path: root/winpr/libwinpr/comm/comm_serial_sys.c

/**
 * 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.
 */

#if defined __linux__ && !defined ANDROID

#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"
#ifdef __UCLIBC__
#include "comm.h"
#endif

#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 BOOL _get_properties(WINPR_COMM* pComm, COMMPROP* pProperties)
{
	/* 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;

	ZeroMemory(&futureState, sizeof(struct termios));
	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;

	ZeroMemory(&currentState, sizeof(struct termios));
	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;

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

	if (pSerialChars->XonChar == pSerialChars->XoffChar)
	{
		/* https://msdn.microsoft.com/en-us/library/windows/hardware/ff546688?v=vs.85.aspx */
		SetLastError(ERROR_INVALID_PARAMETER);
		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, charaters 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;

	ZeroMemory(&currentTermios, sizeof(struct termios));
	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;

	/* 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: prefered to let the underlying driver to deal with
	 * this issue. At least produce a warning message?
	 */

	ZeroMemory(&upcomingTermios, sizeof(struct termios));
	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 &= ~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 &= ~(PARENB | PARODD | CMSPAR);
			break;

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

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

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

		case SPACE_PARITY:
			upcomingTermios.c_cflag &= ~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 &= ~CSIZE;
			upcomingTermios.c_cflag |= CS5;
			break;

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

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

		case 8:
			upcomingTermios.c_cflag &= ~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;

	ZeroMemory(&currentTermios, sizeof(struct termios));
	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;

	ZeroMemory(&upcomingTermios, sizeof(struct termios));
	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 &= ~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 &= ~IXON;
	}

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

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

	// FIXME: could be implemented during read/write I/O
	if (pHandflow->XonLimit != TTY_THRESHOLD_UNTHROTTLE)
	{
		CommLog_Print(WLOG_WARN, "Attempt to set XonLimit with an unsupported value: %" PRId32 "",
		              pHandflow->XonLimit);
		SetLastError(ERROR_NOT_SUPPORTED);
		result = FALSE; /* but keep on */
	}

	/* XoffChar */

	// FIXME: could be implemented during read/write I/O
	if (pHandflow->XoffLimit != TTY_THRESHOLD_THROTTLE)
	{
		CommLog_Print(WLOG_WARN, "Attempt to set XoffLimit with an unsupported value: %" PRId32 "",
		              pHandflow->XoffLimit);
		SetLastError(ERROR_NOT_SUPPORTED);
		result = FALSE; /* but keep on */
	}

	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;

	ZeroMemory(&currentTermios, sizeof(struct termios));
	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 */

	/* XonLimit */

	pHandflow->XonLimit = TTY_THRESHOLD_UNTHROTTLE;

	/* XoffLimit */

	pHandflow->XoffLimit = TTY_THRESHOLD_THROTTLE;

	return TRUE;
}

static BOOL _set_timeouts(WINPR_COMM* pComm, const SERIAL_TIMEOUTS* 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)
{
	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)
{
	if (ioctl(pComm->fd, TIOCMBIS, &lines) < 0)
	{
		char ebuffer[256] = { 0 };
		CommLog_Print(WLOG_WARN, "TIOCMBIS ioctl failed, lines=0x%" PRIX32 ", errno=[%d] %s", lines,
		              errno, winpr_strerror(errno, ebuffer, sizeof(ebuffer)));
		SetLastError(ERROR_IO_DEVICE);
		return FALSE;
	}

	return TRUE;
}

static BOOL _clear_lines(WINPR_COMM* pComm, UINT32 lines)
{
	if (ioctl(pComm->fd, TIOCMBIC, &lines) < 0)
	{
		char ebuffer[256] = { 0 };
		CommLog_Print(WLOG_WARN, "TIOCMBIC ioctl failed, lines=0x%" PRIX32 ", errno=[%d] %s", lines,
		              errno, winpr_strerror(errno, ebuffer, sizeof(ebuffer)));
		SetLastError(ERROR_IO_DEVICE);
		return FALSE;
	}

	return TRUE;
}

static BOOL _set_dtr(WINPR_COMM* pComm)
{
	SERIAL_HANDFLOW handflow;
	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;
	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;
	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;
	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_modemstatus(WINPR_COMM* pComm, ULONG* pRegister)
{
	UINT32 lines = 0;
	if (ioctl(pComm->fd, TIOCMGET, &lines) < 0)
	{
		char ebuffer[256] = { 0 };
		CommLog_Print(WLOG_WARN, "TIOCMGET ioctl failed, errno=[%d] %s", errno,
		              winpr_strerror(errno, ebuffer, sizeof(ebuffer)));
		SetLastError(ERROR_IO_DEVICE);
		return FALSE;
	}

	ZeroMemory(pRegister, sizeof(ULONG));

	/* FIXME: Is the last read of the MSR register available or
	 * cached somewhere? Not quite sure we need to return the 4
	 * LSBits anyway. A direct access to the register -- which
	 * would reset the register -- is likely not expected from
	 * this function.
	 */

	/* #define SERIAL_MSR_DCTS     0x01 */
	/* #define SERIAL_MSR_DDSR     0x02 */
	/* #define SERIAL_MSR_TERI     0x04 */
	/* #define SERIAL_MSR_DDCD     0x08 */

	if (lines & TIOCM_CTS)
		*pRegister |= SERIAL_MSR_CTS;
	if (lines & TIOCM_DSR)
		*pRegister |= SERIAL_MSR_DSR;
	if (lines & TIOCM_RI)
		*pRegister |= SERIAL_MSR_RI;
	if (lines & TIOCM_CD)
		*pRegister |= SERIAL_MSR_DCD;

	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 */
	}

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

	if (*pWaitMask == 0)
	{
		/* clearing pending events */

		if (ioctl(pComm->fd, TIOCGICOUNT, &(pComm->counters)) < 0)
		{
			char ebuffer[256] = { 0 };
			CommLog_Print(WLOG_WARN, "TIOCGICOUNT ioctl failed, errno=[%d] %s.", errno,
			              winpr_strerror(errno, ebuffer, sizeof(ebuffer)));

			if (pComm->permissive)
			{
				/* counters could not be reset but keep on */
				ZeroMemory(&(pComm->counters), sizeof(struct serial_icounter_struct));
			}
			else
			{
				SetLastError(ERROR_IO_DEVICE);
				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)
{
	*pWaitMask = pComm->WaitEventMask;
	return TRUE;
}

static BOOL _set_queue_size(WINPR_COMM* pComm, const SERIAL_QUEUE_SIZE* 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)
{
	if ((*pPurgeMask & ~(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 (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 */
		}
	}

	if (*pPurgeMask & SERIAL_PURGE_RXABORT)
	{
		/* Purges all read (IRP_MJ_READ) requests. */

		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 */
		}
	}

	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)
{
	/* http://msdn.microsoft.com/en-us/library/jj673022%28v=vs.85%29.aspx */

	struct serial_icounter_struct currentCounters;

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

	ZeroMemory(pCommstatus, sizeof(SERIAL_STATUS));

	ZeroMemory(&currentCounters, sizeof(struct serial_icounter_struct));
	if (ioctl(pComm->fd, TIOCGICOUNT, &currentCounters) < 0)
	{
		char ebuffer[256] = { 0 };
		CommLog_Print(WLOG_WARN, "TIOCGICOUNT ioctl failed, errno=[%d] %s.", errno,
		              winpr_strerror(errno, ebuffer, sizeof(ebuffer)));
		CommLog_Print(WLOG_WARN, "  could not read counters.");

		if (pComm->permissive)
		{
			/* Errors and events based on counters could not be
			 * detected but keep on.
			 */
			ZeroMemory(&currentCounters, sizeof(struct serial_icounter_struct));
		}
		else
		{
			SetLastError(ERROR_IO_DEVICE);
			LeaveCriticalSection(&pComm->EventsLock);
			return FALSE;
		}
	}

	/* 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;
	}

	/* HoldReasons */

	/* TODO: SERIAL_TX_WAITING_FOR_CTS */

	/* TODO: SERIAL_TX_WAITING_FOR_DSR */

	/* TODO: SERIAL_TX_WAITING_FOR_DCD */

	/* TODO: SERIAL_TX_WAITING_FOR_XON */

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

	/* TODO: SERIAL_TX_WAITING_XOFF_SENT */

	/* AmountInInQueue */

	if (ioctl(pComm->fd, TIOCINQ, &(pCommstatus->AmountInInQueue)) < 0)
	{
		char ebuffer[256] = { 0 };
		CommLog_Print(WLOG_WARN, "TIOCINQ ioctl failed, errno=[%d] %s", errno,
		              winpr_strerror(errno, ebuffer, sizeof(ebuffer)));
		SetLastError(ERROR_IO_DEVICE);

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

	/*  AmountInOutQueue */

	if (ioctl(pComm->fd, TIOCOUTQ, &(pCommstatus->AmountInOutQueue)) < 0)
	{
		char ebuffer[256] = { 0 };
		CommLog_Print(WLOG_WARN, "TIOCOUTQ ioctl failed, errno=[%d] %s", errno,
		              winpr_strerror(errno, ebuffer, sizeof(ebuffer)));
		SetLastError(ERROR_IO_DEVICE);

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

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

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

	/* other events based on counters */

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

	if ((currentCounters.tx != pComm->counters.tx) && /* at least a transmission occurred AND ...*/
	    (pCommstatus->AmountInOutQueue == 0))         /* output bufer 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 &= ~SERIAL_EV_TXEMPTY;
	}

	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;
	}

	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 &= ~SERIAL_EV_RX80FULL;
	}

	pComm->counters = currentCounters;

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

static BOOL _refresh_PendingEvents(WINPR_COMM* pComm)
{
	SERIAL_STATUS serialStatus;

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

	return TRUE;
}

static void _consume_event(WINPR_COMM* pComm, ULONG* pOutputMask, ULONG event)
{
	if ((pComm->WaitEventMask & event) && (pComm->PendingEvents & event))
	{
		pComm->PendingEvents &= ~event; /* consumed */
		*pOutputMask |= event;
	}
}

/*
 * NB: see also: _set_wait_mask()
 */
static BOOL _wait_on_mask(WINPR_COMM* pComm, ULONG* pOutputMask)
{
	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))
		{
			EnterCriticalSection(&pComm->EventsLock);
			pComm->PendingEvents &= ~SERIAL_EV_WINPR_WAITING;
			LeaveCriticalSection(&pComm->EventsLock);
			return FALSE;
		}

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

		if (pComm->PendingEvents & SERIAL_EV_WINPR_STOP)
		{
			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);

			pComm->PendingEvents &= ~SERIAL_EV_WINPR_WAITING;
			LeaveCriticalSection(&pComm->EventsLock);
			return TRUE;
		}

		_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_CTS);
		_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)
		{
			/* at least an event occurred */

			EnterCriticalSection(&pComm->EventsLock);
			pComm->PendingEvents &= ~SERIAL_EV_WINPR_WAITING;
			LeaveCriticalSection(&pComm->EventsLock);
			return TRUE;
		}

		/* 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 */
	}
}

static BOOL _set_break_on(WINPR_COMM* pComm)
{
	if (ioctl(pComm->fd, TIOCSBRK, NULL) < 0)
	{
		char ebuffer[256] = { 0 };
		CommLog_Print(WLOG_WARN, "TIOCSBRK ioctl failed, errno=[%d] %s", errno,
		              winpr_strerror(errno, ebuffer, sizeof(ebuffer)));
		SetLastError(ERROR_IO_DEVICE);
		return FALSE;
	}

	return TRUE;
}

static BOOL _set_break_off(WINPR_COMM* pComm)
{
	if (ioctl(pComm->fd, TIOCCBRK, NULL) < 0)
	{
		char ebuffer[256] = { 0 };
		CommLog_Print(WLOG_WARN, "TIOCSBRK ioctl failed, errno=[%d] %s", errno,
		              winpr_strerror(errno, ebuffer, sizeof(ebuffer)));
		SetLastError(ERROR_IO_DEVICE);
		return FALSE;
	}

	return TRUE;
}

static BOOL _set_xoff(WINPR_COMM* pComm)
{
	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)
{
	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)
{
	UINT32 lines = 0;
	if (ioctl(pComm->fd, TIOCMGET, &lines) < 0)
	{
		char ebuffer[256] = { 0 };
		CommLog_Print(WLOG_WARN, "TIOCMGET ioctl failed, errno=[%d] %s", errno,
		              winpr_strerror(errno, ebuffer, sizeof(ebuffer)));
		SetLastError(ERROR_IO_DEVICE);
		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_COMM* pComm, ULONG* 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 = -1;

	/* 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_COMM* pComm)
{
	/* http://msdn.microsoft.com/en-us/library/dn265347%28v=vs.85%29.aspx */
	return TRUE;
}

static 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,
};

SERIAL_DRIVER* SerialSys_s(void)
{
	return &_SerialSys;
}

#endif /* __linux__ */