123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141 | // Copyright (C) 2013 David Faure <faure+bluesystems@kde.org>// Copyright (C) 2016 The Qt Company Ltd.// Copyright (C) 2017 Intel Corporation.// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only#include"private/qlockfile_p.h"#include"private/qfilesystementry_p.h"#include <qt_windows.h>#include <psapi.h>#include"QtCore/qfileinfo.h"#include"QtCore/qdatetime.h"#include"QtCore/qdebug.h"#include"QtCore/qthread.h" QT_BEGIN_NAMESPACE staticinlineboolfileExists(const wchar_t*fileName){ WIN32_FILE_ATTRIBUTE_DATA data;returnGetFileAttributesEx(fileName, GetFileExInfoStandard, &data);}QLockFile::LockError QLockFilePrivate::tryLock_sys(){const QFileSystemEntry fileEntry(fileName);// When writing, allow others to read.// When reading, QFile will allow others to read and write, all good.// Adding FILE_SHARE_DELETE would allow forceful deletion of stale files,// but Windows doesn't allow recreating it while this handle is open anyway,// so this would only create confusion (can't lock, but no lock file to read from).const DWORD dwShareMode = FILE_SHARE_READ; SECURITY_ATTRIBUTES securityAtts = {sizeof(SECURITY_ATTRIBUTES), NULL, FALSE }; HANDLE fh =CreateFile((const wchar_t*)fileEntry.nativeFilePath().utf16(), GENERIC_READ | GENERIC_WRITE, dwShareMode,&securityAtts, CREATE_NEW,// error if already exists FILE_ATTRIBUTE_NORMAL, NULL);if(fh == INVALID_HANDLE_VALUE) {const DWORD lastError =GetLastError();switch(lastError) {case ERROR_SHARING_VIOLATION:case ERROR_ALREADY_EXISTS:case ERROR_FILE_EXISTS:returnQLockFile::LockFailedError;case ERROR_ACCESS_DENIED:// readonly file, or file still in use by another process.// Assume the latter if the file exists, since we don't create it readonly.returnfileExists((const wchar_t*)fileEntry.nativeFilePath().utf16())?QLockFile::LockFailedError :QLockFile::PermissionError;default:qWarning("Got unexpected locking error %llu",quint64(lastError));returnQLockFile::UnknownError;}}// We hold the lock, continue. fileHandle = fh; QByteArray fileData =lockFileContents(); DWORD bytesWritten =0;QLockFile::LockError error =QLockFile::NoError;if(!WriteFile(fh, fileData.constData(), fileData.size(), &bytesWritten, NULL) || !FlushFileBuffers(fh)) error =QLockFile::UnknownError;// partition fullreturn error;}boolQLockFilePrivate::removeStaleLock(){// QFile::remove fails on Windows if the other process is still using the file, so it's not stale.returnQFile::remove(fileName);}boolQLockFilePrivate::isProcessRunning(qint64 pid,const QString &appname){ HANDLE procHandle = ::OpenProcess(PROCESS_QUERY_INFORMATION, FALSE, pid);if(!procHandle)return false;// We got a handle but check if process is still alive DWORD exitCode =0;if(!::GetExitCodeProcess(procHandle, &exitCode)) exitCode =0;::CloseHandle(procHandle);if(exitCode != STILL_ACTIVE)return false;const QString processName =processNameByPid(pid);if(!processName.isEmpty() && processName != appname)return false;// PID got reused by a different application.return true;} QString QLockFilePrivate::processNameByPid(qint64 pid){ HANDLE hProcess =OpenProcess(PROCESS_QUERY_INFORMATION | PROCESS_VM_READ, FALSE,DWORD(pid));if(!hProcess) {returnQString();}wchar_t buf[MAX_PATH];const DWORD length =GetModuleFileNameExW(hProcess, NULL, buf,sizeof(buf) /sizeof(wchar_t));CloseHandle(hProcess);if(!length)returnQString(); QString name =QString::fromWCharArray(buf, length);int i = name.lastIndexOf(u'\\');if(i >=0) name.remove(0, i +1); i = name.lastIndexOf(u'.');if(i >=0) name.truncate(i);return name;}voidQLockFile::unlock(){Q_D(QLockFile);if(!d->isLocked)return;CloseHandle(d->fileHandle);int attempts =0;static const int maxAttempts =500;// 500mswhile(!QFile::remove(d->fileName) && ++attempts < maxAttempts) {// Someone is reading the lock file right now (on Windows this prevents deleting it).QThread::msleep(1);}if(attempts == maxAttempts) {qWarning() <<"Could not remove our own lock file"<< d->fileName <<". Either other users of the lock file are reading it constantly for 500 ms, ""or we (no longer) have permissions to delete the file";// This is bad because other users of this lock file will now have to wait for the// stale-lock-timeout...} d->lockError =QLockFile::NoError; d->isLocked =false;} QT_END_NAMESPACE
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