/****************************************************************************
**
** Copyright (C) 2017 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the Qt Debug Bridge.
**
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** accordance with the commercial license agreement provided with the
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** the Free Software Foundation and appearing in the file LICENSE.GPL3
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#include "interruptsignalhandler.h"

#include "libqdb/make_unique.h"

#include <QtCore/qdebug.h>
#include <QtCore/qsocketnotifier.h>

#include <signal.h>
#include <sys/socket.h>
#include <unistd.h>

class InterruptSignalHandlerPrivate : public QObject
{
    Q_OBJECT
public:
    InterruptSignalHandlerPrivate(InterruptSignalHandler *owner);

    static void sigIntHandler(int signalId);

public slots:
    void handleSigInt();

public:
    static int s_socketPair[2];
    struct sigaction oldIntAction;
    struct sigaction oldTermAction;
    std::unique_ptr<QSocketNotifier> socketNotifier = nullptr;

private:
    InterruptSignalHandler *q;
};

int InterruptSignalHandlerPrivate::s_socketPair[2] = {0, 0};

InterruptSignalHandler::InterruptSignalHandler(QObject *parent)
    : QObject{parent}, d{new InterruptSignalHandlerPrivate{this}}
{
    if (socketpair(AF_UNIX, SOCK_STREAM, 0, d->s_socketPair))
        qFatal("Could not create socketpair for signal handling in InterruptSignalHandler");

    d->socketNotifier = make_unique<QSocketNotifier>(d->s_socketPair[1], QSocketNotifier::Read);
    connect(d->socketNotifier.get(), &QSocketNotifier::activated, d, &InterruptSignalHandlerPrivate::handleSigInt);

    if (!installSignalHandler())
        qFatal("Could not install signal handler in InterruptSignalHandler");
}

InterruptSignalHandler::~InterruptSignalHandler()
{
    delete d;
}

bool InterruptSignalHandler::installSignalHandler()
{
    struct sigaction action;
    action.sa_handler = &InterruptSignalHandlerPrivate::sigIntHandler;
    sigemptyset(&action.sa_mask);
    action.sa_flags = 0;
    action.sa_flags |= SA_RESTART;

    if (sigaction(SIGINT, &action, &d->oldIntAction))
        return false;
    if (sigaction(SIGTERM, &action, &d->oldTermAction))
        return false;

    return true;
}

InterruptSignalHandlerPrivate::InterruptSignalHandlerPrivate(InterruptSignalHandler *owner)
    : q{owner}
{

}

void InterruptSignalHandlerPrivate::sigIntHandler(int signalId)
{
    Q_UNUSED(signalId);

    char a = 1;
    write(s_socketPair[0], &a, sizeof(a));
}

void InterruptSignalHandlerPrivate::handleSigInt()
{
    char tmp;
    read(s_socketPair[1], &tmp, sizeof(tmp));

    // Reset signal actions to allow further signals to interrupt hanging qdb
    sigaction(SIGINT, &oldIntAction, nullptr);
    sigaction(SIGTERM, &oldTermAction, nullptr);

    emit q->interrupted();
}

#include "interruptsignalhandler_unix.moc"