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
|
// 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 "qsharedmemory.h"
#include "qsharedmemory_p.h"
#include "qtipccommon_p.h"
#include <qdir.h>
#include <qdebug.h>
#include <errno.h>
#if QT_CONFIG(sharedmemory)
#if QT_CONFIG(sysv_shm)
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/mman.h>
#include <sys/shm.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include "private/qcore_unix_p.h"
#if defined(Q_OS_DARWIN)
#include "private/qcore_mac_p.h"
#endif
QT_BEGIN_NAMESPACE
using namespace Qt::StringLiterals;
using namespace QtIpcCommon;
bool QSharedMemorySystemV::runtimeSupportCheck()
{
#if defined(Q_OS_DARWIN)
if (qt_apple_isSandboxed())
return false;
#endif
static const bool result = []() {
(void)shmget(IPC_PRIVATE, ~size_t(0), 0); // this will fail
return errno != ENOSYS;
}();
return result;
}
inline void QSharedMemorySystemV::updateNativeKeyFile(const QNativeIpcKey &nativeKey)
{
Q_ASSERT(nativeKeyFile.isEmpty() );
if (!nativeKey.nativeKey().isEmpty())
nativeKeyFile = QFile::encodeName(nativeKey.nativeKey());
}
/*!
\internal
If not already made create the handle used for accessing the shared memory.
*/
key_t QSharedMemorySystemV::handle(QSharedMemoryPrivate *self)
{
// already made
if (unix_key)
return unix_key;
// don't allow making handles on empty keys
if (nativeKeyFile.isEmpty())
updateNativeKeyFile(self->nativeKey);
if (nativeKeyFile.isEmpty()) {
self->setError(QSharedMemory::KeyError,
QSharedMemory::tr("%1: key is empty")
.arg("QSharedMemory::handle:"_L1));
return 0;
}
unix_key = ftok(nativeKeyFile, int(self->nativeKey.type()));
if (unix_key < 0) {
self->setUnixErrorString("QSharedMemory::handle"_L1);
nativeKeyFile.clear();
unix_key = 0;
}
return unix_key;
}
bool QSharedMemorySystemV::cleanHandle(QSharedMemoryPrivate *self)
{
if (unix_key == 0)
return true;
// Get the number of current attachments
struct shmid_ds shmid_ds;
QByteArray keyfile = std::exchange(nativeKeyFile, QByteArray());
int id = shmget(unix_key, 0, 0400);
unix_key = 0;
if (shmctl(id, IPC_STAT, &shmid_ds))
return errno != EINVAL;
// If there are still attachments, keep the keep file and shm
if (shmid_ds.shm_nattch != 0)
return true;
if (shmctl(id, IPC_RMID, &shmid_ds) < 0) {
if (errno != EINVAL) {
self->setUnixErrorString("QSharedMemory::remove"_L1);
return false;
}
};
// remove file
return unlink(keyfile) == 0;
}
bool QSharedMemorySystemV::create(QSharedMemoryPrivate *self, qsizetype size)
{
// build file if needed
bool createdFile = false;
updateNativeKeyFile(self->nativeKey);
int built = createUnixKeyFile(nativeKeyFile);
if (built == -1) {
self->setError(QSharedMemory::KeyError,
QSharedMemory::tr("%1: unable to make key")
.arg("QSharedMemory::handle:"_L1));
return false;
}
if (built == 1) {
createdFile = true;
}
// get handle
if (!handle(self)) {
if (createdFile)
unlink(nativeKeyFile);
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:
self->setError(QSharedMemory::InvalidSize,
QSharedMemory::tr("%1: system-imposed size restrictions")
.arg("QSharedMemory::handle"_L1));
break;
default:
self->setUnixErrorString(function);
}
if (createdFile && self->error != QSharedMemory::AlreadyExists)
unlink(nativeKeyFile);
return false;
}
return true;
}
bool QSharedMemorySystemV::attach(QSharedMemoryPrivate *self, QSharedMemory::AccessMode mode)
{
// grab the shared memory segment id
int id = shmget(unix_key, 0, (mode == QSharedMemory::ReadOnly ? 0400 : 0600));
if (-1 == id) {
self->setUnixErrorString("QSharedMemory::attach (shmget)"_L1);
unix_key = 0;
nativeKeyFile.clear();
return false;
}
// grab the memory
self->memory = shmat(id, nullptr, (mode == QSharedMemory::ReadOnly ? SHM_RDONLY : 0));
if (self->memory == MAP_FAILED) {
self->memory = nullptr;
self->setUnixErrorString("QSharedMemory::attach (shmat)"_L1);
return false;
}
// grab the size
shmid_ds shmid_ds;
if (!shmctl(id, IPC_STAT, &shmid_ds)) {
self->size = (qsizetype)shmid_ds.shm_segsz;
} else {
self->setUnixErrorString("QSharedMemory::attach (shmctl)"_L1);
return false;
}
return true;
}
bool QSharedMemorySystemV::detach(QSharedMemoryPrivate *self)
{
// detach from the memory segment
if (shmdt(self->memory) < 0) {
const auto function = "QSharedMemory::detach"_L1;
switch (errno) {
case EINVAL:
self->setError(QSharedMemory::NotFound,
QSharedMemory::tr("%1: not attached").arg(function));
break;
default:
self->setUnixErrorString(function);
}
return false;
}
self->memory = nullptr;
self->size = 0;
return cleanHandle(self);
}
QT_END_NAMESPACE
#endif // QT_CONFIG(sysv_shm)
#endif // QT_CONFIG(sharedmemory)
|
