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tdelibs/tdeabc/lock.cpp

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/*
This file is part of libtdeabc.
Copyright (c) 2001,2003 Cornelius Schumacher <schumacher@kde.org>
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public License
along with this library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.
*/
#include "lock.h"
#include <tdeapplication.h>
#include <kdebug.h>
#include <tdelocale.h>
#include <kstandarddirs.h>
#include <tdetempfile.h>
#include <tqfile.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
using namespace TDEABC;
Lock::Lock( const TQString &identifier )
: mIdentifier( identifier )
{
mIdentifier.replace( "/", "_" );
}
Lock::~Lock()
{
unlock();
}
TQString Lock::locksDir()
{
return locateLocal( "data", "tdeabc/lock/" );
}
bool Lock::readLockFile( const TQString &filename, int &pid, TQString &app )
{
TQFile file( filename );
if ( !file.open( IO_ReadOnly ) ) return false;
TQTextStream t( &file );
pid = t.readLine().toInt();
app = t.readLine();
return true;
}
bool Lock::writeLockFile( const TQString &filename )
{
TQFile file( filename );
if ( !file.open( IO_WriteOnly ) ) return false;
TQTextStream t( &file );
t << ::getpid() << endl << TQString( TDEGlobal::instance()->instanceName() );
return true;
}
TQString Lock::lockFileName() const
{
return locksDir() + mIdentifier + ".lock";
}
bool Lock::lock()
{
kdDebug(5700) << "Lock::lock()" << endl;
TQString lockName = lockFileName();
kdDebug(5700) << "-- lock name: " << lockName << endl;
if ( TQFile::exists( lockName ) ) { // check if it is a stale lock file
int pid;
TQString app;
if ( !readLockFile( lockFileName(), pid, app ) ) {
mError = i18n("Unable to open lock file.");
return false;
}
int retval = ::kill( pid, 0 );
if ( retval == -1 && errno == ESRCH ) { // process doesn't exists anymore
TQFile::remove( lockName );
kdWarning(5700) << "Removed stale lock file from process '" << app << "'"
<< endl;
} else {
TQString identifier( mIdentifier );
identifier.replace( '_', '/' );
mError = i18n("The address book '%1' is locked by application '%2'.\nIf you believe this is incorrect, just remove the lock file from '%3'")
.arg( identifier ).arg( app ).arg( locateLocal( "data", "tdeabc/lock/*.lock" ) );
return false;
}
}
TQString lockUniqueName;
lockUniqueName = mIdentifier + kapp->randomString( 8 );
mLockUniqueName = locateLocal( "data", "tdeabc/lock/" + lockUniqueName );
kdDebug(5700) << "-- lock unique name: " << mLockUniqueName << endl;
// Create unique file
writeLockFile( mLockUniqueName );
// Create lock file
int result = ::link( TQFile::encodeName( mLockUniqueName ),
TQFile::encodeName( lockName ) );
if ( result == 0 ) {
mError = "";
emit locked();
return true;
}
// TODO: check stat
mError = i18n("Error");
return false;
}
bool Lock::unlock()
{
int pid;
TQString app;
if ( readLockFile( lockFileName(), pid, app ) ) {
if ( pid == getpid() ) {
TQFile::remove( lockFileName() );
TQFile::remove( mLockUniqueName );
emit unlocked();
} else {
mError = i18n("Unlock failed. Lock file is owned by other process: %1 (%2)")
.arg( app ).arg( TQString::number( pid ) );
kdDebug() << "Lock::unlock(): " << mError << endl;
return false;
}
}
mError = "";
return true;
}
TQString Lock::error() const
{
return mError;
}
#include "lock.moc"