Exemplo n.º 1
0
int
ntpdmain(
	int argc,
	char *argv[]
	)
{
	l_fp		now;
	struct recvbuf *rbuf;
	const char *	logfilename;
# ifdef HAVE_UMASK
	mode_t		uv;
# endif
# if defined(HAVE_GETUID) && !defined(MPE) /* MPE lacks the concept of root */
	uid_t		uid;
# endif
# if defined(HAVE_WORKING_FORK)
	long		wait_sync = 0;
	int		pipe_fds[2];
	int		rc;
	int		exit_code;
#  ifdef _AIX
	struct sigaction sa;
#  endif
#  if !defined(HAVE_SETSID) && !defined (HAVE_SETPGID) && defined(TIOCNOTTY)
	int		fid;
#  endif
# endif	/* HAVE_WORKING_FORK*/
# ifdef SCO5_CLOCK
	int		fd;
	int		zero;
# endif

# ifdef NEED_PTHREAD_WARMUP
	my_pthread_warmup();
# endif
	
# ifdef HAVE_UMASK
	uv = umask(0);
	if (uv)
		umask(uv);
	else
		umask(022);
# endif
	saved_argc = argc;
	saved_argv = argv;
	progname = argv[0];
	initializing = TRUE;		/* mark that we are initializing */
	parse_cmdline_opts(&argc, &argv);
# ifdef DEBUG
	debug = OPT_VALUE_SET_DEBUG_LEVEL;
#  ifdef HAVE_SETLINEBUF
	setlinebuf(stdout);
#  endif
# endif

	if (HAVE_OPT(NOFORK) || HAVE_OPT(QUIT)
# ifdef DEBUG
	    || debug
# endif
	    || HAVE_OPT(SAVECONFIGQUIT))
		nofork = TRUE;

	init_logging(progname, NLOG_SYNCMASK, TRUE);
	/* honor -l/--logfile option to log to a file */
	if (HAVE_OPT(LOGFILE)) {
		logfilename = OPT_ARG(LOGFILE);
		syslogit = FALSE;
		change_logfile(logfilename, FALSE);
	} else {
		logfilename = NULL;
		if (nofork)
			msyslog_term = TRUE;
		if (HAVE_OPT(SAVECONFIGQUIT))
			syslogit = FALSE;
	}
	msyslog(LOG_NOTICE, "%s: Starting", Version);

	{
		int i;
		char buf[1024];	/* Secret knowledge of msyslog buf length */
		char *cp = buf;

		/* Note that every arg has an initial space character */
		snprintf(cp, sizeof(buf), "Command line:");
		cp += strlen(cp);

		for (i = 0; i < saved_argc ; ++i) {
			snprintf(cp, sizeof(buf) - (cp - buf),
				" %s", saved_argv[i]);
			cp += strlen(cp);
		}
		msyslog(LOG_INFO, "%s", buf);
	}

	/*
	 * Install trap handlers to log errors and assertion failures.
	 * Default handlers print to stderr which doesn't work if detached.
	 */
	isc_assertion_setcallback(assertion_failed);
	isc_error_setfatal(library_fatal_error);
	isc_error_setunexpected(library_unexpected_error);

	/* MPE lacks the concept of root */
# if defined(HAVE_GETUID) && !defined(MPE)
	uid = getuid();
	if (uid && !HAVE_OPT( SAVECONFIGQUIT )) {
		msyslog_term = TRUE;
		msyslog(LOG_ERR,
			"must be run as root, not uid %ld", (long)uid);
		exit(1);
	}
# endif

/*
 * Enable the Multi-Media Timer for Windows?
 */
# ifdef SYS_WINNT
	if (HAVE_OPT( MODIFYMMTIMER ))
		set_mm_timer(MM_TIMER_HIRES);
# endif

#ifdef HAVE_DNSREGISTRATION
/*
 * Enable mDNS registrations?
 */
	if (HAVE_OPT( MDNS )) {
		mdnsreg = TRUE;
	}
#endif  /* HAVE_DNSREGISTRATION */

	if (HAVE_OPT( NOVIRTUALIPS ))
		listen_to_virtual_ips = 0;

	/*
	 * --interface, listen on specified interfaces
	 */
	if (HAVE_OPT( INTERFACE )) {
		int		ifacect = STACKCT_OPT( INTERFACE );
		const char**	ifaces  = STACKLST_OPT( INTERFACE );
		sockaddr_u	addr;

		while (ifacect-- > 0) {
			add_nic_rule(
				is_ip_address(*ifaces, AF_UNSPEC, &addr)
					? MATCH_IFADDR
					: MATCH_IFNAME,
				*ifaces, -1, ACTION_LISTEN);
			ifaces++;
		}
	}

	if (HAVE_OPT( NICE ))
		priority_done = 0;

# ifdef HAVE_SCHED_SETSCHEDULER
	if (HAVE_OPT( PRIORITY )) {
		config_priority = OPT_VALUE_PRIORITY;
		config_priority_override = 1;
		priority_done = 0;
	}
# endif

# ifdef HAVE_WORKING_FORK
	/* make sure the FDs are initialised */
	pipe_fds[0] = -1;
	pipe_fds[1] = -1;
	do {					/* 'loop' once */
		if (!HAVE_OPT( WAIT_SYNC ))
			break;
		wait_sync = OPT_VALUE_WAIT_SYNC;
		if (wait_sync <= 0) {
			wait_sync = 0;
			break;
		}
		/* -w requires a fork() even with debug > 0 */
		nofork = FALSE;
		if (pipe(pipe_fds)) {
			exit_code = (errno) ? errno : -1;
			msyslog(LOG_ERR,
				"Pipe creation failed for --wait-sync: %m");
			exit(exit_code);
		}
		waitsync_fd_to_close = pipe_fds[1];
	} while (0);				/* 'loop' once */
# endif	/* HAVE_WORKING_FORK */

	init_lib();
# ifdef SYS_WINNT
	/*
	 * Start interpolation thread, must occur before first
	 * get_systime()
	 */
	init_winnt_time();
# endif
	/*
	 * Initialize random generator and public key pair
	 */
	get_systime(&now);

	ntp_srandom((int)(now.l_i * now.l_uf));

	/*
	 * Detach us from the terminal.  May need an #ifndef GIZMO.
	 */
	if (!nofork) {

# ifdef HAVE_WORKING_FORK
		rc = fork();
		if (-1 == rc) {
			exit_code = (errno) ? errno : -1;
			msyslog(LOG_ERR, "fork: %m");
			exit(exit_code);
		}
		if (rc > 0) {	
			/* parent */
			exit_code = wait_child_sync_if(pipe_fds[0],
						       wait_sync);
			exit(exit_code);
		}
		
		/*
		 * child/daemon 
		 * close all open files excepting waitsync_fd_to_close.
		 * msyslog() unreliable until after init_logging().
		 */
		closelog();
		if (syslog_file != NULL) {
			fclose(syslog_file);
			syslog_file = NULL;
			syslogit = TRUE;
		}
		close_all_except(waitsync_fd_to_close);
		INSIST(0 == open("/dev/null", 0) && 1 == dup2(0, 1) \
			&& 2 == dup2(0, 2));

		init_logging(progname, 0, TRUE);
		/* we lost our logfile (if any) daemonizing */
		setup_logfile(logfilename);

#  ifdef SYS_DOMAINOS
		{
			uid_$t puid;
			status_$t st;

			proc2_$who_am_i(&puid);
			proc2_$make_server(&puid, &st);
		}
#  endif	/* SYS_DOMAINOS */
#  ifdef HAVE_SETSID
		if (setsid() == (pid_t)-1)
			msyslog(LOG_ERR, "setsid(): %m");
#  elif defined(HAVE_SETPGID)
		if (setpgid(0, 0) == -1)
			msyslog(LOG_ERR, "setpgid(): %m");
#  else		/* !HAVE_SETSID && !HAVE_SETPGID follows */
#   ifdef TIOCNOTTY
		fid = open("/dev/tty", 2);
		if (fid >= 0) {
			ioctl(fid, (u_long)TIOCNOTTY, NULL);
			close(fid);
		}
#   endif	/* TIOCNOTTY */
		ntp_setpgrp(0, getpid());
#  endif	/* !HAVE_SETSID && !HAVE_SETPGID */
#  ifdef _AIX
		/* Don't get killed by low-on-memory signal. */
		sa.sa_handler = catch_danger;
		sigemptyset(&sa.sa_mask);
		sa.sa_flags = SA_RESTART;
		sigaction(SIGDANGER, &sa, NULL);
#  endif	/* _AIX */
# endif		/* HAVE_WORKING_FORK */
	}

# ifdef SCO5_CLOCK
	/*
	 * SCO OpenServer's system clock offers much more precise timekeeping
	 * on the base CPU than the other CPUs (for multiprocessor systems),
	 * so we must lock to the base CPU.
	 */
	fd = open("/dev/at1", O_RDONLY);		
	if (fd >= 0) {
		zero = 0;
		if (ioctl(fd, ACPU_LOCK, &zero) < 0)
			msyslog(LOG_ERR, "cannot lock to base CPU: %m");
		close(fd);
	}
# endif

	/* Setup stack size in preparation for locking pages in memory. */
# if defined(HAVE_MLOCKALL)
#  ifdef HAVE_SETRLIMIT
	ntp_rlimit(RLIMIT_STACK, DFLT_RLIMIT_STACK * 4096, 4096, "4k");
#   ifdef RLIMIT_MEMLOCK
	/*
	 * The default RLIMIT_MEMLOCK is very low on Linux systems.
	 * Unless we increase this limit malloc calls are likely to
	 * fail if we drop root privilege.  To be useful the value
	 * has to be larger than the largest ntpd resident set size.
	 */
	ntp_rlimit(RLIMIT_MEMLOCK, DFLT_RLIMIT_MEMLOCK * 1024 * 1024, 1024 * 1024, "MB");
#   endif	/* RLIMIT_MEMLOCK */
#  endif	/* HAVE_SETRLIMIT */
# else	/* !HAVE_MLOCKALL follows */
#  ifdef HAVE_PLOCK
#   ifdef PROCLOCK
#    ifdef _AIX
	/*
	 * set the stack limit for AIX for plock().
	 * see get_aix_stack() for more info.
	 */
	if (ulimit(SET_STACKLIM, (get_aix_stack() - 8 * 4096)) < 0)
		msyslog(LOG_ERR,
			"Cannot adjust stack limit for plock: %m");
#    endif	/* _AIX */
#   endif	/* PROCLOCK */
#  endif	/* HAVE_PLOCK */
# endif	/* !HAVE_MLOCKALL */

	/*
	 * Set up signals we pay attention to locally.
	 */
# ifdef SIGDIE1
	signal_no_reset(SIGDIE1, finish);
	signal_no_reset(SIGDIE2, finish);
	signal_no_reset(SIGDIE3, finish);
	signal_no_reset(SIGDIE4, finish);
# endif
# ifdef SIGBUS
	signal_no_reset(SIGBUS, finish);
# endif

# if !defined(SYS_WINNT) && !defined(VMS)
#  ifdef DEBUG
	(void) signal_no_reset(MOREDEBUGSIG, moredebug);
	(void) signal_no_reset(LESSDEBUGSIG, lessdebug);
#  else
	(void) signal_no_reset(MOREDEBUGSIG, no_debug);
	(void) signal_no_reset(LESSDEBUGSIG, no_debug);
#  endif	/* DEBUG */
# endif	/* !SYS_WINNT && !VMS */

	/*
	 * Set up signals we should never pay attention to.
	 */
# ifdef SIGPIPE
	signal_no_reset(SIGPIPE, SIG_IGN);
# endif

	/*
	 * Call the init_ routines to initialize the data structures.
	 *
	 * Exactly what command-line options are we expecting here?
	 */
	INIT_SSL();
	init_auth();
	init_util();
	init_restrict();
	init_mon();
	init_timer();
	init_request();
	init_control();
	init_peer();
# ifdef REFCLOCK
	init_refclock();
# endif
	set_process_priority();
	init_proto();		/* Call at high priority */
	init_io();
	init_loopfilter();
	mon_start(MON_ON);	/* monitor on by default now	  */
				/* turn off in config if unwanted */

	/*
	 * Get the configuration.  This is done in a separate module
	 * since this will definitely be different for the gizmo board.
	 */
	getconfig(argc, argv);

	if (-1 == cur_memlock) {
# if defined(HAVE_MLOCKALL)
		/*
		 * lock the process into memory
		 */
		if (   !HAVE_OPT(SAVECONFIGQUIT)
#  ifdef RLIMIT_MEMLOCK
		    && -1 != DFLT_RLIMIT_MEMLOCK
#  endif
		    && 0 != mlockall(MCL_CURRENT|MCL_FUTURE))
			msyslog(LOG_ERR, "mlockall(): %m");
# else	/* !HAVE_MLOCKALL follows */
#  ifdef HAVE_PLOCK
#   ifdef PROCLOCK
		/*
		 * lock the process into memory
		 */
		if (!HAVE_OPT(SAVECONFIGQUIT) && 0 != plock(PROCLOCK))
			msyslog(LOG_ERR, "plock(PROCLOCK): %m");
#   else	/* !PROCLOCK follows  */
#    ifdef TXTLOCK
		/*
		 * Lock text into ram
		 */
		if (!HAVE_OPT(SAVECONFIGQUIT) && 0 != plock(TXTLOCK))
			msyslog(LOG_ERR, "plock(TXTLOCK) error: %m");
#    else	/* !TXTLOCK follows */
		msyslog(LOG_ERR, "plock() - don't know what to lock!");
#    endif	/* !TXTLOCK */
#   endif	/* !PROCLOCK */
#  endif	/* HAVE_PLOCK */
# endif	/* !HAVE_MLOCKALL */
	}

	loop_config(LOOP_DRIFTINIT, 0);
	report_event(EVNT_SYSRESTART, NULL, NULL);
	initializing = FALSE;

# ifdef HAVE_DROPROOT
	if (droproot) {
		/* Drop super-user privileges and chroot now if the OS supports this */

#  ifdef HAVE_LINUX_CAPABILITIES
		/* set flag: keep privileges accross setuid() call (we only really need cap_sys_time): */
		if (prctl( PR_SET_KEEPCAPS, 1L, 0L, 0L, 0L ) == -1) {
			msyslog( LOG_ERR, "prctl( PR_SET_KEEPCAPS, 1L ) failed: %m" );
			exit(-1);
		}
#  elif HAVE_SOLARIS_PRIVS
		/* Nothing to do here */
#  else
		/* we need a user to switch to */
		if (user == NULL) {
			msyslog(LOG_ERR, "Need user name to drop root privileges (see -u flag!)" );
			exit(-1);
		}
#  endif	/* HAVE_LINUX_CAPABILITIES || HAVE_SOLARIS_PRIVS */

		if (user != NULL) {
			if (isdigit((unsigned char)*user)) {
				sw_uid = (uid_t)strtoul(user, &endp, 0);
				if (*endp != '\0')
					goto getuser;

				if ((pw = getpwuid(sw_uid)) != NULL) {
					free(user);
					user = estrdup(pw->pw_name);
					sw_gid = pw->pw_gid;
				} else {
					errno = 0;
					msyslog(LOG_ERR, "Cannot find user ID %s", user);
					exit (-1);
				}

			} else {
getuser:
				errno = 0;
				if ((pw = getpwnam(user)) != NULL) {
					sw_uid = pw->pw_uid;
					sw_gid = pw->pw_gid;
				} else {
					if (errno)
						msyslog(LOG_ERR, "getpwnam(%s) failed: %m", user);
					else
						msyslog(LOG_ERR, "Cannot find user `%s'", user);
					exit (-1);
				}
			}
		}
		if (group != NULL) {
			if (isdigit((unsigned char)*group)) {
				sw_gid = (gid_t)strtoul(group, &endp, 0);
				if (*endp != '\0')
					goto getgroup;
			} else {
getgroup:
				if ((gr = getgrnam(group)) != NULL) {
					sw_gid = gr->gr_gid;
				} else {
					errno = 0;
					msyslog(LOG_ERR, "Cannot find group `%s'", group);
					exit (-1);
				}
			}
		}

		if (chrootdir ) {
			/* make sure cwd is inside the jail: */
			if (chdir(chrootdir)) {
				msyslog(LOG_ERR, "Cannot chdir() to `%s': %m", chrootdir);
				exit (-1);
			}
			if (chroot(chrootdir)) {
				msyslog(LOG_ERR, "Cannot chroot() to `%s': %m", chrootdir);
				exit (-1);
			}
			if (chdir("/")) {
				msyslog(LOG_ERR, "Cannot chdir() to`root after chroot(): %m");
				exit (-1);
			}
		}
#  ifdef HAVE_SOLARIS_PRIVS
		if ((lowprivs = priv_str_to_set(LOWPRIVS, ",", NULL)) == NULL) {
			msyslog(LOG_ERR, "priv_str_to_set() failed:%m");
			exit(-1);
		}
		if ((highprivs = priv_allocset()) == NULL) {
			msyslog(LOG_ERR, "priv_allocset() failed:%m");
			exit(-1);
		}
		(void) getppriv(PRIV_PERMITTED, highprivs);
		(void) priv_intersect(highprivs, lowprivs);
		if (setppriv(PRIV_SET, PRIV_PERMITTED, lowprivs) == -1) {
			msyslog(LOG_ERR, "setppriv() failed:%m");
			exit(-1);
		}
#  endif /* HAVE_SOLARIS_PRIVS */
		if (user && initgroups(user, sw_gid)) {
			msyslog(LOG_ERR, "Cannot initgroups() to user `%s': %m", user);
			exit (-1);
		}
		if (group && setgid(sw_gid)) {
			msyslog(LOG_ERR, "Cannot setgid() to group `%s': %m", group);
			exit (-1);
		}
		if (group && setegid(sw_gid)) {
			msyslog(LOG_ERR, "Cannot setegid() to group `%s': %m", group);
			exit (-1);
		}
		if (group) {
			if (0 != setgroups(1, &sw_gid)) {
				msyslog(LOG_ERR, "setgroups(1, %d) failed: %m", sw_gid);
				exit (-1);
			}
		}
		else if (pw)
			if (0 != initgroups(pw->pw_name, pw->pw_gid)) {
				msyslog(LOG_ERR, "initgroups(<%s>, %d) filed: %m", pw->pw_name, pw->pw_gid);
				exit (-1);
			}
		if (user && setuid(sw_uid)) {
			msyslog(LOG_ERR, "Cannot setuid() to user `%s': %m", user);
			exit (-1);
		}
		if (user && seteuid(sw_uid)) {
			msyslog(LOG_ERR, "Cannot seteuid() to user `%s': %m", user);
			exit (-1);
		}

#  if !defined(HAVE_LINUX_CAPABILITIES) && !defined(HAVE_SOLARIS_PRIVS)
		/*
		 * for now assume that the privilege to bind to privileged ports
		 * is associated with running with uid 0 - should be refined on
		 * ports that allow binding to NTP_PORT with uid != 0
		 */
		disable_dynamic_updates |= (sw_uid != 0);  /* also notifies routing message listener */
#  endif /* !HAVE_LINUX_CAPABILITIES && !HAVE_SOLARIS_PRIVS */

		if (disable_dynamic_updates && interface_interval) {
			interface_interval = 0;
			msyslog(LOG_INFO, "running as non-root disables dynamic interface tracking");
		}

#  ifdef HAVE_LINUX_CAPABILITIES
		{
			/*
			 *  We may be running under non-root uid now, but we still hold full root privileges!
			 *  We drop all of them, except for the crucial one or two: cap_sys_time and
			 *  cap_net_bind_service if doing dynamic interface tracking.
			 */
			cap_t caps;
			char *captext;
			
			captext = (0 != interface_interval)
				      ? "cap_sys_time,cap_net_bind_service=pe"
				      : "cap_sys_time=pe";
			caps = cap_from_text(captext);
			if (!caps) {
				msyslog(LOG_ERR,
					"cap_from_text(%s) failed: %m",
					captext);
				exit(-1);
			}
			if (-1 == cap_set_proc(caps)) {
				msyslog(LOG_ERR,
					"cap_set_proc() failed to drop root privs: %m");
				exit(-1);
			}
			cap_free(caps);
		}
#  endif	/* HAVE_LINUX_CAPABILITIES */
#  ifdef HAVE_SOLARIS_PRIVS
		if (priv_delset(lowprivs, "proc_setid") == -1) {
			msyslog(LOG_ERR, "priv_delset() failed:%m");
			exit(-1);
		}
		if (setppriv(PRIV_SET, PRIV_PERMITTED, lowprivs) == -1) {
			msyslog(LOG_ERR, "setppriv() failed:%m");
			exit(-1);
		}
		priv_freeset(lowprivs);
		priv_freeset(highprivs);
#  endif /* HAVE_SOLARIS_PRIVS */
		root_dropped = TRUE;
		fork_deferred_worker();
	}	/* if (droproot) */
# endif	/* HAVE_DROPROOT */

/* libssecomp sandboxing */
#if defined (LIBSECCOMP) && (KERN_SECCOMP)
	scmp_filter_ctx ctx;

	if ((ctx = seccomp_init(SCMP_ACT_KILL)) < 0)
		msyslog(LOG_ERR, "%s: seccomp_init(SCMP_ACT_KILL) failed: %m", __func__);
	else {
		msyslog(LOG_DEBUG, "%s: seccomp_init(SCMP_ACT_KILL) succeeded", __func__);
	}

#ifdef __x86_64__
int scmp_sc[] = {
	SCMP_SYS(adjtimex),
	SCMP_SYS(bind),
	SCMP_SYS(brk),
	SCMP_SYS(chdir),
	SCMP_SYS(clock_gettime),
	SCMP_SYS(clock_settime),
	SCMP_SYS(close),
	SCMP_SYS(connect),
	SCMP_SYS(exit_group),
	SCMP_SYS(fstat),
	SCMP_SYS(fsync),
	SCMP_SYS(futex),
	SCMP_SYS(getitimer),
	SCMP_SYS(getsockname),
	SCMP_SYS(ioctl),
	SCMP_SYS(lseek),
	SCMP_SYS(madvise),
	SCMP_SYS(mmap),
	SCMP_SYS(munmap),
	SCMP_SYS(open),
	SCMP_SYS(poll),
	SCMP_SYS(read),
	SCMP_SYS(recvmsg),
	SCMP_SYS(rename),
	SCMP_SYS(rt_sigaction),
	SCMP_SYS(rt_sigprocmask),
	SCMP_SYS(rt_sigreturn),
	SCMP_SYS(select),
	SCMP_SYS(sendto),
	SCMP_SYS(setitimer),
	SCMP_SYS(setsid),
	SCMP_SYS(socket),
	SCMP_SYS(stat),
	SCMP_SYS(time),
	SCMP_SYS(write),
};
#endif
#ifdef __i386__
int scmp_sc[] = {
	SCMP_SYS(_newselect),
	SCMP_SYS(adjtimex),
	SCMP_SYS(brk),
	SCMP_SYS(chdir),
	SCMP_SYS(clock_gettime),
	SCMP_SYS(clock_settime),
	SCMP_SYS(close),
	SCMP_SYS(exit_group),
	SCMP_SYS(fsync),
	SCMP_SYS(futex),
	SCMP_SYS(getitimer),
	SCMP_SYS(madvise),
	SCMP_SYS(mmap),
	SCMP_SYS(mmap2),
	SCMP_SYS(munmap),
	SCMP_SYS(open),
	SCMP_SYS(poll),
	SCMP_SYS(read),
	SCMP_SYS(rename),
	SCMP_SYS(rt_sigaction),
	SCMP_SYS(rt_sigprocmask),
	SCMP_SYS(select),
	SCMP_SYS(setitimer),
	SCMP_SYS(setsid),
	SCMP_SYS(sigprocmask),
	SCMP_SYS(sigreturn),
	SCMP_SYS(socketcall),
	SCMP_SYS(stat64),
	SCMP_SYS(time),
	SCMP_SYS(write),
};
#endif
	{
		int i;

		for (i = 0; i < COUNTOF(scmp_sc); i++) {
			if (seccomp_rule_add(ctx,
			    SCMP_ACT_ALLOW, scmp_sc[i], 0) < 0) {
				msyslog(LOG_ERR,
				    "%s: seccomp_rule_add() failed: %m",
				    __func__);
			}
		}
	}

	if (seccomp_load(ctx) < 0)
		msyslog(LOG_ERR, "%s: seccomp_load() failed: %m",
		    __func__);	
	else {
		msyslog(LOG_DEBUG, "%s: seccomp_load() succeeded", __func__);
	}
#endif /* LIBSECCOMP and KERN_SECCOMP */

# ifdef HAVE_IO_COMPLETION_PORT

	for (;;) {
		GetReceivedBuffers();
# else /* normal I/O */

	BLOCK_IO_AND_ALARM();
	was_alarmed = FALSE;

	for (;;) {
		if (alarm_flag) {	/* alarmed? */
			was_alarmed = TRUE;
			alarm_flag = FALSE;
		}

		if (!was_alarmed && !has_full_recv_buffer()) {
			/*
			 * Nothing to do.  Wait for something.
			 */
			io_handler();
		}

		if (alarm_flag) {	/* alarmed? */
			was_alarmed = TRUE;
			alarm_flag = FALSE;
		}

		if (was_alarmed) {
			UNBLOCK_IO_AND_ALARM();
			/*
			 * Out here, signals are unblocked.  Call timer routine
			 * to process expiry.
			 */
			timer();
			was_alarmed = FALSE;
			BLOCK_IO_AND_ALARM();
		}

# endif		/* !HAVE_IO_COMPLETION_PORT */

# ifdef DEBUG_TIMING
		{
			l_fp pts;
			l_fp tsa, tsb;
			int bufcount = 0;

			get_systime(&pts);
			tsa = pts;
# endif
			rbuf = get_full_recv_buffer();
			while (rbuf != NULL) {
				if (alarm_flag) {
					was_alarmed = TRUE;
					alarm_flag = FALSE;
				}
				UNBLOCK_IO_AND_ALARM();

				if (was_alarmed) {
					/* avoid timer starvation during lengthy I/O handling */
					timer();
					was_alarmed = FALSE;
				}

				/*
				 * Call the data procedure to handle each received
				 * packet.
				 */
				if (rbuf->receiver != NULL) {
# ifdef DEBUG_TIMING
					l_fp dts = pts;

					L_SUB(&dts, &rbuf->recv_time);
					DPRINTF(2, ("processing timestamp delta %s (with prec. fuzz)\n", lfptoa(&dts, 9)));
					collect_timing(rbuf, "buffer processing delay", 1, &dts);
					bufcount++;
# endif
					(*rbuf->receiver)(rbuf);
				} else {
					msyslog(LOG_ERR, "fatal: receive buffer callback NULL");
					abort();
				}

				BLOCK_IO_AND_ALARM();
				freerecvbuf(rbuf);
				rbuf = get_full_recv_buffer();
			}
# ifdef DEBUG_TIMING
			get_systime(&tsb);
			L_SUB(&tsb, &tsa);
			if (bufcount) {
				collect_timing(NULL, "processing", bufcount, &tsb);
				DPRINTF(2, ("processing time for %d buffers %s\n", bufcount, lfptoa(&tsb, 9)));
			}
		}
# endif

		/*
		 * Go around again
		 */

# ifdef HAVE_DNSREGISTRATION
		if (mdnsreg && (current_time - mdnsreg ) > 60 && mdnstries && sys_leap != LEAP_NOTINSYNC) {
			mdnsreg = current_time;
			msyslog(LOG_INFO, "Attempting to register mDNS");
			if ( DNSServiceRegister (&mdns, 0, 0, NULL, "_ntp._udp", NULL, NULL, 
			    htons(NTP_PORT), 0, NULL, NULL, NULL) != kDNSServiceErr_NoError ) {
				if (!--mdnstries) {
					msyslog(LOG_ERR, "Unable to register mDNS, giving up.");
				} else {	
					msyslog(LOG_INFO, "Unable to register mDNS, will try later.");
				}
			} else {
				msyslog(LOG_INFO, "mDNS service registered.");
				mdnsreg = FALSE;
			}
		}
# endif /* HAVE_DNSREGISTRATION */

	}
	UNBLOCK_IO_AND_ALARM();
	return 1;
}
#endif	/* !SIM */


#if !defined(SIM) && defined(SIGDIE1)
/*
 * finish - exit gracefully
 */
static RETSIGTYPE
finish(
	int sig
	)
{
	const char *sig_desc;

	sig_desc = NULL;
#ifdef HAVE_STRSIGNAL
	sig_desc = strsignal(sig);
#endif
	if (sig_desc == NULL)
		sig_desc = "";
	msyslog(LOG_NOTICE, "%s exiting on signal %d (%s)", progname,
		sig, sig_desc);
	/* See Bug 2513 and Bug 2522 re the unlink of PIDFILE */
# ifdef HAVE_DNSREGISTRATION
	if (mdns != NULL)
		DNSServiceRefDeallocate(mdns);
# endif
	peer_cleanup();
	exit(0);
}
#endif	/* !SIM && SIGDIE1 */


#ifndef SIM
/*
 * wait_child_sync_if - implements parent side of -w/--wait-sync
 */
# ifdef HAVE_WORKING_FORK
static int
wait_child_sync_if(
	int	pipe_read_fd,
	long	wait_sync
	)
{
	int	rc;
	int	exit_code;
	time_t	wait_end_time;
	time_t	cur_time;
	time_t	wait_rem;
	fd_set	readset;
	struct timeval wtimeout;

	if (0 == wait_sync) 
		return 0;

	/* waitsync_fd_to_close used solely by child */
	close(waitsync_fd_to_close);
	wait_end_time = time(NULL) + wait_sync;
	do {
		cur_time = time(NULL);
		wait_rem = (wait_end_time > cur_time)
				? (wait_end_time - cur_time)
				: 0;
		wtimeout.tv_sec = wait_rem;
		wtimeout.tv_usec = 0;
		FD_ZERO(&readset);
		FD_SET(pipe_read_fd, &readset);
		rc = select(pipe_read_fd + 1, &readset, NULL, NULL,
			    &wtimeout);
		if (-1 == rc) {
			if (EINTR == errno)
				continue;
			exit_code = (errno) ? errno : -1;
			msyslog(LOG_ERR,
				"--wait-sync select failed: %m");
			return exit_code;
		}
		if (0 == rc) {
			/*
			 * select() indicated a timeout, but in case
			 * its timeouts are affected by a step of the
			 * system clock, select() again with a zero 
			 * timeout to confirm.
			 */
			FD_ZERO(&readset);
			FD_SET(pipe_read_fd, &readset);
			wtimeout.tv_sec = 0;
			wtimeout.tv_usec = 0;
			rc = select(pipe_read_fd + 1, &readset, NULL,
				    NULL, &wtimeout);
			if (0 == rc)	/* select() timeout */
				break;
			else		/* readable */
				return 0;
		} else			/* readable */
			return 0;
	} while (wait_rem > 0);

	fprintf(stderr, "%s: -w/--wait-sync %ld timed out.\n",
		progname, wait_sync);
	return ETIMEDOUT;
}
Exemplo n.º 2
0
int ntpsim(int argc, char *argv[])
{
    Event *curr_event;
    struct timeval seed;

    /* Initialize the local Clock 
     */
    simclock.local_time = 0;
    simclock.adj = 0;
    simclock.slew = 0;

    /* Initialize the simulation 
     */
    simulation.num_of_servers = 0;
    simulation.beep_delay = BEEP_DLY;
    simulation.sim_time = 0;
    simulation.end_time = SIM_TIME;

    /*
     * Initialize ntp variables
     */
    initializing = 1;
    init_auth();
    init_util();
    init_restrict();
    init_mon();
    init_timer();
    init_lib();
    init_request();
    init_control();
    init_peer();
    init_proto();
    init_io();
    init_loopfilter();
    mon_start(MON_OFF);    

    /* Call getconfig to parse the configuration file */
    getconfig(argc, argv);
    initializing = 0;
    loop_config(LOOP_DRIFTCOMP, old_drift / 1e6);

    /*
     * Watch out here, we want the real time, not the silly stuff.
     */
    gettimeofday(&seed, NULL);
    ntp_srandom(seed.tv_usec);


    /* Initialize the event queue */
    event_queue = create_priority_queue((int(*)(void *, void*)) 
					determine_event_ordering);

    /* Initialize the receive queue */
    recv_queue = create_priority_queue((int(*)(void *, void*))
				       determine_recv_buf_ordering);

    /* Push a beep and a timer on the event queue */
    enqueue(event_queue, event(0, BEEP));
    enqueue(event_queue, event(simulation.sim_time + 1.0, TIMER));
    /* 
     * Pop the queue until nothing is left or time is exceeded
     */
    /* maxtime = simulation.sim_time + simulation.end_time;*/
    while (simulation.sim_time <= simulation.end_time &&
	   (!empty(event_queue))) {
	curr_event = dequeue(event_queue);
	/* Update all the clocks to the time on the event */
	sim_update_clocks(curr_event);

	/* Execute the function associated with the event */
	event_ptr[curr_event->function](curr_event);
	free_node(curr_event);
    }
    return (0);
}
Exemplo n.º 3
0
/*
 * Main program.  Initialize us, disconnect us from the tty if necessary,
 * and loop waiting for I/O and/or timer expiries.
 */
int
ntpdmain(
	int argc,
	char *argv[]
	)
{
	l_fp now;
	struct recvbuf *rbuf;
#ifdef _AIX			/* HMS: ifdef SIGDANGER? */
	struct sigaction sa;
#endif

	progname = argv[0];
	initializing = 1;		/* mark that we are initializing */
	process_commandline_opts(&argc, &argv);
	init_logging(progname, 1);	/* Open the log file */

	char *error = NULL;
	if (sandbox_init("ntpd", SANDBOX_NAMED, &error) == -1) {
		msyslog(LOG_ERR, "sandbox_init(ntpd, SANDBOX_NAMED) failed: %s", error);
		sandbox_free_error(error);
	}
#ifdef HAVE_UMASK
	{
		mode_t uv;

		uv = umask(0);
		if(uv)
			(void) umask(uv);
		else
			(void) umask(022);
	}
#endif

#if defined(HAVE_GETUID) && !defined(MPE) /* MPE lacks the concept of root */
	{
		uid_t uid;

		uid = getuid();
		if (uid && !HAVE_OPT( SAVECONFIGQUIT )) {
			msyslog(LOG_ERR, "ntpd: must be run as root, not uid %ld", (long)uid);
			printf("must be run as root, not uid %ld\n", (long)uid);
			exit(1);
		}
	}
#endif

	/* getstartup(argc, argv); / * startup configuration, may set debug */

#ifdef DEBUG
	debug = DESC(DEBUG_LEVEL).optOccCt;
	DPRINTF(1, ("%s\n", Version));
#endif

	/* honor -l/--logfile option to log to a file */
	setup_logfile();

/*
 * Enable the Multi-Media Timer for Windows?
 */
#ifdef SYS_WINNT
	if (HAVE_OPT( MODIFYMMTIMER ))
		set_mm_timer(MM_TIMER_HIRES);
#endif

	if (HAVE_OPT( NOFORK ) || HAVE_OPT( QUIT )
#ifdef DEBUG
	    || debug
#endif
	    || HAVE_OPT( SAVECONFIGQUIT ))
		nofork = 1;

	if (HAVE_OPT( NOVIRTUALIPS ))
		listen_to_virtual_ips = 0;

	/*
	 * --interface, listen on specified interfaces
	 */
	if (HAVE_OPT( INTERFACE )) {
		int	ifacect = STACKCT_OPT( INTERFACE );
		const char**	ifaces  = STACKLST_OPT( INTERFACE );
		isc_netaddr_t	netaddr;

		while (ifacect-- > 0) {
			add_nic_rule(
				is_ip_address(*ifaces, &netaddr)
					? MATCH_IFADDR
					: MATCH_IFNAME,
				*ifaces, -1, ACTION_LISTEN);
			ifaces++;
		}
	}

	if (HAVE_OPT( NICE ))
		priority_done = 0;

#if defined(HAVE_SCHED_SETSCHEDULER)
	if (HAVE_OPT( PRIORITY )) {
		config_priority = OPT_VALUE_PRIORITY;
		config_priority_override = 1;
		priority_done = 0;
	}
#endif

#ifdef SYS_WINNT
	/*
	 * Start interpolation thread, must occur before first
	 * get_systime()
	 */
	init_winnt_time();
#endif
	/*
	 * Initialize random generator and public key pair
	 */
	get_systime(&now);

	ntp_srandom((int)(now.l_i * now.l_uf));

#if !defined(VMS)
# ifndef NODETACH
	/*
	 * Detach us from the terminal.  May need an #ifndef GIZMO.
	 */
	if (!nofork) {

		/*
		 * Install trap handlers to log errors and assertion
		 * failures.  Default handlers print to stderr which 
		 * doesn't work if detached.
		 */
		isc_assertion_setcallback(assertion_failed);
		isc_error_setfatal(library_fatal_error);
		isc_error_setunexpected(library_unexpected_error);

#  ifndef SYS_WINNT
#   ifdef HAVE_DAEMON
		daemon(0, 0);
#   else /* not HAVE_DAEMON */
		if (fork())	/* HMS: What about a -1? */
			exit(0);

		{
#if !defined(F_CLOSEM)
			u_long s;
			int max_fd;
#endif /* !FCLOSEM */
			if (syslog_file != NULL) {
				fclose(syslog_file);
				syslog_file = NULL;
			}
#if defined(F_CLOSEM)
			/*
			 * From 'Writing Reliable AIX Daemons,' SG24-4946-00,
			 * by Eric Agar (saves us from doing 32767 system
			 * calls)
			 */
			if (fcntl(0, F_CLOSEM, 0) == -1)
			    msyslog(LOG_ERR, "ntpd: failed to close open files(): %m");
#else  /* not F_CLOSEM */

# if defined(HAVE_SYSCONF) && defined(_SC_OPEN_MAX)
			max_fd = sysconf(_SC_OPEN_MAX);
# else /* HAVE_SYSCONF && _SC_OPEN_MAX */
			max_fd = getdtablesize();
# endif /* HAVE_SYSCONF && _SC_OPEN_MAX */
			for (s = 0; s < max_fd; s++)
				(void) close((int)s);
#endif /* not F_CLOSEM */
			(void) open("/", 0);
			(void) dup2(0, 1);
			(void) dup2(0, 2);

			init_logging(progname, 0);
			/* we lost our logfile (if any) daemonizing */
			setup_logfile();

#ifdef SYS_DOMAINOS
			{
				uid_$t puid;
				status_$t st;

				proc2_$who_am_i(&puid);
				proc2_$make_server(&puid, &st);
			}
#endif /* SYS_DOMAINOS */
#if defined(HAVE_SETPGID) || defined(HAVE_SETSID)
# ifdef HAVE_SETSID
			if (setsid() == (pid_t)-1)
				msyslog(LOG_ERR, "ntpd: setsid(): %m");
# else
			if (setpgid(0, 0) == -1)
				msyslog(LOG_ERR, "ntpd: setpgid(): %m");
# endif
#else /* HAVE_SETPGID || HAVE_SETSID */
			{
# if defined(TIOCNOTTY)
				int fid;

				fid = open("/dev/tty", 2);
				if (fid >= 0)
				{
					(void) ioctl(fid, (u_long) TIOCNOTTY, (char *) 0);
					(void) close(fid);
				}
# endif /* defined(TIOCNOTTY) */
# ifdef HAVE_SETPGRP_0
				(void) setpgrp();
# else /* HAVE_SETPGRP_0 */
				(void) setpgrp(0, getpid());
# endif /* HAVE_SETPGRP_0 */
			}
#endif /* HAVE_SETPGID || HAVE_SETSID */
#ifdef _AIX
			/* Don't get killed by low-on-memory signal. */
			sa.sa_handler = catch_danger;
			sigemptyset(&sa.sa_mask);
			sa.sa_flags = SA_RESTART;

			(void) sigaction(SIGDANGER, &sa, NULL);
#endif /* _AIX */
		}
#   endif /* not HAVE_DAEMON */
#  endif /* SYS_WINNT */
	}
# endif /* NODETACH */
#endif /* VMS */

#ifdef SCO5_CLOCK
	/*
	 * SCO OpenServer's system clock offers much more precise timekeeping
	 * on the base CPU than the other CPUs (for multiprocessor systems),
	 * so we must lock to the base CPU.
	 */
	{
	    int fd = open("/dev/at1", O_RDONLY);
	    if (fd >= 0) {
		int zero = 0;
		if (ioctl(fd, ACPU_LOCK, &zero) < 0)
		    msyslog(LOG_ERR, "cannot lock to base CPU: %m");
		close( fd );
	    } /* else ...
	       *   If we can't open the device, this probably just isn't
	       *   a multiprocessor system, so we're A-OK.
	       */
	}
#endif

#if defined(HAVE_MLOCKALL) && defined(MCL_CURRENT) && defined(MCL_FUTURE)
# ifdef HAVE_SETRLIMIT
	/*
	 * Set the stack limit to something smaller, so that we don't lock a lot
	 * of unused stack memory.
	 */
	{
	    struct rlimit rl;

	    /* HMS: must make the rlim_cur amount configurable */
	    if (getrlimit(RLIMIT_STACK, &rl) != -1
		&& (rl.rlim_cur = 50 * 4096) < rl.rlim_max)
	    {
		    if (setrlimit(RLIMIT_STACK, &rl) == -1)
		    {
			    msyslog(LOG_ERR,
				"Cannot adjust stack limit for mlockall: %m");
		    }
	    }
#  ifdef RLIMIT_MEMLOCK
	    /*
	     * The default RLIMIT_MEMLOCK is very low on Linux systems.
	     * Unless we increase this limit malloc calls are likely to
	     * fail if we drop root privlege.  To be useful the value
	     * has to be larger than the largest ntpd resident set size.
	     */
	    rl.rlim_cur = rl.rlim_max = 32*1024*1024;
	    if (setrlimit(RLIMIT_MEMLOCK, &rl) == -1) {
		msyslog(LOG_ERR, "Cannot set RLIMIT_MEMLOCK: %m");
	    }
#  endif /* RLIMIT_MEMLOCK */
	}
# endif /* HAVE_SETRLIMIT */
	/*
	 * lock the process into memory
	 */
	if (mlockall(MCL_CURRENT|MCL_FUTURE) < 0)
		msyslog(LOG_ERR, "mlockall(): %m");
#else /* not (HAVE_MLOCKALL && MCL_CURRENT && MCL_FUTURE) */
# ifdef HAVE_PLOCK
#  ifdef PROCLOCK
#   ifdef _AIX
	/*
	 * set the stack limit for AIX for plock().
	 * see get_aix_stack() for more info.
	 */
	if (ulimit(SET_STACKLIM, (get_aix_stack() - 8*4096)) < 0)
	{
		msyslog(LOG_ERR,"Cannot adjust stack limit for plock on AIX: %m");
	}
#   endif /* _AIX */
	/*
	 * lock the process into memory
	 */
	if (plock(PROCLOCK) < 0)
		msyslog(LOG_ERR, "plock(PROCLOCK): %m");
#  else /* not PROCLOCK */
#   ifdef TXTLOCK
	/*
	 * Lock text into ram
	 */
	if (plock(TXTLOCK) < 0)
		msyslog(LOG_ERR, "plock(TXTLOCK) error: %m");
#   else /* not TXTLOCK */
	msyslog(LOG_ERR, "plock() - don't know what to lock!");
#   endif /* not TXTLOCK */
#  endif /* not PROCLOCK */
# endif /* HAVE_PLOCK */
#endif /* not (HAVE_MLOCKALL && MCL_CURRENT && MCL_FUTURE) */

	/*
	 * Set up signals we pay attention to locally.
	 */
#ifdef SIGDIE1
	(void) signal_no_reset(SIGDIE1, finish);
#endif	/* SIGDIE1 */
#ifdef SIGDIE2
	(void) signal_no_reset(SIGDIE2, finish);
#endif	/* SIGDIE2 */
#ifdef SIGDIE3
	(void) signal_no_reset(SIGDIE3, finish);
#endif	/* SIGDIE3 */
#ifdef SIGDIE4
	(void) signal_no_reset(SIGDIE4, finish);
#endif	/* SIGDIE4 */

#ifdef SIGBUS
	(void) signal_no_reset(SIGBUS, finish);
#endif /* SIGBUS */

#if !defined(SYS_WINNT) && !defined(VMS)
# ifdef DEBUG
	(void) signal_no_reset(MOREDEBUGSIG, moredebug);
	(void) signal_no_reset(LESSDEBUGSIG, lessdebug);
# else
	(void) signal_no_reset(MOREDEBUGSIG, no_debug);
	(void) signal_no_reset(LESSDEBUGSIG, no_debug);
# endif /* DEBUG */
#endif /* !SYS_WINNT && !VMS */

	/*
	 * Set up signals we should never pay attention to.
	 */
#if defined SIGPIPE
	(void) signal_no_reset(SIGPIPE, SIG_IGN);
#endif	/* SIGPIPE */

	/*
	 * Call the init_ routines to initialize the data structures.
	 *
	 * Exactly what command-line options are we expecting here?
	 */
	init_auth();
	init_util();
	init_restrict();
	init_mon();
	init_timer();
	init_lib();
	init_request();
	init_control();
	init_peer();
#ifdef REFCLOCK
	init_refclock();
#endif
	set_process_priority();
	init_proto();		/* Call at high priority */
	init_io();
	init_loopfilter();
	mon_start(MON_ON);	/* monitor on by default now	  */
				/* turn off in config if unwanted */

	/*
	 * Get the configuration.  This is done in a separate module
	 * since this will definitely be different for the gizmo board.
	 */
	getconfig(argc, argv);
	NLOG(NLOG_SYSINFO) /* 'if' clause for syslog */
	msyslog(LOG_NOTICE, "%s", Version);
	report_event(EVNT_SYSRESTART, NULL, NULL);
	loop_config(LOOP_DRIFTCOMP, old_drift);
	initializing = 0;

#ifdef HAVE_DROPROOT
	if( droproot ) {
		/* Drop super-user privileges and chroot now if the OS supports this */

#ifdef HAVE_LINUX_CAPABILITIES
		/* set flag: keep privileges accross setuid() call (we only really need cap_sys_time): */
		if (prctl( PR_SET_KEEPCAPS, 1L, 0L, 0L, 0L ) == -1) {
			msyslog( LOG_ERR, "prctl( PR_SET_KEEPCAPS, 1L ) failed: %m" );
			exit(-1);
		}
#else
		/* we need a user to switch to */
		if (user == NULL) {
			msyslog(LOG_ERR, "Need user name to drop root privileges (see -u flag!)" );
			exit(-1);
		}
#endif /* HAVE_LINUX_CAPABILITIES */

		if (user != NULL) {
			if (isdigit((unsigned char)*user)) {
				sw_uid = (uid_t)strtoul(user, &endp, 0);
				if (*endp != '\0')
					goto getuser;

				if ((pw = getpwuid(sw_uid)) != NULL) {
					user = strdup(pw->pw_name);
					if (NULL == user) {
						msyslog(LOG_ERR, "strdup() failed: %m");
						exit (-1);
					}
					sw_gid = pw->pw_gid;
				} else {
					errno = 0;
					msyslog(LOG_ERR, "Cannot find user ID %s", user);
					exit (-1);
				}

			} else {
getuser:
				errno = 0;
				if ((pw = getpwnam(user)) != NULL) {
					sw_uid = pw->pw_uid;
					sw_gid = pw->pw_gid;
				} else {
					if (errno)
					    msyslog(LOG_ERR, "getpwnam(%s) failed: %m", user);
					else
					    msyslog(LOG_ERR, "Cannot find user `%s'", user);
					exit (-1);
				}
			}
		}
		if (group != NULL) {
			if (isdigit((unsigned char)*group)) {
				sw_gid = (gid_t)strtoul(group, &endp, 0);
				if (*endp != '\0')
					goto getgroup;
			} else {
getgroup:
				if ((gr = getgrnam(group)) != NULL) {
					sw_gid = gr->gr_gid;
				} else {
					errno = 0;
					msyslog(LOG_ERR, "Cannot find group `%s'", group);
					exit (-1);
				}
			}
		}

		if (chrootdir ) {
			/* make sure cwd is inside the jail: */
			if (chdir(chrootdir)) {
				msyslog(LOG_ERR, "Cannot chdir() to `%s': %m", chrootdir);
				exit (-1);
			}
			if (chroot(chrootdir)) {
				msyslog(LOG_ERR, "Cannot chroot() to `%s': %m", chrootdir);
				exit (-1);
			}
			if (chdir("/")) {
				msyslog(LOG_ERR, "Cannot chdir() to`root after chroot(): %m");
				exit (-1);
			}
		}
		if (user && initgroups(user, sw_gid)) {
			msyslog(LOG_ERR, "Cannot initgroups() to user `%s': %m", user);
			exit (-1);
		}
		if (group && setgid(sw_gid)) {
			msyslog(LOG_ERR, "Cannot setgid() to group `%s': %m", group);
			exit (-1);
		}
		if (group && setegid(sw_gid)) {
			msyslog(LOG_ERR, "Cannot setegid() to group `%s': %m", group);
			exit (-1);
		}
		if (user && setuid(sw_uid)) {
			msyslog(LOG_ERR, "Cannot setuid() to user `%s': %m", user);
			exit (-1);
		}
		if (user && seteuid(sw_uid)) {
			msyslog(LOG_ERR, "Cannot seteuid() to user `%s': %m", user);
			exit (-1);
		}

#ifndef HAVE_LINUX_CAPABILITIES
		/*
		 * for now assume that the privilege to bind to privileged ports
		 * is associated with running with uid 0 - should be refined on
		 * ports that allow binding to NTP_PORT with uid != 0
		 */
		disable_dynamic_updates |= (sw_uid != 0);  /* also notifies routing message listener */
#endif

		if (disable_dynamic_updates && interface_interval) {
			interface_interval = 0;
			msyslog(LOG_INFO, "running in unprivileged mode disables dynamic interface tracking");
		}

#ifdef HAVE_LINUX_CAPABILITIES
		do {
			/*
			 *  We may be running under non-root uid now, but we still hold full root privileges!
			 *  We drop all of them, except for the crucial one or two: cap_sys_time and
			 *  cap_net_bind_service if doing dynamic interface tracking.
			 */
			cap_t caps;
			char *captext = (interface_interval)
				? "cap_sys_time,cap_net_bind_service=ipe"
				: "cap_sys_time=ipe";
			if( ! ( caps = cap_from_text( captext ) ) ) {
				msyslog( LOG_ERR, "cap_from_text() failed: %m" );
				exit(-1);
			}
			if( cap_set_proc( caps ) == -1 ) {
				msyslog( LOG_ERR, "cap_set_proc() failed to drop root privileges: %m" );
				exit(-1);
			}
			cap_free( caps );
		} while(0);
#endif /* HAVE_LINUX_CAPABILITIES */

	}    /* if( droproot ) */
#endif /* HAVE_DROPROOT */

	/*
	 * Use select() on all on all input fd's for unlimited
	 * time.  select() will terminate on SIGALARM or on the
	 * reception of input.	Using select() means we can't do
	 * robust signal handling and we get a potential race
	 * between checking for alarms and doing the select().
	 * Mostly harmless, I think.
	 */
	/* On VMS, I suspect that select() can't be interrupted
	 * by a "signal" either, so I take the easy way out and
	 * have select() time out after one second.
	 * System clock updates really aren't time-critical,
	 * and - lacking a hardware reference clock - I have
	 * yet to learn about anything else that is.
	 */
#if defined(HAVE_IO_COMPLETION_PORT)

	for (;;) {
		GetReceivedBuffers();
#else /* normal I/O */

	BLOCK_IO_AND_ALARM();
	was_alarmed = 0;
	for (;;)
	{
# if !defined(HAVE_SIGNALED_IO)
		extern fd_set activefds;
		extern int maxactivefd;

		fd_set rdfdes;
		int nfound;
# endif

		if (alarm_flag)		/* alarmed? */
		{
			was_alarmed = 1;
			alarm_flag = 0;
		}

		if (!was_alarmed && has_full_recv_buffer() == ISC_FALSE)
		{
			/*
			 * Nothing to do.  Wait for something.
			 */
# ifndef HAVE_SIGNALED_IO
			rdfdes = activefds;
#  if defined(VMS) || defined(SYS_VXWORKS)
			/* make select() wake up after one second */
			{
				struct timeval t1;

				t1.tv_sec = 1; t1.tv_usec = 0;
				nfound = select(maxactivefd+1, &rdfdes, (fd_set *)0,
						(fd_set *)0, &t1);
			}
#  else
			nfound = select(maxactivefd+1, &rdfdes, (fd_set *)0,
					(fd_set *)0, (struct timeval *)0);
#  endif /* VMS */
			if (nfound > 0)
			{
				l_fp ts;

				get_systime(&ts);

				(void)input_handler(&ts);
			}
			else if (nfound == -1 && errno != EINTR)
				msyslog(LOG_ERR, "select() error: %m");
#  ifdef DEBUG
			else if (debug > 5)
				msyslog(LOG_DEBUG, "select(): nfound=%d, error: %m", nfound);
#  endif /* DEBUG */
# else /* HAVE_SIGNALED_IO */

			wait_for_signal();
# endif /* HAVE_SIGNALED_IO */
			if (alarm_flag)		/* alarmed? */
			{
				was_alarmed = 1;
				alarm_flag = 0;
			}
		}

		if (was_alarmed)
		{
			UNBLOCK_IO_AND_ALARM();
			/*
			 * Out here, signals are unblocked.  Call timer routine
			 * to process expiry.
			 */
			timer();
			was_alarmed = 0;
			BLOCK_IO_AND_ALARM();
		}

#endif /* ! HAVE_IO_COMPLETION_PORT */

#ifdef DEBUG_TIMING
		{
			l_fp pts;
			l_fp tsa, tsb;
			int bufcount = 0;

			get_systime(&pts);
			tsa = pts;
#endif
			rbuf = get_full_recv_buffer();
			while (rbuf != NULL)
			{
				if (alarm_flag)
				{
					was_alarmed = 1;
					alarm_flag = 0;
				}
				UNBLOCK_IO_AND_ALARM();

				if (was_alarmed)
				{	/* avoid timer starvation during lengthy I/O handling */
					timer();
					was_alarmed = 0;
				}

				/*
				 * Call the data procedure to handle each received
				 * packet.
				 */
				if (rbuf->receiver != NULL)	/* This should always be true */
				{
#ifdef DEBUG_TIMING
					l_fp dts = pts;

					L_SUB(&dts, &rbuf->recv_time);
					DPRINTF(2, ("processing timestamp delta %s (with prec. fuzz)\n", lfptoa(&dts, 9)));
					collect_timing(rbuf, "buffer processing delay", 1, &dts);
					bufcount++;
#endif
					(rbuf->receiver)(rbuf);
				} else {
					msyslog(LOG_ERR, "receive buffer corruption - receiver found to be NULL - ABORTING");
					abort();
				}

				BLOCK_IO_AND_ALARM();
				freerecvbuf(rbuf);
				rbuf = get_full_recv_buffer();
			}
#ifdef DEBUG_TIMING
			get_systime(&tsb);
			L_SUB(&tsb, &tsa);
			if (bufcount) {
				collect_timing(NULL, "processing", bufcount, &tsb);
				DPRINTF(2, ("processing time for %d buffers %s\n", bufcount, lfptoa(&tsb, 9)));
			}
		}
#endif

		/*
		 * Go around again
		 */

#ifdef HAVE_DNSREGISTRATION
		if (mdnsreg && (current_time - mdnsreg ) > 60 && mdnstries && sys_leap != LEAP_NOTINSYNC) {
			mdnsreg = current_time;
			msyslog(LOG_INFO, "Attemping to register mDNS");
			if ( DNSServiceRegister (&mdns, 0, 0, NULL, "_ntp._udp", NULL, NULL, 
			    htons(NTP_PORT), 0, NULL, NULL, NULL) != kDNSServiceErr_NoError ) {
				if (!--mdnstries) {
					msyslog(LOG_ERR, "Unable to register mDNS, giving up.");
				} else {	
					msyslog(LOG_INFO, "Unable to register mDNS, will try later.");
				}
			} else {
				msyslog(LOG_INFO, "mDNS service registered.");
				mdnsreg = 0;
			}
		}
#endif /* HAVE_DNSREGISTRATION */

	}
	UNBLOCK_IO_AND_ALARM();
	return 1;
}


#ifdef SIGDIE2
/*
 * finish - exit gracefully
 */
static RETSIGTYPE
finish(
	int sig
	)
{
	msyslog(LOG_NOTICE, "ntpd exiting on signal %d", sig);
#ifdef HAVE_DNSREGISTRATION
	if (mdns != NULL)
		DNSServiceRefDeallocate(mdns);
#endif
	switch (sig) {
# ifdef SIGBUS
	case SIGBUS:
		printf("\nfinish(SIGBUS)\n");
		exit(0);
# endif
	case 0:			/* Should never happen... */
		return;

	default:
		exit(0);
	}
}