPR_COMM* pComm, UINT32 lines)
{
  WINPR_ASSERT(pComm);

  return CommIoCtl(pComm, TIOCMBIC, &lines);
}

static BOOL set_dtr(WINPR_COMM* pComm)
{
  SERIAL_HANDFLOW handflow = { 0 };
  WINPR_ASSERT(pComm);

  if (!get_handflow(pComm, &handflow))
    return FALSE;

  /* SERIAL_DTR_HANDSHAKE not supported as of today */
  WINPR_ASSERT((handflow.ControlHandShake & SERIAL_DTR_HANDSHAKE) == 0);

  if (handflow.ControlHandShake & SERIAL_DTR_HANDSHAKE)
  {
    SetLastError(ERROR_INVALID_PARAMETER);
    return FALSE;
  }

  return set_lines(pComm, TIOCM_DTR);
}

static BOOL clear_dtr(WINPR_COMM* pComm)
{
  SERIAL_HANDFLOW handflow = { 0 };
  WINPR_ASSERT(pComm);

  if (!get_handflow(pComm, &handflow))
    return FALSE;

  /* SERIAL_DTR_HANDSHAKE not supported as of today */
  WINPR_ASSERT((handflow.ControlHandShake & SERIAL_DTR_HANDSHAKE) == 0);

  if (handflow.ControlHandShake & SERIAL_DTR_HANDSHAKE)
  {
    SetLastError(ERROR_INVALID_PARAMETER);
    return FALSE;
  }

  return clear_lines(pComm, TIOCM_DTR);
}

static BOOL set_rts(WINPR_COMM* pComm)
{
  SERIAL_HANDFLOW handflow = { 0 };
  WINPR_ASSERT(pComm);

  if (!get_handflow(pComm, &handflow))
    return FALSE;

  if (handflow.FlowReplace & SERIAL_RTS_HANDSHAKE)
  {
    SetLastError(ERROR_INVALID_PARAMETER);
    return FALSE;
  }

  return set_lines(pComm, TIOCM_RTS);
}

static BOOL clear_rts(WINPR_COMM* pComm)
{
  SERIAL_HANDFLOW handflow = { 0 };
  WINPR_ASSERT(pComm);
  if (!get_handflow(pComm, &handflow))
    return FALSE;

  if (handflow.FlowReplace & SERIAL_RTS_HANDSHAKE)
  {
    SetLastError(ERROR_INVALID_PARAMETER);
    return FALSE;
  }

  return clear_lines(pComm, TIOCM_RTS);
}

static BOOL get_raw_modemstatus(WINPR_COMM* pComm, int* pRegister)
{
  WINPR_ASSERT(pComm);
  WINPR_ASSERT(pRegister);

  const BOOL rc = CommIoCtl(pComm, TIOCMGET, pRegister);

  char buffer[128] = { 0 };
  CommLog_Print(WLOG_DEBUG, "status %s",
                get_modem_status_str(*pRegister, buffer, sizeof(buffer)));
  return rc;
}

static BOOL get_modemstatus(WINPR_COMM* pComm, ULONG* pRegister)
{
  int lines = 0;

  if (!get_raw_modemstatus(pComm, &lines))
    return FALSE;

  *pRegister = 0;
  if (lines & TIOCM_CTS)
    *pRegister |= SERIAL_MSR_CTS | SERIAL_MSR_DCTS;
  if (lines & TIOCM_DSR)
    *pRegister |= SERIAL_MSR_DSR | SERIAL_MSR_DDSR;
  if (lines & TIOCM_RI)
    *pRegister |= SERIAL_MSR_RI | SERIAL_MSR_TERI;
  if (lines & TIOCM_CD)
    *pRegister |= SERIAL_MSR_DCD | SERIAL_MSR_DDCD;

  return TRUE;
}

/* http://msdn.microsoft.com/en-us/library/windows/hardware/hh439605%28v=vs.85%29.aspx */
static const ULONG SERIAL_SYS_SUPPORTED_EV_MASK =
    SERIAL_EV_RXCHAR | SERIAL_EV_RXFLAG | SERIAL_EV_TXEMPTY | SERIAL_EV_CTS | SERIAL_EV_DSR |
    SERIAL_EV_RLSD | SERIAL_EV_BREAK | SERIAL_EV_ERR | SERIAL_EV_RING |
    /* SERIAL_EV_PERR     | */
    SERIAL_EV_RX80FULL /*|
    SERIAL_EV_EVENT1   |
    SERIAL_EV_EVENT2*/
    ;

static BOOL is_wait_set(WINPR_COMM* pComm)
{
  WINPR_ASSERT(pComm);

  EnterCriticalSection(&pComm->EventsLock);
  const BOOL isWaiting = (pComm->PendingEvents & SERIAL_EV_WINPR_WAITING) != 0;
  LeaveCriticalSection(&pComm->EventsLock);
  return isWaiting;
}

static BOOL set_wait_mask(WINPR_COMM* pComm, const ULONG* pWaitMask)
{
  ULONG possibleMask = 0;

  WINPR_ASSERT(pComm);
  WINPR_ASSERT(pWaitMask);

  /* Stops pending IOCTL_SERIAL_WAIT_ON_MASK
   * http://msdn.microsoft.com/en-us/library/ff546805%28v=vs.85%29.aspx
   */
  if (is_wait_set(pComm))
  {
    /* FIXME: any doubt on reading PendingEvents out of a critical section? */

    EnterCriticalSection(&pComm->EventsLock);
    pComm->PendingEvents |= SERIAL_EV_WINPR_STOP;
    LeaveCriticalSection(&pComm->EventsLock);

    /* waiting the end of the pending wait_on_mask() */
    while (is_wait_set(pComm))
      Sleep(10); /* 10ms */

    EnterCriticalSection(&pComm->EventsLock);
    pComm->PendingEvents &= (uint32_t)~SERIAL_EV_WINPR_STOP;
    LeaveCriticalSection(&pComm->EventsLock);
  }

  /* NB: ensure to leave the critical section before to return */
  EnterCriticalSection(&pComm->EventsLock);

  if (*pWaitMask == 0)
  {
    /* clearing pending events */
    if (!CommUpdateIOCount(pComm, FALSE))
    {
      LeaveCriticalSection(&pComm->EventsLock);
      return FALSE;
    }

    pComm->PendingEvents = 0;
  }

  possibleMask = *pWaitMask & SERIAL_SYS_SUPPORTED_EV_MASK;

  if (possibleMask != *pWaitMask)
  {
    CommLog_Print(WLOG_WARN,
                  "Not all wait events supported (Serial.sys), requested events= 0x%08" PRIX32
                  ", possible events= 0x%08" PRIX32 "",
                  *pWaitMask, possibleMask);

    /* FIXME: shall we really set the possibleMask and return FALSE? */
    pComm->WaitEventMask = possibleMask;

    LeaveCriticalSection(&pComm->EventsLock);
    return FALSE;
  }

  pComm->WaitEventMask = possibleMask;

  LeaveCriticalSection(&pComm->EventsLock);
  return TRUE;
}

static BOOL get_wait_mask(WINPR_COMM* pComm, ULONG* pWaitMask)
{
  WINPR_ASSERT(pComm);
  WINPR_ASSERT(pWaitMask);

  *pWaitMask = pComm->WaitEventMask;
  return TRUE;
}

static BOOL set_queue_size(WINPR_ATTR_UNUSED WINPR_COMM* pComm, const SERIAL_QUEUE_SIZE* pQueueSize)
{
  WINPR_ASSERT(pComm);
  WINPR_ASSERT(pQueueSize);

  if ((pQueueSize->InSize <= N_TTY_BUF_SIZE) && (pQueueSize->OutSize <= N_TTY_BUF_SIZE))
    return TRUE; /* nothing to do */

  /* FIXME: could be implemented on top of N_TTY */

  if (pQueueSize->InSize > N_TTY_BUF_SIZE)
    CommLog_Print(WLOG_WARN,
                  "Requested an incompatible input buffer size: %" PRIu32
                  ", keeping on with a %" PRIu32 " bytes buffer.",
                  pQueueSize->InSize, N_TTY_BUF_SIZE);

  if (pQueueSize->OutSize > N_TTY_BUF_SIZE)
    CommLog_Print(WLOG_WARN,
                  "Requested an incompatible output buffer size: %" PRIu32
                  ", keeping on with a %" PRIu32 " bytes buffer.",
                  pQueueSize->OutSize, N_TTY_BUF_SIZE);

  SetLastError(ERROR_CANCELLED);
  return FALSE;
}

static BOOL purge(WINPR_COMM* pComm, const ULONG* pPurgeMask)
{
  WINPR_ASSERT(pComm);
  WINPR_ASSERT(pPurgeMask);

  if ((*pPurgeMask & (uint32_t)~(SERIAL_PURGE_TXABORT | SERIAL_PURGE_RXABORT |
                                 SERIAL_PURGE_TXCLEAR | SERIAL_PURGE_RXCLEAR)) > 0)
  {
    CommLog_Print(WLOG_WARN, "Invalid purge mask: 0x%" PRIX32 "\n", *pPurgeMask);
    SetLastError(ERROR_INVALID_PARAMETER);
    return FALSE;
  }

  /* FIXME: currently relying too much on the fact the server
   * sends a single IRP_MJ_WRITE or IRP_MJ_READ at a time
   * (taking care though that one IRP_MJ_WRITE and one
   * IRP_MJ_READ can be sent simultaneously) */

  if (*pPurgeMask & SERIAL_PURGE_TXABORT)
  {
    /* Purges all write (IRP_MJ_WRITE) requests. */
#if defined(WINPR_HAVE_SYS_EVENTFD_H)
    if (eventfd_write(pComm->fd_write_event, WINPR_PURGE_TXABORT) < 0)
    {
      if (errno != EAGAIN)
      {
        char ebuffer[256] = { 0 };
        CommLog_Print(WLOG_WARN, "eventfd_write failed, errno=[%d] %s", errno,
                      winpr_strerror(errno, ebuffer, sizeof(ebuffer)));
      }

      WINPR_ASSERT(errno == EAGAIN); /* no reader <=> no pending IRP_MJ_WRITE */
    }
#endif
  }

  if (*pPurgeMask & SERIAL_PURGE_RXABORT)
  {
    /* Purges all read (IRP_MJ_READ) requests. */
#if defined(WINPR_HAVE_SYS_EVENTFD_H)
    if (eventfd_write(pComm->fd_read_event, WINPR_PURGE_RXABORT) < 0)
    {
      if (errno != EAGAIN)
      {
        char ebuffer[256] = { 0 };
        CommLog_Print(WLOG_WARN, "eventfd_write failed, errno=[%d] %s", errno,
                      winpr_strerror(errno, ebuffer, sizeof(ebuffer)));
      }

      WINPR_ASSERT(errno == EAGAIN); /* no reader <=> no pending IRP_MJ_READ */
    }
#endif
  }

  if (*pPurgeMask & SERIAL_PURGE_TXCLEAR)
  {
    /* Purges the transmit buffer, if one exists. */

    if (tcflush(pComm->fd, TCOFLUSH) < 0)
    {
      char ebuffer[256] = { 0 };
      CommLog_Print(WLOG_WARN, "tcflush(TCOFLUSH) failure, errno=[%d] %s", errno,
                    winpr_strerror(errno, ebuffer, sizeof(ebuffer)));
      SetLastError(ERROR_CANCELLED);
      return FALSE;
    }
  }

  if (*pPurgeMask & SERIAL_PURGE_RXCLEAR)
  {
    /* Purges the receive buffer, if one exists. */

    if (tcflush(pComm->fd, TCIFLUSH) < 0)
    {
      char ebuffer[256] = { 0 };
      CommLog_Print(WLOG_WARN, "tcflush(TCIFLUSH) failure, errno=[%d] %s", errno,
                    winpr_strerror(errno, ebuffer, sizeof(ebuffer)));
      SetLastError(ERROR_CANCELLED);
      return FALSE;
    }
  }

  return TRUE;
}

/* NB: get_commstatus also produces most of the events consumed by  wait_on_mask(). Exceptions:
 *  - SERIAL_EV_RXFLAG: FIXME: once EventChar supported
 *
 */
static BOOL get_commstatus(WINPR_COMM* pComm, SERIAL_STATUS* pCommstatus)
{
  BOOL rc = FALSE;
  /* http://msdn.microsoft.com/en-us/library/jj673022%28v=vs.85%29.aspx */
#if defined(WINPR_HAVE_COMM_COUNTERS)
  struct serial_icounter_struct currentCounters = { 0 };
#endif
  WINPR_ASSERT(pComm);
  WINPR_ASSERT(pCommstatus);

  /* NB: ensure to leave the critical section before to return */
  EnterCriticalSection(&pComm->EventsLock);

  ZeroMemory(pCommstatus, sizeof(SERIAL_STATUS));

  int status = 0;
  if (!get_raw_modemstatus(pComm, &status))
    goto fail;

#if defined(WINPR_HAVE_COMM_COUNTERS)
  if (!CommUpdateIOCount(pComm, FALSE))
    goto fail;
  currentCounters = pComm->counters;

  /* NB: preferred below (currentCounters.* != pComm->counters.*) over (currentCounters.* >
   * pComm->counters.*) thinking the counters can loop */

  /* Errors */

  if (currentCounters.buf_overrun != pComm->counters.buf_overrun)
  {
    pCommstatus->Errors |= SERIAL_ERROR_QUEUEOVERRUN;
  }

  if (currentCounters.overrun != pComm->counters.overrun)
  {
    pCommstatus->Errors |= SERIAL_ERROR_OVERRUN;
    pComm->PendingEvents |= SERIAL_EV_ERR;
  }

  if (currentCounters.brk != pComm->counters.brk)
  {
    pCommstatus->Errors |= SERIAL_ERROR_BREAK;
    pComm->PendingEvents |= SERIAL_EV_BREAK;
  }

  if (currentCounters.parity != pComm->counters.parity)
  {
    pCommstatus->Errors |= SERIAL_ERROR_PARITY;
    pComm->PendingEvents |= SERIAL_EV_ERR;
  }

  if (currentCounters.frame != pComm->counters.frame)
  {
    pCommstatus->Errors |= SERIAL_ERROR_FRAMING;
    pComm->PendingEvents |= SERIAL_EV_ERR;
  }
#endif

  /* HoldReasons */

  if (status & TIOCM_CTS)
    pComm->PendingEvents |= SERIAL_EV_CTS;

  /* TODO: SERIAL_TX_WAITING_FOR_XON */

  /* TODO: SERIAL_TX_WAITING_ON_BREAK, see LCR's bit 6 */

  /* TODO: SERIAL_TX_WAITING_XOFF_SENT */

  if (status & TIOCM_SR)
    pComm->PendingEvents |= SERIAL_EV_RXFLAG | SERIAL_EV_RXCHAR;

  /* AmountInInQueue */
  int available = 0;
  if (!CommIoCtl(pComm, FIONREAD, &available))
    goto fail;

#if defined(__linux__)
  if (!CommIoCtl(pComm, TIOCINQ, &pCommstatus->AmountInInQueue))
    goto fail;
#endif

  /*  AmountInOutQueue */

  if (!CommIoCtl(pComm, TIOCOUTQ, &pCommstatus->AmountInOutQueue))
    goto fail;

  /*  BOOLEAN EofReceived; FIXME: once EofChar supported */

  /*  BOOLEAN WaitForImmediate; TODO: once IOCTL_SERIAL_IMMEDIATE_CHAR fully supported */

  /* other events based on counters */

  if (available > 0)
    pComm->PendingEvents |= SERIAL_EV_RXFLAG | SERIAL_EV_RXCHAR;

  if (pCommstatus->AmountInOutQueue == 0) /* output buffer is now empty */
  {
    pComm->PendingEvents |= SERIAL_EV_TXEMPTY;
  }
  else
  {
    /* FIXME: "now empty" from the specs is ambiguous, need to track previous completed
     * transmission? */
    pComm->PendingEvents &= (uint32_t)~SERIAL_EV_TXEMPTY;
  }

#if defined(WINPR_HAVE_COMM_COUNTERS)
  if (currentCounters.tx != pComm->counters.tx)
  {
    pComm->PendingEvents &= (uint32_t)~SERIAL_EV_TXEMPTY;
  }
  else
  {
    pComm->PendingEvents |= SERIAL_EV_TXEMPTY;
  }

  if (currentCounters.rx != pComm->counters.rx)
  {
    pComm->PendingEvents |= SERIAL_EV_RXFLAG | SERIAL_EV_RXCHAR;
  }

  if (currentCounters.cts != pComm->counters.cts)
  {
    pComm->PendingEvents |= SERIAL_EV_CTS;
  }

  if (currentCounters.dsr != pComm->counters.dsr)
  {
    pComm->PendingEvents |= SERIAL_EV_DSR;
  }

  if (currentCounters.dcd != pComm->counters.dcd)
  {
    pComm->PendingEvents |= SERIAL_EV_RLSD;
  }

  if (currentCounters.rng != pComm->counters.rng)
  {
    pComm->PendingEvents |= SERIAL_EV_RING;
  }
  pComm->counters = currentCounters;
#endif

  if (pCommstatus->AmountInInQueue > (0.8 * N_TTY_BUF_SIZE))
  {
    pComm->PendingEvents |= SERIAL_EV_RX80FULL;
  }
  else
  {
    /* FIXME: "is 80 percent full" from the specs is ambiguous, need to track when it previously
     * * occurred? */
    pComm->PendingEvents &= (uint32_t)~SERIAL_EV_RX80FULL;
  }

  rc = TRUE;
fail:
  LeaveCriticalSection(&pComm->EventsLock);
  return rc;
}

static BOOL refresh_PendingEvents(WINPR_COMM* pComm)
{
  SERIAL_STATUS serialStatus = { 0 };

  WINPR_ASSERT(pComm);

  /* NB: also ensures PendingEvents to be up to date */
  if (!get_commstatus(pComm, &serialStatus))
  {
    return FALSE;
  }

  return TRUE;
}

static void consume_event(WINPR_COMM* pComm, ULONG* pOutputMask, ULONG event)
{
  WINPR_ASSERT(pComm);
  WINPR_ASSERT(pOutputMask);

  if ((pComm->WaitEventMask & event) && (pComm->PendingEvents & event))
  {
    pComm->PendingEvents &= ~event; /* consumed */
    *pOutputMask |= event;
  }
}

static BOOL unlock_return(WINPR_COMM* pComm, BOOL res)
{
  EnterCriticalSection(&pComm->EventsLock);
  pComm->PendingEvents &= (uint32_t)~SERIAL_EV_WINPR_WAITING;
  LeaveCriticalSection(&pComm->EventsLock);
  return res;
}

/*
 * NB: see also: set_wait_mask()
 */
static BOOL wait_on_mask(WINPR_COMM* pComm, ULONG* pOutputMask)
{
  WINPR_ASSERT(pComm);
  WINPR_ASSERT(*pOutputMask == 0);

  EnterCriticalSection(&pComm->EventsLock);
  pComm->PendingEvents |= SERIAL_EV_WINPR_WAITING;
  LeaveCriticalSection(&pComm->EventsLock);

  while (TRUE)
  {
    /* NB: EventsLock also used by  refresh_PendingEvents() */
    if (!refresh_PendingEvents(pComm))
      return unlock_return(pComm, FALSE);

    /* NB: ensure to leave the critical section before to return */
    EnterCriticalSection(&pComm->EventsLock);

    if (pComm->PendingEvents & SERIAL_EV_WINPR_STOP)
    {
      /* pOutputMask must remain empty but should
       * not have been modified.
       *
       * http://msdn.microsoft.com/en-us/library/ff546805%28v=vs.85%29.aspx
       */
      WINPR_ASSERT(*pOutputMask == 0);

      LeaveCriticalSection(&pComm->EventsLock);
      break;
    }

    consume_event(pComm, pOutputMask, SERIAL_EV_RXCHAR);
    consume_event(pComm, pOutputMask, SERIAL_EV_RXFLAG);
    consume_event(pComm, pOutputMask, SERIAL_EV_TXEMPTY);
    consume_event(pComm, pOutputMask, SERIAL_EV_DSR);
    consume_event(pComm, pOutputMask, SERIAL_EV_RLSD);
    consume_event(pComm, pOutputMask, SERIAL_EV_BREAK);
    consume_event(pComm, pOutputMask, SERIAL_EV_ERR);
    consume_event(pComm, pOutputMask, SERIAL_EV_RING);
    consume_event(pComm, pOutputMask, SERIAL_EV_RX80FULL);

    LeaveCriticalSection(&pComm->EventsLock);

    /* NOTE: PendingEvents can be modified from now on but
     * not pOutputMask */

    if (*pOutputMask != 0)
      break;

    /* waiting for a modification of PendingEvents.
     *
     * NOTE: previously used a semaphore but used
     * sem_timedwait() anyway. Finally preferred a simpler
     * solution with Sleep() without the burden of the
     * semaphore initialization and destroying.
     */

    Sleep(100); /* 100 ms */
  }

  return unlock_return(pComm, TRUE);
}

static BOOL set_break_on(WINPR_COMM* pComm)
{
  WINPR_ASSERT(pComm);
  return CommIoCtl(pComm, TIOCSBRK, NULL);
}

static BOOL set_break_off(WINPR_COMM* pComm)
{
  WINPR_ASSERT(pComm);

  return CommIoCtl(pComm, TIOCCBRK, NULL);
}

static BOOL set_xoff(WINPR_COMM* pComm)
{
  WINPR_ASSERT(pComm);
  // NOLINTNEXTLINE(concurrency-mt-unsafe)
  if (tcflow(pComm->fd, TCIOFF) < 0)
  {
    char ebuffer[256] = { 0 };
    CommLog_Print(WLOG_WARN, "TCIOFF failure, errno=[%d] %s", errno,
                  winpr_strerror(errno, ebuffer, sizeof(ebuffer)));
    SetLastError(ERROR_IO_DEVICE);
    return FALSE;
  }

  return TRUE;
}

static BOOL set_xon(WINPR_COMM* pComm)
{
  WINPR_ASSERT(pComm);
  // NOLINTNEXTLINE(concurrency-mt-unsafe)
  if (tcflow(pComm->fd, TCION) < 0)
  {
    char ebuffer[256] = { 0 };
    CommLog_Print(WLOG_WARN, "TCION failure, errno=[%d] %s", errno,
                  winpr_strerror(errno, ebuffer, sizeof(ebuffer)));
    SetLastError(ERROR_IO_DEVICE);
    return FALSE;
  }

  return TRUE;
}

static BOOL get_dtrrts(WINPR_COMM* pComm, ULONG* pMask)
{
  int lines = 0;

  WINPR_ASSERT(pComm);
  WINPR_ASSERT(pMask);

  if (!get_raw_modemstatus(pComm, &lines))
    return FALSE;

  *pMask = 0;

  if (!(lines & TIOCM_DTR))
    *pMask |= SERIAL_DTR_STATE;
  if (!(lines & TIOCM_RTS))
    *pMask |= SERIAL_RTS_STATE;

  return TRUE;
}

static BOOL config_size(WINPR_ATTR_UNUSED WINPR_COMM* pComm, ULONG* pSize)
{
  WINPR_ASSERT(pComm);
  WINPR_ASSERT(pSize);

  /* http://msdn.microsoft.com/en-us/library/ff546548%28v=vs.85%29.aspx */
  if (!pSize)
    return FALSE;

  *pSize = 0;
  return TRUE;
}

static BOOL immediate_char(WINPR_COMM* pComm, const UCHAR* pChar)
{
  BOOL result = 0;
  DWORD nbBytesWritten = 0;

  WINPR_ASSERT(pComm);
  WINPR_ASSERT(pChar);

  /* FIXME: CommWriteFile uses a critical section, shall it be
   * interrupted?
   *
   * FIXME: see also get_commstatus()'s WaitForImmediate boolean
   */

  result = CommWriteFile(pComm, pChar, 1, &nbBytesWritten, NULL);

  WINPR_ASSERT(nbBytesWritten == 1);

  return result;
}

static BOOL reset_device(WINPR_ATTR_UNUSED WINPR_COMM* pComm)
{
  /* http://msdn.microsoft.com/en-us/library/dn265347%28v=vs.85%29.aspx */
  WINPR_ASSERT(pComm);

  pComm->XOnLimit = TTY_THRESHOLD_UNTHROTTLE;
  pComm->XOffLimit = TTY_THRESHOLD_THROTTLE;

  (void)CommUpdateIOCount(pComm, TRUE);

  return CommIoCtl(pComm, TIOCMSET, 0);
}

static const SERIAL_DRIVER SerialSys = {
  .id = SerialDriverSerialSys,
  .name = _T("Serial.sys"),
  .set_baud_rate = set_baud_rate,
  .get_baud_rate = get_baud_rate,
  .get_properties = get_properties,
  .set_serial_chars = set_serial_chars,
  .get_serial_chars = get_serial_chars,
  .set_line_control = set_line_control,
  .get_line_control = get_line_control,
  .set_handflow = set_handflow,
  .get_handflow = get_handflow,
  .set_timeouts = set_timeouts,
  .get_timeouts = get_timeouts,
  .set_dtr = set_dtr,
  .clear_dtr = clear_dtr,
  .set_rts = set_rts,
  .clear_rts = clear_rts,
  .get_modemstatus = get_modemstatus,
  .set_wait_mask = set_wait_mask,
  .get_wait_mask = get_wait_mask,
  .wait_on_mask = wait_on_mask,
  .set_queue_size = set_queue_size,
  .purge = purge,
  .get_commstatus = get_commstatus,
  .set_break_on = set_break_on,
  .set_break_off = set_break_off,
  .set_xoff = set_xoff,
  .set_xon = set_xon,
  .get_dtrrts = get_dtrrts,
  .config_size = config_size,
  .immediate_char = immediate_char,
  .reset_device = reset_device,
};

const SERIAL_DRIVER* SerialSys_s(void)
{
  return &SerialSys;
}

Coverage Report

Created: 2025-07-01 06:46