1 /****************************************************************************
2 **
3 ** Copyright (C) 2016 The Qt Company Ltd.
4 ** Copyright (C) 2016 Intel Corporation.
5 ** Contact: https://www.qt.io/licensing/
6 **
7 ** This file is part of the QtDBus module of the Qt Toolkit.
8 **
9 ** $QT_BEGIN_LICENSE:LGPL$
10 ** Commercial License Usage
11 ** Licensees holding valid commercial Qt licenses may use this file in
12 ** accordance with the commercial license agreement provided with the
13 ** Software or, alternatively, in accordance with the terms contained in
14 ** a written agreement between you and The Qt Company. For licensing terms
15 ** and conditions see https://www.qt.io/terms-conditions. For further
16 ** information use the contact form at https://www.qt.io/contact-us.
17 **
18 ** GNU Lesser General Public License Usage
19 ** Alternatively, this file may be used under the terms of the GNU Lesser
20 ** General Public License version 3 as published by the Free Software
21 ** Foundation and appearing in the file LICENSE.LGPL3 included in the
22 ** packaging of this file. Please review the following information to
23 ** ensure the GNU Lesser General Public License version 3 requirements
24 ** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
25 **
26 ** GNU General Public License Usage
27 ** Alternatively, this file may be used under the terms of the GNU
28 ** General Public License version 2.0 or (at your option) the GNU General
29 ** Public license version 3 or any later version approved by the KDE Free
30 ** Qt Foundation. The licenses are as published by the Free Software
31 ** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
32 ** included in the packaging of this file. Please review the following
33 ** information to ensure the GNU General Public License requirements will
34 ** be met: https://www.gnu.org/licenses/gpl-2.0.html and
35 ** https://www.gnu.org/licenses/gpl-3.0.html.
36 **
37 ** $QT_END_LICENSE$
38 **
39 ****************************************************************************/
40
41 #include <QtCore/qglobal.h>
42 #if QT_CONFIG(library)
43 #include <QtCore/qlibrary.h>
44 #include <QtCore/private/qlocking_p.h>
45 #endif
46 #include <QtCore/qmutex.h>
47
48 #ifndef QT_NO_DBUS
49
50 extern "C" void dbus_shutdown();
51
52 QT_BEGIN_NAMESPACE
53
54 void (*qdbus_resolve_me(const char *name))();
55
56 #if !defined QT_LINKED_LIBDBUS
57
58 #if QT_CONFIG(library)
59 static QLibrary *qdbus_libdbus = 0;
60
qdbus_unloadLibDBus()61 void qdbus_unloadLibDBus()
62 {
63 if (qdbus_libdbus) {
64 if (qEnvironmentVariableIsSet("QDBUS_FORCE_SHUTDOWN"))
65 qdbus_libdbus->resolve("dbus_shutdown")();
66 qdbus_libdbus->unload();
67 }
68 delete qdbus_libdbus;
69 qdbus_libdbus = 0;
70 }
71 #endif
72
qdbus_loadLibDBus()73 bool qdbus_loadLibDBus()
74 {
75 #if QT_CONFIG(library)
76 #ifdef QT_BUILD_INTERNAL
77 // this is to simulate a library load failure for our autotest suite.
78 if (!qEnvironmentVariableIsEmpty("QT_SIMULATE_DBUS_LIBFAIL"))
79 return false;
80 #endif
81
82 static bool triedToLoadLibrary = false;
83 static QBasicMutex mutex;
84 const auto locker = qt_scoped_lock(mutex);
85
86 QLibrary *&lib = qdbus_libdbus;
87 if (triedToLoadLibrary)
88 return lib && lib->isLoaded();
89
90 lib = new QLibrary;
91 lib->setLoadHints(QLibrary::ExportExternalSymbolsHint); // make libdbus symbols available for apps that need more advanced control over the dbus
92 triedToLoadLibrary = true;
93
94 static int majorversions[] = { 3, 2, -1 };
95 const QString baseNames[] = {
96 #ifdef Q_OS_WIN
97 QLatin1String("dbus-1"),
98 #endif
99 QLatin1String("libdbus-1")
100 };
101
102 lib->unload();
103 for (const int majorversion : majorversions) {
104 for (const QString &baseName : baseNames) {
105 #ifdef Q_OS_WIN
106 QString suffix;
107 if (majorversion != -1)
108 suffix = QString::number(- majorversion); // negative so it prepends the dash
109 lib->setFileName(baseName + suffix);
110 #else
111 lib->setFileNameAndVersion(baseName, majorversion);
112 #endif
113 if (lib->load() && lib->resolve("dbus_connection_open_private"))
114 return true;
115
116 lib->unload();
117 }
118 }
119
120 delete lib;
121 lib = 0;
122 return false;
123 #else
124 return true;
125 #endif
126 }
127
qdbus_resolve_conditionally(const char * name)128 void (*qdbus_resolve_conditionally(const char *name))()
129 {
130 #if QT_CONFIG(library)
131 if (qdbus_loadLibDBus())
132 return qdbus_libdbus->resolve(name);
133 #else
134 Q_UNUSED(name);
135 #endif
136 return 0;
137 }
138
qdbus_resolve_me(const char * name)139 void (*qdbus_resolve_me(const char *name))()
140 {
141 #if QT_CONFIG(library)
142 if (Q_UNLIKELY(!qdbus_loadLibDBus()))
143 qFatal("Cannot find libdbus-1 in your system to resolve symbol '%s'.", name);
144
145 QFunctionPointer ptr = qdbus_libdbus->resolve(name);
146 if (Q_UNLIKELY(!ptr))
147 qFatal("Cannot resolve '%s' in your libdbus-1.", name);
148
149 return ptr;
150 #else
151 Q_UNUSED(name);
152 return 0;
153 #endif
154 }
155
156 #else
qdbus_unloadLibDBus()157 static void qdbus_unloadLibDBus()
158 {
159 if (qEnvironmentVariableIsSet("QDBUS_FORCE_SHUTDOWN"))
160 dbus_shutdown();
161 }
162
163 #endif // !QT_LINKED_LIBDBUS
164
165 #if defined(QT_LINKED_LIBDBUS) || QT_CONFIG(library)
166 Q_DESTRUCTOR_FUNCTION(qdbus_unloadLibDBus)
167 #endif
168
169 QT_END_NAMESPACE
170
171 #endif // QT_NO_DBUS
172