genode/repos/base-nova/include/signal_session/source_client.h
Norman Feske ca971bbfd8 Move repositories to 'repos/' subdirectory
This patch changes the top-level directory layout as a preparatory
step for improving the tools for managing 3rd-party source codes.
The rationale is described in the issue referenced below.

Issue #1082
2014-05-14 16:08:00 +02:00

98 lines
2.5 KiB
C++

/*
* \brief NOVA-specific signal-source client interface
* \author Norman Feske
* \date 2010-02-03
*
* On NOVA, the signal source server does not provide a blocking
* 'wait_for_signal' function because this kernel does no support
* out-of-order IPC replies. Instead, we use a shared semaphore
* to let the client block until a signal is present at the
* server. The shared semaphore gets initialized with the first
* call of 'wait_for_signal()'.
*/
/*
* Copyright (C) 2010-2013 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__SIGNAL_SESSION__SOURCE_CLIENT_H_
#define _INCLUDE__SIGNAL_SESSION__SOURCE_CLIENT_H_
#include <base/rpc_client.h>
#include <signal_session/nova_source.h>
/* NOVA includes */
#include <nova/syscalls.h>
#include <nova/util.h>
namespace Genode {
class Signal_source_client : public Rpc_client<Nova_signal_source>
{
private:
/**
* Capability referring to a NOVA semaphore
*/
Native_capability _sem;
/**
* Request NOVA semaphore from signal-source server
*/
void _init_sem()
{
/* initialize semaphore only once */
if (_sem.valid()) return;
/* request mapping of semaphore capability selector */
Thread_base * myself = Thread_base::myself();
request_signal_sm_cap(Native_capability(myself->tid().ec_sel + 1),
myself->tid().exc_pt_sel + Nova::PT_SEL_STARTUP);
_sem = Native_capability(myself->tid().exc_pt_sel + Nova::PT_SEL_STARTUP);
call<Rpc_register_semaphore>(_sem);
}
public:
/**
* Constructor
*/
Signal_source_client(Signal_source_capability cap)
: Rpc_client<Nova_signal_source>(
static_cap_cast<Nova_signal_source>(cap)) { }
/*****************************
** Signal source interface **
*****************************/
Signal wait_for_signal()
{
/*
* Make sure that we have acquired the
* semaphore from the server
*/
_init_sem();
/*
* Block on semaphore, will be unblocked if
* signal is available
*/
if (Nova::sm_ctrl(_sem.local_name(), Nova::SEMAPHORE_DOWN))
nova_die();
/*
* Now that the server has unblocked the semaphore, we are sure
* that there is a signal pending. The following 'wait_for_signal'
* request will be immediately answered.
*/
return call<Rpc_wait_for_signal>();
}
};
}
#endif /* _INCLUDE__SIGNAL_SESSION__SOURCE_CLIENT_H_ */