diff options
Diffstat (limited to 'src/ttylocker_unix.cpp')
| -rw-r--r-- | src/ttylocker_unix.cpp | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/src/ttylocker_unix.cpp b/src/ttylocker_unix.cpp new file mode 100644 index 0000000..2d93e87 --- /dev/null +++ b/src/ttylocker_unix.cpp @@ -0,0 +1,212 @@ +/* + License... +*/ + +#include "ttylocker_p_unix.h" + +#if defined (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 <QtCore/qfile.h> +# include <QtCore/qdir.h> +# include <QtCore/qstringlist.h> +#endif // defined (HAVE_BAUDBOY_H) + +// Truncate the full name of the device to short. +// For example the long name "/dev/ttyS0" will cut up to "ttyS0". +static +QString shortNameFromLocation(const QString &location) +{ + return QDir::cleanPath(location).section(QDir::separator() , -1); +} + + +#if !(defined (HAVE_BAUDBOY_H) || defined (HAVE_LOCKDEV_H)) + +static +const char *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 getFirstSharedLockDir() +{ + 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 +// major and minor device number, eg "LCK.30.50" etc. +static QString get_lock_file_in_numeric_form(const QString &location) +{ + QString result = getFirstSharedLockDir(); + if (!result.isEmpty()) { + struct stat buf; + if (::stat(location.toLocal8Bit().constData(), &buf)) + result.clear(); + else { + result.append("/LCK.%1.%2"); + result = result.arg(major(buf.st_rdev)).arg(minor(buf.st_rdev)); + } + } + return result; +} +*/ + +// Returns the name of the lock file which is tied to the +// device name, eg "LCK..ttyS0", etc. +static +QString getLockFileInNamedForm(const QString &location) +{ + QString result(getFirstSharedLockDir()); + if (!result.isEmpty()) { + result.append(QLatin1String("/LCK..%1")); + result = result.arg(shortNameFromLocation(location)); + } + return result; +} + +/* +// Returns the name of the lock file, which is tied to the number of +// the process which uses a device, such as "LCK...999", etc. +static QString get_lock_file_in_pid_form(const QString &location) +{ + QString result = getFirstSharedLockDir(); + if (!result.isEmpty()) { + result.append("/LCK...%1"); + result = result.arg(::getpid()); + } + return result; +} +*/ + +#endif //!(defined (HAVE_BAUDBOY_H) || defined (HAVE_LOCKDEV_H)) + + +QT_BEGIN_NAMESPACE_SERIALPORT + +// Try lock serial device. However, other processes can not access it. +bool TTYLocker::lock(const QString &location) +{ + bool result = false; +#if defined (HAVE_BAUDBOY_H) + if (::ttylock(shortNameFromLocation(location).toLocal8Bit().constData())) + ::ttywait(shortNameFromLocation(location).toLocal8Bit().constData()); + result = (::ttylock(shortNameFromLocation(location).toLocal8Bit().constData()) != -1); +#elif defined (HAVE_LOCKDEV_H) + result = (::dev_lock(shortNameFromLocation(location).toLocal8Bit().constData()) != -1); +#else + QFile f(getLockFileInNamedForm(location)); + 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) + result = true; + f.close(); + } +#endif + return result; +} + +// Try unlock serial device. However, other processes can access it. +bool TTYLocker::unlock(const QString &location) +{ + bool result = true; +#if defined (HAVE_BAUDBOY_H) + result = (::ttyunlock(shortNameFromLocation(location).toLocal8Bit().constData()) != -1); +#elif defined (HAVE_LOCKDEV_H) + result = (::dev_unlock(shortNameFromLocation(location).toLocal8Bit().constData(), ::getpid()) != -1); +#else + QFile f(getLockFileInNamedForm(location)); + f.remove(); +#endif + return result; +} + +// 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 QString &location, bool *currentPid) +{ + bool result = false; +#if defined (HAVE_BAUDBOY_H) + result = (::ttylocked(shortNameFromLocation(location).toLocal8Bit().constData()) != -1); + *currentPid = false; +#elif defined (HAVE_LOCKDEV_H) + result = (::dev_testlock(shortNameFromLocation(location).toLocal8Bit().constData()) != -1); + *currentPid = false; +#else + + enum CheckPidResult { + CHK_PID_PROCESS_NOT_EXISTS, /* process does not exist */ + CHK_PID_PROCESS_EXISTS_FOREIGN, /* process exists and it is "foreign" (ie not current) */ + CHK_PID_PROCESS_EXISTS_CURRENT, /* process exists and it is "their" (ie, current) */ + CHK_PID_UNKNOWN_ERROR /* another error */ + }; + + *currentPid = false; + + QFile f(getLockFileInNamedForm(location)); + if (f.exists()) { + if (!f.open(QIODevice::ReadOnly)) { + result = true; + } else { + QString content(QLatin1String(f.readAll())); + f.close(); + bool ok = false; + int pid = content.section(' ', 0, 0, QString::SectionSkipEmpty).toInt(&ok); + if (ok) { + + // Checks the validity of the process number that was obtained from the Lock file. + enum CheckPidResult pidResult = CHK_PID_UNKNOWN_ERROR; + + if (::kill(pid_t(pid), 0) == -1) { + pidResult = (errno == ESRCH) ? + (CHK_PID_PROCESS_NOT_EXISTS) : (CHK_PID_UNKNOWN_ERROR); + } else { + pidResult = (::getpid() == pid) ? + (CHK_PID_PROCESS_EXISTS_CURRENT) : (CHK_PID_PROCESS_EXISTS_FOREIGN); + } + + switch (pidResult) { + case CHK_PID_PROCESS_NOT_EXISTS: + break; + case CHK_PID_PROCESS_EXISTS_FOREIGN: + result = true; + break; + case CHK_PID_PROCESS_EXISTS_CURRENT: + result = true; + *currentPid = true; + break; + default: + result = true; + } + } + } + } +#endif + return result; +} + +QT_END_NAMESPACE_SERIALPORT |