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| ** This file is part of the QtCore module of the Qt Toolkit. |
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| ****************************************************************************/ |
| |
| #include "qsystemsemaphore.h" |
| #include "qsystemsemaphore_p.h" |
| |
| #include <qdebug.h> |
| #include <qfile.h> |
| #include <qcoreapplication.h> |
| |
| #ifndef QT_POSIX_IPC |
| |
| #ifndef QT_NO_SYSTEMSEMAPHORE |
| |
| #include <sys/types.h> |
| #include <sys/ipc.h> |
| #include <sys/sem.h> |
| #include <fcntl.h> |
| #include <errno.h> |
| |
| #include "private/qcore_unix_p.h" |
| |
| // OpenBSD 4.2 doesn't define EIDRM, see BUGS section: |
| // http://www.openbsd.org/cgi-bin/man.cgi?query=semop&manpath=OpenBSD+4.2 |
| #if defined(Q_OS_OPENBSD) && !defined(EIDRM) |
| #define EIDRM EINVAL |
| #endif |
| |
| QT_BEGIN_NAMESPACE |
| |
| /*! |
| \internal |
| |
| Setup unix_key |
| */ |
| key_t QSystemSemaphorePrivate::handle(QSystemSemaphore::AccessMode mode) |
| { |
| if (key.isEmpty()){ |
| errorString = |
| #if QT_CONFIG(translation) |
| QCoreApplication::tr("%1: key is empty", "QSystemSemaphore") |
| #else |
| QLatin1String("%1: key is empty") |
| #endif |
| .arg(QLatin1String("QSystemSemaphore::handle:")); |
| error = QSystemSemaphore::KeyError; |
| return -1; |
| } |
| |
| // ftok requires that an actual file exists somewhere |
| if (-1 != unix_key) |
| return unix_key; |
| |
| // Create the file needed for ftok |
| int built = QSharedMemoryPrivate::createUnixKeyFile(fileName); |
| if (-1 == built) { |
| errorString = |
| #if QT_CONFIG(translation) |
| QCoreApplication::tr("%1: unable to make key", "QSystemSemaphore") |
| #else |
| QLatin1String("%1: unable to make key") |
| #endif |
| .arg(QLatin1String("QSystemSemaphore::handle:")); |
| error = QSystemSemaphore::KeyError; |
| return -1; |
| } |
| createdFile = (1 == built); |
| |
| #if !defined(QT_NO_SHAREDMEMORY) && !defined(QT_POSIX_IPC) && !defined(Q_OS_ANDROID) |
| // Get the unix key for the created file |
| unix_key = ftok(QFile::encodeName(fileName).constData(), 'Q'); |
| #endif |
| if (-1 == unix_key) { |
| errorString = |
| #if QT_CONFIG(translation) |
| QCoreApplication::tr("%1: ftok failed", "QSystemSemaphore") |
| #else |
| QLatin1String("%1: ftok failed") |
| #endif |
| .arg(QLatin1String("QSystemSemaphore::handle:")); |
| error = QSystemSemaphore::KeyError; |
| return -1; |
| } |
| |
| // Get semaphore |
| semaphore = semget(unix_key, 1, 0600 | IPC_CREAT | IPC_EXCL); |
| if (-1 == semaphore) { |
| if (errno == EEXIST) |
| semaphore = semget(unix_key, 1, 0600 | IPC_CREAT); |
| if (-1 == semaphore) { |
| setErrorString(QLatin1String("QSystemSemaphore::handle")); |
| cleanHandle(); |
| return -1; |
| } |
| } else { |
| createdSemaphore = true; |
| // Force cleanup of file, it is possible that it can be left over from a crash |
| createdFile = true; |
| } |
| |
| if (mode == QSystemSemaphore::Create) { |
| createdSemaphore = true; |
| createdFile = true; |
| } |
| |
| // Created semaphore so initialize its value. |
| if (createdSemaphore && initialValue >= 0) { |
| qt_semun init_op; |
| init_op.val = initialValue; |
| if (-1 == semctl(semaphore, 0, SETVAL, init_op)) { |
| setErrorString(QLatin1String("QSystemSemaphore::handle")); |
| cleanHandle(); |
| return -1; |
| } |
| } |
| |
| return unix_key; |
| } |
| |
| /*! |
| \internal |
| |
| Cleanup the unix_key |
| */ |
| void QSystemSemaphorePrivate::cleanHandle() |
| { |
| unix_key = -1; |
| |
| // remove the file if we made it |
| if (createdFile) { |
| QFile::remove(fileName); |
| createdFile = false; |
| } |
| |
| if (createdSemaphore) { |
| if (-1 != semaphore) { |
| if (-1 == semctl(semaphore, 0, IPC_RMID, 0)) { |
| setErrorString(QLatin1String("QSystemSemaphore::cleanHandle")); |
| #if defined QSYSTEMSEMAPHORE_DEBUG |
| qDebug("QSystemSemaphore::cleanHandle semctl failed."); |
| #endif |
| } |
| semaphore = -1; |
| } |
| createdSemaphore = false; |
| } |
| } |
| |
| /*! |
| \internal |
| */ |
| bool QSystemSemaphorePrivate::modifySemaphore(int count) |
| { |
| if (-1 == handle()) |
| return false; |
| |
| struct sembuf operation; |
| operation.sem_num = 0; |
| operation.sem_op = count; |
| operation.sem_flg = SEM_UNDO; |
| |
| int res; |
| EINTR_LOOP(res, semop(semaphore, &operation, 1)); |
| if (-1 == res) { |
| // If the semaphore was removed be nice and create it and then modifySemaphore again |
| if (errno == EINVAL || errno == EIDRM) { |
| semaphore = -1; |
| cleanHandle(); |
| handle(); |
| return modifySemaphore(count); |
| } |
| setErrorString(QLatin1String("QSystemSemaphore::modifySemaphore")); |
| #if defined QSYSTEMSEMAPHORE_DEBUG |
| qDebug("QSystemSemaphore::modify failed %d %d %d %d %d", |
| count, int(semctl(semaphore, 0, GETVAL)), int(errno), int(EIDRM), int(EINVAL); |
| #endif |
| return false; |
| } |
| |
| clearError(); |
| return true; |
| } |
| |
| |
| QT_END_NAMESPACE |
| |
| #endif // QT_NO_SYSTEMSEMAPHORE |
| |
| #endif // QT_POSIX_IPC |