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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
//! [0]
class MyDaemon : public QObject
{
Q_OBJECT
public:
MyDaemon(QObject *parent = 0);
~MyDaemon();
// Unix signal handlers.
static void hupSignalHandler(int unused);
static void termSignalHandler(int unused);
public slots:
// Qt signal handlers.
void handleSigHup();
void handleSigTerm();
private:
static int sighupFd[2];
static int sigtermFd[2];
QSocketNotifier *snHup;
QSocketNotifier *snTerm;
};
//! [0]
//! [1]
MyDaemon::MyDaemon(QObject *parent)
: QObject(parent)
{
if (::socketpair(AF_UNIX, SOCK_STREAM, 0, sighupFd))
qFatal("Couldn't create HUP socketpair");
if (::socketpair(AF_UNIX, SOCK_STREAM, 0, sigtermFd))
qFatal("Couldn't create TERM socketpair");
snHup = new QSocketNotifier(sighupFd[1], QSocketNotifier::Read, this);
connect(snHup, &QSocketNotifier::activated, this, &MyDaemon::handleSigHup);
snTerm = new QSocketNotifier(sigtermFd[1], QSocketNotifier::Read, this);
connect(snTerm, &QSocketNotifier::activated, this, &MyDaemon::handleSigTerm);
...
}
//! [1]
//! [Init]
int MyDaemon::sighupFd[2] = {0, 0};
int MyDaemon::sigtermFd[2] = {0, 0};
//! [Init]
//! [2]
static int setup_unix_signal_handlers()
{
struct sigaction hup, term;
hup.sa_handler = MyDaemon::hupSignalHandler;
sigemptyset(&hup.sa_mask);
hup.sa_flags = 0;
hup.sa_flags |= SA_RESTART;
if (sigaction(SIGHUP, &hup, 0))
return 1;
term.sa_handler = MyDaemon::termSignalHandler;
sigemptyset(&term.sa_mask);
term.sa_flags = 0;
term.sa_flags |= SA_RESTART;
if (sigaction(SIGTERM, &term, 0))
return 2;
return 0;
}
//! [2]
//! [3]
void MyDaemon::hupSignalHandler(int)
{
char a = 1;
::write(sighupFd[0], &a, sizeof(a));
}
void MyDaemon::termSignalHandler(int)
{
char a = 1;
::write(sigtermFd[0], &a, sizeof(a));
}
//! [3]
//! [4]
void MyDaemon::handleSigTerm()
{
snTerm->setEnabled(false);
char tmp;
::read(sigtermFd[1], &tmp, sizeof(tmp));
// do Qt stuff
snTerm->setEnabled(true);
}
void MyDaemon::handleSigHup()
{
snHup->setEnabled(false);
char tmp;
::read(sighupFd[1], &tmp, sizeof(tmp));
// do Qt stuff
snHup->setEnabled(true);
}
//! [4]