groot.cpp

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//
// Copyright (C) 2001-2013 Graeme Walker <graeme_walker@users.sourceforge.net>
// 
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// 
// This program 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 General Public License for more details.
// 
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.
// ===
//
// groot.cpp
//

#include "gdef.h"
#include "groot.h"
#include "gassert.h"
#include "gprocess.h"
#include "gdebug.h"

G::Root * G::Root::m_this = NULL ;
bool G::Root::m_initialised = false ;
G::Identity G::Root::m_special( G::Identity::invalid() ) ;
G::Identity G::Root::m_nobody( G::Identity::invalid() ) ;

G::Root::Root( bool change_group ) :
        m_change_group(change_group)
{
        if( m_this == NULL && m_initialised )
        {
                Process::beSpecial( m_special , m_change_group ) ;
                m_this = this ;
        }
}

G::Root::~Root()
{
        try
        {
                if( m_this == this && m_initialised )
                {
                        m_this = NULL ;
                        Process::beOrdinary( m_nobody , m_change_group ) ;
                }
        }
        catch( std::exception & e )
        {
                G_ERROR( "G::Root: cannot release root privileges: " << e.what() ) ;
        }
        catch(...)
        {
                G_ERROR( "G::Root: cannot release root privileges" ) ;
        }
}

G::Identity G::Root::start( SignalSafe safe )
{
        if( !m_initialised ) return Identity::invalid() ;
        return Process::beSpecial( safe , m_special , true ) ;
}

void G::Root::stop( SignalSafe safe , Identity identity )
{
        if( identity == Identity::invalid() ) return ;
        Process::beOrdinary( safe , identity , true ) ;
}

void G::Root::init( const std::string & nobody )
{
        Process::revokeExtraGroups() ;
        m_nobody = Identity(nobody) ;
        m_special = Process::beOrdinary( SignalSafe() , m_nobody ) ;
        m_initialised = true ;
}

G::Identity G::Root::nobody()
{
        return m_nobody ;
}