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
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
|
<?php
/**
* Simple version of LockManager based on using FS lock files.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
* http://www.gnu.org/copyleft/gpl.html
*
* @file
* @ingroup LockManager
*/
/**
* Simple version of LockManager based on using FS lock files.
* All locks are non-blocking, which avoids deadlocks.
*
* This should work fine for small sites running off one server.
* Do not use this with 'lockDirectory' set to an NFS mount unless the
* NFS client is at least version 2.6.12. Otherwise, the BSD flock()
* locks will be ignored; see http://nfs.sourceforge.net/#section_d.
*
* @ingroup LockManager
* @since 1.19
*/
class FSLockManager extends LockManager {
/** @var Array Mapping of lock types to the type actually used */
protected $lockTypeMap = array(
self::LOCK_SH => self::LOCK_SH,
self::LOCK_UW => self::LOCK_SH,
self::LOCK_EX => self::LOCK_EX
);
protected $lockDir; // global dir for all servers
/** @var Array Map of (locked key => lock file handle) */
protected $handles = array();
/**
* Construct a new instance from configuration.
*
* $config includes:
* - lockDirectory : Directory containing the lock files
*
* @param array $config
*/
function __construct( array $config ) {
parent::__construct( $config );
$this->lockDir = $config['lockDirectory'];
}
/**
* @see LockManager::doLock()
* @param $paths array
* @param $type int
* @return Status
*/
protected function doLock( array $paths, $type ) {
$status = Status::newGood();
$lockedPaths = array(); // files locked in this attempt
foreach ( $paths as $path ) {
$status->merge( $this->doSingleLock( $path, $type ) );
if ( $status->isOK() ) {
$lockedPaths[] = $path;
} else {
// Abort and unlock everything
$status->merge( $this->doUnlock( $lockedPaths, $type ) );
return $status;
}
}
return $status;
}
/**
* @see LockManager::doUnlock()
* @param $paths array
* @param $type int
* @return Status
*/
protected function doUnlock( array $paths, $type ) {
$status = Status::newGood();
foreach ( $paths as $path ) {
$status->merge( $this->doSingleUnlock( $path, $type ) );
}
return $status;
}
/**
* Lock a single resource key
*
* @param $path string
* @param $type integer
* @return Status
*/
protected function doSingleLock( $path, $type ) {
$status = Status::newGood();
if ( isset( $this->locksHeld[$path][$type] ) ) {
++$this->locksHeld[$path][$type];
} elseif ( isset( $this->locksHeld[$path][self::LOCK_EX] ) ) {
$this->locksHeld[$path][$type] = 1;
} else {
if ( isset( $this->handles[$path] ) ) {
$handle = $this->handles[$path];
} else {
wfSuppressWarnings();
$handle = fopen( $this->getLockPath( $path ), 'a+' );
wfRestoreWarnings();
if ( !$handle ) { // lock dir missing?
wfMkdirParents( $this->lockDir );
$handle = fopen( $this->getLockPath( $path ), 'a+' ); // try again
}
}
if ( $handle ) {
// Either a shared or exclusive lock
$lock = ( $type == self::LOCK_SH ) ? LOCK_SH : LOCK_EX;
if ( flock( $handle, $lock | LOCK_NB ) ) {
// Record this lock as active
$this->locksHeld[$path][$type] = 1;
$this->handles[$path] = $handle;
} else {
fclose( $handle );
$status->fatal( 'lockmanager-fail-acquirelock', $path );
}
} else {
$status->fatal( 'lockmanager-fail-openlock', $path );
}
}
return $status;
}
/**
* Unlock a single resource key
*
* @param $path string
* @param $type integer
* @return Status
*/
protected function doSingleUnlock( $path, $type ) {
$status = Status::newGood();
if ( !isset( $this->locksHeld[$path] ) ) {
$status->warning( 'lockmanager-notlocked', $path );
} elseif ( !isset( $this->locksHeld[$path][$type] ) ) {
$status->warning( 'lockmanager-notlocked', $path );
} else {
$handlesToClose = array();
--$this->locksHeld[$path][$type];
if ( $this->locksHeld[$path][$type] <= 0 ) {
unset( $this->locksHeld[$path][$type] );
}
if ( !count( $this->locksHeld[$path] ) ) {
unset( $this->locksHeld[$path] ); // no locks on this path
if ( isset( $this->handles[$path] ) ) {
$handlesToClose[] = $this->handles[$path];
unset( $this->handles[$path] );
}
}
// Unlock handles to release locks and delete
// any lock files that end up with no locks on them...
if ( wfIsWindows() ) {
// Windows: for any process, including this one,
// calling unlink() on a locked file will fail
$status->merge( $this->closeLockHandles( $path, $handlesToClose ) );
$status->merge( $this->pruneKeyLockFiles( $path ) );
} else {
// Unix: unlink() can be used on files currently open by this
// process and we must do so in order to avoid race conditions
$status->merge( $this->pruneKeyLockFiles( $path ) );
$status->merge( $this->closeLockHandles( $path, $handlesToClose ) );
}
}
return $status;
}
/**
* @param $path string
* @param $handlesToClose array
* @return Status
*/
private function closeLockHandles( $path, array $handlesToClose ) {
$status = Status::newGood();
foreach ( $handlesToClose as $handle ) {
if ( !flock( $handle, LOCK_UN ) ) {
$status->fatal( 'lockmanager-fail-releaselock', $path );
}
if ( !fclose( $handle ) ) {
$status->warning( 'lockmanager-fail-closelock', $path );
}
}
return $status;
}
/**
* @param $path string
* @return Status
*/
private function pruneKeyLockFiles( $path ) {
$status = Status::newGood();
if ( !isset( $this->locksHeld[$path] ) ) {
# No locks are held for the lock file anymore
if ( !unlink( $this->getLockPath( $path ) ) ) {
$status->warning( 'lockmanager-fail-deletelock', $path );
}
unset( $this->handles[$path] );
}
return $status;
}
/**
* Get the path to the lock file for a key
* @param $path string
* @return string
*/
protected function getLockPath( $path ) {
return "{$this->lockDir}/{$this->sha1Base36Absolute( $path )}.lock";
}
/**
* Make sure remaining locks get cleared for sanity
*/
function __destruct() {
while ( count( $this->locksHeld ) ) {
foreach ( $this->locksHeld as $path => $locks ) {
$this->doSingleUnlock( $path, self::LOCK_EX );
$this->doSingleUnlock( $path, self::LOCK_SH );
}
}
}
}
|
