SignalEvent.cc

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//
// Copyright (c) 2020 Fraunhofer Institute for Applied Information Technology (FIT)
//                    Network Research Group (NET)
//                    Schloss Birlinghoven, 53754 Sankt Augustin, GERMANY
//                    Contact: support@wiback.org
//
// This file is part of the SENF code tree.
// It is licensed under the 3-clause BSD License (aka New BSD License).
// See LICENSE.txt in the top level directory for details or visit
// https://opensource.org/licenses/BSD-3-Clause
//


#include "SignalEvent.hh"
#include "SignalEvent.ih"

// Custom includes
#include <senf/Utils/senfassert.hh>
#include <senf/Utils/signalnames.hh>
#include "senf/Utils/IgnoreValue.hh"

//#include "SignalEvent.mpp"
#define prefix_
//-/////////////////////////////////////////////////////////////////////////////////////////////////

prefix_ senf::scheduler::detail::SignalDispatcher::SignalDispatcher()
    : blocked_ (true)
{
    if (pipe(sigPipe_) < 0)
        SENF_THROW_SYSTEM_EXCEPTION("pipe()");
    sigemptyset(&sigSet_);
    detail::FdManager::instance().set(sigPipe_[0], detail::FdManager::EV_READ, this);
}

prefix_ senf::scheduler::detail::SignalDispatcher::~SignalDispatcher()
{
    for (SignalSet::iterator i (handlers_.begin()); i != handlers_.end(); ++i) {
        ::signal(i->signal_, SIG_DFL);
        detail::FIFORunner::instance().dequeue(&(*i));
    }
    sigprocmask(SIG_UNBLOCK, &sigSet_, 0);
    detail::FdManager::instance().remove(sigPipe_[0]);
    close(sigPipe_[0]);
    close(sigPipe_[1]);
}

prefix_ void senf::scheduler::detail::SignalDispatcher::add(SignalEvent & event)
{
    SignalSet::iterator i (handlers_.find(event));
    if (i != handlers_.end())
        throw DuplicateSignalRegistrationException()
            << " for signal " << signalName(event.signal_) << " (" << event.signal_ << ")";

    handlers_.insert(event);
    sigaddset(&sigSet_, event.signal_);
    detail::FIFORunner::instance().enqueue(&event);

    sigset_t sig;
    sigemptyset(&sig);
    sigaddset(&sig, event.signal_);
    sigprocmask(blocked_ ? SIG_BLOCK : SIG_UNBLOCK, &sig, 0);

    // Need to re-register all handlers to update sa_mask
    struct sigaction act;
    act.sa_sigaction = &sigHandler;
    act.sa_mask = sigSet_;
    act.sa_flags = SA_SIGINFO | SA_RESTART;
    for (SignalSet::iterator i (handlers_.begin()); i != handlers_.end(); ++i) {
        if (i->signal_ == SIGCHLD)
            act.sa_flags |= SA_NOCLDSTOP;
        else
            act.sa_flags &= ~SA_NOCLDSTOP;
        if (sigaction(i->signal_, &act, 0) < 0)
            SENF_THROW_SYSTEM_EXCEPTION("sigaction()");
    }
}

prefix_ void senf::scheduler::detail::SignalDispatcher::remove(SignalEvent & event)
{
    ::signal(event.signal_, SIG_DFL);
    detail::FIFORunner::instance().dequeue(&event);
    handlers_.erase(event);
    sigset_t sig;
    sigemptyset(&sig);
    sigaddset(&sig, event.signal_);
    sigprocmask(SIG_UNBLOCK, &sig, 0);
}

prefix_ void senf::scheduler::detail::SignalDispatcher::signal(int events)
{
    siginfo_t info;
    if (read(sigPipe_[0], &info, sizeof(info)) < int(sizeof(info)))
        return;
    SignalSet::iterator i (handlers_.find(info.si_signo, FindNumericSignal()));
    if (i == handlers_.end())
        return;
    i->siginfo_ = info;
    i->setRunnable();
}

prefix_ void senf::scheduler::detail::SignalDispatcher::sigHandler(int signal,
                                                                   ::siginfo_t * siginfo,
                                                                   void *)
{
    SENF_ASSERT( alive(), "Internal failure: Destroyed signal handler called" );
    // The manpage says, si_signo is unused in linux so we set it here
    siginfo->si_signo = signal;
    // We can't do much on error anyway so we ignore errors here
    senf::IGNORE( write(instance().sigPipe_[1], siginfo, sizeof(*siginfo)) );
}

prefix_ void senf::scheduler::SignalEvent::v_run()
{
    cb_(siginfo_);
}

prefix_ char const * senf::scheduler::SignalEvent::v_type()
    const
{
    return "si";
}

prefix_ std::string senf::scheduler::SignalEvent::v_info()
    const
{
    return "";
}

//-/////////////////////////////////////////////////////////////////////////////////////////////////
#undef prefix_
//#include "SignalEvent.mpp"


// Local Variables:
// mode: c++
// fill-column: 100
// comment-column: 40
// c-file-style: "senf"
// indent-tabs-mode: nil
// ispell-local-dictionary: "american"
// compile-command: "scons -u test"
// End: