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1 /**************************************************************************** |
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2 ** |
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3 ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). |
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4 ** All rights reserved. |
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5 ** Contact: Nokia Corporation (qt-info@nokia.com) |
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6 ** |
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7 ** This file is part of the test suite of the Qt Toolkit. |
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8 ** |
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9 ** $QT_BEGIN_LICENSE:LGPL$ |
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10 ** No Commercial Usage |
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11 ** This file contains pre-release code and may not be distributed. |
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12 ** You may use this file in accordance with the terms and conditions |
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13 ** contained in the Technology Preview License Agreement accompanying |
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14 ** this package. |
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15 ** |
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16 ** GNU Lesser General Public License Usage |
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17 ** Alternatively, this file may be used under the terms of the GNU Lesser |
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18 ** General Public License version 2.1 as published by the Free Software |
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19 ** Foundation and appearing in the file LICENSE.LGPL included in the |
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20 ** packaging of this file. Please review the following information to |
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21 ** ensure the GNU Lesser General Public License version 2.1 requirements |
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22 ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. |
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23 ** |
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24 ** In addition, as a special exception, Nokia gives you certain additional |
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25 ** rights. These rights are described in the Nokia Qt LGPL Exception |
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26 ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. |
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27 ** |
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28 ** If you have questions regarding the use of this file, please contact |
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29 ** Nokia at qt-info@nokia.com. |
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30 ** |
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31 ** |
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32 ** |
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33 ** |
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34 ** |
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35 ** |
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36 ** |
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37 ** |
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38 ** $QT_END_LICENSE$ |
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39 ** |
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40 ****************************************************************************/ |
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41 |
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42 |
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43 #include "qsystemlock.h" |
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44 #include "qsystemlock_p.h" |
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45 |
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46 #include <qdebug.h> |
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47 #include <qfile.h> |
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48 |
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49 #include <sys/types.h> |
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50 #include <sys/ipc.h> |
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51 #include <fcntl.h> |
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52 #include <errno.h> |
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53 #include <sys/shm.h> |
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54 #include <unistd.h> |
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55 |
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56 #include <sys/sem.h> |
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57 // We have to define this as on some sem.h will have it |
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58 union qt_semun { |
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59 int val; /* value for SETVAL */ |
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60 struct semid_ds *buf; /* buffer for IPC_STAT, IPC_SET */ |
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61 unsigned short *array; /* array for GETALL, SETALL */ |
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62 }; |
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63 |
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64 #define tr(x) QT_TRANSLATE_NOOP(QLatin1String("QSystemLock"), (x)) |
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65 |
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66 #if defined(Q_OS_SYMBIAN) |
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67 int createUnixKeyFile(const QString &fileName) |
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68 { |
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69 if (QFile::exists(fileName)) |
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70 return 0; |
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71 |
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72 int fd = open(QFile::encodeName(fileName).constData(), |
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73 O_EXCL | O_CREAT | O_RDWR, 0640); |
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74 if (-1 == fd) { |
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75 if (errno == EEXIST) |
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76 return 0; |
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77 return -1; |
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78 } else { |
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79 close(fd); |
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80 } |
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81 return 1; |
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82 } |
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83 #endif |
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84 |
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85 QSystemLockPrivate::QSystemLockPrivate() : |
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86 semaphore(-1), lockCount(0), |
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87 error(QSystemLock::NoError), unix_key(-1), createdFile(false), createdSemaphore(false) |
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88 { |
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89 } |
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90 |
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91 void QSystemLockPrivate::setErrorString(const QString &function) |
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92 { |
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93 switch (errno) { |
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94 case EIDRM: |
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95 errorString = function + QLatin1String(": ") + tr("The semaphore set was removed"); |
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96 error = QSystemLock::UnknownError; |
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97 break; |
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98 default: |
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99 errorString = function + QLatin1String(": ") + tr("unknown error"); |
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100 error = QSystemLock::UnknownError; |
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101 qWarning() << errorString << "key" << key << "errno" << errno << ERANGE << ENOMEM << EINVAL << EINTR << EFBIG << EFAULT << EAGAIN << EACCES << E2BIG; |
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102 } |
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103 } |
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104 |
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105 /*! |
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106 \internal |
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107 |
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108 Setup unix_key |
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109 */ |
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110 key_t QSystemLockPrivate::handle() |
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111 { |
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112 if (key.isEmpty()) |
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113 return -1; |
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114 |
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115 // ftok requires that an actual file exists somewhere |
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116 // If we have already made at some point in the past, |
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117 // double check that it is still there. |
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118 if (-1 != unix_key) { |
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119 int aNewunix_key = ftok(QFile::encodeName(fileName).constData(), 'Q'); |
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120 if (aNewunix_key != unix_key) { |
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121 cleanHandle(); |
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122 } else { |
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123 return unix_key; |
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124 } |
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125 } |
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126 |
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127 // Create the file needed for ftok |
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128 #if defined(Q_OS_SYMBIAN) |
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129 int built = createUnixKeyFile(fileName); |
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130 #else |
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131 int built = QSharedMemoryPrivate::createUnixKeyFile(fileName); |
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132 #endif |
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133 if (-1 == built) |
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134 return -1; |
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135 createdFile = (1 == built); |
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136 |
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137 // Get the unix key for the created file |
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138 unix_key = ftok(QFile::encodeName(fileName).constData(), 'Q'); |
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139 if (-1 == unix_key) { |
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140 setErrorString(QLatin1String("QSystemLock::handle ftok")); |
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141 return -1; |
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142 } |
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143 |
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144 // Get semaphore |
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145 semaphore = semget(unix_key, 1, 0666 | IPC_CREAT | IPC_EXCL); |
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146 if (-1 == semaphore) { |
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147 if (errno == EEXIST) |
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148 semaphore = semget(unix_key, 1, 0666 | IPC_CREAT); |
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149 if (-1 == semaphore) { |
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150 setErrorString(QLatin1String("QSystemLock::handle semget")); |
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151 cleanHandle(); |
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152 return -1; |
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153 } |
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154 } else { |
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155 // Created semaphore, initialize value. |
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156 createdSemaphore = true; |
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157 qt_semun init_op; |
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158 init_op.val = MAX_LOCKS; |
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159 if (-1 == semctl(semaphore, 0, SETVAL, init_op)) { |
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160 setErrorString(QLatin1String("QSystemLock::handle semctl")); |
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161 cleanHandle(); |
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162 return -1; |
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163 } |
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164 } |
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165 |
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166 return unix_key; |
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167 } |
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168 |
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169 /*! |
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170 \internal |
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171 |
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172 Cleanup the unix_key |
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173 */ |
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174 void QSystemLockPrivate::cleanHandle() |
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175 { |
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176 unix_key = -1; |
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177 |
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178 // remove the file if we made it |
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179 if (createdFile) { |
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180 if (!QFile::remove(fileName)) |
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181 setErrorString(QLatin1String("QSystemLock::cleanHandle QFile::remove")); |
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182 createdFile = false; |
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183 } |
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184 |
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185 if (createdSemaphore) { |
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186 if (-1 != semaphore) { |
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187 if (-1 == semctl(semaphore, 0, IPC_RMID)) { |
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188 setErrorString(QLatin1String("QSystemLock::cleanHandle semctl")); |
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189 } |
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190 semaphore = -1; |
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191 } |
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192 createdSemaphore = false; |
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193 } |
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194 } |
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195 |
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196 /*! |
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197 \internal |
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198 |
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199 modifySemaphore generates operation.sem_op and handles recursive behavior. |
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200 */ |
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201 bool QSystemLockPrivate::modifySemaphore(QSystemLockPrivate::Operation op, |
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202 QSystemLock::LockMode mode) |
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203 { |
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204 if (-1 == handle()) |
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205 return false; |
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206 |
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207 if ((lockCount == 0 && op == Lock) || (lockCount > 0 && op == Unlock)) { |
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208 if (op == Unlock) { |
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209 --lockCount; |
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210 Q_ASSERT(lockCount >= 0); |
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211 if (lockCount > 0) |
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212 return true; |
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213 } |
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214 |
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215 struct sembuf operation; |
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216 operation.sem_num = 0; |
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217 operation.sem_op = (mode == QSystemLock::ReadWrite) ? MAX_LOCKS : 1; |
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218 if (op == Lock) |
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219 operation.sem_op *= -1; |
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220 operation.sem_flg = SEM_UNDO; |
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221 |
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222 if (-1 == semop(semaphore, &operation, 1)) { |
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223 setErrorString(QLatin1String("QSystemLock::modify")); |
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224 return false; |
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225 } |
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226 lockedMode = mode; |
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227 } |
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228 if (op == Lock) |
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229 lockCount++; |
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230 |
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231 return true; |
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232 } |
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233 |