From: Patrick Oppenlander <patrick.oppenlan...@gmail.com>
The existing implementation of getting leap second information from a
timezone in get_tz_leap() relies on non-portable C library behaviour.
This leads to "Timezone right/UTC failed leap second check, ignoring"
errors on musl based systems as musl does not support right/* timezones
or returning leap second information in the tm_sec field of struct tm.
This patch adds support for getting leap second information from the
leap-seconds.list file included with tzdata and adds a new configuration
directive leapsecdb to switch on the feature.
---
conf.c | 14 ++++
conf.h | 1 +
doc/chrony.conf.adoc | 19 ++++-
reference.c | 162 +++++++++++++++++++++++++++++++++++++++++--
4 files changed, 188 insertions(+), 8 deletions(-)
diff --git a/conf.c b/conf.c
index fa74459..3b1f70c 100644
--- a/conf.c
+++ b/conf.c
@@ -249,6 +249,9 @@ static REF_LeapMode leapsec_mode = REF_LeapModeSystem;
/* Name of a system timezone containing leap seconds occuring at midnight */
static char *leapsec_tz = NULL;
+/* File name of leap second database, usually
/usr/share/zoneinfo/leap-seconds.list */
+static char *leapsec_db = NULL;
+
/* Name of the user to which will be dropped root privileges. */
static char *user;
@@ -471,6 +474,7 @@ CNF_Finalise(void)
Free(hwclock_file);
Free(keys_file);
Free(leapsec_tz);
+ Free(leapsec_db);
Free(logdir);
Free(bind_ntp_iface);
Free(bind_acq_iface);
@@ -620,6 +624,8 @@ CNF_ParseLine(const char *filename, int number, char *line)
parse_leapsecmode(p);
} else if (!strcasecmp(command, "leapsectz")) {
parse_string(p, &leapsec_tz);
+ } else if (!strcasecmp(command, "leapsecdb")) {
+ parse_string(p, &leapsec_db);
} else if (!strcasecmp(command, "local")) {
parse_local(p);
} else if (!strcasecmp(command, "lock_all")) {
@@ -2386,6 +2392,14 @@ CNF_GetLeapSecTimezone(void)
/* ================================================== */
+char *
+CNF_GetLeapSecDatabase(void)
+{
+ return leapsec_db;
+}
+
+/* ================================================== */
+
int
CNF_GetSchedPriority(void)
{
diff --git a/conf.h b/conf.h
index 58ebdeb..b6d9827 100644
--- a/conf.h
+++ b/conf.h
@@ -91,6 +91,7 @@ extern char *CNF_GetNtpSigndSocket(void);
extern char *CNF_GetPidFile(void);
extern REF_LeapMode CNF_GetLeapSecMode(void);
extern char *CNF_GetLeapSecTimezone(void);
+extern char *CNF_GetLeapSecDatabase(void);
/* Value returned in ppm, as read from file */
extern double CNF_GetMaxUpdateSkew(void);
diff --git a/doc/chrony.conf.adoc b/doc/chrony.conf.adoc
index abb8403..2c223fb 100644
--- a/doc/chrony.conf.adoc
+++ b/doc/chrony.conf.adoc
@@ -672,9 +672,10 @@ trusted and required source.
*tai*:::
This option indicates that the reference clock keeps time in TAI instead of UTC
and that *chronyd* should correct its offset by the current TAI-UTC offset. The
-<<leapsectz,*leapsectz*>> directive must be used with this option and the
-database must be kept up to date in order for this correction to work as
-expected. This option does not make sense with PPS refclocks.
+<<leapsectz,*leapsectz*>> or <<leapsecdb,*leapsecdb*>> directive must be used
+with this option and the database must be kept up to date in order for this
+correction to work as expected. This option does not make sense with PPS
+refclocks.
*local*:::
This option specifies that the reference clock is an unsynchronised clock which
is more stable than the system clock (e.g. TCXO, OCXO, or atomic clock) and
@@ -1261,6 +1262,18 @@ $ TZ=right/UTC date -d 'Dec 31 2008 23:59:60'
Wed Dec 31 23:59:60 UTC 2008
----
+[[leapsecdb]]*leapsecdb* _file_::
+This directive specifies the path to a file containing a list of leap seconds.
+It is recommended to use the file _leap-seconds.list_ usually included with the
+system timezone database. The behaviour of this directive is otherwise
equivalent
+to <<leapsectz,*leapsectz*>>.
++
+An example of this directive is:
++
+----
+leapsecdb /usr/share/zoneinfo/leap-seconds.list
+----
+
[[makestep]]*makestep* _threshold_ _limit_::
Normally *chronyd* will cause the system to gradually correct any time offset,
by slowing down or speeding up the clock as required. In certain situations,
diff --git a/reference.c b/reference.c
index 97dfbe9..9d365eb 100644
--- a/reference.c
+++ b/reference.c
@@ -125,6 +125,9 @@ static SCH_TimeoutID leap_timeout_id;
/* Name of a system timezone containing leap seconds occuring at midnight */
static char *leap_tzname;
+/* File name of leap second database, usually
/usr/share/zoneinfo/leap-seconds.list */
+static char *leap_db;
+
/* ================================================== */
static LOG_FileID logfileid;
@@ -155,7 +158,20 @@ static int ref_adjustments;
/* ================================================== */
+/* Leap second database */
+struct leapdb {
+ long long updated;
+ long long expiry;
+ size_t len;
+ struct leap {
+ long long when;
+ int tai_offset;
+ } leap[];
+};
+
static NTP_Leap get_tz_leap(time_t when, int *tai_offset);
+static NTP_Leap get_db_leap(time_t when, int *tai_offset);
+struct leapdb *read_leap_second_database(const char *file);
static void update_leap_status(NTP_Leap leap, time_t now, int reset);
/* ================================================== */
@@ -260,6 +276,18 @@ REF_Initialise(void)
if (leap_mode == REF_LeapModeSystem && !LCL_CanSystemLeap())
leap_mode = REF_LeapModeStep;
+ leap_db = CNF_GetLeapSecDatabase();
+ if (leap_db) {
+ /* Check that the leap database has good data for Jun 30 2012 and Dec 31
2012 */
+ if (get_db_leap(1341014400, &tai_offset) == LEAP_InsertSecond &&
tai_offset == 34 &&
+ get_db_leap(1356912000, &tai_offset) == LEAP_Normal && tai_offset ==
35) {
+ LOG(LOGS_INFO, "Using leap second database %s", leap_db);
+ } else {
+ LOG(LOGS_WARN, "Leap second database %s failed check, ignoring",
leap_db);
+ leap_db = NULL;
+ }
+ }
+
leap_tzname = CNF_GetLeapSecTimezone();
if (leap_tzname) {
/* Check that the timezone has good data for Jun 30 2012 and Dec 31 2012 */
@@ -272,6 +300,11 @@ REF_Initialise(void)
}
}
+ if (leap_db && leap_tzname) {
+ LOG(LOGS_WARN, "Multiple leap second sources, ignoring leapsectz");
+ leap_tzname = NULL;
+ }
+
CNF_GetMakeStep(&make_step_limit, &make_step_threshold);
CNF_GetMaxChange(&max_offset_delay, &max_offset_ignore, &max_offset);
CNF_GetMailOnChange(&do_mail_change, &mail_change_threshold,
&mail_change_user);
@@ -664,6 +697,124 @@ get_tz_leap(time_t when, int *tai_offset)
/* ================================================== */
+static NTP_Leap
+get_db_leap(time_t when, int *tai_offset)
+{
+ static time_t db_leap_check;
+ static NTP_Leap db_leap;
+ static int db_tai_offset;
+ static struct leapdb *db;
+
+ *tai_offset = db_tai_offset;
+
+ /* Do this check at most twice a day */
+ when = when / (12 * 3600) * (12 * 3600);
+ if (db_leap_check == when)
+ return db_leap;
+ db_leap_check = when;
+
+ struct leapdb *new_db = read_leap_second_database(leap_db);
+ if (new_db) {
+ free(db);
+ db = new_db;
+ } else
+ LOG(LOGS_ERR, "Failed to read leap second database %s", leap_db);
+
+ if (!db)
+ return db_leap;
+
+ /* leap second happens at midnight */
+ when = (when / (24 * 3600) + 1) * (24 * 3600);
+
+ /* leap-seconds.list timestamps are relative to 1 Jan 1900, 00:00:00 */
+ long long leap_when = when + 2208988800;
+ db_leap = LEAP_Normal;
+
+ if (leap_when >= db->expiry)
+ LOG(LOGS_WARN, "Leap second database %s needs update", leap_db);
+
+ /* find leap entry */
+ struct leap *lp = db->leap;
+ for (int i = db->len - 1; i >= 0; --i) {
+ lp = db->leap + i;
+ if (leap_when >= lp->when)
+ break;
+ }
+
+ if (leap_when == lp->when) {
+ struct leap *lp_prev = lp > db->leap ? lp - 1 : db->leap;
+ if (lp->tai_offset > lp_prev->tai_offset) {
+ db_leap = LEAP_InsertSecond;
+ } else if (lp->tai_offset < lp_prev->tai_offset)
+ db_leap = LEAP_DeleteSecond;
+ /* tai offset hasn't changed yet! */
+ db_tai_offset = lp_prev->tai_offset;
+ } else
+ db_tai_offset = lp->tai_offset;
+
+ *tai_offset = db_tai_offset;
+ return db_leap;
+}
+
+/* ================================================== */
+
+struct leapdb *
+read_leap_second_database(const char *file)
+{
+ size_t ll = 0;
+ size_t len = 32; /* 28 entries to 1 Jan 2017 */
+ struct leapdb *db = calloc(1, sizeof *db + sizeof *db->leap * len);
+ FILE *f = fopen(file, "r");
+ char *l = NULL;
+
+ if (!db || !f)
+ goto error;
+
+ while (getline(&l, &ll, f) > 0) {
+ if (*l == '#') {
+ /* update time */
+ if (l[1] == '$' && sscanf(l + 2, "%lld", &db->updated) != 1)
+ goto error;
+ /* expiration time */
+ if (l[1] == '@' && sscanf(l + 2, "%lld", &db->expiry) != 1)
+ goto error;
+ /* comment or a special comment we don't care about */
+ continue;
+ }
+
+ if (db->len >= len) {
+ len += len / 2;
+ void *p = realloc(db, sizeof *db + sizeof *db->leap * len);
+ if (!p)
+ goto error;
+ db = p;
+ }
+
+ /* leap entry */
+ struct leap *lp = db->leap + db->len;
+ if (sscanf(l, "%lld %d", &lp->when, &lp->tai_offset) != 2)
+ goto error;
+ ++db->len;
+ }
+
+ /* make sure the database looks sensible */
+ if (!feof(f) || !db->updated || !db->expiry || !db->len)
+ goto error;
+
+ goto out;
+
+error:
+ free(db);
+ db = 0;
+out:
+ free(l);
+ if (f)
+ fclose(f);
+ return db;
+}
+
+/* ================================================== */
+
static void
leap_end_timeout(void *arg)
{
@@ -751,17 +902,18 @@ set_leap_timeout(time_t now)
static void
update_leap_status(NTP_Leap leap, time_t now, int reset)
{
- NTP_Leap tz_leap;
+ NTP_Leap tz_leap = LEAP_Normal;
int leap_sec, tai_offset;
leap_sec = 0;
tai_offset = 0;
- if (leap_tzname && now) {
+ if (leap_db && now)
+ tz_leap = get_db_leap(now, &tai_offset);
+ if (leap_tzname && now)
tz_leap = get_tz_leap(now, &tai_offset);
- if (leap == LEAP_Normal)
- leap = tz_leap;
- }
+ if (leap == LEAP_Normal)
+ leap = tz_leap;
if (leap == LEAP_InsertSecond || leap == LEAP_DeleteSecond) {
/* Check that leap second is allowed today */
--
2.43.0
--
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