source: XMLIO_V2/external/src/POCO/Foundation.save/Poco/SignalHandler.h @ 80

//
// SignalHandler.h
//
// $Id: //poco/1.3/Foundation/include/Poco/SignalHandler.h#2 $
//
// Library: Foundation
// Package: Threading
// Module:  SignalHandler
//
// Definition of the SignalHandler class.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:
// 
// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//


#ifndef Foundation_SignalHandler_INCLUDED
#define Foundation_SignalHandler_INCLUDED


#include "Poco/Foundation.h"


#if defined(POCO_OS_FAMILY_UNIX)


#include <vector>
#include <setjmp.h>


namespace Poco {


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 (Poco::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.
        ///
        /// The SignalHandler can be disabled globally by compiling POCO and client
        /// code with the POCO_NO_SIGNAL_HANDLER macro defined.
{
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 ThreadImpl;
};


#ifndef POCO_NO_SIGNAL_HANDLER
#define poco_throw_on_signal \
        Poco::SignalHandler _poco_signalHandler; \
        int _poco_signal = sigsetjmp(_poco_signalHandler.jumpBuffer(), 1); \
        if (_poco_signal) _poco_signalHandler.throwSignalException(_poco_signal);
#else
#define poco_throw_on_signal
#endif


} // namespace Poco


#endif // POCO_OS_FAMILY_UNIX


#endif // Foundation_SignalHandler_INCLUDED