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//
// SignalHandler.h
//
// Library: Foundation
// Package: Threading
// Module: SignalHandler
//
// Definition of the SignalHandler class.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier: BSL-1.0
//
#ifndef Foundation_SignalHandler_INCLUDED
#define Foundation_SignalHandler_INCLUDED
#include "Poco/Foundation.h"
#if defined(POCO_OS_FAMILY_UNIX) && !defined(POCO_VXWORKS)
#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
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