Adding upstream version 6.0.4-dfsg.upstream/6.0.4-dfsgupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 959 insertions, 0 deletions

diff --git a/src/VBox/Runtime/r3/win/serialport-win.cpp b/src/VBox/Runtime/r3/win/serialport-win.cpp
new file mode 100644
index 00000000..ba479207
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/serialport-win.cpp
@@ -0,0 +1,959 @@
+/* $Id: serialport-win.cpp $ */
+/** @file
+ * IPRT - Serial Port API, Windows Implementation.
+ */
+
+/*
+ * Copyright (C) 2017-2019 Oracle Corporation
+ *
+ * This file is part of VirtualBox Open Source Edition (OSE), as
+ * available from http://www.virtualbox.org. This file is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU
+ * General Public License (GPL) as published by the Free Software
+ * Foundation, in version 2 as it comes in the "COPYING" file of the
+ * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
+ * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
+ * VirtualBox OSE distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/serialport.h>
+#include "internal/iprt.h"
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/cdefs.h>
+#include <iprt/errcore.h>
+#include <iprt/mem.h>
+#include <iprt/string.h>
+#include <iprt/thread.h>
+#include <iprt/time.h>
+#include "internal/magics.h"
+
+#include <iprt/win/windows.h>
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+
+/**
+ * Internal serial port state.
+ */
+typedef struct RTSERIALPORTINTERNAL
+{
+    /** Magic value (RTSERIALPORT_MAGIC). */
+    uint32_t            u32Magic;
+    /** Flags given while opening the serial port. */
+    uint32_t            fOpenFlags;
+    /** The device handle. */
+    HANDLE              hDev;
+    /** The overlapped write structure. */
+    OVERLAPPED          OverlappedWrite;
+    /** The overlapped read structure. */
+    OVERLAPPED          OverlappedRead;
+    /** The overlapped I/O structure when waiting on events. */
+    OVERLAPPED          OverlappedEvt;
+    /** The event handle to wait on for the overlapped event operations of the device. */
+    HANDLE              hEvtDev;
+    /** The event handle to wait on for the overlapped write operations of the device. */
+    HANDLE              hEvtWrite;
+    /** The event handle to wait on for the overlapped read operations of the device. */
+    HANDLE              hEvtRead;
+    /** The event handle to wait on for waking up waiting threads externally. */
+    HANDLE              hEvtIntr;
+    /** Events currently waited for. */
+    uint32_t            fEvtMask;
+    /** Flag whether a write is currently pending. */
+    bool                fWritePending;
+    /** Bounce buffer for writes. */
+    uint8_t            *pbBounceBuf;
+    /** Amount of used buffer space. */
+    size_t              cbBounceBufUsed;
+    /** Amount of allocated buffer space. */
+    size_t              cbBounceBufAlloc;
+    /** The current active port config. */
+    DCB                 PortCfg;
+} RTSERIALPORTINTERNAL;
+/** Pointer to the internal serial port state. */
+typedef RTSERIALPORTINTERNAL *PRTSERIALPORTINTERNAL;
+
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** The pipe buffer size we prefer. */
+#define RTSERIALPORT_NT_SIZE      _32K
+
+
+
+/*********************************************************************************************************************************
+*   Global variables                                                                                                             *
+*********************************************************************************************************************************/
+
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+
+/**
+ * Updatest the current event mask to wait for.
+ *
+ * @returns IPRT status code.
+ * @param   pThis                   The internal serial port instance data.
+ * @param   fEvtMask                The new event mask to change to.
+ */
+static int rtSerialPortWinUpdateEvtMask(PRTSERIALPORTINTERNAL pThis, uint32_t fEvtMask)
+{
+    DWORD dwEvtMask = EV_ERR;
+
+    if (fEvtMask & RTSERIALPORT_EVT_F_DATA_RX)
+        dwEvtMask |= EV_RXCHAR;
+    if (fEvtMask & RTSERIALPORT_EVT_F_DATA_TX)
+        dwEvtMask |= EV_TXEMPTY;
+    if (fEvtMask & RTSERIALPORT_EVT_F_BREAK_DETECTED)
+        dwEvtMask |= EV_BREAK;
+    if (fEvtMask & RTSERIALPORT_EVT_F_STATUS_LINE_CHANGED)
+        dwEvtMask |= EV_CTS | EV_DSR | EV_RING | EV_RLSD;
+
+    int rc = VINF_SUCCESS;
+    if (!SetCommMask(pThis->hDev, dwEvtMask))
+        rc = RTErrConvertFromWin32(GetLastError());
+    else
+        pThis->fEvtMask = fEvtMask;
+
+    return rc;
+}
+
+
+/**
+ * Tries to set the default config on the given serial port.
+ *
+ * @returns IPRT status code.
+ * @param   pThis                   The internal serial port instance data.
+ */
+static int rtSerialPortSetDefaultCfg(PRTSERIALPORTINTERNAL pThis)
+{
+    if (!PurgeComm(pThis->hDev, PURGE_RXABORT | PURGE_RXCLEAR | PURGE_TXABORT | PURGE_TXCLEAR))
+        return RTErrConvertFromWin32(GetLastError());
+
+    pThis->PortCfg.DCBlength = sizeof(pThis->PortCfg);
+    if (!GetCommState(pThis->hDev, &pThis->PortCfg))
+        return RTErrConvertFromWin32(GetLastError());
+
+    pThis->PortCfg.BaudRate    = CBR_9600;
+    pThis->PortCfg.fBinary     = TRUE;
+    pThis->PortCfg.fParity     = TRUE;
+    pThis->PortCfg.fDtrControl = DTR_CONTROL_DISABLE;
+    pThis->PortCfg.ByteSize    = 8;
+    pThis->PortCfg.Parity      = NOPARITY;
+
+    int rc = VINF_SUCCESS;
+    if (!SetCommState(pThis->hDev, &pThis->PortCfg))
+        rc = RTErrConvertFromWin32(GetLastError());
+
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Set timeouts for non blocking mode.
+         * See https://docs.microsoft.com/en-us/windows/desktop/api/winbase/ns-winbase-_commtimeouts .
+         */
+        COMMTIMEOUTS ComTimeouts;
+        RT_ZERO(ComTimeouts);
+        ComTimeouts.ReadIntervalTimeout = MAXDWORD;
+        if (!SetCommTimeouts(pThis->hDev, &ComTimeouts))
+            rc = RTErrConvertFromWin32(GetLastError());
+    }
+
+    return rc;
+}
+
+
+/**
+ * Common worker for handling I/O completion.
+ *
+ * This is used by RTSerialPortClose, RTSerialPortWrite and RTPipeSerialPortNB.
+ *
+ * @returns IPRT status code.
+ * @param   pThis               The pipe instance handle.
+ */
+static int rtSerialPortWriteCheckCompletion(PRTSERIALPORTINTERNAL pThis)
+{
+    int rc = VINF_SUCCESS;
+    DWORD dwRc = WaitForSingleObject(pThis->OverlappedWrite.hEvent, 0);
+    if (dwRc == WAIT_OBJECT_0)
+    {
+        DWORD cbWritten = 0;
+        if (GetOverlappedResult(pThis->hDev, &pThis->OverlappedWrite, &cbWritten, TRUE))
+        {
+            for (;;)
+            {
+                if (cbWritten >= pThis->cbBounceBufUsed)
+                {
+                    pThis->fWritePending = false;
+                    rc = VINF_SUCCESS;
+                    break;
+                }
+
+                /* resubmit the remainder of the buffer - can this actually happen? */
+                memmove(&pThis->pbBounceBuf[0], &pThis->pbBounceBuf[cbWritten], pThis->cbBounceBufUsed - cbWritten);
+                rc = ResetEvent(pThis->OverlappedWrite.hEvent); Assert(rc == TRUE);
+                if (!WriteFile(pThis->hDev, pThis->pbBounceBuf, (DWORD)pThis->cbBounceBufUsed,
+                               &cbWritten, &pThis->OverlappedWrite))
+                {
+                    if (GetLastError() == ERROR_IO_PENDING)
+                        rc = VINF_TRY_AGAIN;
+                    else
+                    {
+                        pThis->fWritePending = false;
+                        rc = RTErrConvertFromWin32(GetLastError());
+                    }
+                    break;
+                }
+                Assert(cbWritten > 0);
+            }
+        }
+        else
+        {
+            pThis->fWritePending = false;
+            rc = RTErrConvertFromWin32(GetLastError());
+        }
+    }
+    else if (dwRc == WAIT_TIMEOUT)
+        rc = VINF_TRY_AGAIN;
+    else
+    {
+        pThis->fWritePending = false;
+        if (dwRc == WAIT_ABANDONED)
+            rc = VERR_INVALID_HANDLE;
+        else
+            rc = RTErrConvertFromWin32(GetLastError());
+    }
+    return rc;
+}
+
+
+RTDECL(int)  RTSerialPortOpen(PRTSERIALPORT phSerialPort, const char *pszPortAddress, uint32_t fFlags)
+{
+    AssertPtrReturn(phSerialPort, VERR_INVALID_POINTER);
+    AssertReturn(VALID_PTR(pszPortAddress) && *pszPortAddress != '\0', VERR_INVALID_PARAMETER);
+    AssertReturn(!(fFlags & ~RTSERIALPORT_OPEN_F_VALID_MASK), VERR_INVALID_PARAMETER);
+    AssertReturn((fFlags & RTSERIALPORT_OPEN_F_READ) || (fFlags & RTSERIALPORT_OPEN_F_WRITE),
+                 VERR_INVALID_PARAMETER);
+
+    int rc = VINF_SUCCESS;
+    PRTSERIALPORTINTERNAL pThis = (PRTSERIALPORTINTERNAL)RTMemAllocZ(sizeof(*pThis));
+    if (pThis)
+    {
+        pThis->u32Magic         = RTSERIALPORT_MAGIC;
+        pThis->fOpenFlags       = fFlags;
+        pThis->fEvtMask         = 0;
+        pThis->fWritePending    = false;
+        pThis->pbBounceBuf      = NULL;
+        pThis->cbBounceBufUsed  = 0;
+        pThis->cbBounceBufAlloc = 0;
+        RT_ZERO(pThis->OverlappedEvt);
+        RT_ZERO(pThis->OverlappedWrite);
+        RT_ZERO(pThis->OverlappedRead);
+        pThis->hEvtDev          = CreateEvent(NULL, TRUE, FALSE, NULL);
+        if (pThis->hEvtDev)
+        {
+            pThis->OverlappedEvt.hEvent = pThis->hEvtDev,
+            pThis->hEvtIntr = CreateEvent(NULL, FALSE, FALSE, NULL);
+            if (pThis->hEvtIntr)
+            {
+                pThis->hEvtWrite = CreateEvent(NULL, TRUE, TRUE, NULL);
+                if (pThis->hEvtWrite)
+                {
+                    pThis->OverlappedWrite.hEvent = pThis->hEvtWrite;
+                    pThis->hEvtRead = CreateEvent(NULL, TRUE, TRUE, NULL);
+                    if (pThis->hEvtRead)
+                    {
+                        pThis->OverlappedRead.hEvent = pThis->hEvtRead;
+                        DWORD fWinFlags = 0;
+
+                        if (fFlags & RTSERIALPORT_OPEN_F_WRITE)
+                            fWinFlags |= GENERIC_WRITE;
+                        if (fFlags & RTSERIALPORT_OPEN_F_READ)
+                            fWinFlags |= GENERIC_READ;
+
+                        pThis->hDev = CreateFile(pszPortAddress,
+                                                 fWinFlags,
+                                                 0, /* Must be opened with exclusive access. */
+                                                 NULL, /* No SECURITY_ATTRIBUTES structure. */
+                                                 OPEN_EXISTING, /* Must use OPEN_EXISTING. */
+                                                 FILE_FLAG_OVERLAPPED, /* Overlapped I/O. */
+                                                 NULL);
+                        if (pThis->hDev)
+                        {
+                            rc = rtSerialPortSetDefaultCfg(pThis);
+                            if (RT_SUCCESS(rc))
+                            {
+                                *phSerialPort = pThis;
+                                return rc;
+                            }
+                        }
+                        else
+                            rc = RTErrConvertFromWin32(GetLastError());
+
+                        CloseHandle(pThis->hEvtRead);
+                    }
+
+                    CloseHandle(pThis->hEvtWrite);
+                }
+
+                CloseHandle(pThis->hEvtIntr);
+            }
+            else
+                rc = RTErrConvertFromWin32(GetLastError());
+
+            CloseHandle(pThis->hEvtDev);
+        }
+        else
+            rc = RTErrConvertFromWin32(GetLastError());
+
+        RTMemFree(pThis);
+    }
+    else
+        rc = VERR_NO_MEMORY;
+
+    return rc;
+}
+
+
+RTDECL(int)  RTSerialPortClose(RTSERIALPORT hSerialPort)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    if (pThis == NIL_RTSERIALPORT)
+        return VINF_SUCCESS;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Do the cleanup.
+     */
+    AssertReturn(ASMAtomicCmpXchgU32(&pThis->u32Magic, RTSERIALPORT_MAGIC_DEAD, RTSERIALPORT_MAGIC), VERR_INVALID_HANDLE);
+
+    if (pThis->fWritePending)
+        rtSerialPortWriteCheckCompletion(pThis);
+
+    CloseHandle(pThis->hDev);
+    CloseHandle(pThis->hEvtDev);
+    CloseHandle(pThis->hEvtWrite);
+    CloseHandle(pThis->hEvtRead);
+    CloseHandle(pThis->hEvtIntr);
+    pThis->hDev      = NULL;
+    pThis->hEvtDev   = NULL;
+    pThis->hEvtWrite = NULL;
+    pThis->hEvtRead  = NULL;
+    pThis->hEvtIntr  = NULL;
+    RTMemFree(pThis);
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(RTHCINTPTR) RTSerialPortToNative(RTSERIALPORT hSerialPort)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, -1);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, -1);
+
+    return (RTHCINTPTR)pThis->hDev;
+}
+
+
+RTDECL(int) RTSerialPortRead(RTSERIALPORT hSerialPort, void *pvBuf, size_t cbToRead, size_t *pcbRead)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pvBuf, VERR_INVALID_POINTER);
+    AssertReturn(cbToRead > 0, VERR_INVALID_PARAMETER);
+
+    /*
+     * Kick of an overlapped read.
+     */
+    int rc = VINF_SUCCESS;
+    uint8_t *pbBuf = (uint8_t *)pvBuf;
+
+    while (   cbToRead > 0
+           && RT_SUCCESS(rc))
+    {
+        BOOL fSucc = ResetEvent(pThis->OverlappedRead.hEvent); Assert(fSucc == TRUE); RT_NOREF(fSucc);
+        DWORD cbRead = 0;
+        if (ReadFile(pThis->hDev, pbBuf,
+                     cbToRead <= ~(DWORD)0 ? (DWORD)cbToRead : ~(DWORD)0,
+                     &cbRead, &pThis->OverlappedRead))
+        {
+            if (pcbRead)
+            {
+                *pcbRead = cbRead;
+                break;
+            }
+            rc = VINF_SUCCESS;
+        }
+        else if (GetLastError() == ERROR_IO_PENDING)
+        {
+            DWORD dwWait = WaitForSingleObject(pThis->OverlappedRead.hEvent, INFINITE);
+            if (dwWait == WAIT_OBJECT_0)
+            {
+                if (GetOverlappedResult(pThis->hDev, &pThis->OverlappedRead, &cbRead, TRUE /*fWait*/))
+                {
+                    if (pcbRead)
+                    {
+                        *pcbRead = cbRead;
+                        break;
+                    }
+                    rc = VINF_SUCCESS;
+                }
+                else
+                    rc = RTErrConvertFromWin32(GetLastError());
+            }
+            else
+            {
+                Assert(dwWait == WAIT_FAILED);
+                rc = RTErrConvertFromWin32(GetLastError());
+            }
+        }
+        else
+            rc = RTErrConvertFromWin32(GetLastError());
+
+        if (RT_SUCCESS(rc))
+        {
+            cbToRead -= cbRead;
+            pbBuf    += cbRead;
+        }
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTSerialPortReadNB(RTSERIALPORT hSerialPort, void *pvBuf, size_t cbToRead, size_t *pcbRead)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pvBuf, VERR_INVALID_POINTER);
+    AssertReturn(cbToRead > 0, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pcbRead, VERR_INVALID_POINTER);
+
+    *pcbRead = 0;
+
+    /* Check whether there is data waiting in the input queue. */
+    int rc = VINF_SUCCESS;
+    COMSTAT ComStat; RT_ZERO(ComStat);
+    if (ClearCommError(pThis->hDev, NULL, &ComStat))
+    {
+        if (ComStat.cbInQue > 0)
+        {
+            DWORD dwToRead = RT_MIN(ComStat.cbInQue, (DWORD)cbToRead);
+            /* Kick of an overlapped read.  It should return immediately */
+            BOOL fSucc = ResetEvent(pThis->OverlappedRead.hEvent); Assert(fSucc == TRUE); RT_NOREF(fSucc);
+            DWORD cbRead = 0;
+            if (   cbToRead == 0
+                || ReadFile(pThis->hDev, pvBuf, dwToRead,
+                            &cbRead, &pThis->OverlappedRead))
+                *pcbRead = cbRead;
+            else if (GetLastError() == ERROR_IO_PENDING)
+            {
+                /* This shouldn't actually happen, so turn this into a synchronous read. */
+                if (GetOverlappedResult(pThis->hDev, &pThis->OverlappedRead, &cbRead, TRUE /*fWait*/))
+                    *pcbRead = cbRead;
+                else
+                    rc = RTErrConvertFromWin32(GetLastError());
+            }
+            else
+                rc = RTErrConvertFromWin32(GetLastError());
+        }
+        else
+            rc = VINF_TRY_AGAIN;
+    }
+    else
+        rc = RTErrConvertFromWin32(GetLastError());
+
+    return rc;
+}
+
+
+RTDECL(int) RTSerialPortWrite(RTSERIALPORT hSerialPort, const void *pvBuf, size_t cbToWrite, size_t *pcbWritten)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pvBuf, VERR_INVALID_POINTER);
+    AssertReturn(cbToWrite > 0, VERR_INVALID_PARAMETER);
+
+    /* If I/O is pending, check if it has completed. */
+    int rc = VINF_SUCCESS;
+    if (pThis->fWritePending)
+        rc = rtSerialPortWriteCheckCompletion(pThis);
+    if (rc == VINF_SUCCESS)
+    {
+        const uint8_t *pbBuf = (const uint8_t *)pvBuf;
+
+        while (   cbToWrite > 0
+               && RT_SUCCESS(rc))
+        {
+            BOOL fSucc = ResetEvent(pThis->OverlappedWrite.hEvent); Assert(fSucc == TRUE); RT_NOREF(fSucc);
+            DWORD cbWritten = 0;
+            if (WriteFile(pThis->hDev, pbBuf,
+                          cbToWrite <= ~(DWORD)0 ? (DWORD)cbToWrite : ~(DWORD)0,
+                          &cbWritten, &pThis->OverlappedWrite))
+            {
+                if (pcbWritten)
+                {
+                    *pcbWritten = cbWritten;
+                    break;
+                }
+                rc = VINF_SUCCESS;
+            }
+            else if (GetLastError() == ERROR_IO_PENDING)
+            {
+                DWORD dwWait = WaitForSingleObject(pThis->OverlappedWrite.hEvent, INFINITE);
+                if (dwWait == WAIT_OBJECT_0)
+                {
+                    if (GetOverlappedResult(pThis->hDev, &pThis->OverlappedWrite, &cbWritten, TRUE /*fWait*/))
+                    {
+                        if (pcbWritten)
+                        {
+                            *pcbWritten = cbWritten;
+                            break;
+                        }
+                        rc = VINF_SUCCESS;
+                    }
+                    else
+                        rc = RTErrConvertFromWin32(GetLastError());
+                }
+                else
+                {
+                    Assert(dwWait == WAIT_FAILED);
+                    rc = RTErrConvertFromWin32(GetLastError());
+                }
+            }
+            else
+                rc = RTErrConvertFromWin32(GetLastError());
+
+            if (RT_SUCCESS(rc))
+            {
+                cbToWrite -= cbWritten;
+                pbBuf     += cbWritten;
+            }
+        }
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTSerialPortWriteNB(RTSERIALPORT hSerialPort, const void *pvBuf, size_t cbToWrite, size_t *pcbWritten)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pvBuf, VERR_INVALID_POINTER);
+    AssertReturn(cbToWrite > 0, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pcbWritten, VERR_INVALID_POINTER);
+
+    /* If I/O is pending, check if it has completed. */
+    int rc = VINF_SUCCESS;
+    if (pThis->fWritePending)
+        rc = rtSerialPortWriteCheckCompletion(pThis);
+    if (rc == VINF_SUCCESS)
+    {
+        Assert(!pThis->fWritePending);
+
+        /* Do the bounce buffering. */
+        if (    pThis->cbBounceBufAlloc < cbToWrite
+            &&  pThis->cbBounceBufAlloc < RTSERIALPORT_NT_SIZE)
+        {
+            if (cbToWrite > RTSERIALPORT_NT_SIZE)
+                cbToWrite = RTSERIALPORT_NT_SIZE;
+            void *pv = RTMemRealloc(pThis->pbBounceBuf, RT_ALIGN_Z(cbToWrite, _1K));
+            if (pv)
+            {
+                pThis->pbBounceBuf = (uint8_t *)pv;
+                pThis->cbBounceBufAlloc = RT_ALIGN_Z(cbToWrite, _1K);
+            }
+            else
+                rc = VERR_NO_MEMORY;
+        }
+        else if (cbToWrite > RTSERIALPORT_NT_SIZE)
+            cbToWrite = RTSERIALPORT_NT_SIZE;
+        if (RT_SUCCESS(rc) && cbToWrite)
+        {
+            memcpy(pThis->pbBounceBuf, pvBuf, cbToWrite);
+            pThis->cbBounceBufUsed = (uint32_t)cbToWrite;
+
+            /* Submit the write. */
+            rc = ResetEvent(pThis->OverlappedWrite.hEvent); Assert(rc == TRUE);
+            DWORD cbWritten = 0;
+            if (WriteFile(pThis->hDev, pThis->pbBounceBuf, (DWORD)pThis->cbBounceBufUsed,
+                          &cbWritten, &pThis->OverlappedWrite))
+            {
+                *pcbWritten = RT_MIN(cbWritten, cbToWrite); /* paranoia^3 */
+                rc = VINF_SUCCESS;
+            }
+            else if (GetLastError() == ERROR_IO_PENDING)
+            {
+                *pcbWritten = cbToWrite;
+                pThis->fWritePending = true;
+                rc = VINF_SUCCESS;
+            }
+            else
+                rc = RTErrConvertFromWin32(GetLastError());
+        }
+        else if (RT_SUCCESS(rc))
+            *pcbWritten = 0;
+    }
+    else if (RT_SUCCESS(rc))
+        *pcbWritten = 0;
+
+    return rc;
+}
+
+
+RTDECL(int) RTSerialPortCfgQueryCurrent(RTSERIALPORT hSerialPort, PRTSERIALPORTCFG pCfg)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+
+    pCfg->uBaudRate = pThis->PortCfg.BaudRate;
+    switch (pThis->PortCfg.Parity)
+    {
+        case NOPARITY:
+            pCfg->enmParity = RTSERIALPORTPARITY_NONE;
+            break;
+        case EVENPARITY:
+            pCfg->enmParity = RTSERIALPORTPARITY_EVEN;
+            break;
+        case ODDPARITY:
+            pCfg->enmParity = RTSERIALPORTPARITY_ODD;
+            break;
+        case MARKPARITY:
+            pCfg->enmParity = RTSERIALPORTPARITY_MARK;
+            break;
+        case SPACEPARITY:
+            pCfg->enmParity = RTSERIALPORTPARITY_SPACE;
+            break;
+        default:
+            AssertFailed();
+            return VERR_INTERNAL_ERROR;
+    }
+
+    switch (pThis->PortCfg.ByteSize)
+    {
+        case 5:
+            pCfg->enmDataBitCount = RTSERIALPORTDATABITS_5BITS;
+            break;
+        case 6:
+            pCfg->enmDataBitCount = RTSERIALPORTDATABITS_6BITS;
+            break;
+        case 7:
+            pCfg->enmDataBitCount = RTSERIALPORTDATABITS_7BITS;
+            break;
+        case 8:
+            pCfg->enmDataBitCount = RTSERIALPORTDATABITS_8BITS;
+            break;
+        default:
+            AssertFailed();
+            return VERR_INTERNAL_ERROR;
+    }
+
+    switch (pThis->PortCfg.StopBits)
+    {
+        case ONESTOPBIT:
+            pCfg->enmStopBitCount = RTSERIALPORTSTOPBITS_ONE;
+            break;
+        case ONE5STOPBITS:
+            pCfg->enmStopBitCount = RTSERIALPORTSTOPBITS_ONEPOINTFIVE;
+            break;
+        case TWOSTOPBITS:
+            pCfg->enmStopBitCount = RTSERIALPORTSTOPBITS_TWO;
+            break;
+        default:
+            AssertFailed();
+            return VERR_INTERNAL_ERROR;
+    }
+
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int) RTSerialPortCfgSet(RTSERIALPORT hSerialPort, PCRTSERIALPORTCFG pCfg, PRTERRINFO pErrInfo)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+
+    RT_NOREF(pErrInfo);
+
+    DCB DcbNew;
+    memcpy(&DcbNew, &pThis->PortCfg, sizeof(DcbNew));
+    DcbNew.BaudRate = pCfg->uBaudRate;
+
+    switch (pCfg->enmParity)
+    {
+        case RTSERIALPORTPARITY_NONE:
+            DcbNew.Parity = NOPARITY;
+            break;
+        case RTSERIALPORTPARITY_EVEN:
+            DcbNew.Parity = EVENPARITY;
+            break;
+        case RTSERIALPORTPARITY_ODD:
+            DcbNew.Parity = ODDPARITY;
+            break;
+        case RTSERIALPORTPARITY_MARK:
+            DcbNew.Parity = MARKPARITY;
+            break;
+        case RTSERIALPORTPARITY_SPACE:
+            DcbNew.Parity = SPACEPARITY;
+            break;
+        default:
+            AssertFailedReturn(VERR_INVALID_PARAMETER);
+    }
+
+    switch (pCfg->enmDataBitCount)
+    {
+        case RTSERIALPORTDATABITS_5BITS:
+            DcbNew.ByteSize = 5;
+            break;
+        case RTSERIALPORTDATABITS_6BITS:
+            DcbNew.ByteSize = 6;
+            break;
+        case RTSERIALPORTDATABITS_7BITS:
+            DcbNew.ByteSize = 7;
+            break;
+        case RTSERIALPORTDATABITS_8BITS:
+            DcbNew.ByteSize = 8;
+            break;
+        default:
+            AssertFailedReturn(VERR_INVALID_PARAMETER);
+    }
+
+    switch (pCfg->enmStopBitCount)
+    {
+        case RTSERIALPORTSTOPBITS_ONE:
+            DcbNew.StopBits = ONESTOPBIT;
+            break;
+        case RTSERIALPORTSTOPBITS_ONEPOINTFIVE:
+            AssertReturn(pCfg->enmDataBitCount == RTSERIALPORTDATABITS_5BITS, VERR_INVALID_PARAMETER);
+            DcbNew.StopBits = ONE5STOPBITS;
+            break;
+        case RTSERIALPORTSTOPBITS_TWO:
+            AssertReturn(pCfg->enmDataBitCount != RTSERIALPORTDATABITS_5BITS, VERR_INVALID_PARAMETER);
+            DcbNew.StopBits = TWOSTOPBITS;
+            break;
+        default:
+            AssertFailedReturn(VERR_INVALID_PARAMETER);
+    }
+
+    int rc = VINF_SUCCESS;
+    if (!SetCommState(pThis->hDev, &DcbNew))
+        rc = RTErrConvertFromWin32(GetLastError());
+    else
+        memcpy(&pThis->PortCfg, &DcbNew, sizeof(DcbNew));
+
+    return rc;
+}
+
+
+RTDECL(int) RTSerialPortEvtPoll(RTSERIALPORT hSerialPort, uint32_t fEvtMask, uint32_t *pfEvtsRecv,
+                                RTMSINTERVAL msTimeout)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(!(fEvtMask & ~RTSERIALPORT_EVT_F_VALID_MASK), VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pfEvtsRecv, VERR_INVALID_POINTER);
+
+    *pfEvtsRecv = 0;
+
+    int rc = VINF_SUCCESS;
+    if (fEvtMask != pThis->fEvtMask)
+        rc = rtSerialPortWinUpdateEvtMask(pThis, fEvtMask);
+
+    /*
+     * EV_RXCHAR is triggered only if a byte is received after the event mask is set,
+     * not if there is already something in the input buffer. Thatswhy we check the input
+     * buffer for any stored data and the output buffer whether it is empty and return
+     * the appropriate flags.
+     */
+    if (RT_SUCCESS(rc))
+    {
+        COMSTAT ComStat; RT_ZERO(ComStat);
+        if (!ClearCommError(pThis->hDev, NULL, &ComStat))
+            return RTErrConvertFromWin32(GetLastError());
+
+        /* Check whether data is already waiting in the input buffer. */
+        if (   (fEvtMask & RTSERIALPORT_EVT_F_DATA_RX)
+            && ComStat.cbInQue > 0)
+            *pfEvtsRecv |= RTSERIALPORT_EVT_F_DATA_RX;
+
+        /* Check whether the output buffer is empty. */
+        if (   (fEvtMask & RTSERIALPORT_EVT_F_DATA_TX)
+            && ComStat.cbOutQue == 0)
+            *pfEvtsRecv |= RTSERIALPORT_EVT_F_DATA_TX;
+
+        /* Return if there is at least one event. */
+        if (*pfEvtsRecv != 0)
+            return VINF_SUCCESS;
+    }
+
+    if (RT_SUCCESS(rc))
+    {
+        DWORD dwEventMask = 0;
+        HANDLE ahWait[2];
+        ahWait[0] = pThis->hEvtDev;
+        ahWait[1] = pThis->hEvtIntr;
+
+        RT_ZERO(pThis->OverlappedEvt);
+        pThis->OverlappedEvt.hEvent = pThis->hEvtDev;
+
+        if (!WaitCommEvent(pThis->hDev, &dwEventMask, &pThis->OverlappedEvt))
+        {
+            DWORD dwRet = GetLastError();
+            if (dwRet == ERROR_IO_PENDING)
+            {
+                dwRet = WaitForMultipleObjects(2, ahWait, FALSE, msTimeout == RT_INDEFINITE_WAIT ? INFINITE : msTimeout);
+                if (dwRet == WAIT_TIMEOUT)
+                    rc = VERR_TIMEOUT;
+                else if (dwRet == WAIT_FAILED)
+                    rc = RTErrConvertFromWin32(GetLastError());
+                else if (dwRet != WAIT_OBJECT_0)
+                    rc = VERR_INTERRUPTED;
+            }
+            else
+                rc = RTErrConvertFromWin32(dwRet);
+        }
+
+        if (RT_SUCCESS(rc))
+        {
+            /* Check the event */
+            if (dwEventMask & EV_RXCHAR)
+                *pfEvtsRecv |= RTSERIALPORT_EVT_F_DATA_RX;
+            if (dwEventMask & EV_TXEMPTY)
+            {
+                if (pThis->fWritePending)
+                {
+                    rc = rtSerialPortWriteCheckCompletion(pThis);
+                    if (rc == VINF_SUCCESS)
+                        *pfEvtsRecv |= RTSERIALPORT_EVT_F_DATA_TX;
+                    else
+                        rc = VINF_SUCCESS;
+                }
+                else
+                    *pfEvtsRecv |= RTSERIALPORT_EVT_F_DATA_TX;
+            }
+            if (dwEventMask & EV_BREAK)
+                *pfEvtsRecv |= RTSERIALPORT_EVT_F_BREAK_DETECTED;
+            if (dwEventMask & (EV_CTS | EV_DSR | EV_RING | EV_RLSD))
+                *pfEvtsRecv |= RTSERIALPORT_EVT_F_STATUS_LINE_CHANGED;
+        }
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTSerialPortEvtPollInterrupt(RTSERIALPORT hSerialPort)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+
+    if (!SetEvent(pThis->hEvtIntr))
+        return RTErrConvertFromWin32(GetLastError());
+
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int) RTSerialPortChgBreakCondition(RTSERIALPORT hSerialPort, bool fSet)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+
+    BOOL fSucc = FALSE;
+    if (fSet)
+        fSucc = SetCommBreak(pThis->hDev);
+    else
+        fSucc = ClearCommBreak(pThis->hDev);
+
+    int rc = VINF_SUCCESS;
+    if (!fSucc)
+        rc = RTErrConvertFromWin32(GetLastError());
+
+    return rc;
+}
+
+
+RTDECL(int) RTSerialPortChgStatusLines(RTSERIALPORT hSerialPort, uint32_t fClear, uint32_t fSet)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+
+    BOOL fSucc = TRUE;
+    if (fSet & RTSERIALPORT_CHG_STS_LINES_F_DTR)
+        fSucc = EscapeCommFunction(pThis->hDev, SETDTR);
+    if (   fSucc
+        && (fSet & RTSERIALPORT_CHG_STS_LINES_F_RTS))
+        fSucc = EscapeCommFunction(pThis->hDev, SETRTS);
+
+    if (   fSucc
+        && (fClear & RTSERIALPORT_CHG_STS_LINES_F_DTR))
+        fSucc = EscapeCommFunction(pThis->hDev, CLRDTR);
+    if (   fSucc
+        && (fClear & RTSERIALPORT_CHG_STS_LINES_F_RTS))
+        fSucc = EscapeCommFunction(pThis->hDev, CLRRTS);
+
+    int rc = VINF_SUCCESS;
+    if (!fSucc)
+        rc = RTErrConvertFromWin32(GetLastError());
+
+    return rc;
+}
+
+
+RTDECL(int) RTSerialPortQueryStatusLines(RTSERIALPORT hSerialPort, uint32_t *pfStsLines)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pfStsLines, VERR_INVALID_POINTER);
+
+    *pfStsLines = 0;
+
+    int rc = VINF_SUCCESS;
+    DWORD fStsLinesQueried = 0;
+
+    /* Get the new state */
+    if (GetCommModemStatus(pThis->hDev, &fStsLinesQueried))
+    {
+        *pfStsLines |= (fStsLinesQueried & MS_RLSD_ON) ? RTSERIALPORT_STS_LINE_DCD : 0;
+        *pfStsLines |= (fStsLinesQueried & MS_RING_ON) ? RTSERIALPORT_STS_LINE_RI  : 0;
+        *pfStsLines |= (fStsLinesQueried & MS_DSR_ON) ? RTSERIALPORT_STS_LINE_DSR : 0;
+        *pfStsLines |= (fStsLinesQueried & MS_CTS_ON) ? RTSERIALPORT_STS_LINE_CTS : 0;
+    }
+    else
+        rc = RTErrConvertFromWin32(GetLastError());
+
+    return rc;
+}
+