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363e89b1e

Denys Vlasenko

2009-11-24

FAILED Duration: 32s

Subject

ntpd: use MSG_DONTWAIT; better readability

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 →

networking/ntpd.c +108 -101

networking/ntpd.c+108 -101

@@ -16,7 +16,7 @@
	#define INTERVAL_QUERY_PATHETIC 60
	#define INTERVAL_QUERY_AGRESSIVE 5

-	#define TRUSTLEVEL_BADPEER 6
+	#define TRUSTLEVEL_BADPEER 6 /* bad if less than TRUSTLEVEL_BADPEER */
	#define TRUSTLEVEL_PATHETIC 2
	#define TRUSTLEVEL_AGRESSIVE 8
	#define TRUSTLEVEL_MAX 10
@@ -214,14 +214,13 @@ add_peers(const char *s)
	}

	static double
-	gettime(void)
+	gettime_fp(void)
	{
	struct timeval tv;
	gettimeofday(&tv, NULL); /* never fails */
-	return (tv.tv_sec + JAN_1970 + 1.0e-6 * tv.tv_usec);
+	return (tv.tv_sec + 1.0e-6 * tv.tv_usec + JAN_1970);
	}

-
	static void
	d_to_tv(double d, struct timeval *tv)
	{
@@ -298,9 +297,9 @@ sendmsg_wrap(int fd,

	errno = 0;
	if (!from) {
-	ret = sendto(fd, msg, len, 0, to, addrlen);
+	ret = sendto(fd, msg, len, MSG_DONTWAIT, to, addrlen);
	} else {
-	ret = send_to_from(fd, msg, len, 0, to, from, addrlen);
+	ret = send_to_from(fd, msg, len, MSG_DONTWAIT, to, from, addrlen);
	}
	if (ret != len) {
	bb_perror_msg("send failed");
@@ -310,7 +309,7 @@ sendmsg_wrap(int fd,
	}

	static int
-	client_query(ntp_peer_t *p)
+	send_query_to_peer(ntp_peer_t *p)
	{
	if (p->query.fd == -1) {
	p->query.fd = xsocket(p->lsa->u.sa.sa_family, SOCK_DGRAM, 0);
@@ -336,7 +335,7 @@ client_query(ntp_peer_t *p)

	p->query.msg.xmttime.int_partl = random();
	p->query.msg.xmttime.fractionl = random();
-	p->query.xmttime = gettime();
+	p->query.xmttime = gettime_fp();

	if (sendmsg_wrap(p->query.fd, /from:/ NULL, /to:/ &p->lsa->u.sa, /addrlen:/ p->lsa->len,
	&p->query.msg, NTP_MSGSIZE_NOAUTH) == -1) {
@@ -377,6 +376,7 @@ adjtime_wrap(void)
	{
	ntp_peer_t *p;
	unsigned offset_cnt;
+	unsigned middle;
	int i = 0;
	ntp_peer_t **peers;
	double offset_median;
@@ -394,7 +394,10 @@ adjtime_wrap(void)
	offset_cnt++;
	}

-	peers = xzalloc(sizeof(ntp_peer_t ) offset_cnt);
+	if (offset_cnt == 0)
+	goto clear_good;
+
+	peers = xzalloc(sizeof(peers[0]) * offset_cnt);
	for (item = G.ntp_peers; item != NULL; item = item->link) {
	p = (ntp_peer_t *) item->data;
	if (p->trustlevel < TRUSTLEVEL_BADPEER)
@@ -402,62 +405,55 @@ adjtime_wrap(void)
	peers[i++] = p;
	}

-	qsort(peers, offset_cnt, sizeof(ntp_peer_t *), offset_compare);
-
-	if (offset_cnt != 0) {
-	if ((offset_cnt & 1) == 0) {
-	//TODO: try offset_cnt /= 2...
-	offset_median =
-	(peers[offset_cnt / 2 - 1]->update.offset +
-	peers[offset_cnt / 2]->update.offset) / 2;
-	G.status.rootdelay =
-	(peers[offset_cnt / 2 - 1]->update.delay +
-	peers[offset_cnt / 2]->update.delay) / 2;
-	G.status.stratum = MAX(
-	peers[offset_cnt / 2 - 1]->update.status.stratum,
-	peers[offset_cnt / 2]->update.status.stratum);
-	} else {
-	offset_median = peers[offset_cnt / 2]->update.offset;
-	G.status.rootdelay = peers[offset_cnt / 2]->update.delay;
-	G.status.stratum = peers[offset_cnt / 2]->update.status.stratum;
-	}
-	G.status.leap = peers[offset_cnt / 2]->update.status.leap;
+	qsort(peers, offset_cnt, sizeof(peers[0]), offset_compare);

-	bb_info_msg("adjusting local clock by %fs", offset_median);
+	middle = offset_cnt / 2;
+	if ((offset_cnt & 1) == 0) {
+	offset_median = (peers[middle-1]->update.offset + peers[middle]->update.offset) / 2;
+	G.status.rootdelay = (peers[middle-1]->update.delay + peers[middle]->update.delay) / 2;
+	G.status.stratum = MAX(peers[middle-1]->update.status.stratum, peers[middle]->update.status.stratum);
+	} else {
+	offset_median = peers[middle]->update.offset;
+	G.status.rootdelay = peers[middle]->update.delay;
+	G.status.stratum = peers[middle]->update.status.stratum;
+	}
+	G.status.leap = peers[middle]->update.status.leap;

-	d_to_tv(offset_median, &tv);
-	if (adjtime(&tv, &olddelta) == -1)
-	bb_error_msg("adjtime failed");
-	else if (!G.firstadj
-	&& olddelta.tv_sec == 0
-	&& olddelta.tv_usec == 0
-	&& !G.status.synced
-	) {
-	bb_info_msg("clock synced");
-	G.status.synced = 1;
-	} else if (G.status.synced) {
-	bb_info_msg("clock unsynced");
-	G.status.synced = 0;
-	}
+	bb_info_msg("adjusting local clock by %fs", offset_median);

-	G.firstadj = 0;
-	G.status.reftime = gettime();
-	G.status.stratum++; /* one more than selected peer */
-	G.scale = updated_scale(offset_median);
+	d_to_tv(offset_median, &tv);
+	if (adjtime(&tv, &olddelta) == -1)
+	bb_error_msg("adjtime failed");
+	else if (!G.firstadj
+	&& olddelta.tv_sec == 0
+	&& olddelta.tv_usec == 0
+	&& !G.status.synced
+	) {
+	bb_info_msg("clock synced");
+	G.status.synced = 1;
+	} else if (G.status.synced) {
+	bb_info_msg("clock unsynced");
+	G.status.synced = 0;
+	}
+
+	G.firstadj = 0;
+	G.status.reftime = gettime_fp();
+	G.status.stratum++; /* one more than selected peer */
+	G.scale = updated_scale(offset_median);

-	G.status.refid4 = peers[offset_cnt / 2]->update.status.refid4;
+	G.status.refid4 = peers[middle]->update.status.refid4;

-	lsa = peers[offset_cnt / 2]->lsa;
-	G.status.refid =
+	lsa = peers[middle]->lsa;
+	G.status.refid =
	#if ENABLE_FEATURE_IPV6
-	lsa->u.sa.sa_family != AF_INET ?
-	G.status.refid4 :
+	lsa->u.sa.sa_family != AF_INET ?
+	G.status.refid4 :
	#endif
-	lsa->u.sin.sin_addr.s_addr;
-	}
+	lsa->u.sin.sin_addr.s_addr;

	free(peers);

+	clear_good:
	for (item = G.ntp_peers; item != NULL; item = item->link) {
	p = (ntp_peer_t *) item->data;
	p->update.good = 0;
@@ -514,7 +510,7 @@ settime(double offset)
	}

	static void
-	client_update(ntp_peer_t *p)
+	update_peer_data(ntp_peer_t *p)
	{
	int i, best = 0, good = 0;

@@ -561,7 +557,7 @@ scale_interval(time_t requested)
	}

	static void
-	client_dispatch(ntp_peer_t *p)
+	recv_and_process_peer_pkt(ntp_peer_t *p)
	{
	char *addr;
	ssize_t size;
@@ -572,13 +568,13 @@ client_dispatch(ntp_peer_t *p)

	addr = xmalloc_sockaddr2dotted_noport(&p->lsa->u.sa);

-	//TODO: use MSG_DONTWAIT flag?
-	size = recv(p->query.fd, &msg, sizeof(msg), 0);
+	size = recv(p->query.fd, &msg, sizeof(msg), MSG_DONTWAIT);
	if (size == -1) {
	bb_perror_msg("recv(%s) error", addr);
	if (errno == EHOSTUNREACH \|\| errno == EHOSTDOWN
	\|\| errno == ENETUNREACH \|\| errno == ENETDOWN
	\|\| errno == ECONNREFUSED \|\| errno == EADDRNOTAVAIL
+	\|\| errno == EAGAIN
	) {
	//TODO: always do this?
	set_next(p, error_interval());
@@ -587,7 +583,7 @@ client_dispatch(ntp_peer_t *p)
	xfunc_die();
	}

-	T4 = gettime();
+	T4 = gettime_fp();

	if (size != NTP_MSGSIZE_NOAUTH && size != NTP_MSGSIZE) {
	bb_error_msg("malformed packet received from %s", addr);
@@ -639,6 +635,7 @@ client_dispatch(ntp_peer_t *p)
	goto bail;
	}
	offset->error = (T2 - T1) - (T3 - T4);
+	// Can we use (T4 - JAN_1970) instead of time(NULL)?
	offset->rcvd = time(NULL);
	offset->good = 1;

@@ -664,21 +661,19 @@ client_dispatch(ntp_peer_t *p)

	/* every received reply which we do not discard increases trust */
	if (p->trustlevel < TRUSTLEVEL_MAX) {
-	if (p->trustlevel < TRUSTLEVEL_BADPEER
-	&& p->trustlevel + 1 >= TRUSTLEVEL_BADPEER
-	) {
-	bb_info_msg("peer %s now valid", addr);
-	}
	p->trustlevel++;
+	if (p->trustlevel == TRUSTLEVEL_BADPEER)
+	bb_info_msg("peer %s now valid", addr);
	}

	bb_info_msg("reply from %s: offset %f delay %f, next query %ds", addr,
	offset->offset, offset->delay, (int) interval);

-	client_update(p);
+	update_peer_data(p);
	settime(offset->offset);

-	if (++p->shift >= OFFSET_ARRAY_SIZE)
+	p->shift++;
+	if (p->shift >= OFFSET_ARRAY_SIZE)
	p->shift = 0;

	bail:
@@ -687,7 +682,7 @@ client_dispatch(ntp_peer_t *p)

	#if ENABLE_FEATURE_NTPD_SERVER
	static void
-	server_dispatch(int fd)
+	recv_and_process_client_pkt(void /int fd/)
	{
	ssize_t size;
	uint8_t version;
@@ -702,12 +697,14 @@ server_dispatch(int fd)
	to = get_sock_lsa(G.listen_fd);
	from = xzalloc(to->len);

-	//TODO: use MGS_DONTWAIT flag?
-	size = recv_from_to(fd, &msg, sizeof(msg), 0, from, &to->u.sa, to->len);
+	size = recv_from_to(G.listen_fd, &msg, sizeof(msg), MSG_DONTWAIT, from, &to->u.sa, to->len);
	if (size != NTP_MSGSIZE_NOAUTH && size != NTP_MSGSIZE) {
	char *addr;
-	if (size < 0)
-	bb_error_msg_and_die("recv_from_to");
+	if (size < 0) {
+	if (errno == EAGAIN)
+	goto bail;
+	bb_perror_msg_and_die("recv_from_to");
+	}
	addr = xmalloc_sockaddr2dotted_noport(from);
	bb_error_msg("malformed packet received from %s", addr);
	free(addr);
@@ -727,18 +724,18 @@ server_dispatch(int fd)
	msg.stratum = G.status.stratum;
	msg.ppoll = query_ppoll;
	msg.precision = G.status.precision;
-	rectime = gettime();
+	rectime = gettime_fp();
	msg.xmttime = msg.rectime = d_to_lfp(rectime);
	msg.reftime = d_to_lfp(G.status.reftime);
-	//msg.xmttime = d_to_lfp(gettime()); // = msg.rectime
+	//msg.xmttime = d_to_lfp(gettime_fp()); // = msg.rectime
	msg.orgtime = query_xmttime;
	msg.rootdelay = d_to_sfp(G.status.rootdelay);
	version = (query_status & VERSION_MASK); /* ... >> VERSION_SHIFT - done below instead */
	msg.refid = (version > (3 << VERSION_SHIFT)) ? G.status.refid4 : G.status.refid;

-	/* We reply from the address packet was sent to,
+	/* We reply from the local address packet was sent to,
	* this makes to/from look swapped here: */
-	sendmsg_wrap(fd,
+	sendmsg_wrap(G.listen_fd,
	/from:/ &to->u.sa, /to:/ from, /addrlen:/ to->len,
	&msg, size);

@@ -910,20 +907,23 @@ int ntpd_main(int argc UNUSED_PARAM, char **argv)
	ntp_init(argv);

	{
-	unsigned new_cnt = g.peer_cnt;
-	idx2peer = xzalloc(sizeof(void ) new_cnt);
+	unsigned cnt = g.peer_cnt;
	/* if ENABLE_FEATURE_NTPD_SERVER, + 1 for listen_fd: */
-	pfd = xzalloc(sizeof(pfd[0]) * (new_cnt + ENABLE_FEATURE_NTPD_SERVER));
+	idx2peer = xzalloc(sizeof(void ) (cnt + ENABLE_FEATURE_NTPD_SERVER));
+	pfd = xzalloc(sizeof(pfd[0]) * (cnt + ENABLE_FEATURE_NTPD_SERVER));
	}

	while (!bb_got_signal) {
	llist_t *item;
-	unsigned i, j, first_peer_idx;
+	unsigned i, j;
	unsigned sent_cnt, trial_cnt;
	int nfds, timeout;
-	time_t nextaction;
+	time_t cur_time, nextaction;

-	nextaction = time(NULL) + 3600;
+	/* Nothing between here and poll() blocks for any significant time */
+
+	cur_time = time(NULL);
+	nextaction = cur_time + 3600;

	i = 0;
	#if ENABLE_FEATURE_NTPD_SERVER
@@ -933,22 +933,19 @@ int ntpd_main(int argc UNUSED_PARAM, char **argv)
	i++;
	}
	#endif
-	first_peer_idx = i;
+	/* Pass over peer list, send requests, time out on receives */
	sent_cnt = trial_cnt = 0;
	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 <= time(NULL)) {
+	if (p->next != 0 && p->next <= cur_time) {
+	/* Time to send new req */
	trial_cnt++;
-	if (client_query(p) == 0)
+	if (send_query_to_peer(p) == 0)
	sent_cnt++;
	}
-	if (p->next > 0 && p->next < nextaction)
-	nextaction = p->next;
-	if (p->deadline > 0 && p->deadline < nextaction)
-	nextaction = p->deadline;
-
-	if (p->deadline > 0 && p->deadline <= time(NULL)) {
+	if (p->deadline != 0 && p->deadline <= cur_time) {
+	/* Timed out waiting for reply */
	char *addr = xmalloc_sockaddr2dotted_noport(&p->lsa->u.sa);

	timeout = error_interval();
@@ -964,39 +961,49 @@ int ntpd_main(int argc UNUSED_PARAM, char **argv)
	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->state == STATE_QUERY_SENT) {
+	/* Wait for reply from this peer */
	pfd[i].fd = p->query.fd;
	pfd[i].events = POLLIN;
-	idx2peer[i - first_peer_idx] = p;
+	idx2peer[i] = p;
	i++;
	}
	}

	if ((trial_cnt > 0 && sent_cnt == 0) \|\| g.peer_cnt == 0)
-	settime(0); /* no good peers, don't wait */
+	settime(0); /* no good peers, don't wait */

-	timeout = nextaction - time(NULL);
+	timeout = nextaction - cur_time;
	if (timeout < 0)
	timeout = 0;

+	/* Here we may block */
	if (g.verbose)
	bb_error_msg("entering poll %u secs", timeout);
	nfds = poll(pfd, i, timeout * 1000);
+	if (nfds <= 0)
+	continue;

+	/* Process any received packets */
	j = 0;
	#if ENABLE_FEATURE_NTPD_SERVER
-	//TODO: simplify. There is only one server fd!
-	for (; nfds > 0 && j < first_peer_idx; j++) {
-	if (pfd[j].revents & (POLLIN\|POLLERR)) {
+	if (g.listen_fd != -1) {
+	if (pfd[0].revents /* & (POLLIN\|POLLERR)*/) {
	nfds--;
-	server_dispatch(pfd[j].fd);
+	recv_and_process_client_pkt(/g.listen_fd/);
	}
+	j = 1;
	}
	#endif
-	for (; nfds > 0 && j < i; j++) {
-	if (pfd[j].revents & (POLLIN\|POLLERR)) {
+	for (; nfds != 0 && j < i; j++) {
+	if (pfd[j].revents /* & (POLLIN\|POLLERR)*/) {
	nfds--;
-	client_dispatch(idx2peer[j - first_peer_idx]);
+	recv_and_process_peer_pkt(idx2peer[j]);
	}
	}
	} /* while (!bb_got_signal) */