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
|
// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
#include "qplatformdefs.h"
#include "qsharedmemory.h"
#include "qsharedmemory_p.h"
#include "qsystemsemaphore.h"
#include <qdir.h>
#include <qdebug.h>
#include <errno.h>
#ifndef QT_POSIX_IPC
#if QT_CONFIG(sharedmemory)
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#endif // QT_CONFIG(sharedmemory)
#include "private/qcore_unix_p.h"
#if QT_CONFIG(sharedmemory)
QT_BEGIN_NAMESPACE
using namespace Qt::StringLiterals;
/*!
\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 (nativeKey.isEmpty()) {
errorString = QSharedMemory::tr("%1: key is empty").arg("QSharedMemory::handle:"_L1);
error = QSharedMemory::KeyError;
return 0;
}
// ftok requires that an actual file exists somewhere
if (!QFile::exists(nativeKey)) {
errorString = QSharedMemory::tr("%1: UNIX key file doesn't exist").arg("QSharedMemory::handle:"_L1);
error = QSharedMemory::NotFound;
return 0;
}
unix_key = ftok(QFile::encodeName(nativeKey).constData(), 'Q');
if (-1 == unix_key) {
errorString = QSharedMemory::tr("%1: ftok failed").arg("QSharedMemory::handle:"_L1);
error = QSharedMemory::KeyError;
unix_key = 0;
}
return unix_key;
}
#endif // QT_CONFIG(sharedmemory)
#if QT_CONFIG(sharedmemory) || QT_CONFIG(systemsemaphore)
/*!
\internal
Creates the unix file if needed.
returns \c true if the unix file was created.
-1 error
0 already existed
1 created
*/
int QT_PREPEND_NAMESPACE(QSharedMemoryPrivate)::createUnixKeyFile(const QString &fileName)
{
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_CONFIG(sharedmemory) || QT_CONFIG(systemsemaphore)
#if QT_CONFIG(sharedmemory)
bool QSharedMemoryPrivate::cleanHandle()
{
unix_key = 0;
return true;
}
bool QSharedMemoryPrivate::create(qsizetype size)
{
// build file if needed
bool createdFile = false;
int built = createUnixKeyFile(nativeKey);
if (built == -1) {
errorString = QSharedMemory::tr("%1: unable to make key").arg("QSharedMemory::handle:"_L1);
error = QSharedMemory::KeyError;
return false;
}
if (built == 1) {
createdFile = true;
}
// get handle
if (!handle()) {
if (createdFile)
QFile::remove(nativeKey);
return false;
}
// create
if (-1 == shmget(unix_key, size_t(size), 0600 | IPC_CREAT | IPC_EXCL)) {
const auto function = "QSharedMemory::create"_L1;
switch (errno) {
case EINVAL:
errorString = QSharedMemory::tr("%1: system-imposed size restrictions").arg("QSharedMemory::handle"_L1);
error = QSharedMemory::InvalidSize;
break;
default:
setErrorString(function);
}
if (createdFile && error != QSharedMemory::AlreadyExists)
QFile::remove(nativeKey);
return false;
}
return true;
}
bool QSharedMemoryPrivate::attach(QSharedMemory::AccessMode mode)
{
// grab the shared memory segment id
int id = shmget(unix_key, 0, (mode == QSharedMemory::ReadOnly ? 0400 : 0600));
if (-1 == id) {
setErrorString("QSharedMemory::attach (shmget)"_L1);
return false;
}
// grab the memory
memory = shmat(id, nullptr, (mode == QSharedMemory::ReadOnly ? SHM_RDONLY : 0));
if ((void *)-1 == memory) {
memory = nullptr;
setErrorString("QSharedMemory::attach (shmat)"_L1);
return false;
}
// grab the size
shmid_ds shmid_ds;
if (!shmctl(id, IPC_STAT, &shmid_ds)) {
size = (qsizetype)shmid_ds.shm_segsz;
} else {
setErrorString("QSharedMemory::attach (shmctl)"_L1);
return false;
}
return true;
}
bool QSharedMemoryPrivate::detach()
{
// detach from the memory segment
if (-1 == shmdt(memory)) {
const auto function = "QSharedMemory::detach"_L1;
switch (errno) {
case EINVAL:
errorString = QSharedMemory::tr("%1: not attached").arg(function);
error = QSharedMemory::NotFound;
break;
default:
setErrorString(function);
}
return false;
}
memory = nullptr;
size = 0;
// Get the number of current attachments
int id = shmget(unix_key, 0, 0400);
cleanHandle();
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
if (-1 == shmctl(id, IPC_RMID, &shmid_ds)) {
setErrorString("QSharedMemory::remove"_L1);
switch (errno) {
case EINVAL:
return true;
default:
return false;
}
}
// remove file
if (!QFile::remove(nativeKey))
return false;
}
return true;
}
QT_END_NAMESPACE
#endif // QT_CONFIG(sharedmemory)
#endif // QT_POSIX_IPC
|
