genode/base-okl4/include/base/ipc_msgbuf.h
2012-01-03 15:35:05 +01:00

69 lines
1.4 KiB
C++

/*
* \brief OKL4-specific layout of IPC message buffer
* \author Norman Feske
* \date 2009-03-25
*
* On OKL4, we do not directly use the a kernel-specific message-buffer layout.
* The IPC goes through the UTCBs of the sending and receiving threads. Because
* on Genode, message buffers are decoupled from threads, we need to copy-in
* and copy-out the message payload between the message buffers and the used
* UTCBs.
*/
/*
* Copyright (C) 2009-2012 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU General Public License version 2.
*/
#ifndef _INCLUDE__BASE__IPC_MSGBUF_H_
#define _INCLUDE__BASE__IPC_MSGBUF_H_
namespace Genode {
/**
* IPC message buffer layout
*/
class Msgbuf_base
{
protected:
size_t _size;
char _msg_start[]; /* symbol marks start of message */
public:
/*
* Begin of actual message buffer
*/
char buf[];
/**
* Return size of message buffer
*/
inline size_t size() const { return _size; };
/**
* Return address of message buffer
*/
inline void *addr() { return &_msg_start[0]; };
};
/**
* Instance of IPC message buffer with specified buffer size
*/
template <unsigned BUF_SIZE>
class Msgbuf : public Msgbuf_base
{
public:
char buf[BUF_SIZE];
Msgbuf() { _size = BUF_SIZE; }
};
}
#endif /* _INCLUDE__BASE__IPC_MSGBUF_H_ */