signalhandler.h

This software aims to create an applet and panel tools to manage a wireless interface card, such as

//
// SignalHandler.h
//
// $Id: //poco/Main/Foundation/include/Foundation/SignalHandler.h#2 $
//
// Definition of the SignalHandler class.
//
// Copyright (c) 2004-2005, Guenter Obiltschnig/Applied Informatics.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
//
// 1. Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the
//    documentation and/or other materials provided with the distribution.
//
// 3. Redistributions in any form must be accompanied by information on
//    how to obtain complete source code for this software and any
//    accompanying software that uses this software.  The source code
//    must either be included in the distribution or be available for no
//    more than the cost of distribution plus a nominal fee, and must be
//    freely redistributable under reasonable conditions.  For an
//    executable file, complete source code means the source code for all
//    modules it contains.  It does not include source code for modules or
//    files that typically accompany the major components of the operating
//    system on which the executable file runs.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
// FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
// COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
// BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
// ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//


#ifndef Foundation_SignalHandler_INCLUDED
#define Foundation_SignalHandler_INCLUDED


#ifndef Foundation_Foundation_INCLUDED
#include "Foundation/Foundation.h"
#endif


#if defined(POCO_OS_FAMILY_UNIX)


#ifndef STD_VECTOR_INCLUDED
#include <vector>
#define STD_VECTOR_INCLUDED
#endif
#ifndef STD_SETJMP_H_INCLUDED
#include <setjmp.h>
#define STD_SETJMP_H_INCLUDED
#endif


Foundation_BEGIN


class Foundation_API SignalHandler
	/// This helper class simplifies the handling of POSIX signals.
	///
	/// The class provides a signal handler (installed with
	/// installHandlers()) that translates certain POSIX
	/// signals (SIGILL, SIGBUS, SIGSEGV, SIGSYS) into 
	/// C++ exceptions.
	///
	/// Internally, a stack of sigjmp_buf structs is maintained for
	/// each thread. The constructor pushes a new sigjmp_buf onto
	/// the current thread's stack. The destructor pops the sigjmp_buf
	/// from the stack.
	///
	/// The poco_throw_on_signal macro creates an instance of SignalHandler
	/// on the stack, which results in a new sigjmp_buf being created.
	/// The sigjmp_buf is then set-up with sigsetjmp().
	///
	/// The handleSignal() method, which is invoked when a signal arrives,
	/// checks if a sigjmp_buf is available for the current thread.
	/// If so, siglongjmp() is used to jump out of the signal handler.
	///
	/// Typical usage is as follows:
	///
	///     try
	///     {
	///          poco_throw_on_signal;
	///          ...
	///     }
	///     catch (Foundation::SignalException&)
	///     {
	///         ...
	///     }
	///
	/// The best way to deal with a SignalException is to log as much context
	/// information as possible, to aid in debugging, and then to exit.
{
public:
	SignalHandler();
		/// Creates the SignalHandler.

	~SignalHandler();
		/// Destroys the SignalHandler.

	sigjmp_buf& jumpBuffer();
		/// Returns the top-most sigjmp_buf for the current thread.

	static void throwSignalException(int sig);
		/// Throws a SignalException with a textual description  
		/// of the given signal as argument. 
	
	static void install();
		/// Installs signal handlers for SIGILL, SIGBUS, SIGSEGV
		/// and SIGSYS.

protected:
	static void handleSignal(int sig);
		/// The actual signal handler.

	struct JumpBuffer
		/// sigjmp_buf cannot be used to instantiate a std::vector,
		/// so we provide a wrapper struct.
	{
		sigjmp_buf buf;
	};
	typedef std::vector<JumpBuffer> JumpBufferVec;

	static JumpBufferVec& jumpBufferVec();
		/// Returns the JumpBufferVec for the current thread.

private:
	static JumpBufferVec _jumpBufferVec;
	
	friend class ThreadImp;
};


#define poco_throw_on_signal \
	Foundation::SignalHandler _poco_signalHandler; \
	int _poco_signal = sigsetjmp(_poco_signalHandler.jumpBuffer(), 1); \
	if (_poco_signal) _poco_signalHandler.throwSignalException(_poco_signal);


Foundation_END


#endif // POCO_OS_FAMILY_UNIX


#endif // Foundation_SignalHandler_INCLUDED