SDaemonFramework.h

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//
// Date:      19 May 2003
//            11 August 2003
//            27 November 2005
//            2  December 2005  umask(0) added
//
// Copyright (c) Sergey Satskiy 2003
//               <sergesatsky@yahoo.com>
//
// Permission to copy, use, modify, sell and distribute this software 
// is granted provided this copyright notice appears in all copies. 
// This software is provided "as is" without express or implied
// warranty, and with no claim as to its suitability for any purpose.
//



#ifndef SDAEMONFRAMEWORK_H
#define SDAEMONFRAMEWORK_H

#include <unistd.h>
#include <stdlib.h>
#include <signal.h>
#include <sys/stat.h>



    // Anonymous namespace gives ability compiled with no problems
    // even if the file is included into many .cpp files
namespace
{
    #if DAEMON == 1

    volatile bool    ParentRun( true );

    volatile bool    DaemonOK( false );


    void SigOKHandler( int  Unused )
    {
        signal( Unused, SIG_IGN );
        DaemonOK = true; 
        ParentRun = false;
    }

    void SigFailedHandler( int  Unused )
    {
        signal( Unused, SIG_IGN );
        DaemonOK = false; 
        ParentRun = false;
    }

        // Signalling functions prototypes
    inline void SignalOK( void );
    inline void SignalFailed( void );

    #endif

    
    inline void Daemonise( void )
    {

         #if DAEMON == 1
         signal( SIGUSR1, SigOKHandler );
         signal( SIGUSR2, SigFailedHandler );

         if ( getppid() != 1 )
         {
            signal( SIGTTOU, SIG_IGN );
            signal( SIGTTIN, SIG_IGN );
            signal( SIGTSTP, SIG_IGN );
    
                // Become a daemon
            if ( fork() != 0 )
            {
                    // Parent process
                while ( ParentRun ) 
                {
                    sleep( 1 );
                }
            
                if ( DaemonOK )     
                {
                    exit( 0 );
                }

                exit( 1 );
            }

                // Child process
            if ( setsid() == -1 )
            {
                SignalFailed();
                exit( 1 );
            }
        }

            // Close file descriptors of stdin, stdout and stderr
        if ( ttyname( 0 ) != NULL ) close( 0 );
        if ( ttyname( 1 ) != NULL ) close( 1 );
        if ( ttyname( 2 ) != NULL ) close( 2 );
        

        #ifdef HOME
        chdir( HOME );              // To be sure not staying nowhere
        setenv( "HOME", HOME, 1 );  
        #else
        chdir( "/" );
        setenv( "HOME", "/", 1 );
        #endif                      // #ifdef HOME
        
        #endif      // #if DAEMON == 1
    
            // Daemon should not inherit the files mask
            // To make the non-daemon process behaviour uniform do it 
            //    in any case
        umask( 0 );

        return;
    }


    inline void SignalOK( void )
    {
        #if DAEMON == 1
        kill( getppid(), SIGUSR1 );
        #endif
    }

    inline void SignalFailed( void )
    {
        #if DAEMON == 1
        kill( getppid(), SIGUSR2 );
        #endif
    }

}   // End of anonymous namespace


#endif

---