Revision control
++ // Copyright (C) 2016 The Qt Company Ltd.
++ // Copyright (C) 2021 Alex Trotsenko <alex1973tr@gmail.com>
++ // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
++ // Qt-Security score:critical reason:data-parser
++
++ #include "qwindowspipereader_p.h"
++ #include <qcoreapplication.h>
++ #include <QMutexLocker>
++ #include <QPointer>
++
++ QT_BEGIN_NAMESPACE
++
++ using namespace Qt::StringLiterals;
++
++ static const DWORD minReadBufferSize = 4096;
++
++ /*!
++ \class QWindowsPipeReader
++ \inmodule QtCore
++ \internal
++ */
++ QWindowsPipeReader::QWindowsPipeReader(QObject *parent)
++ : QObject(parent),
++ handle(INVALID_HANDLE_VALUE),
++ eventHandle(CreateEvent(NULL, FALSE, FALSE, NULL)),
++ syncHandle(CreateEvent(NULL, TRUE, FALSE, NULL)),
++ waitObject(NULL),
++ readBufferMaxSize(0),
++ actualReadBufferSize(0),
++ pendingReadBytes(0),
++ lastError(ERROR_SUCCESS),
++ state(Stopped),
++ readSequenceStarted(false),
++ pipeBroken(true),
++ readyReadPending(false),
++ winEventActPosted(false)
++ {
++ ZeroMemory(&overlapped, sizeof(OVERLAPPED));
++ overlapped.hEvent = eventHandle;
++ waitObject = CreateThreadpoolWait(waitCallback, this, NULL);
++ if (waitObject == NULL)
++ qErrnoWarning("QWindowsPipeReader: CreateThreadpollWait failed.");
++ }
++
++ QWindowsPipeReader::~QWindowsPipeReader()
++ {
++ stop();
++
++ // Wait for thread pool callback to complete, as it can be still
++ // executing some completion code.
++ WaitForThreadpoolWaitCallbacks(waitObject, FALSE);
++ CloseThreadpoolWait(waitObject);
++ CloseHandle(eventHandle);
++ CloseHandle(syncHandle);
++ }
++
++ /*!
++ Sets the handle to read from. The handle must be valid.
++ Do not call this function while the pipe is running.
++ */
++ void QWindowsPipeReader::setHandle(HANDLE hPipeReadEnd)
++ {
++ readBuffer.clear();
++ actualReadBufferSize = 0;
++ readyReadPending = false;
++ pendingReadBytes = 0;
++ handle = hPipeReadEnd;
++ pipeBroken = false;
++ lastError = ERROR_SUCCESS;
++ }
++
++ /*!
++ Stops the asynchronous read sequence.
++ If the read sequence is running then the I/O operation is canceled.
++ */
++ void QWindowsPipeReader::stop()
++ {
++ cancelAsyncRead(Stopped);
++ pipeBroken = true;
++ }
++
++ /*!
++ Stops the asynchronous read sequence.
++ Reads all pending bytes into the internal buffer.
++ */
++ void QWindowsPipeReader::drainAndStop()
++ {
++ cancelAsyncRead(Draining);
++ pipeBroken = true;
++ }
++
++ /*!
++ Stops the asynchronous read sequence.
++ Clears the internal buffer and discards any pending data.
++ */
++ void QWindowsPipeReader::stopAndClear()
++ {
++ cancelAsyncRead(Stopped);
++ readBuffer.clear();
++ actualReadBufferSize = 0;
++ // QLocalSocket is supposed to write data in the 'Closing'
++ // state, so we don't set 'pipeBroken' flag here. Also, avoid
++ // setting this flag in checkForReadyRead().
++ lastError = ERROR_SUCCESS;
++ }
++
++ /*!
++ Stops the asynchronous read sequence.
++ */
++ void QWindowsPipeReader::cancelAsyncRead(State newState)
++ {
++ if (state != Running)
++ return;
++
++ mutex.lock();
++ state = newState;
++ if (readSequenceStarted) {
++ // This can legitimately fail due to the GetOverlappedResult()
++ // in the callback not being locked. We ignore ERROR_NOT_FOUND
++ // in this case.
++ if (!CancelIoEx(handle, &overlapped)) {
++ const DWORD dwError = GetLastError();
++ if (dwError != ERROR_NOT_FOUND) {
++ qErrnoWarning(dwError, "QWindowsPipeReader: CancelIoEx on handle %p failed.",
++ handle);
++ }
++ }
++
++ // Wait for callback to complete.
++ do {
++ mutex.unlock();
++ waitForNotification();
++ mutex.lock();
++ } while (readSequenceStarted);
++ }
++ mutex.unlock();
++
++ // Finish reading to keep the class state consistent. Note that
++ // signals are not emitted in the call below, as the caller is
++ // expected to do that synchronously.
++ consumePending();
++ }
++
++ /*!
++ Sets the size of internal read buffer.
++ */
++ void QWindowsPipeReader::setMaxReadBufferSize(qint64 size)
++ {
++ QMutexLocker locker(&mutex);
++ readBufferMaxSize = size;
++ }
++
++ /*!
++ Returns \c true if async operation is in progress, there is
++ pending data to read, or a read error is pending.
++ */
++ bool QWindowsPipeReader::isReadOperationActive() const
++ {
++ QMutexLocker locker(&mutex);
++ return readSequenceStarted || readyReadPending
++ || (lastError != ERROR_SUCCESS && !pipeBroken);
++ }
++
++ /*!
++ Returns the number of bytes we've read so far.
++ */
++ qint64 QWindowsPipeReader::bytesAvailable() const
++ {
++ return actualReadBufferSize;
++ }
++
++ /*!
++ Copies at most \c{maxlen} bytes from the internal read buffer to \c{data}.
++ */
++ qint64 QWindowsPipeReader::read(char *data, qint64 maxlen)
++ {
++ QMutexLocker locker(&mutex);
++ qint64 readSoFar;
++
++ // If startAsyncRead() has read data, copy it to its destination.
++ if (maxlen == 1 && actualReadBufferSize > 0) {
++ *data = readBuffer.getChar();
++ actualReadBufferSize--;
++ readSoFar = 1;
++ } else {
++ readSoFar = readBuffer.read(data, qMin(actualReadBufferSize, maxlen));
++ actualReadBufferSize -= readSoFar;
++ }
++
++ if (!pipeBroken) {
++ startAsyncReadHelper(&locker);
++ if (readSoFar == 0)
++ return -2; // signal EWOULDBLOCK
++ }
++
++ return readSoFar;
++ }
++
++ /*!
++ Reads a line from the internal buffer, but no more than \c{maxlen}
++ characters. A terminating '\0' byte is always appended to \c{data},
++ so \c{maxlen} must be larger than 1.
++ */
++ qint64 QWindowsPipeReader::readLine(char *data, qint64 maxlen)
++ {
++ QMutexLocker locker(&mutex);
++ qint64 readSoFar = 0;
++
++ if (actualReadBufferSize > 0) {
++ readSoFar = readBuffer.readLine(data, qMin(actualReadBufferSize + 1, maxlen));
++ actualReadBufferSize -= readSoFar;
++ }
++
++ if (!pipeBroken) {
++ startAsyncReadHelper(&locker);
++ if (readSoFar == 0)
++ return -2; // signal EWOULDBLOCK
++ }
++
++ return readSoFar;
++ }
++
++ /*!
++ Skips up to \c{maxlen} bytes from the internal read buffer.
++ */
++ qint64 QWindowsPipeReader::skip(qint64 maxlen)
++ {
++ QMutexLocker locker(&mutex);
++
++ const qint64 skippedSoFar = readBuffer.skip(qMin(actualReadBufferSize, maxlen));
++ actualReadBufferSize -= skippedSoFar;
++
++ if (!pipeBroken) {
++ startAsyncReadHelper(&locker);
++ if (skippedSoFar == 0)
++ return -2; // signal EWOULDBLOCK
++ }
++
++ return skippedSoFar;
++ }
++
++ /*!
++ Returns \c true if a complete line of data can be read from the buffer.
++ */
++ bool QWindowsPipeReader::canReadLine() const
++ {
++ QMutexLocker locker(&mutex);
++ return readBuffer.indexOf('\n', actualReadBufferSize) >= 0;
++ }
++
++ /*!
++ Starts an asynchronous read sequence on the pipe.
++ */
++ void QWindowsPipeReader::startAsyncRead()
++ {
++ QMutexLocker locker(&mutex);
++ startAsyncReadHelper(&locker);
++ }
++
++ void QWindowsPipeReader::startAsyncReadHelper(QMutexLocker<QMutex> *locker)
++ {
++ if (readSequenceStarted || lastError != ERROR_SUCCESS)
++ return;
++
++ state = Running;
++ startAsyncReadLocked();
++
++ // Do not post the event, if the read operation will be completed asynchronously.
++ if (!readyReadPending && lastError == ERROR_SUCCESS)
++ return;
++
++ if (!winEventActPosted) {
++ winEventActPosted = true;
++ locker->unlock();
++ QCoreApplication::postEvent(this, new QEvent(QEvent::WinEventAct));
++ } else {
++ locker->unlock();
++ }
++
++ SetEvent(syncHandle);
++ }
++
++ /*!
++ Starts a new read sequence. Thread-safety should be ensured
++ by the caller.
++ */
++ void QWindowsPipeReader::startAsyncReadLocked()
++ {
++ // Determine the number of bytes to read.
++ qint64 bytesToRead = qMax(checkPipeState(), state == Running ? minReadBufferSize : 0);
++
++ // This can happen only while draining; just do nothing in this case.
++ if (bytesToRead == 0)
++ return;
++
++ while (lastError == ERROR_SUCCESS) {
++ if (readBufferMaxSize && bytesToRead > (readBufferMaxSize - readBuffer.size())) {
++ bytesToRead = readBufferMaxSize - readBuffer.size();
++ if (bytesToRead <= 0) {
++ // Buffer is full. User must read data from the buffer
++ // before we can read more from the pipe.
++ return;
++ }
++ }
++
++ char *ptr = readBuffer.reserve(bytesToRead);
++
++ // ReadFile() returns true, if the read operation completes synchronously.
++ // We don't need to call GetOverlappedResult() additionally, because
++ // 'numberOfBytesRead' is valid in this case.
++ DWORD numberOfBytesRead;
++ DWORD errorCode = ERROR_SUCCESS;
++ if (!ReadFile(handle, ptr, bytesToRead, &numberOfBytesRead, &overlapped)) {
++ errorCode = GetLastError();
++ if (errorCode == ERROR_IO_PENDING) {
++ Q_ASSERT(state == Running);
++ // Operation has been queued and will complete in the future.
++ readSequenceStarted = true;
++ SetThreadpoolWait(waitObject, eventHandle, NULL);
++ return;
++ }
++ }
++
++ if (!readCompleted(errorCode, numberOfBytesRead))
++ return;
++
++ // In the 'Draining' state, we have to get all the data with one call
++ // to ReadFile(). Note that message mode pipes are not supported here.
++ if (state == Draining) {
++ Q_ASSERT(bytesToRead == qint64(numberOfBytesRead));
++ return;
++ }
++
++ // We need to loop until all pending data has been read and an
++ // operation is queued for asynchronous completion.
++ // If the pipe is configured to work in message mode, we read
++ // the data in chunks.
++ bytesToRead = qMax(checkPipeState(), minReadBufferSize);
++ }
++ }
++
++ /*!
++ \internal
++
++ Thread pool callback procedure.
++ */
++ void QWindowsPipeReader::waitCallback(PTP_CALLBACK_INSTANCE instance, PVOID context,
++ PTP_WAIT wait, TP_WAIT_RESULT waitResult)
++ {
++ Q_UNUSED(instance);
++ Q_UNUSED(wait);
++ Q_UNUSED(waitResult);
++ QWindowsPipeReader *pipeReader = reinterpret_cast<QWindowsPipeReader *>(context);
++
++ // Get the result of the asynchronous operation.
++ DWORD numberOfBytesTransfered = 0;
++ DWORD errorCode = ERROR_SUCCESS;
++ if (!GetOverlappedResult(pipeReader->handle, &pipeReader->overlapped,
++ &numberOfBytesTransfered, FALSE))
++ errorCode = GetLastError();
++
++ pipeReader->mutex.lock();
++
++ pipeReader->readSequenceStarted = false;
++
++ // Do not overwrite error code, if error has been detected by
++ // checkPipeState() in waitForPipeClosed(). Also, if the reader was
++ // stopped, the only reason why this function can be called is the
++ // completion of a cancellation. No signals should be emitted, and
++ // no new read sequence should be started in this case.
++ if (pipeReader->lastError == ERROR_SUCCESS && pipeReader->state != Stopped) {
++ // Ignore ERROR_OPERATION_ABORTED. We have canceled the I/O operation
++ // specifically for flushing the pipe.
++ if (pipeReader->state == Draining && errorCode == ERROR_OPERATION_ABORTED)
++ errorCode = ERROR_SUCCESS;
++
++ if (pipeReader->readCompleted(errorCode, numberOfBytesTransfered))
++ pipeReader->startAsyncReadLocked();
++
++ if (pipeReader->state == Running && !pipeReader->winEventActPosted) {
++ pipeReader->winEventActPosted = true;
++ pipeReader->mutex.unlock();
++ QCoreApplication::postEvent(pipeReader, new QEvent(QEvent::WinEventAct));
++ } else {
++ pipeReader->mutex.unlock();
++ }
++ } else {
++ pipeReader->mutex.unlock();
++ }
++
++ // We set the event only after unlocking to avoid additional context
++ // switches due to the released thread immediately running into the lock.
++ SetEvent(pipeReader->syncHandle);
++ }
++
++ /*!
++ Will be called whenever the read operation completes. Returns \c true if
++ no error occurred; otherwise returns \c false.
++ */
++ bool QWindowsPipeReader::readCompleted(DWORD errorCode, DWORD numberOfBytesRead)
++ {
++ // ERROR_MORE_DATA is not an error. We're connected to a message mode
++ // pipe and the message didn't fit into the pipe's system
++ // buffer. We will read the remaining data in the next call.
++ if (errorCode == ERROR_SUCCESS || errorCode == ERROR_MORE_DATA) {
++ readyReadPending = true;
++ pendingReadBytes += numberOfBytesRead;
++ readBuffer.truncate(actualReadBufferSize + pendingReadBytes);
++ return true;
++ }
++
++ lastError = errorCode;
++ return false;
++ }
++
++ /*!
++ Receives notification that the read operation has completed.
++ */
++ bool QWindowsPipeReader::event(QEvent *e)
++ {
++ if (e->type() == QEvent::WinEventAct) {
++ consumePendingAndEmit(true);
++ return true;
++ }
++ return QObject::event(e);
++ }
++
++ /*!
++ Updates the read buffer size and emits pending signals in the main thread.
++ Returns \c true, if readyRead() was emitted.
++ */
++ bool QWindowsPipeReader::consumePendingAndEmit(bool allowWinActPosting)
++ {
++ ResetEvent(syncHandle);
++ mutex.lock();
++
++ // Enable QEvent::WinEventAct posting.
++ if (allowWinActPosting)
++ winEventActPosted = false;
++
++ const bool emitReadyRead = consumePending();
++ const DWORD dwError = lastError;
++
++ mutex.unlock();
++
++ // Trigger 'pipeBroken' only once. This flag must be updated before
++ // emitting the readyRead() signal. Otherwise, the read sequence will
++ // be considered not finished, and we may hang if a slot connected
++ // to readyRead() calls waitForReadyRead().
++ const bool emitPipeClosed = (dwError != ERROR_SUCCESS && !pipeBroken);
++ if (emitPipeClosed)
++ pipeBroken = true;
++
++ // Disable any further processing, if the pipe was stopped.
++ // We are not allowed to emit signals in either 'Stopped'
++ // or 'Draining' state.
++ if (state != Running)
++ return false;
++
++ if (!emitPipeClosed) {
++ if (emitReadyRead)
++ emit readyRead();
++ } else {
++ QPointer<QWindowsPipeReader> alive(this);
++ if (emitReadyRead)
++ emit readyRead();
++ if (alive && dwError != ERROR_BROKEN_PIPE && dwError != ERROR_PIPE_NOT_CONNECTED)
++ emit winError(dwError, "QWindowsPipeReader::consumePendingAndEmit"_L1);
++ if (alive)
++ emit pipeClosed();
++ }
++
++ return emitReadyRead;
++ }
++
++ /*!
++ Updates the read buffer size. Returns \c true, if readyRead()
++ should be emitted. Thread-safety should be ensured by the caller.
++ */
++ bool QWindowsPipeReader::consumePending()
++ {
++ if (readyReadPending) {
++ readyReadPending = false;
++ actualReadBufferSize += pendingReadBytes;
++ pendingReadBytes = 0;
++ return true;
++ }
++
++ return false;
++ }
++
++ /*!
++ Returns the number of available bytes in the pipe.
++ */
++ DWORD QWindowsPipeReader::checkPipeState()
++ {
++ DWORD bytes;
++ if (PeekNamedPipe(handle, nullptr, 0, nullptr, &bytes, nullptr))
++ return bytes;
++
++ lastError = GetLastError();
++ return 0;
++ }
++
++ bool QWindowsPipeReader::waitForNotification()
++ {
++ DWORD waitRet;
++ do {
++ waitRet = WaitForSingleObjectEx(syncHandle, INFINITE, TRUE);
++ if (waitRet == WAIT_OBJECT_0)
++ return true;
++
++ // Some I/O completion routine was called. Wait some more.
++ } while (waitRet == WAIT_IO_COMPLETION);
++
++ return false;
++ }
++
++ QT_END_NAMESPACE
++
++ #include "moc_qwindowspipereader_p.cpp"