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
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
|
/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the either Technology Preview License Agreement or the
** Beta Release License Agreement.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain
** additional rights. These rights are described in the Nokia Qt LGPL
** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this
** package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
** If you are unsure which license is appropriate for your use, please
** contact the sales department at http://www.qtsoftware.com/contact.
** $QT_END_LICENSE$
**
****************************************************************************/
#include "qplatformdefs.h"
#include "qsharedmemory.h"
#include "qsharedmemory_p.h"
#include "qsystemsemaphore.h"
#include <qdir.h>
#include <qdebug.h>
#include <errno.h>
#ifndef QT_NO_SHAREDMEMORY
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include "private/qcore_unix_p.h"
QT_BEGIN_NAMESPACE
QSharedMemoryPrivate::QSharedMemoryPrivate()
: QObjectPrivate(), memory(0), size(0), error(QSharedMemory::NoError),
#ifndef QT_NO_SYSTEMSEMAPHORE
systemSemaphore(QString()), lockedByMe(false),
#endif
unix_key(0)
{
}
void QSharedMemoryPrivate::setErrorString(const QString &function)
{
// EINVAL is handled in functions so they can give better error strings
switch (errno) {
case EACCES:
errorString = QSharedMemory::tr("%1: permission denied").arg(function);
error = QSharedMemory::PermissionDenied;
break;
case EEXIST:
errorString = QSharedMemory::tr("%1: already exists").arg(function);
error = QSharedMemory::AlreadyExists;
break;
case ENOENT:
errorString = QSharedMemory::tr("%1: doesn't exists").arg(function);
error = QSharedMemory::NotFound;
break;
case EMFILE:
case ENOMEM:
case ENOSPC:
errorString = QSharedMemory::tr("%1: out of resources").arg(function);
error = QSharedMemory::OutOfResources;
break;
default:
errorString = QSharedMemory::tr("%1: unknown error %2").arg(function).arg(errno);
error = QSharedMemory::UnknownError;
#if defined QSHAREDMEMORY_DEBUG
qDebug() << errorString << "key" << key << "errno" << errno << EINVAL;
#endif
}
}
/*!
\internal
If not already made create the handle used for accessing the shared memory.
*/
key_t QSharedMemoryPrivate::handle()
{
// already made
if (unix_key)
return unix_key;
// don't allow making handles on empty keys
if (key.isEmpty()) {
errorString = QSharedMemory::tr("%1: key is empty").arg(QLatin1String("QSharedMemory::handle:"));
error = QSharedMemory::KeyError;
return 0;
}
// ftok requires that an actual file exists somewhere
QString fileName = makePlatformSafeKey(key);
if (!QFile::exists(fileName)) {
errorString = QSharedMemory::tr("%1: unix key file doesn't exists").arg(QLatin1String("QSharedMemory::handle:"));
error = QSharedMemory::NotFound;
return 0;
}
unix_key = ftok(QFile::encodeName(fileName).constData(), 'Q');
if (-1 == unix_key) {
errorString = QSharedMemory::tr("%1: ftok failed").arg(QLatin1String("QSharedMemory::handle:"));
error = QSharedMemory::KeyError;
unix_key = 0;
}
return unix_key;
}
#endif // QT_NO_SHAREDMEMORY
#if !(defined(QT_NO_SHAREDMEMORY) && defined(QT_NO_SYSTEMSEMAPHORE))
/*!
\internal
Creates the unix file if needed.
returns true if the unix file was created.
-1 error
0 already existed
1 created
*/
int QSharedMemoryPrivate::createUnixKeyFile(const QString &fileName)
{
if (QFile::exists(fileName))
return 0;
int fd = qt_safe_open(QFile::encodeName(fileName).constData(),
O_EXCL | O_CREAT | O_RDWR, 0640);
if (-1 == fd) {
if (errno == EEXIST)
return 0;
return -1;
} else {
close(fd);
}
return 1;
}
#endif // QT_NO_SHAREDMEMORY && QT_NO_SYSTEMSEMAPHORE
#ifndef QT_NO_SHAREDMEMORY
bool QSharedMemoryPrivate::cleanHandle()
{
unix_key = 0;
return true;
}
bool QSharedMemoryPrivate::create(int size)
{
// build file if needed
bool createdFile = false;
int built = createUnixKeyFile(makePlatformSafeKey(key));
if (built == -1) {
errorString = QSharedMemory::tr("%1: unable to make key").arg(QLatin1String("QSharedMemory::handle:"));
error = QSharedMemory::KeyError;
return false;
}
if (built == 1) {
createdFile = true;
}
// get handle
if (!handle()) {
if (createdFile)
QFile::remove(makePlatformSafeKey(key));
return false;
}
// create
if (-1 == shmget(handle(), size, 0666 | IPC_CREAT | IPC_EXCL)) {
QString function = QLatin1String("QSharedMemory::create");
switch (errno) {
case EINVAL:
errorString = QSharedMemory::tr("%1: system-imposed size restrictions").arg(QLatin1String("QSharedMemory::handle"));
error = QSharedMemory::InvalidSize;
break;
default:
setErrorString(function);
}
if (createdFile && error != QSharedMemory::AlreadyExists)
QFile::remove(makePlatformSafeKey(key));
return false;
}
return true;
}
bool QSharedMemoryPrivate::attach(QSharedMemory::AccessMode mode)
{
// grab the shared memory segment id
if (!handle())
return false;
int id = shmget(handle(), 0, (mode == QSharedMemory::ReadOnly ? 0444 : 0660));
if (-1 == id) {
setErrorString(QLatin1String("QSharedMemory::attach (shmget)"));
return false;
}
// grab the memory
memory = shmat(id, 0, (mode == QSharedMemory::ReadOnly ? SHM_RDONLY : 0));
if ((void*) - 1 == memory) {
memory = 0;
setErrorString(QLatin1String("QSharedMemory::attach (shmat)"));
return false;
}
// grab the size
shmid_ds shmid_ds;
if (!shmctl(id, IPC_STAT, &shmid_ds)) {
size = (int)shmid_ds.shm_segsz;
} else {
setErrorString(QLatin1String("QSharedMemory::attach (shmctl)"));
return false;
}
return true;
}
bool QSharedMemoryPrivate::detach()
{
// detach from the memory segment
if (-1 == shmdt(memory)) {
QString function = QLatin1String("QSharedMemory::detach");
switch (errno) {
case EINVAL:
errorString = QSharedMemory::tr("%1: not attached").arg(function);
error = QSharedMemory::NotFound;
break;
default:
setErrorString(function);
}
return false;
}
memory = 0;
// Get the number of current attachments
if (!handle())
return false;
int id = shmget(handle(), 0, 0444);
unix_key = 0;
struct shmid_ds shmid_ds;
if (0 != shmctl(id, IPC_STAT, &shmid_ds)) {
switch (errno) {
case EINVAL:
return true;
default:
return false;
}
}
// If there are no attachments then remove it.
if (shmid_ds.shm_nattch == 0) {
// mark for removal
struct shmid_ds shmid_ds;
if (-1 == shmctl(id, IPC_RMID, &shmid_ds)) {
setErrorString(QLatin1String("QSharedMemory::remove"));
switch (errno) {
case EINVAL:
return true;
default:
return false;
}
}
// remove file
if (!QFile::remove(makePlatformSafeKey(key)))
return false;
}
return true;
}
QT_END_NAMESPACE
#endif // QT_NO_SHAREDMEMORY
|