diff options
| author | Joerg Bornemann <joerg.bornemann@theqtcompany.com> | 2015-04-29 14:36:24 +0200 |
|---|---|---|
| committer | Joerg Bornemann <joerg.bornemann@theqtcompany.com> | 2015-05-26 11:01:14 +0000 |
| commit | 80c8d324b335753d5b1758f29775b844904bb2c6 (patch) | |
| tree | 8865d7629eba535fbf9564d15f15025641375a8e /src/corelib/io/qlockfile.cpp | |
| parent | a0e5210d8b6b21d33800e1fac30efbf2868f9f5b (diff) | |
take process name into account for QLockFile's pid clash resolution
To cover the situation that the process ID got reused, the current
process name is compared to the name of the process that corresponds
to the process ID from the lock file.
If the process names differ, the lock file is considered stale.
[ChangeLog][QtCore][QLockFile] Detection of stale lock files got more
robust and takes the name of the process that belongs to the stored
PID into account.
Task-number: QTBUG-45497
Change-Id: Ic3c0d7e066435451203e77b9b9ce2d70bfb9c570
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@theqtcompany.com>
Reviewed-by: David Faure <david.faure@kdab.com>
Diffstat (limited to 'src/corelib/io/qlockfile.cpp')
| -rw-r--r-- | src/corelib/io/qlockfile.cpp | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/src/corelib/io/qlockfile.cpp b/src/corelib/io/qlockfile.cpp index 4f5aeff395..2bd996d213 100644 --- a/src/corelib/io/qlockfile.cpp +++ b/src/corelib/io/qlockfile.cpp @@ -1,6 +1,7 @@ /**************************************************************************** ** ** Copyright (C) 2013 David Faure <faure+bluesystems@kde.org> +** Copyright (C) 2015 The Qt Company Ltd. ** Contact: http://www.qt.io/licensing/ ** ** This file is part of the QtCore module of the Qt Toolkit. @@ -66,9 +67,12 @@ QT_BEGIN_NAMESPACE If the process holding the lock crashes, the lock file stays on disk and can prevent any other process from accessing the shared resource, ever. For this reason, QLockFile - tries to detect such a "stale" lock file, based on the process ID written into the file, - and (in case that process ID got reused meanwhile), on the last modification time of - the lock file (30s by default, for the use case of a short-lived operation). + tries to detect such a "stale" lock file, based on the process ID written into the file. + To cover the situation that the process ID got reused meanwhile, the current process name is + compared to the name of the process that corresponds to the process ID from the lock file. + If the process names differ, the lock file is considered stale. + Additionally, the last modification time of the lock file (30s by default, for the use case of a + short-lived operation) is taken into account. If the lock file is found to be stale, it will be deleted. For the use case of protecting a resource over a long time, you should therefore call @@ -122,7 +126,7 @@ QLockFile::~QLockFile() The value of \a staleLockTime is used by lock() and tryLock() in order to determine when an existing lock file is considered stale, i.e. left over by a crashed process. This is useful for the case where the PID got reused - meanwhile, so the only way to detect a stale lock file is by the fact that + meanwhile, so one way to detect a stale lock file is by the fact that it has been around for a long time. \sa staleLockTime() |