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-rwxr-xr-xnxcomp/ReadBuffer.cpp627
1 files changed, 627 insertions, 0 deletions
diff --git a/nxcomp/ReadBuffer.cpp b/nxcomp/ReadBuffer.cpp
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+++ b/nxcomp/ReadBuffer.cpp
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+/**************************************************************************/
+/* */
+/* Copyright (c) 2001, 2007 NoMachine, http://www.nomachine.com/. */
+/* */
+/* NXCOMP, NX protocol compression and NX extensions to this software */
+/* are copyright of NoMachine. Redistribution and use of the present */
+/* software is allowed according to terms specified in the file LICENSE */
+/* which comes in the source distribution. */
+/* */
+/* Check http://www.nomachine.com/licensing.html for applicability. */
+/* */
+/* NX and NoMachine are trademarks of NoMachine S.r.l. */
+/* */
+/* All rights reserved. */
+/* */
+/**************************************************************************/
+
+#include "ReadBuffer.h"
+
+#include "Transport.h"
+
+//
+// Set the verbosity level.
+//
+
+#define PANIC
+#define WARNING
+#undef TEST
+#undef DEBUG
+
+ReadBuffer::ReadBuffer(Transport *transport)
+
+ : transport_(transport)
+{
+ //
+ // The read buffer will grow until
+ // reaching the maximum buffer size
+ // and then will remain stable at
+ // that size.
+ //
+
+ initialReadSize_ = READ_BUFFER_DEFAULT_SIZE;
+ maximumBufferSize_ = READ_BUFFER_DEFAULT_SIZE;
+
+ size_ = 0;
+ buffer_ = NULL;
+
+ owner_ = 1;
+ length_ = 0;
+ start_ = 0;
+
+ remaining_ = 0;
+}
+
+ReadBuffer::~ReadBuffer()
+{
+ if (owner_ == 1)
+ {
+ delete [] buffer_;
+ }
+}
+
+void ReadBuffer::readMessage(const unsigned char *message, unsigned int length)
+{
+ //
+ // To be here we must be the real owner
+ // of the buffer and there must not be
+ // pending bytes in the transport.
+ //
+
+ #ifdef TEST
+
+ if (owner_ == 0)
+ {
+ *logofs << "ReadBuffer: PANIC! Class for FD#"
+ << transport_ -> fd() << " doesn't "
+ << "appear to be the owner of the buffer "
+ << "while borrowing from the caller.\n"
+ << logofs_flush;
+
+ HandleCleanup();
+ }
+
+ #endif
+
+ //
+ // Be sure that any outstanding data from
+ // the transport is appended to our own
+ // byffer.
+ //
+
+ if (transport_ -> pending() != 0)
+ {
+ #ifdef WARNING
+ *logofs << "ReadBuffer: WARNING! Class for FD#"
+ << transport_ -> fd() << " has pending "
+ << "data in the transport while "
+ << "borrowing from the caller.\n"
+ << logofs_flush;
+ #endif
+
+ readMessage();
+
+ if (owner_ == 0)
+ {
+ convertBuffer();
+ }
+ }
+
+ //
+ // Can't borrow the buffer if there is data
+ // from a partial message. In this case add
+ // the new data to the end of our buffer.
+ //
+
+ if (length_ == 0)
+ {
+ #ifdef TEST
+ *logofs << "ReadBuffer: Borrowing " << length
+ << " bytes from the caller for FD#"
+ << transport_ -> fd() << " with "
+ << length_ << " bytes in the buffer.\n"
+ << logofs_flush;
+ #endif
+
+ delete [] buffer_;
+
+ buffer_ = (unsigned char *) message;
+ size_ = length;
+
+ length_ = length;
+
+ owner_ = 0;
+ start_ = 0;
+ }
+ else
+ {
+ #ifdef TEST
+ *logofs << "ReadBuffer: Appending " << length
+ << " bytes from the caller for FD#"
+ << transport_ -> fd() << " with "
+ << length_ << " bytes in the buffer.\n"
+ << logofs_flush;
+ #endif
+
+ appendBuffer(message, length);
+ }
+}
+
+int ReadBuffer::readMessage()
+{
+ int pendingLength = transport_ -> pending();
+
+ if (pendingLength > 0)
+ {
+ //
+ // Can't move the data in the borrowed buffer,
+ // so use the tansport buffer only if we don't
+ // have any partial message. This can happen
+ // with the proxy where we need to deflate the
+ // stream.
+ //
+
+ if (length_ == 0)
+ {
+ unsigned char *newBuffer;
+
+ length_ = transport_ -> getPending(newBuffer);
+
+ if (newBuffer == NULL)
+ {
+ #ifdef PANIC
+ *logofs << "ReadBuffer: PANIC! Failed to borrow "
+ << length_ << " bytes of memory for buffer "
+ << "in context [A].\n" << logofs_flush;
+ #endif
+
+ cerr << "Error" << ": Failed to borrow memory for "
+ << "read buffer in context [A].\n";
+
+ HandleCleanup();
+ }
+
+ delete [] buffer_;
+
+ buffer_ = newBuffer;
+ size_ = length_;
+
+ owner_ = 0;
+ start_ = 0;
+
+ #ifdef TEST
+ *logofs << "ReadBuffer: Borrowed " << length_
+ << " pending bytes for FD#" << transport_ ->
+ fd() << ".\n" << logofs_flush;
+ #endif
+
+ return length_;
+ }
+ #ifdef TEST
+ else
+ {
+ *logofs << "ReadBuffer: WARNING! Cannot borrow "
+ << pendingLength << " bytes for FD#"
+ << transport_ -> fd() << " with "
+ << length_ << " bytes in the buffer.\n"
+ << logofs_flush;
+ }
+ #endif
+ }
+
+ unsigned int readLength = suggestedLength(pendingLength);
+
+ #ifdef DEBUG
+ *logofs << "ReadBuffer: Requested " << readLength
+ << " bytes for FD#" << transport_ -> fd()
+ << " with readable " << transport_ -> readable()
+ << " remaining " << remaining_ << " pending "
+ << transport_ -> pending() << ".\n"
+ << logofs_flush;
+ #endif
+
+ if (readLength < initialReadSize_)
+ {
+ readLength = initialReadSize_;
+ }
+
+ #ifdef DEBUG
+ *logofs << "ReadBuffer: Buffer size is " << size_
+ << " length " << length_ << " and start "
+ << start_ << ".\n" << logofs_flush;
+ #endif
+
+ //
+ // We can't use the transport buffer
+ // to read our own data in it.
+ //
+
+ #ifdef TEST
+
+ if (owner_ == 0)
+ {
+ *logofs << "ReadBuffer: PANIC! Class for FD#"
+ << transport_ -> fd() << " doesn't "
+ << "appear to be the owner of the buffer "
+ << "while reading.\n" << logofs_flush;
+
+ HandleCleanup();
+ }
+
+ #endif
+
+ //
+ // Be sure that we have enough space
+ // to store all the requested data.
+ //
+
+ if (buffer_ == NULL || length_ + readLength > size_)
+ {
+ unsigned int newSize = length_ + readLength;
+
+ #ifdef TEST
+ *logofs << "ReadBuffer: Resizing buffer for FD#"
+ << transport_ -> fd() << " in read from "
+ << size_ << " to " << newSize << " bytes.\n"
+ << logofs_flush;
+ #endif
+
+ unsigned char *newBuffer = allocateBuffer(newSize);
+
+ memcpy(newBuffer, buffer_ + start_, length_);
+
+ delete [] buffer_;
+
+ buffer_ = newBuffer;
+ size_ = newSize;
+
+ transport_ -> pendingReset();
+
+ owner_ = 1;
+ }
+ else if (start_ != 0 && length_ != 0)
+ {
+ //
+ // If any bytes are left due to a partial
+ // message, shift them to the beginning
+ // of the buffer.
+ //
+
+ #ifdef TEST
+ *logofs << "ReadBuffer: Moving " << length_
+ << " bytes of data " << "at beginning of "
+ << "the buffer for FD#" << transport_ -> fd()
+ << ".\n" << logofs_flush;
+ #endif
+
+ memmove(buffer_, buffer_ + start_, length_);
+ }
+
+ start_ = 0;
+
+ #ifdef DEBUG
+ *logofs << "ReadBuffer: Buffer size is now " << size_
+ << " length is " << length_ << " and start is "
+ << start_ << ".\n" << logofs_flush;
+ #endif
+
+ unsigned char *readData = buffer_ + length_;
+
+ #ifdef DEBUG
+ *logofs << "ReadBuffer: Going to read " << readLength
+ << " bytes from FD#" << transport_ -> fd() << ".\n"
+ << logofs_flush;
+ #endif
+
+ int bytesRead = transport_ -> read(readData, readLength);
+
+ if (bytesRead > 0)
+ {
+ #ifdef TEST
+ *logofs << "ReadBuffer: Read " << bytesRead
+ << " bytes from FD#" << transport_ -> fd()
+ << ".\n" << logofs_flush;
+ #endif
+
+ length_ += bytesRead;
+ }
+ else if (bytesRead < 0)
+ {
+ //
+ // Check if there is more data pending than the
+ // size of the provided buffer. After reading
+ // the requested amount, in fact, the transport
+ // may have decompressed the data and produced
+ // more input. This trick allows us to always
+ // borrow the buffer from the transport, even
+ // when the partial read would have prevented
+ // that.
+ //
+
+ if (transport_ -> pending() > 0)
+ {
+ #ifdef TEST
+ *logofs << "ReadBuffer: WARNING! Trying to read some "
+ << "more with " << transport_ -> pending()
+ << " bytes pending for FD#" << transport_ ->
+ fd() << ".\n" << logofs_flush;
+ #endif
+
+ return readMessage();
+ }
+
+ #ifdef TEST
+ *logofs << "ReadBuffer: Error detected reading "
+ << "from FD#" << transport_ -> fd()
+ << ".\n" << logofs_flush;
+ #endif
+
+ return -1;
+ }
+ #ifdef TEST
+ else
+ {
+ *logofs << "ReadBuffer: No data read from FD#"
+ << transport_ -> fd() << " with remaining "
+ << remaining_ << ".\n" << logofs_flush;
+ }
+ #endif
+
+ return bytesRead;
+}
+
+const unsigned char *ReadBuffer::getMessage(unsigned int &controlLength,
+ unsigned int &dataLength)
+{
+ #ifdef TEST
+
+ if (transport_ -> pending() > 0)
+ {
+ *logofs << "ReadBuffer: PANIC! The transport "
+ << "appears to have data pending.\n"
+ << logofs_flush;
+
+ HandleCleanup();
+ }
+
+ #endif
+
+ if (length_ == 0)
+ {
+ #ifdef DEBUG
+ *logofs << "ReadBuffer: No message can be located "
+ << "for FD#" << transport_ -> fd() << ".\n"
+ << logofs_flush;
+ #endif
+
+ if (owner_ == 0)
+ {
+ buffer_ = NULL;
+ size_ = 0;
+
+ transport_ -> pendingReset();
+
+ owner_ = 1;
+ start_ = 0;
+ }
+
+ return NULL;
+ }
+
+ unsigned int trailerLength;
+
+ #ifdef DEBUG
+ *logofs << "ReadBuffer: Going to locate message with "
+ << "start at " << start_ << " and length "
+ << length_ << " for FD#" << transport_ -> fd()
+ << ".\n" << logofs_flush;
+ #endif
+
+ int located = locateMessage(buffer_ + start_, buffer_ + start_ + length_,
+ controlLength, dataLength, trailerLength);
+
+ if (located == 0)
+ {
+ //
+ // No more complete messages are in
+ // the buffer.
+ //
+
+ #ifdef DEBUG
+ *logofs << "ReadBuffer: No message was located "
+ << "for FD#" << transport_ -> fd()
+ << ".\n" << logofs_flush;
+ #endif
+
+ if (owner_ == 0)
+ {
+ //
+ // Must move the remaining bytes in
+ // our own buffer.
+ //
+
+ convertBuffer();
+ }
+
+ return NULL;
+ }
+ else
+ {
+ const unsigned char *result = buffer_ + start_;
+
+ if (dataLength > 0)
+ {
+ //
+ // Message contains data, so go to the
+ // first byte of payload.
+ //
+
+ result += trailerLength;
+
+ start_ += (dataLength + trailerLength);
+ length_ -= (dataLength + trailerLength);
+ }
+ else
+ {
+ //
+ // It is a control message.
+ //
+
+ start_ += (controlLength + trailerLength);
+ length_ -= (controlLength + trailerLength);
+ }
+
+ #ifdef DEBUG
+ *logofs << "ReadBuffer: Located message for FD#"
+ << transport_ -> fd() << " with control length "
+ << controlLength << " and data length "
+ << dataLength << ".\n" << logofs_flush;
+ #endif
+
+ remaining_ = 0;
+
+ return result;
+ }
+}
+
+int ReadBuffer::setSize(int initialReadSize, int maximumBufferSize)
+{
+ initialReadSize_ = initialReadSize;
+ maximumBufferSize_ = maximumBufferSize;
+
+ #ifdef TEST
+ *logofs << "ReadBuffer: WARNING! Set buffer parameters to "
+ << initialReadSize_ << "/" << maximumBufferSize_
+ << " for object at "<< this << ".\n"
+ << logofs_flush;
+ #endif
+
+ return 1;
+}
+
+void ReadBuffer::fullReset()
+{
+ #ifdef TEST
+
+ if (owner_ == 0)
+ {
+ *logofs << "ReadBuffer: PANIC! Class for FD#"
+ << transport_ -> fd() << " doesn't "
+ << "appear to be the owner of the buffer "
+ << "in reset.\n" << logofs_flush;
+
+ HandleCleanup();
+ }
+
+ #endif
+
+ if (length_ == 0 && size_ > maximumBufferSize_)
+ {
+ #ifdef TEST
+ *logofs << "ReadBuffer: Resizing buffer for FD#"
+ << transport_ -> fd() << " in reset from "
+ << size_ << " to " << maximumBufferSize_
+ << " bytes.\n" << logofs_flush;
+ #endif
+
+ delete [] buffer_;
+
+ int newSize = maximumBufferSize_;
+
+ unsigned char *newBuffer = allocateBuffer(newSize);
+
+ buffer_ = newBuffer;
+ size_ = newSize;
+
+ transport_ -> pendingReset();
+
+ owner_ = 1;
+ start_ = 0;
+ }
+}
+
+unsigned char *ReadBuffer::allocateBuffer(unsigned int newSize)
+{
+ unsigned char *newBuffer = new unsigned char[newSize];
+
+ if (newBuffer == NULL)
+ {
+ #ifdef PANIC
+ *logofs << "ReadBuffer: PANIC! Can't allocate "
+ << newSize << " bytes of memory for buffer "
+ << "in context [B].\n" << logofs_flush;
+ #endif
+
+ cerr << "Error" << ": Can't allocate memory for "
+ << "read buffer in context [B].\n";
+
+ HandleCleanup();
+ }
+
+ #ifdef VALGRIND
+
+ memset(newBuffer, '\0', newSize);
+
+ #endif
+
+ return newBuffer;
+}
+
+void ReadBuffer::appendBuffer(const unsigned char *message, unsigned int length)
+{
+ if (start_ + length_ + length > size_)
+ {
+ unsigned int newSize = length_ + length + initialReadSize_;
+
+ #ifdef TEST
+ *logofs << "ReadBuffer: WARNING! Resizing buffer "
+ << "for FD#" << transport_ -> fd()
+ << " from " << size_ << " to " << newSize
+ << " bytes.\n" << logofs_flush;
+ #endif
+
+ unsigned char *newBuffer = allocateBuffer(newSize);
+
+ memcpy(newBuffer, buffer_ + start_, length_);
+
+ delete [] buffer_;
+
+ buffer_ = newBuffer;
+ size_ = newSize;
+
+ start_ = 0;
+ }
+
+ memcpy(buffer_ + start_ + length_, message, length);
+
+ length_ += length;
+
+ transport_ -> pendingReset();
+
+ owner_ = 1;
+}
+
+void ReadBuffer::convertBuffer()
+{
+ unsigned int newSize = length_ + initialReadSize_;
+
+ #ifdef TEST
+ *logofs << "ReadBuffer: WARNING! Converting "
+ << length_ << " bytes to own buffer "
+ << "for FD#" << transport_ -> fd()
+ << " with new size " << newSize
+ << " bytes.\n" << logofs_flush;
+ #endif
+
+ unsigned char *newBuffer = allocateBuffer(newSize);
+
+ memcpy(newBuffer, buffer_ + start_, length_);
+
+ buffer_ = newBuffer;
+ size_ = newSize;
+
+ transport_ -> pendingReset();
+
+ owner_ = 1;
+ start_ = 0;
+}
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