1 | /* |
2 | This file is part of libkabc. |
3 | Copyright (c) 2001,2003 Cornelius Schumacher <schumacher@kde.org> |
4 | |
5 | This library is free software; you can redistribute it and/or |
6 | modify it under the terms of the GNU Library General Public |
7 | License as published by the Free Software Foundation; either |
8 | version 2 of the License, or (at your option) any later version. |
9 | |
10 | This library is distributed in the hope that it will be useful, |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
13 | Library General Public License for more details. |
14 | |
15 | You should have received a copy of the GNU Library General Public License |
16 | along with this library; see the file COPYING.LIB. If not, write to |
17 | the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, |
18 | Boston, MA 02110-1301, USA. |
19 | */ |
20 | |
21 | #include "lock.h" |
22 | |
23 | #include <krandom.h> |
24 | #include <kcomponentdata.h> |
25 | #include <kdebug.h> |
26 | #include <kglobal.h> |
27 | #include <klocalizedstring.h> |
28 | #include <kstandarddirs.h> |
29 | |
30 | #include <QtCore/QFile> |
31 | #include <QtCore/QTextStream> |
32 | |
33 | #include <errno.h> |
34 | #include <signal.h> |
35 | #include <sys/types.h> |
36 | #include <sys/stat.h> |
37 | #include <unistd.h> |
38 | |
39 | using namespace KABC; |
40 | |
41 | class Lock::Private |
42 | { |
43 | public: |
44 | Private( const QString &identifier ) |
45 | : mIdentifier( identifier ), |
46 | mOrigIdentifier( identifier ) |
47 | { |
48 | mIdentifier.replace( QLatin1Char( '/' ), QLatin1Char( '_' ) ); |
49 | #ifdef Q_WS_WIN |
50 | mIdentifier.replace( QLatin1Char( ':' ), QLatin1Char( '_' ) ); |
51 | #endif |
52 | } |
53 | |
54 | QString mIdentifier; |
55 | QString mOrigIdentifier; |
56 | QString mLockUniqueName; |
57 | QString mError; |
58 | }; |
59 | |
60 | Lock::Lock( const QString &identifier ) |
61 | : d( new Private( identifier ) ) |
62 | { |
63 | } |
64 | |
65 | Lock::~Lock() |
66 | { |
67 | unlock(); |
68 | |
69 | delete d; |
70 | } |
71 | |
72 | QString Lock::locksDir() |
73 | { |
74 | return KStandardDirs::locateLocal( "data" , QLatin1String( "kabc/lock/" ) ); |
75 | } |
76 | |
77 | bool Lock::readLockFile( const QString &filename, int &pid, QString &app ) |
78 | { |
79 | QFile file( filename ); |
80 | if ( !file.open( QIODevice::ReadOnly ) ) { |
81 | return false; |
82 | } |
83 | |
84 | QTextStream t( &file ); |
85 | t >> pid >> ws >> app; |
86 | |
87 | return true; |
88 | } |
89 | |
90 | bool Lock::writeLockFile( const QString &filename ) |
91 | { |
92 | QFile file( filename ); |
93 | if ( !file.open( QIODevice::WriteOnly ) ) { |
94 | return false; |
95 | } |
96 | |
97 | QTextStream t( &file ); |
98 | t << ::getpid() << endl << QString( KGlobal::mainComponent().componentName() ); |
99 | |
100 | return true; |
101 | } |
102 | |
103 | QString Lock::lockFileName() const |
104 | { |
105 | return locksDir() + d->mIdentifier + QLatin1String( ".lock" ); |
106 | } |
107 | |
108 | bool Lock::lock() |
109 | { |
110 | QString lockName = lockFileName(); |
111 | kDebug() << "-- lock name:" << lockName; |
112 | |
113 | if ( QFile::exists( lockName ) ) { // check if it is a stale lock file |
114 | int pid; |
115 | QString app; |
116 | |
117 | if ( !readLockFile( lockFileName(), pid, app ) ) { |
118 | d->mError = i18n( "Unable to open lock file." ); |
119 | return false; |
120 | } |
121 | |
122 | int retval = ::kill( pid, 0 ); |
123 | if ( retval == -1 && errno == ESRCH ) { // process doesn't exists anymore |
124 | QFile::remove( lockName ); |
125 | kWarning() << "Removed stale lock file from process '" << app << "'" ; |
126 | } else { |
127 | d->mError = i18n( "The resource '%1' is locked by application '%2'." , |
128 | d->mOrigIdentifier, app ); |
129 | return false; |
130 | } |
131 | } |
132 | |
133 | QString lockUniqueName; |
134 | lockUniqueName = d->mIdentifier + KRandom::randomString( 8 ); |
135 | d->mLockUniqueName = KStandardDirs::locateLocal( |
136 | "data" , QLatin1String( "kabc/lock/" ) + lockUniqueName ); |
137 | kDebug() << "-- lock unique name:" << d->mLockUniqueName; |
138 | |
139 | // Create unique file |
140 | writeLockFile( d->mLockUniqueName ); |
141 | |
142 | // Create lock file |
143 | int result = ::link( QFile::encodeName( d->mLockUniqueName ), |
144 | QFile::encodeName( lockName ) ); |
145 | |
146 | if ( result == 0 ) { |
147 | d->mError.clear(); |
148 | emit locked(); |
149 | return true; |
150 | } |
151 | |
152 | // TODO: check stat |
153 | |
154 | d->mError = i18n( "Error" ); |
155 | return false; |
156 | } |
157 | |
158 | bool Lock::unlock() |
159 | { |
160 | int pid; |
161 | QString app; |
162 | if ( readLockFile( lockFileName(), pid, app ) ) { |
163 | if ( pid == getpid() ) { |
164 | QFile::remove( lockFileName() ); |
165 | QFile::remove( d->mLockUniqueName ); |
166 | emit unlocked(); |
167 | } else { |
168 | d->mError = i18n( "Unlock failed. Lock file is owned by other process: %1 (%2)" , app, pid ); |
169 | kDebug() << d->mError; |
170 | return false; |
171 | } |
172 | } |
173 | |
174 | d->mError.clear(); |
175 | |
176 | return true; |
177 | } |
178 | |
179 | QString Lock::error() const |
180 | { |
181 | return d->mError; |
182 | } |
183 | |
184 | |