xref: /freebsd-11-stable/contrib/ntp/ntpd/ntpd.c (revision d253d22565a6ac6a7a59fe0ecfb092f7023ed833)
1 /*
2  * ntpd.c - main program for the fixed point NTP daemon
3  */
4 
5 #ifdef HAVE_CONFIG_H
6 # include <config.h>
7 #endif
8 
9 #include "ntp_machine.h"
10 #include "ntpd.h"
11 #include "ntp_io.h"
12 #include "ntp_stdlib.h"
13 #include <ntp_random.h>
14 
15 #include "ntp_config.h"
16 #include "ntp_syslog.h"
17 #include "ntp_assert.h"
18 #include "isc/error.h"
19 #include "isc/strerror.h"
20 #include "isc/formatcheck.h"
21 #include "iosignal.h"
22 
23 #ifdef SIM
24 # include "ntpsim.h"
25 #endif
26 
27 #include "ntp_libopts.h"
28 #include "ntpd-opts.h"
29 
30 /* there's a short treatise below what the thread stuff is for.
31  * [Bug 2954] enable the threading warm-up only for Linux.
32  */
33 #if defined(HAVE_PTHREADS) && HAVE_PTHREADS && !defined(NO_THREADS)
34 # ifdef HAVE_PTHREAD_H
35 #  include <pthread.h>
36 # endif
37 # if defined(linux)
38 #  define NEED_PTHREAD_WARMUP
39 # endif
40 #endif
41 
42 #ifdef HAVE_UNISTD_H
43 # include <unistd.h>
44 #endif
45 #ifdef HAVE_SYS_STAT_H
46 # include <sys/stat.h>
47 #endif
48 #ifdef HAVE_SYS_WAIT_H
49 # include <sys/wait.h>
50 #endif
51 #include <stdio.h>
52 #ifdef HAVE_SYS_PARAM_H
53 # include <sys/param.h>
54 #endif
55 #ifdef HAVE_SYS_SIGNAL_H
56 # include <sys/signal.h>
57 #else
58 # include <signal.h>
59 #endif
60 #ifdef HAVE_SYS_IOCTL_H
61 # include <sys/ioctl.h>
62 #endif /* HAVE_SYS_IOCTL_H */
63 #if defined(HAVE_RTPRIO)
64 # ifdef HAVE_SYS_LOCK_H
65 #  include <sys/lock.h>
66 # endif
67 # include <sys/rtprio.h>
68 #else
69 # ifdef HAVE_PLOCK
70 #  ifdef HAVE_SYS_LOCK_H
71 #	include <sys/lock.h>
72 #  endif
73 # endif
74 #endif
75 #if defined(HAVE_SCHED_SETSCHEDULER)
76 # ifdef HAVE_SCHED_H
77 #  include <sched.h>
78 # else
79 #  ifdef HAVE_SYS_SCHED_H
80 #   include <sys/sched.h>
81 #  endif
82 # endif
83 #endif
84 #if defined(HAVE_SYS_MMAN_H)
85 # include <sys/mman.h>
86 #endif
87 
88 #ifdef HAVE_SYSEXITS_H
89 # include <sysexits.h>
90 #endif
91 
92 #ifdef HAVE_TERMIOS_H
93 # include <termios.h>
94 #endif
95 
96 #ifdef SYS_DOMAINOS
97 # include <apollo/base.h>
98 #endif /* SYS_DOMAINOS */
99 
100 
101 #include "recvbuff.h"
102 #include "ntp_cmdargs.h"
103 
104 #if 0				/* HMS: I don't think we need this. 961223 */
105 #ifdef LOCK_PROCESS
106 # ifdef SYS_SOLARIS
107 #  include <sys/mman.h>
108 # else
109 #  include <sys/lock.h>
110 # endif
111 #endif
112 #endif
113 
114 #ifdef SYS_WINNT
115 # include "ntservice.h"
116 #endif
117 
118 #ifdef _AIX
119 # include <ulimit.h>
120 #endif /* _AIX */
121 
122 #ifdef SCO5_CLOCK
123 # include <sys/ci/ciioctl.h>
124 #endif
125 
126 #ifdef HAVE_DROPROOT
127 # include <ctype.h>
128 # include <grp.h>
129 # include <pwd.h>
130 #ifdef HAVE_LINUX_CAPABILITIES
131 # include <sys/capability.h>
132 # include <sys/prctl.h>
133 #endif /* HAVE_LINUX_CAPABILITIES */
134 #if defined(HAVE_PRIV_H) && defined(HAVE_SOLARIS_PRIVS)
135 # include <priv.h>
136 #endif /* HAVE_PRIV_H */
137 #endif /* HAVE_DROPROOT */
138 
139 #if defined (LIBSECCOMP) && (KERN_SECCOMP)
140 /* # include <sys/types.h> */
141 # include <sys/resource.h>
142 # include <seccomp.h>
143 #endif /* LIBSECCOMP and KERN_SECCOMP */
144 
145 #ifdef HAVE_DNSREGISTRATION
146 # include <dns_sd.h>
147 DNSServiceRef mdns;
148 #endif
149 
150 /* In case 'sysexits.h' is unavailable, define some exit codes here: */
151 #ifndef EX_SOFTWARE
152 # define EX_SOFTWARE	70
153 #endif
154 #ifndef EX_OSERR
155 # define EX_OSERR	71
156 #endif
157 #ifndef EX_IOERR
158 # define EX_IOERR	74
159 #endif
160 #ifndef EX_PROTOCOL
161 #define EX_PROTOCOL	76
162 #endif
163 
164 
165 #ifdef HAVE_SETPGRP_0
166 # define ntp_setpgrp(x, y)	setpgrp()
167 #else
168 # define ntp_setpgrp(x, y)	setpgrp(x, y)
169 #endif
170 
171 #ifdef HAVE_SOLARIS_PRIVS
172 # define LOWPRIVS "basic,sys_time,net_privaddr,proc_setid,!proc_info,!proc_session,!proc_exec"
173 static priv_set_t *lowprivs = NULL;
174 static priv_set_t *highprivs = NULL;
175 #endif /* HAVE_SOLARIS_PRIVS */
176 /*
177  * Scheduling priority we run at
178  */
179 #define NTPD_PRIO	(-12)
180 
181 int priority_done = 2;		/* 0 - Set priority */
182 				/* 1 - priority is OK where it is */
183 				/* 2 - Don't set priority */
184 				/* 1 and 2 are pretty much the same */
185 
186 int listen_to_virtual_ips = TRUE;
187 
188 /*
189  * No-fork flag.  If set, we do not become a background daemon.
190  */
191 int nofork;			/* Fork by default */
192 
193 #ifdef HAVE_DNSREGISTRATION
194 /*
195  * mDNS registration flag. If set, we attempt to register with the mDNS system, but only
196  * after we have synched the first time. If the attempt fails, then try again once per
197  * minute for up to 5 times. After all, we may be starting before mDNS.
198  */
199 int mdnsreg = FALSE;
200 int mdnstries = 5;
201 #endif  /* HAVE_DNSREGISTRATION */
202 
203 #ifdef HAVE_LINUX_CAPABILITIES
204 int have_caps;		/* runtime check whether capabilities work */
205 #endif /* HAVE_LINUX_CAPABILITIES */
206 
207 #ifdef HAVE_DROPROOT
208 int droproot;
209 int root_dropped;
210 char *user;		/* User to switch to */
211 char *group;		/* group to switch to */
212 const char *chrootdir;	/* directory to chroot to */
213 uid_t sw_uid;
214 gid_t sw_gid;
215 struct group *gr;
216 struct passwd *pw;
217 #endif /* HAVE_DROPROOT */
218 
219 #ifdef HAVE_WORKING_FORK
220 int	daemon_pipe[2] = { -1, -1 };
221 #endif
222 
223 /*
224  * Version declaration
225  */
226 extern const char *Version;
227 
228 char const *progname;
229 
230 int was_alarmed;
231 
232 #ifdef DECL_SYSCALL
233 /*
234  * We put this here, since the argument profile is syscall-specific
235  */
236 extern int syscall	(int, ...);
237 #endif /* DECL_SYSCALL */
238 
239 
240 #if !defined(SIM) && defined(SIGDIE1)
241 static volatile int signalled	= 0;
242 static volatile int signo	= 0;
243 
244 /* In an ideal world, 'finish_safe()' would declared as noreturn... */
245 static	void		finish_safe	(int);
246 static	RETSIGTYPE	finish		(int);
247 #endif
248 
249 #if !defined(SIM) && defined(HAVE_WORKING_FORK)
250 static int	wait_child_sync_if	(int, unsigned long);
251 static int	wait_child_exit_if	(pid_t, int);
252 #endif
253 
254 #if !defined(SIM) && !defined(SYS_WINNT)
255 # ifdef	DEBUG
256 static	RETSIGTYPE	moredebug	(int);
257 static	RETSIGTYPE	lessdebug	(int);
258 # else	/* !DEBUG follows */
259 static	RETSIGTYPE	no_debug	(int);
260 # endif	/* !DEBUG */
261 #endif	/* !SIM && !SYS_WINNT */
262 
263 #ifndef WORK_FORK
264 int	saved_argc;
265 char **	saved_argv;
266 #endif
267 
268 #ifndef SIM
269 int		ntpdmain		(int, char **);
270 static void	set_process_priority	(void);
271 static void	assertion_failed	(const char *, int,
272 					 isc_assertiontype_t,
273 					 const char *)
274 			__attribute__	((__noreturn__));
275 static void	library_fatal_error	(const char *, int,
276 					 const char *, va_list)
277 					ISC_FORMAT_PRINTF(3, 0);
278 static void	library_unexpected_error(const char *, int,
279 					 const char *, va_list)
280 					ISC_FORMAT_PRINTF(3, 0);
281 #endif	/* !SIM */
282 
283 
284 /* Bug2332 unearthed a problem in the interaction of reduced user
285  * privileges, the limits on memory usage and some versions of the
286  * pthread library on Linux systems. The 'pthread_cancel()' function and
287  * likely some others need to track the stack of the thread involved,
288  * and uses a function that comes from GCC (--> libgcc_s.so) to do
289  * this. Unfortunately the developers of glibc decided to load the
290  * library on demand, which speeds up program start but can cause
291  * trouble here: Due to all the things NTPD does to limit its resource
292  * usage, this deferred load of libgcc_s does not always work once the
293  * restrictions are in effect.
294  *
295  * One way out of this was attempting a forced link against libgcc_s
296  * when possible because it makes the library available immediately
297  * without deferred load. (The symbol resolution would still be dynamic
298  * and on demand, but the code would already be in the process image.)
299  *
300  * This is a tricky thing to do, since it's not necessary everywhere,
301  * not possible everywhere, has shown to break the build of other
302  * programs in the NTP suite and is now generally frowned upon.
303  *
304  * So we take a different approach here: We creat a worker thread that does
305  * actually nothing except waiting for cancellation and cancel it. If
306  * this is done before all the limitations are put in place, the
307  * machinery is pre-heated and all the runtime stuff should be in place
308  * and useable when needed.
309  *
310  * This uses only the standard pthread API and should work with all
311  * implementations of pthreads. It is not necessary everywhere, but it's
312  * cheap enough to go on nearly unnoticed.
313  *
314  * Addendum: Bug 2954 showed that the assumption that this should work
315  * with all OS is wrong -- at least FreeBSD bombs heavily.
316  */
317 #ifdef NEED_PTHREAD_WARMUP
318 
319 /* simple thread function: sleep until cancelled, just to exercise
320  * thread cancellation.
321  */
322 static void*
my_pthread_warmup_worker(void * thread_args)323 my_pthread_warmup_worker(
324 	void *thread_args)
325 {
326 	(void)thread_args;
327 	for (;;)
328 		sleep(10);
329 	return NULL;
330 }
331 
332 /* pre-heat threading: create a thread and cancel it, just to exercise
333  * thread cancellation.
334  */
335 static void
my_pthread_warmup(void)336 my_pthread_warmup(void)
337 {
338 	pthread_t 	thread;
339 	pthread_attr_t	thr_attr;
340 	int       	rc;
341 
342 	pthread_attr_init(&thr_attr);
343 #if defined(HAVE_PTHREAD_ATTR_GETSTACKSIZE) && \
344     defined(HAVE_PTHREAD_ATTR_SETSTACKSIZE) && \
345     defined(PTHREAD_STACK_MIN)
346 	{
347 		size_t ssmin = 32*1024;	/* 32kB should be minimum */
348 		if (ssmin < PTHREAD_STACK_MIN)
349 			ssmin = PTHREAD_STACK_MIN;
350 		rc = pthread_attr_setstacksize(&thr_attr, ssmin);
351 		if (0 != rc)
352 			msyslog(LOG_ERR,
353 				"my_pthread_warmup: pthread_attr_setstacksize() -> %s",
354 				strerror(rc));
355 	}
356 #endif
357 	rc = pthread_create(
358 		&thread, &thr_attr, my_pthread_warmup_worker, NULL);
359 	pthread_attr_destroy(&thr_attr);
360 	if (0 != rc) {
361 		msyslog(LOG_ERR,
362 			"my_pthread_warmup: pthread_create() -> %s",
363 			strerror(rc));
364 	} else {
365 		pthread_cancel(thread);
366 		pthread_join(thread, NULL);
367 	}
368 }
369 
370 #endif /*defined(NEED_PTHREAD_WARMUP)*/
371 
372 #ifdef NEED_EARLY_FORK
373 static void
dummy_callback(void)374 dummy_callback(void) { return; }
375 
376 static void
fork_nonchroot_worker(void)377 fork_nonchroot_worker(void) {
378 	getaddrinfo_sometime("localhost", "ntp", NULL, INITIAL_DNS_RETRY,
379 			     (gai_sometime_callback)&dummy_callback, NULL);
380 }
381 #endif /* NEED_EARLY_FORK */
382 
383 void
parse_cmdline_opts(int * pargc,char *** pargv)384 parse_cmdline_opts(
385 	int *	pargc,
386 	char ***pargv
387 	)
388 {
389 	static int	parsed;
390 	static int	optct;
391 
392 	if (!parsed)
393 		optct = ntpOptionProcess(&ntpdOptions, *pargc, *pargv);
394 
395 	parsed = 1;
396 
397 	*pargc -= optct;
398 	*pargv += optct;
399 }
400 
401 
402 #ifdef SIM
403 int
main(int argc,char * argv[])404 main(
405 	int argc,
406 	char *argv[]
407 	)
408 {
409 	progname = argv[0];
410 	parse_cmdline_opts(&argc, &argv);
411 #ifdef DEBUG
412 	debug = OPT_VALUE_SET_DEBUG_LEVEL;
413 	DPRINTF(1, ("%s\n", Version));
414 #endif
415 
416 	return ntpsim(argc, argv);
417 }
418 #elif defined(NO_MAIN_ALLOWED)
419 CALL(ntpd,"ntpd",ntpdmain);
420 #elif !defined(SYS_WINNT)
421 int
main(int argc,char * argv[])422 main(
423 	int argc,
424 	char *argv[]
425 	)
426 {
427 	return ntpdmain(argc, argv);
428 }
429 #endif /* !SYS_WINNT */
430 
431 #ifdef _AIX
432 /*
433  * OK. AIX is different than solaris in how it implements plock().
434  * If you do NOT adjust the stack limit, you will get the MAXIMUM
435  * stack size allocated and PINNED with you program. To check the
436  * value, use ulimit -a.
437  *
438  * To fix this, we create an automatic variable and set our stack limit
439  * to that PLUS 32KB of extra space (we need some headroom).
440  *
441  * This subroutine gets the stack address.
442  *
443  * Grover Davidson and Matt Ladendorf
444  *
445  */
446 static char *
get_aix_stack(void)447 get_aix_stack(void)
448 {
449 	char ch;
450 	return (&ch);
451 }
452 
453 /*
454  * Signal handler for SIGDANGER.
455  */
456 static void
catch_danger(int signo)457 catch_danger(int signo)
458 {
459 	msyslog(LOG_INFO, "ntpd: setpgid(): %m");
460 	/* Make the system believe we'll free something, but don't do it! */
461 	return;
462 }
463 #endif /* _AIX */
464 
465 /*
466  * Set the process priority
467  */
468 #ifndef SIM
469 static void
set_process_priority(void)470 set_process_priority(void)
471 {
472 
473 # ifdef DEBUG
474 	if (debug > 1)
475 		msyslog(LOG_DEBUG, "set_process_priority: %s: priority_done is <%d>",
476 			((priority_done)
477 			 ? "Leave priority alone"
478 			 : "Attempt to set priority"
479 				),
480 			priority_done);
481 # endif /* DEBUG */
482 
483 # if defined(HAVE_SCHED_SETSCHEDULER)
484 	if (!priority_done) {
485 		extern int config_priority_override, config_priority;
486 		int pmax, pmin;
487 		struct sched_param sched;
488 
489 		pmax = sched_get_priority_max(SCHED_FIFO);
490 		sched.sched_priority = pmax;
491 		if ( config_priority_override ) {
492 			pmin = sched_get_priority_min(SCHED_FIFO);
493 			if ( config_priority > pmax )
494 				sched.sched_priority = pmax;
495 			else if ( config_priority < pmin )
496 				sched.sched_priority = pmin;
497 			else
498 				sched.sched_priority = config_priority;
499 		}
500 		if ( sched_setscheduler(0, SCHED_FIFO, &sched) == -1 )
501 			msyslog(LOG_ERR, "sched_setscheduler(): %m");
502 		else
503 			++priority_done;
504 	}
505 # endif /* HAVE_SCHED_SETSCHEDULER */
506 # ifdef HAVE_RTPRIO
507 #  ifdef RTP_SET
508 	if (!priority_done) {
509 		struct rtprio srtp;
510 
511 		srtp.type = RTP_PRIO_REALTIME;	/* was: RTP_PRIO_NORMAL */
512 		srtp.prio = 0;		/* 0 (hi) -> RTP_PRIO_MAX (31,lo) */
513 
514 		if (rtprio(RTP_SET, getpid(), &srtp) < 0)
515 			msyslog(LOG_ERR, "rtprio() error: %m");
516 		else
517 			++priority_done;
518 	}
519 #  else	/* !RTP_SET follows */
520 	if (!priority_done) {
521 		if (rtprio(0, 120) < 0)
522 			msyslog(LOG_ERR, "rtprio() error: %m");
523 		else
524 			++priority_done;
525 	}
526 #  endif	/* !RTP_SET */
527 # endif	/* HAVE_RTPRIO */
528 # if defined(NTPD_PRIO) && NTPD_PRIO != 0
529 #  ifdef HAVE_ATT_NICE
530 	if (!priority_done) {
531 		errno = 0;
532 		if (-1 == nice (NTPD_PRIO) && errno != 0)
533 			msyslog(LOG_ERR, "nice() error: %m");
534 		else
535 			++priority_done;
536 	}
537 #  endif	/* HAVE_ATT_NICE */
538 #  ifdef HAVE_BSD_NICE
539 	if (!priority_done) {
540 		if (-1 == setpriority(PRIO_PROCESS, 0, NTPD_PRIO))
541 			msyslog(LOG_ERR, "setpriority() error: %m");
542 		else
543 			++priority_done;
544 	}
545 #  endif	/* HAVE_BSD_NICE */
546 # endif	/* NTPD_PRIO && NTPD_PRIO != 0 */
547 	if (!priority_done)
548 		msyslog(LOG_ERR, "set_process_priority: No way found to improve our priority");
549 }
550 #endif	/* !SIM */
551 
552 #if !defined(SIM) && !defined(SYS_WINNT)
553 /*
554  * Detach from terminal (much like daemon())
555  * Nothe that this function calls exit()
556  */
557 # ifdef HAVE_WORKING_FORK
558 static void
detach_from_terminal(int pipe[2],long wait_sync,const char * logfilename)559 detach_from_terminal(
560 	int pipe[2],
561 	long wait_sync,
562 	const char *logfilename
563 	)
564 {
565 	pid_t	cpid;
566 	int	exit_code;
567 #  if !defined(HAVE_SETSID) && !defined (HAVE_SETPGID) && defined(TIOCNOTTY)
568 	int		fid;
569 #  endif
570 #  ifdef _AIX
571 	struct sigaction sa;
572 #  endif
573 
574 	cpid = fork();
575 	if (0 != cpid) {
576 		/* parent */
577 		if (-1 == cpid) {
578 			msyslog(LOG_ERR, "fork: %m");
579 			exit_code = EX_OSERR;
580 		} else {
581 			close(pipe[1]);
582 			pipe[1] = -1;
583 			exit_code = wait_child_sync_if(
584 					pipe[0], wait_sync);
585 			DPRINTF(1, ("sync_if: rc=%d\n", exit_code));
586 			if (exit_code <= 0) {
587 				/* probe daemon exit code -- wait for
588 				 * child process if we have an unexpected
589 				 * EOF on the monitor pipe.
590 				 */
591 				exit_code = wait_child_exit_if(
592 						cpid, (exit_code < 0));
593 				DPRINTF(1, ("exit_if: rc=%d\n", exit_code));
594 			}
595 		}
596 		exit(exit_code);
597 	}
598 
599 	/*
600 	 * child/daemon
601 	 * close all open files excepting waitsync_fd_to_close.
602 	 * msyslog() unreliable until after init_logging().
603 	 */
604 	closelog();
605 	if (syslog_file != NULL) {
606 		fclose(syslog_file);
607 		syslog_file = NULL;
608 		syslogit = TRUE;
609 	}
610 	close_all_except(pipe[1]);
611 	pipe[0] = -1;
612 	INSIST(0 == open("/dev/null", 0) && 1 == dup2(0, 1) \
613 		&& 2 == dup2(0, 2));
614 
615 	init_logging(progname, 0, TRUE);
616 	/* we lost our logfile (if any) daemonizing */
617 	setup_logfile(logfilename);
618 
619 #  ifdef SYS_DOMAINOS
620 	{
621 		uid_$t puid;
622 		status_$t st;
623 
624 		proc2_$who_am_i(&puid);
625 		proc2_$make_server(&puid, &st);
626 	}
627 #  endif	/* SYS_DOMAINOS */
628 #  ifdef HAVE_SETSID
629 	if (setsid() == (pid_t)-1)
630 		msyslog(LOG_ERR, "setsid(): %m");
631 #  elif defined(HAVE_SETPGID)
632 	if (setpgid(0, 0) == -1)
633 		msyslog(LOG_ERR, "setpgid(): %m");
634 #  else		/* !HAVE_SETSID && !HAVE_SETPGID follows */
635 #   ifdef TIOCNOTTY
636 	fid = open("/dev/tty", 2);
637 	if (fid >= 0) {
638 		ioctl(fid, (u_long)TIOCNOTTY, NULL);
639 		close(fid);
640 	}
641 #   endif	/* TIOCNOTTY */
642 	ntp_setpgrp(0, getpid());
643 #  endif	/* !HAVE_SETSID && !HAVE_SETPGID */
644 #  ifdef _AIX
645 	/* Don't get killed by low-on-memory signal. */
646 	sa.sa_handler = catch_danger;
647 	sigemptyset(&sa.sa_mask);
648 	sa.sa_flags = SA_RESTART;
649 	sigaction(SIGDANGER, &sa, NULL);
650 #  endif	/* _AIX */
651 
652 	return;
653 }
654 # endif /* HAVE_WORKING_FORK */
655 
656 #ifdef HAVE_DROPROOT
657 /*
658  * Map user name/number to user ID
659 */
660 static int
map_user()661 map_user(
662 	)
663 {
664 	char *endp;
665 
666 	if (isdigit((unsigned char)*user)) {
667 		sw_uid = (uid_t)strtoul(user, &endp, 0);
668 		if (*endp != '\0')
669 			goto getuser;
670 
671 		if ((pw = getpwuid(sw_uid)) != NULL) {
672 			free(user);
673 			user = estrdup(pw->pw_name);
674 			sw_gid = pw->pw_gid;
675 		} else {
676 			errno = 0;
677 			msyslog(LOG_ERR, "Cannot find user ID %s", user);
678 			return 0;
679 		}
680 
681 	} else {
682 getuser:
683 		errno = 0;
684 		if ((pw = getpwnam(user)) != NULL) {
685 			sw_uid = pw->pw_uid;
686 			sw_gid = pw->pw_gid;
687 		} else {
688 			if (errno)
689 				msyslog(LOG_ERR, "getpwnam(%s) failed: %m", user);
690 			else
691 				msyslog(LOG_ERR, "Cannot find user `%s'", user);
692 			return 0;
693 		}
694 	}
695 
696 	return 1;
697 }
698 
699 /*
700  * Map group name/number to group ID
701 */
702 static int
map_group(void)703 map_group(void)
704 {
705 	char *endp;
706 
707 	if (isdigit((unsigned char)*group)) {
708 		sw_gid = (gid_t)strtoul(group, &endp, 0);
709 		if (*endp != '\0')
710 			goto getgroup;
711 	} else {
712 getgroup:
713 		if ((gr = getgrnam(group)) != NULL) {
714 			sw_gid = gr->gr_gid;
715 		} else {
716 			errno = 0;
717 			msyslog(LOG_ERR, "Cannot find group `%s'", group);
718 			return 0;
719 		}
720 	}
721 
722 	return 1;
723 }
724 
725 static int
set_group_ids(void)726 set_group_ids(void)
727 {
728 	if (user && initgroups(user, sw_gid)) {
729 		msyslog(LOG_ERR, "Cannot initgroups() to user `%s': %m", user);
730 		return 0;
731 	}
732 	if (group && setgid(sw_gid)) {
733 		msyslog(LOG_ERR, "Cannot setgid() to group `%s': %m", group);
734 		return 0;
735 	}
736 	if (group && setegid(sw_gid)) {
737 		msyslog(LOG_ERR, "Cannot setegid() to group `%s': %m", group);
738 		return 0;
739 	}
740 	if (group) {
741 		if (0 != setgroups(1, &sw_gid)) {
742 			msyslog(LOG_ERR, "setgroups(1, %d) failed: %m", sw_gid);
743 			return 0;
744 		}
745 	}
746 	else if (pw)
747 		if (0 != initgroups(pw->pw_name, pw->pw_gid)) {
748 			msyslog(LOG_ERR, "initgroups(<%s>, %d) filed: %m", pw->pw_name, pw->pw_gid);
749 			return 0;
750 		}
751 	return 1;
752 }
753 
754 static int
set_user_ids(void)755 set_user_ids(void)
756 {
757 	if (user && setuid(sw_uid)) {
758 		msyslog(LOG_ERR, "Cannot setuid() to user `%s': %m", user);
759 		return 0;
760 	}
761 	if (user && seteuid(sw_uid)) {
762 		msyslog(LOG_ERR, "Cannot seteuid() to user `%s': %m", user);
763 		return 0;
764 	}
765 	return 1;
766 }
767 
768 /*
769  * Change (effective) user and group IDs, also initialize the supplementary group access list
770  */
771 int set_user_group_ids(void);
772 int
set_user_group_ids(void)773 set_user_group_ids(void)
774 {
775 	/* If the the user was already mapped, no need to map it again */
776 	if ((NULL != user) && (0 == sw_uid)) {
777 		if (0 == map_user())
778 			exit (-1);
779 	}
780 	/* same applies for the group */
781 	if ((NULL != group) && (0 == sw_gid)) {
782 		if (0 == map_group())
783 			exit (-1);
784 	}
785 
786 	if (getegid() != sw_gid && 0 == set_group_ids())
787 		return 0;
788 	if (geteuid() != sw_uid && 0 == set_user_ids())
789 		return 0;
790 
791 	return 1;
792 }
793 #endif /* HAVE_DROPROOT */
794 #endif /* !SIM */
795 
796 /*
797  * Main program.  Initialize us, disconnect us from the tty if necessary,
798  * and loop waiting for I/O and/or timer expiries.
799  */
800 #ifndef SIM
801 int
ntpdmain(int argc,char * argv[])802 ntpdmain(
803 	int argc,
804 	char *argv[]
805 	)
806 {
807 	l_fp		now;
808 	struct recvbuf *rbuf;
809 	const char *	logfilename;
810 # ifdef HAVE_UMASK
811 	mode_t		uv;
812 # endif
813 # if defined(HAVE_GETUID) && !defined(MPE) /* MPE lacks the concept of root */
814 	uid_t		uid;
815 # endif
816 # if defined(HAVE_WORKING_FORK)
817 	long		wait_sync = 0;
818 # endif	/* HAVE_WORKING_FORK*/
819 # ifdef SCO5_CLOCK
820 	int		fd;
821 	int		zero;
822 # endif
823 
824 # ifdef NEED_PTHREAD_WARMUP
825 	my_pthread_warmup();
826 # endif
827 
828 # ifdef HAVE_UMASK
829 	uv = umask(0);
830 	if (uv)
831 		umask(uv);
832 	else
833 		umask(022);
834 # endif
835 	saved_argc = argc;
836 	saved_argv = argv;
837 	progname = argv[0];
838 	initializing = TRUE;		/* mark that we are initializing */
839 	parse_cmdline_opts(&argc, &argv);
840 # ifdef DEBUG
841 	debug = OPT_VALUE_SET_DEBUG_LEVEL;
842 #  ifdef HAVE_SETLINEBUF
843 	setlinebuf(stdout);
844 #  endif
845 # endif
846 
847 	if (HAVE_OPT(NOFORK) || HAVE_OPT(QUIT)
848 # ifdef DEBUG
849 	    || debug
850 # endif
851 	    || HAVE_OPT(SAVECONFIGQUIT))
852 		nofork = TRUE;
853 
854 	init_logging(progname, NLOG_SYNCMASK, TRUE);
855 	/* honor -l/--logfile option to log to a file */
856 	if (HAVE_OPT(LOGFILE)) {
857 		logfilename = OPT_ARG(LOGFILE);
858 		syslogit = FALSE;
859 		change_logfile(logfilename, FALSE);
860 	} else {
861 		logfilename = NULL;
862 		if (nofork)
863 			msyslog_term = TRUE;
864 		if (HAVE_OPT(SAVECONFIGQUIT))
865 			syslogit = FALSE;
866 	}
867 	msyslog(LOG_NOTICE, "%s: Starting", Version);
868 
869 	{
870 		int i;
871 		char buf[1024];	/* Secret knowledge of msyslog buf length */
872 		char *cp = buf;
873 
874 		/* Note that every arg has an initial space character */
875 		snprintf(cp, sizeof(buf), "Command line:");
876 		cp += strlen(cp);
877 
878 		for (i = 0; i < saved_argc ; ++i) {
879 			snprintf(cp, sizeof(buf) - (cp - buf),
880 				" %s", saved_argv[i]);
881 			cp += strlen(cp);
882 		}
883 		msyslog(LOG_NOTICE, "%s", buf);
884 	}
885 
886 	msyslog(LOG_NOTICE, "----------------------------------------------------");
887 	msyslog(LOG_NOTICE, "ntp-4 is maintained by Network Time Foundation,");
888 	msyslog(LOG_NOTICE, "Inc. (NTF), a non-profit 501(c)(3) public-benefit");
889 	msyslog(LOG_NOTICE, "corporation.  Support and training for ntp-4 are");
890 	msyslog(LOG_NOTICE, "available at https://www.nwtime.org/support");
891 	msyslog(LOG_NOTICE, "----------------------------------------------------");
892 
893 	/*
894 	 * Install trap handlers to log errors and assertion failures.
895 	 * Default handlers print to stderr which doesn't work if detached.
896 	 */
897 	isc_assertion_setcallback(assertion_failed);
898 	isc_error_setfatal(library_fatal_error);
899 	isc_error_setunexpected(library_unexpected_error);
900 
901 	/* MPE lacks the concept of root */
902 # if defined(HAVE_GETUID) && !defined(MPE)
903 	uid = getuid();
904 	if (uid && !HAVE_OPT( SAVECONFIGQUIT )) {
905 		msyslog_term = TRUE;
906 		msyslog(LOG_ERR,
907 			"must be run as root, not uid %ld", (long)uid);
908 		exit(1);
909 	}
910 # endif
911 
912 /*
913  * Enable the Multi-Media Timer for Windows?
914  */
915 # ifdef SYS_WINNT
916 	if (HAVE_OPT( MODIFYMMTIMER ))
917 		set_mm_timer(MM_TIMER_HIRES);
918 # endif
919 
920 #ifdef HAVE_DNSREGISTRATION
921 /*
922  * Enable mDNS registrations?
923  */
924 	if (HAVE_OPT( MDNS )) {
925 		mdnsreg = TRUE;
926 	}
927 #endif  /* HAVE_DNSREGISTRATION */
928 
929 	if (HAVE_OPT( NOVIRTUALIPS ))
930 		listen_to_virtual_ips = 0;
931 
932 	/*
933 	 * --interface, listen on specified interfaces
934 	 */
935 	if (HAVE_OPT( INTERFACE )) {
936 		int		ifacect = STACKCT_OPT( INTERFACE );
937 		const char**	ifaces  = STACKLST_OPT( INTERFACE );
938 		sockaddr_u	addr;
939 
940 		while (ifacect-- > 0) {
941 			add_nic_rule(
942 				is_ip_address(*ifaces, AF_UNSPEC, &addr)
943 					? MATCH_IFADDR
944 					: MATCH_IFNAME,
945 				*ifaces, -1, ACTION_LISTEN);
946 			ifaces++;
947 		}
948 	}
949 
950 	if (HAVE_OPT( NICE ))
951 		priority_done = 0;
952 
953 # ifdef HAVE_SCHED_SETSCHEDULER
954 	if (HAVE_OPT( PRIORITY )) {
955 		config_priority = OPT_VALUE_PRIORITY;
956 		config_priority_override = 1;
957 		priority_done = 0;
958 	}
959 # endif
960 
961 # ifdef HAVE_WORKING_FORK
962 	/* make sure the FDs are initialised
963 	 *
964 	 * note: if WAIT_SYNC is requested, we *have* to fork. This will
965 	 * overide any '-n' (nofork) or '-d' (debug) option presented on
966 	 * the command line!
967 	 */
968 	if (HAVE_OPT(WAIT_SYNC)) {
969 		wait_sync = OPT_VALUE_WAIT_SYNC;
970 		if (wait_sync <= 0)
971 			wait_sync = 0;
972 		else
973 			nofork = FALSE;
974 	}
975 	if ( !nofork && pipe(daemon_pipe)) {
976 		msyslog(LOG_ERR,
977 			"Pipe creation failed for --wait-sync/daemon: %m");
978 		exit(EX_OSERR);
979 	}
980 # endif	/* HAVE_WORKING_FORK */
981 
982 	init_lib();
983 # ifdef SYS_WINNT
984 	/*
985 	 * Make sure the service is initialized before we do anything else
986 	 */
987 	ntservice_init();
988 
989 	/*
990 	 * Start interpolation thread, must occur before first
991 	 * get_systime()
992 	 */
993 	init_winnt_time();
994 # endif
995 	/*
996 	 * Initialize random generator and public key pair
997 	 */
998 	get_systime(&now);
999 
1000 	ntp_srandom((int)(now.l_i * now.l_uf));
1001 
1002 	/*
1003 	 * Detach us from the terminal.  May need an #ifndef GIZMO.
1004 	 */
1005 # ifdef HAVE_WORKING_FORK
1006 	if (!nofork) {
1007 		detach_from_terminal(daemon_pipe, wait_sync, logfilename);
1008 	}
1009 # endif		/* HAVE_WORKING_FORK */
1010 
1011 # ifdef SCO5_CLOCK
1012 	/*
1013 	 * SCO OpenServer's system clock offers much more precise timekeeping
1014 	 * on the base CPU than the other CPUs (for multiprocessor systems),
1015 	 * so we must lock to the base CPU.
1016 	 */
1017 	fd = open("/dev/at1", O_RDONLY);
1018 	if (fd >= 0) {
1019 		zero = 0;
1020 		if (ioctl(fd, ACPU_LOCK, &zero) < 0)
1021 			msyslog(LOG_ERR, "cannot lock to base CPU: %m");
1022 		close(fd);
1023 	}
1024 # endif
1025 
1026 	/* Setup stack size in preparation for locking pages in memory. */
1027 # if defined(HAVE_MLOCKALL)
1028 #  ifdef HAVE_SETRLIMIT
1029 	ntp_rlimit(RLIMIT_STACK, DFLT_RLIMIT_STACK * 4096, 4096, "4k");
1030 #   if defined(RLIMIT_MEMLOCK) && defined(DFLT_RLIMIT_MEMLOCK) && DFLT_RLIMIT_MEMLOCK != -1
1031 	/*
1032 	 * The default RLIMIT_MEMLOCK is very low on Linux systems.
1033 	 * Unless we increase this limit malloc calls are likely to
1034 	 * fail if we drop root privilege.  To be useful the value
1035 	 * has to be larger than the largest ntpd resident set size.
1036 	 */
1037 	ntp_rlimit(RLIMIT_MEMLOCK, DFLT_RLIMIT_MEMLOCK * 1024 * 1024, 1024 * 1024, "MB");
1038 #   endif	/* RLIMIT_MEMLOCK */
1039 #  endif	/* HAVE_SETRLIMIT */
1040 # else	/* !HAVE_MLOCKALL follows */
1041 #  ifdef HAVE_PLOCK
1042 #   ifdef PROCLOCK
1043 #    ifdef _AIX
1044 	/*
1045 	 * set the stack limit for AIX for plock().
1046 	 * see get_aix_stack() for more info.
1047 	 */
1048 	if (ulimit(SET_STACKLIM, (get_aix_stack() - 8 * 4096)) < 0)
1049 		msyslog(LOG_ERR,
1050 			"Cannot adjust stack limit for plock: %m");
1051 #    endif	/* _AIX */
1052 #   endif	/* PROCLOCK */
1053 #  endif	/* HAVE_PLOCK */
1054 # endif	/* !HAVE_MLOCKALL */
1055 
1056 	/*
1057 	 * Set up signals we pay attention to locally.
1058 	 */
1059 # ifdef SIGDIE1
1060 	signal_no_reset(SIGDIE1, finish);
1061 	signal_no_reset(SIGDIE2, finish);
1062 	signal_no_reset(SIGDIE3, finish);
1063 	signal_no_reset(SIGDIE4, finish);
1064 # endif
1065 # ifdef SIGBUS
1066 	signal_no_reset(SIGBUS, finish);
1067 # endif
1068 
1069 # if !defined(SYS_WINNT) && !defined(VMS)
1070 #  ifdef DEBUG
1071 	(void) signal_no_reset(MOREDEBUGSIG, moredebug);
1072 	(void) signal_no_reset(LESSDEBUGSIG, lessdebug);
1073 #  else
1074 	(void) signal_no_reset(MOREDEBUGSIG, no_debug);
1075 	(void) signal_no_reset(LESSDEBUGSIG, no_debug);
1076 #  endif	/* DEBUG */
1077 # endif	/* !SYS_WINNT && !VMS */
1078 
1079 	/*
1080 	 * Set up signals we should never pay attention to.
1081 	 */
1082 # ifdef SIGPIPE
1083 	signal_no_reset(SIGPIPE, SIG_IGN);
1084 # endif
1085 
1086 	/*
1087 	 * Call the init_ routines to initialize the data structures.
1088 	 *
1089 	 * Exactly what command-line options are we expecting here?
1090 	 */
1091 	INIT_SSL();
1092 	init_auth();
1093 	init_util();
1094 	init_restrict();
1095 	init_mon();
1096 	init_timer();
1097 	init_request();
1098 	init_control();
1099 	init_peer();
1100 # ifdef REFCLOCK
1101 	init_refclock();
1102 # endif
1103 	set_process_priority();
1104 	init_proto();		/* Call at high priority */
1105 	init_io();
1106 	init_loopfilter();
1107 	mon_start(MON_ON);	/* monitor on by default now	  */
1108 				/* turn off in config if unwanted */
1109 
1110 	/*
1111 	 * Get the configuration.  This is done in a separate module
1112 	 * since this will definitely be different for the gizmo board.
1113 	 */
1114 	getconfig(argc, argv);
1115 
1116 	if (-1 == cur_memlock) {
1117 # if defined(HAVE_MLOCKALL)
1118 		/*
1119 		 * lock the process into memory
1120 		 */
1121 		if (   !HAVE_OPT(SAVECONFIGQUIT)
1122 #  ifdef RLIMIT_MEMLOCK
1123 		    && -1 != DFLT_RLIMIT_MEMLOCK
1124 #  endif
1125 		    && 0 != mlockall(MCL_CURRENT|MCL_FUTURE))
1126 			msyslog(LOG_ERR, "mlockall(): %m");
1127 # else	/* !HAVE_MLOCKALL follows */
1128 #  ifdef HAVE_PLOCK
1129 #   ifdef PROCLOCK
1130 		/*
1131 		 * lock the process into memory
1132 		 */
1133 		if (!HAVE_OPT(SAVECONFIGQUIT) && 0 != plock(PROCLOCK))
1134 			msyslog(LOG_ERR, "plock(PROCLOCK): %m");
1135 #   else	/* !PROCLOCK follows  */
1136 #    ifdef TXTLOCK
1137 		/*
1138 		 * Lock text into ram
1139 		 */
1140 		if (!HAVE_OPT(SAVECONFIGQUIT) && 0 != plock(TXTLOCK))
1141 			msyslog(LOG_ERR, "plock(TXTLOCK) error: %m");
1142 #    else	/* !TXTLOCK follows */
1143 		msyslog(LOG_ERR, "plock() - don't know what to lock!");
1144 #    endif	/* !TXTLOCK */
1145 #   endif	/* !PROCLOCK */
1146 #  endif	/* HAVE_PLOCK */
1147 # endif	/* !HAVE_MLOCKALL */
1148 	}
1149 
1150 	loop_config(LOOP_DRIFTINIT, 0);
1151 	report_event(EVNT_SYSRESTART, NULL, NULL);
1152 	initializing = FALSE;
1153 
1154 # ifdef HAVE_LINUX_CAPABILITIES
1155 	{
1156 		/*  Check that setting capabilities actually works; we might be
1157 		 *  run on a kernel with disabled capabilities. We must not
1158 		 *  drop privileges in this case.
1159 		 */
1160 		cap_t caps;
1161 		caps = cap_from_text("cap_sys_time,cap_setuid,cap_setgid,cap_sys_chroot,cap_net_bind_service=pe");
1162 		if ( ! caps) {
1163 			msyslog( LOG_ERR, "cap_from_text() failed: %m" );
1164 			exit(-1);
1165 		}
1166 		have_caps = (cap_set_proc(caps) == 0);
1167 		cap_free(caps);	/* caps not NULL here! */
1168 	}
1169 # endif /* HAVE_LINUX_CAPABILITIES */
1170 
1171 # ifdef HAVE_DROPROOT
1172 #  ifdef HAVE_LINUX_CAPABILITIES
1173 	if (droproot && have_caps) {
1174 #  else
1175 	if (droproot) {
1176 #  endif /*HAVE_LINUX_CAPABILITIES*/
1177 
1178 #  ifdef NEED_EARLY_FORK
1179 		fork_nonchroot_worker();
1180 #  endif
1181 
1182 		/* Drop super-user privileges and chroot now if the OS supports this */
1183 
1184 #  ifdef HAVE_LINUX_CAPABILITIES
1185 		/* set flag: keep privileges accross setuid() call (we only really need cap_sys_time): */
1186 		if (prctl( PR_SET_KEEPCAPS, 1L, 0L, 0L, 0L ) == -1) {
1187 			msyslog( LOG_ERR, "prctl( PR_SET_KEEPCAPS, 1L ) failed: %m" );
1188 			exit(-1);
1189 		}
1190 #  elif HAVE_SOLARIS_PRIVS
1191 		/* Nothing to do here */
1192 #  else
1193 		/* we need a user to switch to */
1194 		if (user == NULL) {
1195 			msyslog(LOG_ERR, "Need user name to drop root privileges (see -u flag!)" );
1196 			exit(-1);
1197 		}
1198 #  endif	/* HAVE_LINUX_CAPABILITIES || HAVE_SOLARIS_PRIVS */
1199 
1200 		if (user != NULL) {
1201 			if (0 == map_user())
1202 				exit (-1);
1203 		}
1204 		if (group != NULL) {
1205 			if (0 == map_group())
1206 				exit (-1);
1207 		}
1208 
1209 		if (chrootdir ) {
1210 			/* make sure cwd is inside the jail: */
1211 			if (chdir(chrootdir)) {
1212 				msyslog(LOG_ERR, "Cannot chdir() to `%s': %m", chrootdir);
1213 				exit (-1);
1214 			}
1215 			if (chroot(chrootdir)) {
1216 				msyslog(LOG_ERR, "Cannot chroot() to `%s': %m", chrootdir);
1217 				exit (-1);
1218 			}
1219 			if (chdir("/")) {
1220 				msyslog(LOG_ERR, "Cannot chdir() to`root after chroot(): %m");
1221 				exit (-1);
1222 			}
1223 		}
1224 #  ifdef HAVE_SOLARIS_PRIVS
1225 		if ((lowprivs = priv_str_to_set(LOWPRIVS, ",", NULL)) == NULL) {
1226 			msyslog(LOG_ERR, "priv_str_to_set() failed:%m");
1227 			exit(-1);
1228 		}
1229 		if ((highprivs = priv_allocset()) == NULL) {
1230 			msyslog(LOG_ERR, "priv_allocset() failed:%m");
1231 			exit(-1);
1232 		}
1233 		(void) getppriv(PRIV_PERMITTED, highprivs);
1234 		(void) priv_intersect(highprivs, lowprivs);
1235 		if (setppriv(PRIV_SET, PRIV_PERMITTED, lowprivs) == -1) {
1236 			msyslog(LOG_ERR, "setppriv() failed:%m");
1237 			exit(-1);
1238 		}
1239 #  endif /* HAVE_SOLARIS_PRIVS */
1240 		if (0 == set_user_group_ids())
1241 			exit(-1);
1242 
1243 #  if !defined(HAVE_LINUX_CAPABILITIES) && !defined(HAVE_SOLARIS_PRIVS)
1244 		/*
1245 		 * for now assume that the privilege to bind to privileged ports
1246 		 * is associated with running with uid 0 - should be refined on
1247 		 * ports that allow binding to NTP_PORT with uid != 0
1248 		 */
1249 		disable_dynamic_updates |= (sw_uid != 0);  /* also notifies routing message listener */
1250 #  endif /* !HAVE_LINUX_CAPABILITIES && !HAVE_SOLARIS_PRIVS */
1251 
1252 		if (disable_dynamic_updates && interface_interval) {
1253 			interface_interval = 0;
1254 			msyslog(LOG_INFO, "running as non-root disables dynamic interface tracking");
1255 		}
1256 
1257 #  ifdef HAVE_LINUX_CAPABILITIES
1258 		{
1259 			/*
1260 			 *  We may be running under non-root uid now, but we still hold full root privileges!
1261 			 *  We drop all of them, except for the crucial one or two: cap_sys_time and
1262 			 *  cap_net_bind_service if doing dynamic interface tracking.
1263 			 */
1264 			cap_t caps;
1265 			char *captext;
1266 
1267 			captext = (0 != interface_interval)
1268 				      ? "cap_sys_time,cap_net_bind_service=pe"
1269 				      : "cap_sys_time=pe";
1270 			caps = cap_from_text(captext);
1271 			if (!caps) {
1272 				msyslog(LOG_ERR,
1273 					"cap_from_text(%s) failed: %m",
1274 					captext);
1275 				exit(-1);
1276 			}
1277 			if (-1 == cap_set_proc(caps)) {
1278 				msyslog(LOG_ERR,
1279 					"cap_set_proc() failed to drop root privs: %m");
1280 				exit(-1);
1281 			}
1282 			cap_free(caps);
1283 		}
1284 #  endif	/* HAVE_LINUX_CAPABILITIES */
1285 #  ifdef HAVE_SOLARIS_PRIVS
1286 		if (priv_delset(lowprivs, "proc_setid") == -1) {
1287 			msyslog(LOG_ERR, "priv_delset() failed:%m");
1288 			exit(-1);
1289 		}
1290 		if (setppriv(PRIV_SET, PRIV_PERMITTED, lowprivs) == -1) {
1291 			msyslog(LOG_ERR, "setppriv() failed:%m");
1292 			exit(-1);
1293 		}
1294 		priv_freeset(lowprivs);
1295 		priv_freeset(highprivs);
1296 #  endif /* HAVE_SOLARIS_PRIVS */
1297 		root_dropped = TRUE;
1298 		fork_deferred_worker();
1299 	}	/* if (droproot) */
1300 # endif	/* HAVE_DROPROOT */
1301 
1302 /* libssecomp sandboxing */
1303 #if defined (LIBSECCOMP) && (KERN_SECCOMP)
1304 	scmp_filter_ctx ctx;
1305 
1306 	if ((ctx = seccomp_init(SCMP_ACT_KILL)) < 0)
1307 		msyslog(LOG_ERR, "%s: seccomp_init(SCMP_ACT_KILL) failed: %m", __func__);
1308 	else {
1309 		msyslog(LOG_DEBUG, "%s: seccomp_init(SCMP_ACT_KILL) succeeded", __func__);
1310 	}
1311 
1312 #ifdef __x86_64__
1313 int scmp_sc[] = {
1314 	SCMP_SYS(adjtimex),
1315 	SCMP_SYS(bind),
1316 	SCMP_SYS(brk),
1317 	SCMP_SYS(chdir),
1318 	SCMP_SYS(clock_gettime),
1319 	SCMP_SYS(clock_settime),
1320 	SCMP_SYS(close),
1321 	SCMP_SYS(connect),
1322 	SCMP_SYS(exit_group),
1323 	SCMP_SYS(fstat),
1324 	SCMP_SYS(fsync),
1325 	SCMP_SYS(futex),
1326 	SCMP_SYS(getitimer),
1327 	SCMP_SYS(getsockname),
1328 	SCMP_SYS(ioctl),
1329 	SCMP_SYS(lseek),
1330 	SCMP_SYS(madvise),
1331 	SCMP_SYS(mmap),
1332 	SCMP_SYS(munmap),
1333 	SCMP_SYS(open),
1334 	SCMP_SYS(poll),
1335 	SCMP_SYS(read),
1336 	SCMP_SYS(recvmsg),
1337 	SCMP_SYS(rename),
1338 	SCMP_SYS(rt_sigaction),
1339 	SCMP_SYS(rt_sigprocmask),
1340 	SCMP_SYS(rt_sigreturn),
1341 	SCMP_SYS(select),
1342 	SCMP_SYS(sendto),
1343 	SCMP_SYS(setitimer),
1344 	SCMP_SYS(setsid),
1345 	SCMP_SYS(socket),
1346 	SCMP_SYS(stat),
1347 	SCMP_SYS(time),
1348 	SCMP_SYS(write),
1349 };
1350 #endif
1351 #ifdef __i386__
1352 int scmp_sc[] = {
1353 	SCMP_SYS(_newselect),
1354 	SCMP_SYS(adjtimex),
1355 	SCMP_SYS(brk),
1356 	SCMP_SYS(chdir),
1357 	SCMP_SYS(clock_gettime),
1358 	SCMP_SYS(clock_settime),
1359 	SCMP_SYS(close),
1360 	SCMP_SYS(exit_group),
1361 	SCMP_SYS(fsync),
1362 	SCMP_SYS(futex),
1363 	SCMP_SYS(getitimer),
1364 	SCMP_SYS(madvise),
1365 	SCMP_SYS(mmap),
1366 	SCMP_SYS(mmap2),
1367 	SCMP_SYS(munmap),
1368 	SCMP_SYS(open),
1369 	SCMP_SYS(poll),
1370 	SCMP_SYS(read),
1371 	SCMP_SYS(rename),
1372 	SCMP_SYS(rt_sigaction),
1373 	SCMP_SYS(rt_sigprocmask),
1374 	SCMP_SYS(select),
1375 	SCMP_SYS(setitimer),
1376 	SCMP_SYS(setsid),
1377 	SCMP_SYS(sigprocmask),
1378 	SCMP_SYS(sigreturn),
1379 	SCMP_SYS(socketcall),
1380 	SCMP_SYS(stat64),
1381 	SCMP_SYS(time),
1382 	SCMP_SYS(write),
1383 };
1384 #endif
1385 	{
1386 		int i;
1387 
1388 		for (i = 0; i < COUNTOF(scmp_sc); i++) {
1389 			if (seccomp_rule_add(ctx,
1390 			    SCMP_ACT_ALLOW, scmp_sc[i], 0) < 0) {
1391 				msyslog(LOG_ERR,
1392 				    "%s: seccomp_rule_add() failed: %m",
1393 				    __func__);
1394 			}
1395 		}
1396 	}
1397 
1398 	if (seccomp_load(ctx) < 0)
1399 		msyslog(LOG_ERR, "%s: seccomp_load() failed: %m",
1400 		    __func__);
1401 	else {
1402 		msyslog(LOG_DEBUG, "%s: seccomp_load() succeeded", __func__);
1403 	}
1404 #endif /* LIBSECCOMP and KERN_SECCOMP */
1405 
1406 #if defined(SYS_WINNT)
1407 	ntservice_isup();
1408 #elif defined(HAVE_WORKING_FORK)
1409 	if (daemon_pipe[1] != -1) {
1410 		write(daemon_pipe[1], "R\n", 2);
1411 	}
1412 #endif /* HAVE_WORKING_FORK */
1413 
1414 # ifndef HAVE_IO_COMPLETION_PORT
1415 	BLOCK_IO_AND_ALARM();
1416 	was_alarmed = FALSE;
1417 # endif
1418 
1419 	for (;;) {
1420 #if !defined(SIM) && defined(SIGDIE1)
1421 		if (signalled)
1422 			finish_safe(signo);
1423 #endif
1424 # ifdef HAVE_IO_COMPLETION_PORT
1425 		GetReceivedBuffers();
1426 
1427 # else /* normal I/O */
1428 		if (alarm_flag) {	/* alarmed? */
1429 			was_alarmed = TRUE;
1430 			alarm_flag = FALSE;
1431 		}
1432 
1433 		/* collect async name/addr results */
1434 		if (!was_alarmed)
1435 		    harvest_blocking_responses();
1436 
1437 		if (!was_alarmed && !has_full_recv_buffer()) {
1438 			/*
1439 			 * Nothing to do.  Wait for something.
1440 			 */
1441 			io_handler();
1442 		}
1443 
1444 		if (alarm_flag) {	/* alarmed? */
1445 			was_alarmed = TRUE;
1446 			alarm_flag = FALSE;
1447 		}
1448 
1449 		if (was_alarmed) {
1450 			UNBLOCK_IO_AND_ALARM();
1451 			/*
1452 			 * Out here, signals are unblocked.  Call timer routine
1453 			 * to process expiry.
1454 			 */
1455 			timer();
1456 			was_alarmed = FALSE;
1457 			BLOCK_IO_AND_ALARM();
1458 		}
1459 
1460 # endif		/* !HAVE_IO_COMPLETION_PORT */
1461 
1462 # ifdef DEBUG_TIMING
1463 		{
1464 			l_fp pts;
1465 			l_fp tsa, tsb;
1466 			int bufcount = 0;
1467 
1468 			get_systime(&pts);
1469 			tsa = pts;
1470 # endif
1471 			rbuf = get_full_recv_buffer();
1472 			while (rbuf != NULL) {
1473 				if (alarm_flag) {
1474 					was_alarmed = TRUE;
1475 					alarm_flag = FALSE;
1476 				}
1477 				UNBLOCK_IO_AND_ALARM();
1478 
1479 				if (was_alarmed) {
1480 					/* avoid timer starvation during lengthy I/O handling */
1481 					timer();
1482 					was_alarmed = FALSE;
1483 				}
1484 
1485 				/*
1486 				 * Call the data procedure to handle each received
1487 				 * packet.
1488 				 */
1489 				if (rbuf->receiver != NULL) {
1490 # ifdef DEBUG_TIMING
1491 					l_fp dts = pts;
1492 
1493 					L_SUB(&dts, &rbuf->recv_time);
1494 					DPRINTF(2, ("processing timestamp delta %s (with prec. fuzz)\n", lfptoa(&dts, 9)));
1495 					collect_timing(rbuf, "buffer processing delay", 1, &dts);
1496 					bufcount++;
1497 # endif
1498 					(*rbuf->receiver)(rbuf);
1499 				} else {
1500 					msyslog(LOG_ERR, "fatal: receive buffer callback NULL");
1501 					abort();
1502 				}
1503 
1504 				BLOCK_IO_AND_ALARM();
1505 				freerecvbuf(rbuf);
1506 				rbuf = get_full_recv_buffer();
1507 			}
1508 # ifdef DEBUG_TIMING
1509 			get_systime(&tsb);
1510 			L_SUB(&tsb, &tsa);
1511 			if (bufcount) {
1512 				collect_timing(NULL, "processing", bufcount, &tsb);
1513 				DPRINTF(2, ("processing time for %d buffers %s\n", bufcount, lfptoa(&tsb, 9)));
1514 			}
1515 		}
1516 # endif
1517 
1518 		/*
1519 		 * Go around again
1520 		 */
1521 
1522 # ifdef HAVE_DNSREGISTRATION
1523 		if (mdnsreg && (current_time - mdnsreg ) > 60 && mdnstries && sys_leap != LEAP_NOTINSYNC) {
1524 			mdnsreg = current_time;
1525 			msyslog(LOG_INFO, "Attempting to register mDNS");
1526 			if ( DNSServiceRegister (&mdns, 0, 0, NULL, "_ntp._udp", NULL, NULL,
1527 			    htons(NTP_PORT), 0, NULL, NULL, NULL) != kDNSServiceErr_NoError ) {
1528 				if (!--mdnstries) {
1529 					msyslog(LOG_ERR, "Unable to register mDNS, giving up.");
1530 				} else {
1531 					msyslog(LOG_INFO, "Unable to register mDNS, will try later.");
1532 				}
1533 			} else {
1534 				msyslog(LOG_INFO, "mDNS service registered.");
1535 				mdnsreg = FALSE;
1536 			}
1537 		}
1538 # endif /* HAVE_DNSREGISTRATION */
1539 
1540 	}
1541 	UNBLOCK_IO_AND_ALARM();
1542 	return 1;
1543 }
1544 #endif	/* !SIM */
1545 
1546 
1547 #if !defined(SIM) && defined(SIGDIE1)
1548 /*
1549  * finish - exit gracefully
1550  */
1551 static void
1552 finish_safe(
1553 	int	sig
1554 	)
1555 {
1556 	const char *sig_desc;
1557 
1558 	sig_desc = NULL;
1559 #ifdef HAVE_STRSIGNAL
1560 	sig_desc = strsignal(sig);
1561 #endif
1562 	if (sig_desc == NULL)
1563 		sig_desc = "";
1564 	msyslog(LOG_NOTICE, "%s exiting on signal %d (%s)", progname,
1565 		sig, sig_desc);
1566 	/* See Bug 2513 and Bug 2522 re the unlink of PIDFILE */
1567 # ifdef HAVE_DNSREGISTRATION
1568 	if (mdns != NULL)
1569 		DNSServiceRefDeallocate(mdns);
1570 # endif
1571 	peer_cleanup();
1572 	exit(0);
1573 }
1574 
1575 static RETSIGTYPE
1576 finish(
1577 	int	sig
1578 	)
1579 {
1580 	signalled = 1;
1581 	signo = sig;
1582 }
1583 
1584 #endif	/* !SIM && SIGDIE1 */
1585 
1586 
1587 #ifndef SIM
1588 /*
1589  * wait_child_sync_if - implements parent side of -w/--wait-sync
1590  */
1591 # ifdef HAVE_WORKING_FORK
1592 
1593 static int
1594 wait_child_sync_if(
1595 	int		pipe_read_fd,
1596 	unsigned long	wait_sync
1597 	)
1598 {
1599 	int	rc;
1600 	char	ch;
1601 	time_t	wait_end_time;
1602 	time_t	cur_time;
1603 	time_t	wait_rem;
1604 	fd_set	readset;
1605 	struct timeval wtimeout;
1606 
1607 	/* we wait a bit for the child in *any* case, because on failure
1608 	 * of the child we have to get and inspect the exit code!
1609 	 */
1610 	wait_end_time = time(NULL);
1611 	if (wait_sync)
1612 		wait_end_time += wait_sync;
1613 	else
1614 		wait_end_time += 30;
1615 
1616 	do {
1617 		cur_time = time(NULL);
1618 		wait_rem = (wait_end_time > cur_time)
1619 				? (wait_end_time - cur_time)
1620 				: 0;
1621 		wtimeout.tv_sec = wait_rem;
1622 		wtimeout.tv_usec = 0;
1623 		FD_ZERO(&readset);
1624 		FD_SET(pipe_read_fd, &readset);
1625 		rc = select(pipe_read_fd + 1, &readset, NULL, NULL,
1626 			    &wtimeout);
1627 		if (-1 == rc) {
1628 			if (EINTR == errno)
1629 				continue;
1630 			msyslog(LOG_ERR,
1631 				"daemon startup: select failed: %m");
1632 			return EX_IOERR;
1633 		}
1634 		if (0 == rc) {
1635 			/*
1636 			 * select() indicated a timeout, but in case
1637 			 * its timeouts are affected by a step of the
1638 			 * system clock, select() again with a zero
1639 			 * timeout to confirm.
1640 			 */
1641 			FD_ZERO(&readset);
1642 			FD_SET(pipe_read_fd, &readset);
1643 			wtimeout.tv_sec = 0;
1644 			wtimeout.tv_usec = 0;
1645 			rc = select(pipe_read_fd + 1, &readset, NULL,
1646 				    NULL, &wtimeout);
1647 			if (0 == rc)	/* select() timeout */
1648 				break;
1649 		}
1650 		rc = read(pipe_read_fd, &ch, 1);
1651 		if (rc == 0) {
1652 			DPRINTF(2, ("daemon control: got EOF\n"));
1653 			return -1;	/* unexpected EOF, check daemon */
1654 		} else if (rc == 1) {
1655 			DPRINTF(2, ("daemon control: got '%c'\n",
1656 				    (ch >= ' ' ? ch : '.')));
1657 			if (ch == 'R' && !wait_sync)
1658 				return 0;
1659 			if (ch == 'S' && wait_sync)
1660 				return 0;
1661 		} else {
1662 			DPRINTF(2, ("daemon control: read 1 char failed: %s\n",
1663 				    strerror(errno)));
1664 			return EX_IOERR;
1665 		}
1666 	} while (wait_rem > 0);
1667 
1668 	if (wait_sync) {
1669 		fprintf(stderr, "%s: -w/--wait-sync %ld timed out.\n",
1670 			progname, wait_sync);
1671 		return EX_PROTOCOL;
1672 	} else {
1673 		fprintf(stderr, "%s: daemon startup monitoring timed out.\n",
1674 			progname);
1675 		return 0;
1676 	}
1677 }
1678 
1679 
1680 static int
1681 wait_child_exit_if(
1682 	pid_t	cpid,
1683 	int	blocking
1684 	)
1685 {
1686 #    ifdef HAVE_WAITPID
1687 	int	rc = 0;
1688 	int	wstatus;
1689 	if (cpid == waitpid(cpid, &wstatus, (blocking ? 0 : WNOHANG))) {
1690 		DPRINTF(1, ("child (pid=%d) dead now\n", cpid));
1691 		if (WIFEXITED(wstatus)) {
1692 			rc = WEXITSTATUS(wstatus);
1693 			msyslog(LOG_ERR, "daemon child exited with code %d",
1694 				rc);
1695 		} else if (WIFSIGNALED(wstatus)) {
1696 			rc = EX_SOFTWARE;
1697 			msyslog(LOG_ERR, "daemon child died with signal %d",
1698 				WTERMSIG(wstatus));
1699 		} else {
1700 			rc = EX_SOFTWARE;
1701 			msyslog(LOG_ERR, "daemon child died with unknown cause");
1702 		}
1703 	} else {
1704 		DPRINTF(1, ("child (pid=%d) still alive\n", cpid));
1705 	}
1706 	return rc;
1707 #    else
1708 	UNUSED_ARG(cpid);
1709 	return 0;
1710 #    endif
1711 }
1712 
1713 # endif	/* HAVE_WORKING_FORK */
1714 
1715 
1716 /*
1717  * assertion_failed - Redirect assertion failures to msyslog().
1718  */
1719 static void
1720 assertion_failed(
1721 	const char *file,
1722 	int line,
1723 	isc_assertiontype_t type,
1724 	const char *cond
1725 	)
1726 {
1727 	isc_assertion_setcallback(NULL);    /* Avoid recursion */
1728 
1729 	msyslog(LOG_ERR, "%s:%d: %s(%s) failed",
1730 		file, line, isc_assertion_typetotext(type), cond);
1731 	msyslog(LOG_ERR, "exiting (due to assertion failure)");
1732 
1733 #if defined(DEBUG) && defined(SYS_WINNT)
1734 	if (debug)
1735 		DebugBreak();
1736 #endif
1737 
1738 	abort();
1739 }
1740 
1741 
1742 /*
1743  * library_fatal_error - Handle fatal errors from our libraries.
1744  */
1745 static void
1746 library_fatal_error(
1747 	const char *file,
1748 	int line,
1749 	const char *format,
1750 	va_list args
1751 	)
1752 {
1753 	char errbuf[256];
1754 
1755 	isc_error_setfatal(NULL);  /* Avoid recursion */
1756 
1757 	msyslog(LOG_ERR, "%s:%d: fatal error:", file, line);
1758 	vsnprintf(errbuf, sizeof(errbuf), format, args);
1759 	msyslog(LOG_ERR, "%s", errbuf);
1760 	msyslog(LOG_ERR, "exiting (due to fatal error in library)");
1761 
1762 #if defined(DEBUG) && defined(SYS_WINNT)
1763 	if (debug)
1764 		DebugBreak();
1765 #endif
1766 
1767 	abort();
1768 }
1769 
1770 
1771 /*
1772  * library_unexpected_error - Handle non fatal errors from our libraries.
1773  */
1774 # define MAX_UNEXPECTED_ERRORS 100
1775 int unexpected_error_cnt = 0;
1776 static void
1777 library_unexpected_error(
1778 	const char *file,
1779 	int line,
1780 	const char *format,
1781 	va_list args
1782 	)
1783 {
1784 	char errbuf[256];
1785 
1786 	if (unexpected_error_cnt >= MAX_UNEXPECTED_ERRORS)
1787 		return;	/* avoid clutter in log */
1788 
1789 	msyslog(LOG_ERR, "%s:%d: unexpected error:", file, line);
1790 	vsnprintf(errbuf, sizeof(errbuf), format, args);
1791 	msyslog(LOG_ERR, "%s", errbuf);
1792 
1793 	if (++unexpected_error_cnt == MAX_UNEXPECTED_ERRORS)
1794 		msyslog(LOG_ERR, "Too many errors.  Shutting up.");
1795 
1796 }
1797 #endif	/* !SIM */
1798 
1799 #if !defined(SIM) && !defined(SYS_WINNT)
1800 # ifdef DEBUG
1801 
1802 /*
1803  * moredebug - increase debugging verbosity
1804  */
1805 static RETSIGTYPE
1806 moredebug(
1807 	int sig
1808 	)
1809 {
1810 	int saved_errno = errno;
1811 
1812 	if (debug < 255)
1813 	{
1814 		debug++;
1815 		msyslog(LOG_DEBUG, "debug raised to %d", debug);
1816 	}
1817 	errno = saved_errno;
1818 }
1819 
1820 
1821 /*
1822  * lessdebug - decrease debugging verbosity
1823  */
1824 static RETSIGTYPE
1825 lessdebug(
1826 	int sig
1827 	)
1828 {
1829 	int saved_errno = errno;
1830 
1831 	if (debug > 0)
1832 	{
1833 		debug--;
1834 		msyslog(LOG_DEBUG, "debug lowered to %d", debug);
1835 	}
1836 	errno = saved_errno;
1837 }
1838 
1839 # else	/* !DEBUG follows */
1840 
1841 
1842 /*
1843  * no_debug - We don't do the debug here.
1844  */
1845 static RETSIGTYPE
1846 no_debug(
1847 	int sig
1848 	)
1849 {
1850 	int saved_errno = errno;
1851 
1852 	msyslog(LOG_DEBUG, "ntpd not compiled for debugging (signal %d)", sig);
1853 	errno = saved_errno;
1854 }
1855 # endif	/* !DEBUG */
1856 #endif	/* !SIM && !SYS_WINNT */
1857