1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
|
/****************************************************************************
**
** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** You may use this file under the terms of the BSD license as follows:
**
** "Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are
** met:
** * Redistributions of source code must retain the above copyright
** notice, this list of conditions and the following disclaimer.
** * Redistributions in binary form must reproduce the above copyright
** notice, this list of conditions and the following disclaimer in
** the documentation and/or other materials provided with the
** distribution.
** * Neither the name of Digia Plc and its Subsidiary(-ies) nor the names
** of its contributors may be used to endorse or promote products derived
** from this software without specific prior written permission.
**
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
**
** $QT_END_LICENSE$
**
****************************************************************************/
//! [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, SIGNAL(activated(int)), this, SLOT(handleSigHup()));
snTerm = new QSocketNotifier(sigtermFd[1], QSocketNotifier::Read, this);
connect(snTerm, SIGNAL(activated(int)), this, SLOT(handleSigTerm()));
...
}
//! [1]
//! [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) > 0)
return 1;
term.sa_handler = MyDaemon::termSignalHandler;
sigemptyset(&term.sa_mask);
term.sa_flags |= SA_RESTART;
if (sigaction(SIGTERM, &term, 0) > 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]
|
