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907647fb1

Denys Vlasenko

2009-12-02

FAILED Duration: 33s

Subject

ntpd: implement -x. shrink code a bit. -69 bytes

Binary

No binary (build failed)

Architecture & Compiler Flags

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

—

Build Log

(log yok)

Commit Diff GitHub →

include/usage.h +1 -2 networking/ntpd.c +156 -174

include/usage.h+1 -2

@@ -3217,9 +3217,8 @@
	"\nOptions:" \
	"\n -d Verbose" \
	"\n -n Do not daemonize" \
-	"\n -g Set system time even if offset is > 1000 sec" \
	"\n -q Quit after clock is set" \
-	/* -N exists for mostly compat reasons, thus Not essential to inform */ \
+	/* -N exists for mostly compat reasons, thus not essential to inform */ \
	/* the user that it exists: user may use nice as well */ \
	/* "\n -N Run at high priority" */ \
	"\n -l Run as server on port 123" \

networking/ntpd.c+156 -174

@@ -14,11 +14,14 @@
	# error "Sorry, your kernel has to support IP_PKTINFO"
	#endif

-	#define INTERVAL_QUERY_NORMAL 30 /* sync to peers every n secs */
+
+	/* Sync to peers every N secs */
+	#define INTERVAL_QUERY_NORMAL 30
	#define INTERVAL_QUERY_PATHETIC 60
	#define INTERVAL_QUERY_AGRESSIVE 5

-	#define TRUSTLEVEL_BADPEER 6 /* bad if less than TRUSTLEVEL_BADPEER */
+	/* Bad if less than TRUSTLEVEL_BADPEER */
+	#define TRUSTLEVEL_BADPEER 6
	#define TRUSTLEVEL_PATHETIC 2
	#define TRUSTLEVEL_AGRESSIVE 8
	#define TRUSTLEVEL_MAX 10
@@ -26,30 +29,11 @@
	#define QSCALE_OFF_MIN 0.05
	#define QSCALE_OFF_MAX 0.50

-	#define QUERYTIME_MAX 15 /* single query might take n secs max */
-	#define OFFSET_ARRAY_SIZE 8
-	#define SETTIME_MIN_OFFSET 180 /* min offset for settime at start */
-	#define SETTIME_TIMEOUT 15 /* max seconds to wait with -s */
-
-	/* Style borrowed from NTP ref/tcpdump and updated for SNTPv4 (RFC2030). */
+	/* Single query might take n secs max */
+	#define QUERYTIME_MAX 15
+	/* Min offset for settime at start. "man ntpd" says it's 128 ms */
+	#define STEPTIME_MIN_OFFSET 0.128

-	/*
-	* RFC Section 3
-	*
-	* 0 1 2 3
-	* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
-	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-	* \| Integer Part \|
-	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-	* \| Fraction Part \|
-	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-	*
-	* 0 1 2 3
-	* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
-	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-	* \| Integer Part \| Fraction Part \|
-	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-	*/
	typedef struct {
	uint32_t int_partl;
	uint32_t fractionl;
@@ -85,7 +69,7 @@ typedef struct {
	enum {
	NTP_VERSION = 4,
	NTP_MAXSTRATUM = 15,
-	/* Leap Second Codes (high order two bits) */
+	/* Leap Second Codes (high order two bits of m_status) */
	LI_NOWARNING = (0 << 6), /* no warning */
	LI_PLUSSEC = (1 << 6), /* add a second (61 seconds) */
	LI_MINUSSEC = (2 << 6), /* minus a second (59 seconds) */
@@ -121,33 +105,28 @@ typedef struct {
	uint8_t o_good;
	} ntp_offset_t;

+	#define OFFSET_ARRAY_SIZE 8
	typedef struct {
-	//TODO: periodically re-resolve DNS names?
	len_and_sockaddr *lsa;
+	char *hostname;
	char *dotted;
-	double xmttime;
-	time_t next;
-	time_t deadline;
+	/* When to send new query (if fd == -1)
+	* or when receive times out (if fd >= 0): */
+	time_t next_action_time;
	int fd;
-	uint8_t state;
	uint8_t shift;
	uint8_t trustlevel;
	ntp_msg_t msg;
+	double xmttime;
	ntp_offset_t update;
	ntp_offset_t reply[OFFSET_ARRAY_SIZE];
	} ntp_peer_t;
-	/* for ntp_peer_t::state */
-	enum {
-	STATE_NONE,
-	STATE_QUERY_SENT,
-	STATE_REPLY_RECEIVED,
-	};

	enum {
	OPT_n = (1 << 0),
-	OPT_g = (1 << 1),
-	OPT_q = (1 << 2),
-	OPT_N = (1 << 3),
+	OPT_q = (1 << 1),
+	OPT_N = (1 << 2),
+	OPT_x = (1 << 3),
	/* Insert new options above this line. */
	/* Non-compat options: */
	OPT_p = (1 << 4),
@@ -164,12 +143,13 @@ struct globals {
	#endif
	unsigned verbose;
	unsigned peer_cnt;
+	unsigned scale;
	uint32_t refid;
	uint32_t refid4;
-	uint32_t scale;
	uint8_t synced;
	uint8_t leap;
-	int8_t precision;
+	#define G_precision -6
+	// int8_t precision;
	uint8_t stratum;
	uint8_t time_is_stepped;
	uint8_t first_adj_done;
@@ -183,32 +163,28 @@ static const int const_IPTOS_LOWDELAY = IPTOS_LOWDELAY;
	static void
	set_next(ntp_peer_t *p, unsigned t)
	{
-	p->next = time(NULL) + t;
-	p->deadline = 0;
+	p->next_action_time = time(NULL) + t;
	}

	static void
-	add_peers(const char *s)
+	add_peers(char *s)
	{
	ntp_peer_t *p;

	p = xzalloc(sizeof(*p));
-	//TODO: big ntpd uses all IPs, not just 1st, do we need to mimic that?
-	p->lsa = xhost2sockaddr(s, 123);
-	p->dotted = xmalloc_sockaddr2dotted_noport(&p->lsa->u.sa);
+	p->hostname = s;
+	p->dotted = s;
	p->fd = -1;
	p->msg.m_status = MODE_CLIENT \| (NTP_VERSION << 3);
-	if (STATE_NONE != 0)
-	p->state = STATE_NONE;
	p->trustlevel = TRUSTLEVEL_PATHETIC;
-	set_next(p, 0);
+	p->next_action_time = time(NULL); /* = set_next(p, 0); */

	llist_add_to(&G.ntp_peers, p);
	G.peer_cnt++;
	}

	static double
-	gettime1900fp(void)
+	gettime1900d(void)
	{
	struct timeval tv;
	gettimeofday(&tv, NULL); /* never fails */
@@ -268,13 +244,6 @@ d_to_sfp(double d)
	}
	#endif

-	static void
-	set_deadline(ntp_peer_t *p, time_t t)
-	{
-	p->deadline = time(NULL) + t;
-	p->next = 0;
-	}
-
	static unsigned
	error_interval(void)
	{
@@ -328,8 +297,18 @@ send_query_to_peer(ntp_peer_t *p)
	int fd, family;
	len_and_sockaddr *local_lsa;

+	//TODO: big ntpd uses all IPs, not just 1st, do we need to mimic that?
+	//TODO: periodically re-resolve DNS names?
+	if (!p->lsa) {
+	p->lsa = host2sockaddr(p->hostname, 123);
+	if (!p->lsa) {
+	set_next(p, INTERVAL_QUERY_PATHETIC);
+	return -1;
+	}
+	p->dotted = xmalloc_sockaddr2dotted_noport(&p->lsa->u.sa);
+	}
+
	family = p->lsa->u.sa.sa_family;
-	//was: p->fd = xsocket(family, SOCK_DGRAM, 0);
	p->fd = fd = xsocket_type(&local_lsa, family, SOCK_DGRAM);
	/* local_lsa has "null" address and port 0 now.
	* bind() ensures we have a particular port selected by kernel
@@ -362,23 +341,70 @@ send_query_to_peer(ntp_peer_t *p)

	p->msg.m_xmttime.int_partl = random();
	p->msg.m_xmttime.fractionl = random();
-	p->xmttime = gettime1900fp();
+	p->xmttime = gettime1900d();

	if (do_sendto(p->fd, /from:/ NULL, /to:/ &p->lsa->u.sa, /addrlen:/ p->lsa->len,
	&p->msg, NTP_MSGSIZE_NOAUTH) == -1
	) {
+	close(p->fd);
+	p->fd = -1;
	set_next(p, INTERVAL_QUERY_PATHETIC);
	return -1;
	}

	if (G.verbose)
	bb_error_msg("sent query to %s", p->dotted);
-	p->state = STATE_QUERY_SENT;
-	set_deadline(p, QUERYTIME_MAX);
+	set_next(p, QUERYTIME_MAX);

	return 0;
	}

+
+	/* Time is stepped only once, when the first packet from a peer is received.
+	*/
+	static void
+	step_time_once(double offset)
+	{
+	llist_t *item;
+	struct timeval tv;
+	char buf[80];
+	time_t tval;
+
+	if (G.time_is_stepped)
+	goto bail;
+	G.time_is_stepped = 1;
+
+	/* if the offset is small, don't step, slew (later) */
+	if (offset < STEPTIME_MIN_OFFSET && offset > -STEPTIME_MIN_OFFSET)
+	goto bail;
+
+	gettimeofday(&tv, NULL); /* never fails */
+	offset += tv.tv_sec;
+	offset += 1.0e-6 * tv.tv_usec;
+	d_to_tv(offset, &tv);
+
+	if (settimeofday(&tv, NULL) == -1)
+	bb_perror_msg_and_die("settimeofday");
+
+	tval = tv.tv_sec;
+	strftime(buf, sizeof(buf), "%a %b %e %H:%M:%S %Z %Y", localtime(&tval));
+
+	bb_error_msg("setting clock to %s (offset %fs)", buf, offset);
+
+	for (item = G.ntp_peers; item != NULL; item = item->link) {
+	ntp_peer_t p = (ntp_peer_t ) item->data;
+	p->next_action_time -= offset;
+	}
+
+	bail:
+	if (option_mask32 & OPT_q)
+	exit(0);
+	}
+
+
+	/* Time is periodically slewed when we collect enough
+	* good data points.
+	*/
	static int
	compare_offsets(const void aa, const void bb)
	{
@@ -388,8 +414,7 @@ compare_offsets(const void aa, const void bb)
	return -1;
	return ((a)->update.o_offset > (b)->update.o_offset);
	}
-
-	static uint32_t
+	static unsigned
	updated_scale(double offset)
	{
	if (offset < 0)
@@ -400,7 +425,6 @@ updated_scale(double offset)
	return QSCALE_OFF_MAX / QSCALE_OFF_MIN;
	return QSCALE_OFF_MAX / offset;
	}
-
	static void
	slew_time(void)
	{
@@ -409,7 +433,6 @@ slew_time(void)
	struct timeval tv;

	{
-	len_and_sockaddr *lsa;
	ntp_peer_t *peers = xzalloc(sizeof(peers[0]) G.peer_cnt);
	unsigned goodpeer_cnt = 0;
	unsigned middle;
@@ -418,8 +441,10 @@ slew_time(void)
	ntp_peer_t p = (ntp_peer_t ) item->data;
	if (p->trustlevel < TRUSTLEVEL_BADPEER)
	continue;
-	if (!p->update.o_good)
+	if (!p->update.o_good) {
+	free(peers);
	return;
+	}
	peers[goodpeer_cnt++] = p;
	}

@@ -442,38 +467,38 @@ slew_time(void)
	}
	G.leap = peers[middle]->update.o_leap;
	G.refid4 = peers[middle]->update.o_refid4;
-	lsa = peers[middle]->lsa;
	G.refid =
	#if ENABLE_FEATURE_IPV6
-	lsa->u.sa.sa_family != AF_INET ?
+	peers[middle]->lsa->u.sa.sa_family != AF_INET ?
	G.refid4 :
	#endif
-	lsa->u.sin.sin_addr.s_addr;
+	peers[middle]->lsa->u.sin.sin_addr.s_addr;
	free(peers);
	}
+	//TODO: if (offset_median > BIG) step_time(offset_median)?

-	bb_error_msg("adjusting clock by %fs, our stratum is %u", offset_median, G.stratum);
+	G.scale = updated_scale(offset_median);
+
+	bb_error_msg("adjusting clock by %fs, our stratum is %u, time scale %u",
+	offset_median, G.stratum, G.scale);

	errno = 0;
	d_to_tv(offset_median, &tv);
-	if (adjtime(&tv, &tv) == -1) {
-	bb_perror_msg("adjtime failed"); //TODO: maybe _and_die?
-	} else {
-	if (G.verbose >= 2)
-	bb_error_msg("old adjust: %d.%06u", (int)tv.tv_sec, (unsigned)tv.tv_usec);
-	if (G.first_adj_done) {
-	uint8_t synced = (tv.tv_sec == 0 && tv.tv_usec == 0);
-	if (synced != G.synced) {
-	G.synced = synced;
-	bb_error_msg("clock is %ssynced", synced ? "" : "un");
-	}
+	if (adjtime(&tv, &tv) == -1)
+	bb_perror_msg_and_die("adjtime failed");
+	if (G.verbose >= 2)
+	bb_error_msg("old adjust: %d.%06u", (int)tv.tv_sec, (unsigned)tv.tv_usec);
+
+	if (G.first_adj_done) {
+	uint8_t synced = (tv.tv_sec == 0 && tv.tv_usec == 0);
+	if (synced != G.synced) {
+	G.synced = synced;
+	bb_error_msg("clock is %ssynced", synced ? "" : "un");
	}
-	G.first_adj_done = 1;
	}
+	G.first_adj_done = 1;

-	G.reftime = gettime1900fp();
-	//TODO: log if G.scale changed?
-	G.scale = updated_scale(offset_median);
+	G.reftime = gettime1900d();

	clear_good:
	for (item = G.ntp_peers; item != NULL; item = item->link) {
@@ -482,52 +507,6 @@ slew_time(void)
	}
	}

-	static void
-	step_time_once(double offset)
-	{
-	ntp_peer_t *p;
-	llist_t *item;
-	struct timeval tv;
-	char buf[80];
-	time_t tval;
-
-	if (G.time_is_stepped)
-	goto bail;
-	G.time_is_stepped = 1;
-
-	/* if the offset is small, don't call settimeofday */
-	if (offset < SETTIME_MIN_OFFSET && offset > -SETTIME_MIN_OFFSET)
-	goto bail;
-
-	gettimeofday(&tv, NULL); /* never fails */
-	offset += tv.tv_sec;
-	offset += 1.0e-6 * tv.tv_usec;
-	d_to_tv(offset, &tv);
-
-	if (settimeofday(&tv, NULL) == -1) {
-	bb_perror_msg("settimeofday");
-	goto bail;
-	}
-
-	tval = tv.tv_sec;
-	strftime(buf, sizeof(buf), "%a %b %e %H:%M:%S %Z %Y", localtime(&tval));
-
-	// Do we want to print message below to system log when daemonized?
-	bb_error_msg("setting clock to %s (offset %fs)", buf, offset);
-
-	for (item = G.ntp_peers; item != NULL; item = item->link) {
-	p = (ntp_peer_t *) item->data;
-	if (p->next)
-	p->next -= offset;
-	if (p->deadline)
-	p->deadline -= offset;
-	}
-
-	bail:
-	if (option_mask32 & OPT_q)
-	exit(0);
-	}
-
	static void
	update_peer_data(ntp_peer_t *p)
	{
@@ -567,7 +546,6 @@ scale_interval(unsigned requested)
	r = (unsigned)random() % (unsigned)(MAX(5, interval / 10));
	return (interval + r);
	}
-
	static void
	recv_and_process_peer_pkt(ntp_peer_t *p)
	{
@@ -631,7 +609,7 @@ recv_and_process_peer_pkt(ntp_peer_t *p)
	* d = (T4 - T1) - (T3 - T2) t = ((T2 - T1) + (T3 - T4)) / 2.
	*/

-	T4 = gettime1900fp();
+	T4 = gettime1900d();
	T1 = p->xmttime;
	T2 = lfp_to_d(msg.m_rectime);
	T3 = lfp_to_d(msg.m_xmttime);
@@ -668,7 +646,6 @@ recv_and_process_peer_pkt(ntp_peer_t *p)
	interval = scale_interval(INTERVAL_QUERY_NORMAL);

	set_next(p, interval);
-	p->state = STATE_REPLY_RECEIVED;

	/* every received reply which we do not discard increases trust */
	if (p->trustlevel < TRUSTLEVEL_MAX) {
@@ -690,7 +667,7 @@ recv_and_process_peer_pkt(ntp_peer_t *p)
	p->shift = 0;

	close_sock:
-	/* We do not expect any more packets for now.
+	/* We do not expect any more packets from this peer for now.
	* Closing the socket informs kernel about it.
	* We open a new socket when we send a new query.
	*/
@@ -723,10 +700,10 @@ recv_and_process_client_pkt(void /int fd/)
	if (size < 0) {
	if (errno == EAGAIN)
	goto bail;
-	bb_perror_msg_and_die("recv_from_to");
+	bb_perror_msg_and_die("recv");
	}
	addr = xmalloc_sockaddr2dotted_noport(from);
-	bb_error_msg("malformed packet received from %s", addr);
+	bb_error_msg("malformed packet received from %s: size %u", addr, (int)size);
	free(addr);
	goto bail;
	}
@@ -743,11 +720,11 @@ recv_and_process_client_pkt(void /int fd/)
	MODE_SERVER : MODE_SYM_PAS;
	msg.m_stratum = G.stratum;
	msg.m_ppoll = query_ppoll;
-	msg.m_precision = G.precision;
-	rectime = gettime1900fp();
+	msg.m_precision = G_precision;
+	rectime = gettime1900d();
	msg.m_xmttime = msg.m_rectime = d_to_lfp(rectime);
	msg.m_reftime = d_to_lfp(G.reftime);
-	//msg.m_xmttime = d_to_lfp(gettime1900fp()); // = msg.m_rectime
+	//msg.m_xmttime = d_to_lfp(gettime1900d()); // = msg.m_rectime
	msg.m_orgtime = query_xmttime;
	msg.m_rootdelay = d_to_sfp(G.rootdelay);
	version = (query_status & VERSION_MASK); /* ... >> VERSION_SHIFT - done below instead */
@@ -859,7 +836,6 @@ static NOINLINE void ntp_init(char **argv)
	llist_t *peers;

	srandom(getpid());
-	/* tzset(); - why? it's called automatically when needed, no? */

	if (getuid())
	bb_error_msg_and_die(bb_msg_you_must_be_root);
@@ -867,16 +843,15 @@ static NOINLINE void ntp_init(char **argv)
	peers = NULL;
	opt_complementary = "dd:p::"; /* d: counter, p: list */
	opts = getopt32(argv,
-	"ngqN" /* compat */
+	"nqNx" /* compat */
	"p:"IF_FEATURE_NTPD_SERVER("l") /* NOT compat */
	"d" /* compat */
-	"46aAbLx", /* compat, ignored */
+	"46aAbgL", /* compat, ignored */
	&peers, &G.verbose);
	if (!(opts & (OPT_p\|OPT_l)))
	bb_show_usage();
-	//WRONG
-	// if (opts & OPT_g)
-	// G.time_is_stepped = 1;
+	if (opts & OPT_x) /* disable stepping, only slew is allowed */
+	G.time_is_stepped = 1;
	while (peers)
	add_peers(llist_pop(&peers));
	if (!(opts & OPT_n)) {
@@ -896,23 +871,28 @@ static NOINLINE void ntp_init(char **argv)
	setpriority(PRIO_PROCESS, 0, -15);

	/* Set some globals */
+	#if 0
+	/* With constant b = 100, G.precision is also constant -6.
+	* Uncomment this and you'll see */
	{
	int prec = 0;
	int b;
-	#if 0
+	# if 0
	struct timespec tp;
	/* We can use sys_clock_getres but assuming 10ms tick should be fine */
	clock_getres(CLOCK_REALTIME, &tp);
	tp.tv_sec = 0;
	tp.tv_nsec = 10000000;
	b = 1000000000 / tp.tv_nsec; /* convert to Hz */
-	#else
+	# else
	b = 100; /* b = 1000000000/10000000 = 100 */
-	#endif
+	# endif
	while (b > 1)
	prec--, b >>= 1;
-	G.precision = prec;
+	//G.precision = prec;
+	bb_error_msg("G.precision:%d", prec); /* -6 */
	}
+	#endif
	G.scale = 1;

	bb_signals((1 << SIGTERM) \| (1 << SIGINT), record_signo);
@@ -963,31 +943,33 @@ int ntpd_main(int argc UNUSED_PARAM, char **argv)
	for (item = g.ntp_peers; item != NULL; item = item->link) {
	ntp_peer_t p = (ntp_peer_t ) item->data;

-	if (p->next != 0 && p->next <= cur_time) {
-	/* Time to send new req */
-	trial_cnt++;
-	if (send_query_to_peer(p) == 0)
-	sent_cnt++;
-	}
-	if (p->deadline != 0 && p->deadline <= cur_time) {
-	/* Timed out waiting for reply */
-	timeout = error_interval();
-	bb_error_msg("timed out waiting for %s, "
-	"next query in %us", p->dotted, timeout);
-	if (p->trustlevel >= TRUSTLEVEL_BADPEER) {
-	p->trustlevel /= 2;
-	if (p->trustlevel < TRUSTLEVEL_BADPEER)
-	bb_error_msg("peer %s now invalid", p->dotted);
+	/* Overflow-safe "if (p->next_action_time <= cur_time) ..." */
+	if ((int)(cur_time - p->next_action_time) >= 0) {
+	if (p->fd == -1) {
+	/* Time to send new req */
+	trial_cnt++;
+	if (send_query_to_peer(p) == 0)
+	sent_cnt++;
+	} else {
+	/* Timed out waiting for reply */
+	close(p->fd);
+	p->fd = -1;
+	timeout = error_interval();
+	bb_error_msg("timed out waiting for %s, "
+	"next query in %us", p->dotted, timeout);
+	if (p->trustlevel >= TRUSTLEVEL_BADPEER) {
+	p->trustlevel /= 2;
+	if (p->trustlevel < TRUSTLEVEL_BADPEER)
+	bb_error_msg("peer %s now invalid", p->dotted);
+	}
+	set_next(p, timeout);
	}
-	set_next(p, timeout);
	}

-	if (p->next != 0 && p->next < nextaction)
-	nextaction = p->next;
-	if (p->deadline != 0 && p->deadline < nextaction)
-	nextaction = p->deadline;
+	if (p->next_action_time < nextaction)
+	nextaction = p->next_action_time;

-	if (p->state == STATE_QUERY_SENT) {
+	if (p->fd >= 0) {
	/* Wait for reply from this peer */
	pfd[i].fd = p->fd;
	pfd[i].events = POLLIN;
@@ -1005,7 +987,7 @@ int ntpd_main(int argc UNUSED_PARAM, char **argv)

	/* Here we may block */
	if (g.verbose >= 2)
-	bb_error_msg("poll %u sec, sockets:%u", timeout, i);
+	bb_error_msg("poll %us, sockets:%u", timeout, i);
	nfds = poll(pfd, i, timeout * 1000);
	if (nfds <= 0)
	continue;