slpd_main.c

SLP协议在linux下的实现。此版本为1.2.1版。官方网站为www.openslp.org

    return 0;
}


/*-------------------------------------------------------------------------*/
int Daemonize(const char* pidfile)
/* Turn the calling process into a daemon (detach from tty setuid(), etc   */
/*                                                                         */      
/* Returns: zero on success non-zero if slpd could not daemonize (or if    */
/*          slpd is already running                             .          */
/*-------------------------------------------------------------------------*/
{
    FILE*   fd;
    struct  passwd* pwent;
    pid_t   pid;
    char    pidstr[14];

    /* fork() if we should detach */
    if(G_SlpdCommandLine.detach)
    {
        pid = fork();
    }
    else
    {
        pid = getpid();
    }

    /* parent or child? */
    switch(pid)
    {
    case -1:
        return -1;
    case 0:
        /* child lives */
        break;

    default:
        /* parent writes pid (or child) pid file and dies */
        fd = fopen(pidfile,"w");
        if(fd)
        {
            sprintf(pidstr,"%i",(int)pid);
            fwrite(pidstr,strlen(pidstr),1,fd);
            fclose(fd);
        }
        if(G_SlpdCommandLine.detach)
        {
            exit(0);
        }
        break;
    }

    close(0); 
    close(1); 
    close(2); 
    setsid(); /* will only fail if we are already the process group leader */

    /*----------------*/
    /* suid to daemon */
    /*----------------*/
    /* TODO: why do the following lines mess up my signal handlers? */
    pwent = getpwnam("daemon"); 
    if(pwent)
    {
        if(setgroups(1, &pwent->pw_gid) < 0 ||
           setgid(pwent->pw_gid) < 0 ||
           setuid(pwent->pw_uid) < 0)
        {
            /* TODO: should we log here and return fail */
	    exit(1);
        }
    }
    else
	exit(1);

    /*--------------------*/
    /* Set cwd to / (root)*/
    /*--------------------*/
    chdir("/");
    
    return 0;
}


/*--------------------------------------------------------------------------*/
void SignalHandler(int signum)
/*--------------------------------------------------------------------------*/
{
    switch(signum)
    {
    case SIGALRM:
        G_SIGALRM = 1;
        break;

    case SIGTERM:
        G_SIGTERM = 1;
        break;

    case SIGHUP:
        G_SIGHUP = 1;
        break;

#ifdef DEBUG
    case SIGINT:
        G_SIGINT = 1;
        break;
#endif

    case SIGPIPE:
    default:
        break;
    }
}


/*-------------------------------------------------------------------------*/
int SetUpSignalHandlers()
/*-------------------------------------------------------------------------*/
{
    int result;
    struct sigaction sa;

    sa.sa_handler    = SignalHandler;
    sigemptyset(&sa.sa_mask);
    sa.sa_flags      = 0;//SA_ONESHOT;
#if defined(HAVE_SA_RESTORER)
    sa.sa_restorer   = 0;
#endif

    result = sigaction(SIGALRM,&sa,0);
    result |= sigaction(SIGTERM,&sa,0);
    result |= sigaction(SIGPIPE,&sa,0);

#ifdef DEBUG
    result |= sigaction(SIGINT,&sa,0);
#endif

    signal(SIGHUP,SignalHandler);
    //result |= sigaction(SIGHUP,&sa,0);

    return result;
}

/*=========================================================================*/
int main(int argc, char* argv[])
/*=========================================================================*/
{
    fd_set          readfds;
    fd_set          writefds;
    int             highfd;
    int             fdcount         = 0;

#ifdef DEBUG
    xmalloc_init("/var/log/slpd_xmalloc.log",0);
#endif

    /*------------------------*/
    /* Parse the command line */
    /*------------------------*/
    if(SLPDParseCommandLine(argc,argv))
    {
        SLPDFatal("Invalid command line\n");
    }

    /*------------------------------*/
    /* Make sure we are root        */
    /*------------------------------*/
    if(getuid() != 0)
    {
        SLPDFatal("slpd must be started by root\n");
    }

    /*--------------------------------------*/
    /* Make sure we are not already running */
    /*--------------------------------------*/
    if(CheckPid(G_SlpdCommandLine.pidfile))
    {
        SLPDFatal("slpd is already running. Check %s\n",
                 G_SlpdCommandLine.pidfile);
    }

    /*------------------------------*/
    /* Initialize the log file      */
    /*------------------------------*/
    if(SLPDLogFileOpen(G_SlpdCommandLine.logfile, 1))
    {
        SLPDFatal("Could not open logfile %s\n",G_SlpdCommandLine.logfile);
    }

    /*------------------------*/
    /* Seed the XID generator */
    /*------------------------*/
    SLPXidSeed();

    /*---------------------*/
    /* Log startup message */
    /*---------------------*/
    SLPDLog("****************************************\n");
    SLPDLogTime();
    SLPDLog("SLPD daemon started\n");
    SLPDLog("****************************************\n");
    SLPDLog("Command line = %s\n",argv[0]);
    SLPDLog("Using configuration file = %s\n",G_SlpdCommandLine.cfgfile);
    SLPDLog("Using registration file = %s\n",G_SlpdCommandLine.regfile);
#ifdef ENABLE_SLPv2_SECURITY
    SLPDLog("Using SPI file = %s\n",G_SlpdCommandLine.spifile);
#endif
   
    /*--------------------------------------------------*/
    /* Initialize for the first time                    */
    /*--------------------------------------------------*/
    if(SLPDPropertyInit(G_SlpdCommandLine.cfgfile) ||
#ifdef ENABLE_SLPv2_SECURITY
       SLPDSpiInit(G_SlpdCommandLine.spifile) ||
#endif     
       SLPDDatabaseInit(G_SlpdCommandLine.regfile) ||
       SLPDIncomingInit() ||
       SLPDOutgoingInit() ||
       SLPDKnownDAInit())
    {
        SLPDFatal("slpd initialization failed\n");
    }
    SLPDLog("Agent Interfaces = %s\n",G_SlpdProperty.interfaces);
    SLPDLog("Agent URL = %s\n",G_SlpdProperty.myUrl);

    /*---------------------------*/
    /* make slpd run as a daemon */
    /*---------------------------*/
    if(Daemonize(G_SlpdCommandLine.pidfile))
    {
        SLPDFatal("Could not daemonize\n");
    }

    /*-----------------------*/
    /* Setup signal handlers */
    /*-----------------------*/
    if(SetUpSignalHandlers())
    {
        SLPDFatal("Error setting up signal handlers.\n");
    }

    /*------------------------------*/
    /* Set up alarm to age database */
    /*------------------------------*/
    alarm(SLPD_AGE_INTERVAL);

    /*-----------*/
    /* Main loop */
    /*-----------*/
    SLPDLog("Startup complete entering main run loop ...\n\n");
    G_SIGALRM   = 0;
    G_SIGTERM   = 0;
    G_SIGHUP    = 0;    
#ifdef DEBUG
    G_SIGINT    = 0;
#endif

    while(G_SIGTERM == 0)
    {
        /*--------------------------------------------------------*/
        /* Load the fdsets up with all valid sockets in the list  */
        /*--------------------------------------------------------*/
        highfd = 0;
        FD_ZERO(&readfds);
        FD_ZERO(&writefds);
        LoadFdSets(&G_IncomingSocketList, &highfd, &readfds,&writefds);
        LoadFdSets(&G_OutgoingSocketList, &highfd, &readfds,&writefds);

        /*--------------------------------------------------*/
        /* Before select(), check to see if we got a signal */
        /*--------------------------------------------------*/
        if(G_SIGALRM || G_SIGHUP)
        {
            goto HANDLE_SIGNAL;
        }

        /*-------------*/
        /* Main select */
        /*-------------*/
        fdcount = select(highfd+1,&readfds,&writefds,0,0);
        if(fdcount > 0) /* fdcount will be < 0 when interrupted by a signal */
        {
            SLPDIncomingHandler(&fdcount,&readfds,&writefds);
            SLPDOutgoingHandler(&fdcount,&readfds,&writefds);
        }

        /*----------------*/
        /* Handle signals */
        /*----------------*/
        HANDLE_SIGNAL:
        if(G_SIGHUP)
        {
            HandleSigHup();
            G_SIGHUP = 0;
        }
        if(G_SIGALRM)
        {
            HandleSigAlrm();
            G_SIGALRM = 0;
            alarm(SLPD_AGE_INTERVAL);
        }
#ifdef DEBUG
	if (G_SIGINT)
	{
	    HandleSigInt();
	    G_SIGINT = 0;
	}			
#endif

    } /* End of main loop */

    /* Got SIGTERM */
    HandleSigTerm();

    return 0;
}
#endif /*ifndef _WIN32 */