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Diffstat (limited to 'src/serialport/ttylocker_unix.cpp')
| -rw-r--r-- | src/serialport/ttylocker_unix.cpp | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/src/serialport/ttylocker_unix.cpp b/src/serialport/ttylocker_unix.cpp new file mode 100644 index 0000000..3e36d67 --- /dev/null +++ b/src/serialport/ttylocker_unix.cpp @@ -0,0 +1,178 @@ +/**************************************************************************** +** +** Copyright (C) 2012 Denis Shienkov <scapig@yandex.ru> +** Contact: http://www.qt-project.org/ +** +** This file is part of the QtSerialPort module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** GNU Lesser General Public License Usage +** 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 1.1, 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. +** +** Other Usage +** Alternatively, this file may be used in accordance with the terms and +** conditions contained in a signed written agreement between you and Nokia. +** +** +** +** +** +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "ttylocker_unix_p.h" + +#ifdef HAVE_BAUDBOY_H +# include <baudboy.h> +# include <cstdlib> +#elif defined (HAVE_LOCKDEV_H) +# include <lockdev.h> +# include <unistd.h> +#else +# include <signal.h> +# include <errno.h> +# include <fcntl.h> +# include <sys/stat.h> +# include <unistd.h> +# include <QtCore/qfile.h> +# include <QtCore/qdir.h> +# include <QtCore/qstringlist.h> +#endif // defined (HAVE_BAUDBOY_H) + +QT_BEGIN_NAMESPACE_SERIALPORT + +#if !(defined (HAVE_BAUDBOY_H) || defined (HAVE_LOCKDEV_H)) + +static +const char * const entryLockDirectoryList[] = { + "/var/lock", + "/etc/locks", + "/var/spool/locks", + "/var/spool/uucp", + "/tmp", + 0 +}; + +// Returns the full path first found in the directory where you can create a lock file +// (ie a directory with access to the read/write). +// Verification of directories is of the order in accordance with the order +// of records in the variable lockDirList. +static +QString lookupFirstSharedLockDir() +{ + for (int i = 0; entryLockDirectoryList[i] != 0; ++i) { + if (::access(entryLockDirectoryList[i], R_OK | W_OK) == 0) + return QLatin1String(entryLockDirectoryList[i]); + } + return QString(); +} + +// Returns the name of the lock file which is tied to the +// device name, eg "LCK..ttyS0", etc. +static +QString generateLockFileNameAsNamedForm(const char *portName) +{ + QString result(lookupFirstSharedLockDir()); + if (!result.isEmpty()) + result.append(QLatin1String("/LCK..") + QLatin1String(portName)); + return result; +} + +#endif //!(defined (HAVE_BAUDBOY_H) || defined (HAVE_LOCKDEV_H)) + +// Try lock serial device. However, other processes can not access it. +bool TtyLocker::lock(const char *portName) +{ +#ifdef HAVE_BAUDBOY_H + if (::ttylock(portName) + ::ttywait(portName); + return ::ttylock(portName) != -1; +#elif defined (HAVE_LOCKDEV_H) + return ::dev_lock(portName) != -1; +#else + QFile f(generateLockFileNameAsNamedForm(portName)); + if (f.open(QIODevice::WriteOnly | QIODevice::Truncate)) { + QString content(QLatin1String(" %1 %2\x0A")); + content = content.arg(::getpid()).arg(::getuid()); + if (f.write(content.toLocal8Bit()) > 0) { + f.close(); + return true; + } + f.close(); + } + return false; +#endif +} + +// Try unlock serial device. However, other processes can access it. +bool TtyLocker::unlock(const char *portName) +{ +#ifdef HAVE_BAUDBOY_H + return ::ttyunlock(portName != -1; +#elif defined (HAVE_LOCKDEV_H) + return ::dev_unlock(portName, ::getpid()) != -1; +#else + QFile f(generateLockFileNameAsNamedForm(portName)); + return f.remove(); +#endif +} + +// Verifies the device is locked or not. +// If returned currentPid = true - this means that the device is locked the current process. +bool TtyLocker::isLocked(const char *portName, bool *currentPid) +{ + if (!currentPid) + return true; + + *currentPid = false; + +#ifdef HAVE_BAUDBOY_H + return ::ttylocked(portName) != -1; +#elif defined (HAVE_LOCKDEV_H) + return ::dev_testlock(portName) != -1; +#else + + QFile f(generateLockFileNameAsNamedForm(portName)); + if (!f.exists()) + return false; + if (!f.open(QIODevice::ReadOnly)) + return true; + + QString content(QLatin1String(f.readAll())); + f.close(); + + const pid_t pid = content.section(' ', 0, 0, QString::SectionSkipEmpty).toInt(); + + if (::kill(pid, 0) == -1) { + if (errno == ESRCH) // Process does not exists + return false; + } else { + if (::getpid() == pid) // Process exists and it is "their", i.e current + *currentPid = true; + } + + return true; + +#endif +} + +QT_END_NAMESPACE_SERIALPORT |