Separate ntpd support from chrony support, step 1.

ntp_offset becomes time_offset. There is a new config symbol CHRONY_ENABLE;
most time service code is npw controlled by TIMESERVICE_ENABLE.  The
file ntpshm.c becomes timeexport.c

This change is not complete. More disentanglement has to be done inside
timeexport.c itself; at the moment enabling one but not both of
ntpshm or chrony will probably break its compile.  The point of getting
this commit out is so Gary will see the new baseline code ASAP.

All regression tests pass.

23 files changed, 203 insertions, 179 deletions

diff --git a/SConstruct b/SConstruct
index b63c000a..71fc4a62 100644
--- a/SConstruct
+++ b/SConstruct
@@ -123,6 +123,7 @@ boolopts = (
     ("rtcm104v3",     True,  "rtcm104v3 support"),
     # Time service
     ("ntpshm",        True,  "NTP time hinting support"),
+    ("chrony",        True,  "chrony time hinting support"),
     ("pps",           True,  "PPS time syncing support"),
     # Export methods
     ("socket_export", True,  "data export over sockets"),
@@ -575,8 +576,7 @@ else:
     bluezlibs = []
     env["bluez"] = False
 
-# ntpshm is required for pps support
-if env['pps'] and env['ntpshm'] and config.CheckHeader("sys/timepps.h"):
+if env['pps'] and config.CheckHeader("sys/timepps.h"):
     confdefs.append("#define HAVE_SYS_TIMEPPS_H 1\n")
     announce("You have kernel PPS available.")
 else:
@@ -966,7 +966,7 @@ env.StaticLibrary(target = 'libgps.a', source = libgps_sources)
 
 # Source groups
 
-gpsd_sources = ['gpsd.c','ntpshm.c','shmexport.c','dbusexport.c']
+gpsd_sources = ['gpsd.c','timeexport.c','shmexport.c','dbusexport.c']
 
 if env['systemd']:
     gpsd_sources.append("sd_socket.c")
diff --git a/driver_evermore.c b/driver_evermore.c
index 50b4823f..a73317bf 100644
--- a/driver_evermore.c
+++ b/driver_evermore.c
@@ -633,9 +633,9 @@ const struct gps_type_t evermore_binary =
 #ifdef CONTROLSEND_ENABLE
     .control_send   = evermore_control_send,	/* how to send a control string */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,		/* no method for NTP fudge factor */
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    .time_offset     = NULL,		/* no method for NTP fudge factor */
+#endif /* ENABLE ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* defined(EVERMORE_ENABLE) && defined(BINARY_ENABLE) */
diff --git a/driver_garmin.c b/driver_garmin.c
index 32015573..e51beda0 100644
--- a/driver_garmin.c
+++ b/driver_garmin.c
@@ -1224,8 +1224,8 @@ static ssize_t garmin_control_send(struct gps_device_t *session,
 }
 #endif /* CONTROLSEND_ENABLE */
 
-#ifdef NTPSHM_ENABLE
-static double garmin_ntp_offset(struct gps_device_t *session)
+#ifdef TIMESERVICE_ENABLE
+static double garmin_time_offset(struct gps_device_t *session)
 {
     if (session->sourcetype == source_usb) {
 	return 0.035;		/* Garmin USB, expect +/- 40mS jitter */
@@ -1244,7 +1244,7 @@ static double garmin_ntp_offset(struct gps_device_t *session)
     }
     return 0.430;		/* WTF?  WAG */
 }
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMESERVICE_ENABLE */
 
 /* this is everything we export */
 #ifdef __UNUSED__
@@ -1391,9 +1391,9 @@ const struct gps_type_t garmin_usb_binary_old =
 #ifdef CONTROLSEND_ENABLE
     .control_send   = garmin_control_send,	/* send raw bytes */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = garmin_ntp_offset,
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    .time_offset     = garmin_time_offset,
+#endif /* ENABLE ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* __UNUSED__ */
@@ -1420,9 +1420,9 @@ const struct gps_type_t garmin_usb_binary =
 #ifdef CONTROLSEND_ENABLE
     .control_send   = garmin_control_send,	/* send raw bytes */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = garmin_ntp_offset,
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    .time_offset     = garmin_time_offset,
+#endif /* ENABLE ENABLE */
 };
 /* *INDENT-ON* */
 
@@ -1448,9 +1448,9 @@ const struct gps_type_t garmin_ser_binary =
 #ifdef CONTROLSEND_ENABLE
     .control_send   = garmin_control_send,	/* send raw bytes */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = garmin_ntp_offset,
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    .time_offset     = garmin_time_offset,
+#endif /* ENABLE ENABLE */
 };
 /* *INDENT-ON* */
 
diff --git a/driver_geostar.c b/driver_geostar.c
index d819e4ad..fd264d5f 100644
--- a/driver_geostar.c
+++ b/driver_geostar.c
@@ -599,12 +599,12 @@ static void geostar_mode(struct gps_device_t *session, int mode)
 }
 #endif /* RECONFIGURE_ENABLE */
 
-#ifdef NTPSHM_ENABLE
-static double geostar_ntp_offset(struct gps_device_t *session UNUSED)
+#ifdef TIMESERVICE_ENABLE
+static double geostar_time_offset(struct gps_device_t *session UNUSED)
 {
     return 0.31;
 }
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMESERVICE_ENABLE */
 
 /* this is everything we export */
 /* *INDENT-OFF* */
@@ -629,9 +629,9 @@ const struct gps_type_t geostar_binary =
 #ifdef CONTROLSEND_ENABLE
     .control_send   = geostar_control_send,/* how to send commands */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = geostar_ntp_offset,
-#endif /* NTPSHM_ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    .time_offset     = geostar_time_offset,
+#endif /* TIMESERVICE_ENABLE */
 };
 /* *INDENT-ON* */
 
diff --git a/driver_italk.c b/driver_italk.c
index 2521351f..359614bb 100644
--- a/driver_italk.c
+++ b/driver_italk.c
@@ -418,9 +418,9 @@ const struct gps_type_t italk_binary =
 #ifdef CONTROLSEND_ENABLE
     .control_send   = NULL,		/* no control string sender */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,		/* no method for NTP fudge factor */
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    .time_offset     = NULL,		/* no method for NTP fudge factor */
+#endif /* ENABLE ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* defined(ITRAX_ENABLE) && defined(BINARY_ENABLE) */
diff --git a/driver_navcom.c b/driver_navcom.c
index 5c6fbd24..f04ce80a 100644
--- a/driver_navcom.c
+++ b/driver_navcom.c
@@ -1296,9 +1296,9 @@ const struct gps_type_t navcom_binary =
 #ifdef CONTROLSEND_ENABLE
     .control_send   = navcom_control_send,	/* how to send a control string */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,		/* no method for NTP fudge factor */
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    .time_offset     = NULL,		/* no method for NTP fudge factor */
+#endif /* ENABLE ENABLE */
 };
 /* *INDENT-ON* */
 
diff --git a/driver_nmea2000.c b/driver_nmea2000.c
index 68a942ae..562f37dd 100644
--- a/driver_nmea2000.c
+++ b/driver_nmea2000.c
@@ -1570,9 +1570,9 @@ const struct gps_type_t nmea2000 = {
 #ifdef CONTROLSEND_ENABLE
     .control_send   = NULL,		/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    .time_offset     = NULL,
+#endif /* ENABLE ENABLE */
 };
 /* *INDENT-ON* */
 
diff --git a/driver_oncore.c b/driver_oncore.c
index 0152933a..0179b53f 100644
--- a/driver_oncore.c
+++ b/driver_oncore.c
@@ -454,8 +454,8 @@ static void oncore_event_hook(struct gps_device_t *session, event_t event)
     }
 }
 
-#ifdef NTPSHM_ENABLE
-static double oncore_ntp_offset(struct gps_device_t *session UNUSED)
+#ifdef TIMESERVICE_ENABLE
+static double oncore_time_offset(struct gps_device_t *session UNUSED)
 {
     /*
      * Only one sentence (NAVSOL) ships time.  0.175 seems best at
@@ -464,7 +464,7 @@ static double oncore_ntp_offset(struct gps_device_t *session UNUSED)
      */
     return 0.175;
 }
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMESERVICE_ENABLE */
 
 static gps_mask_t oncore_parse_input(struct gps_device_t *session)
 {
@@ -503,9 +503,9 @@ const struct gps_type_t oncore_binary = {
     /* Control string sender - should provide checksum and headers/trailer */
     .control_send   = oncore_control_send,	/* to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset = oncore_ntp_offset,		/* NTP offset array */
-#endif /* NTPSHM_ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    .time_offset = oncore_time_offset,		/* NTP offset array */
+#endif /* TIMESERVICE_ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* defined(ONCORE_ENABLE) && defined(BINARY_ENABLE) */
diff --git a/driver_proto.c b/driver_proto.c
index f9f7f060..f14e0e75 100644
--- a/driver_proto.c
+++ b/driver_proto.c
@@ -453,8 +453,8 @@ static void _proto__set_mode(struct gps_device_t *session, int mode)
 }
 #endif /* RECONFIGURE_ENABLE */
 
-#ifdef NTPSHM_ENABLE
-static double _proto_ntp_offset(struct gps_device_t *session)
+#ifdef TIMESERVICE_ENABLE
+static double _proto_time_offset(struct gps_device_t *session)
 {
     /*
      * If NTP notification is enabled, the GPS will occasionally NTP
@@ -468,7 +468,7 @@ static double _proto_ntp_offset(struct gps_device_t *session)
      */
     return MAGIC_CONSTANT;
 }
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMESERVICE_ENABLE */
 
 static void _proto__wrapup(struct gps_device_t *session)
 {
@@ -525,9 +525,9 @@ const struct gps_type_t _proto__binary = {
     /* Control string sender - should provide checksum and headers/trailer */
     .control_send   = _proto__control_send,
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = _proto_ntp_offset,
-#endif /* NTPSHM_ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    .time_offset     = _proto_time_offset,
+#endif /* TIMESERVICE_ENABLE */
 /* *INDENT-ON* */
 };
 #endif /* defined(_PROTO__ENABLE) && defined(BINARY_ENABLE) */
diff --git a/driver_sirf.c b/driver_sirf.c
index 48902343..275bbc31 100644
--- a/driver_sirf.c
+++ b/driver_sirf.c
@@ -486,9 +486,9 @@ static gps_mask_t sirf_msg_swversion(struct gps_device_t *session,
     gpsd_report(session->context->debug, LOG_PROG,
 		"SiRF: fv: %0.2f, Driver state flags are: %0x\n",
 		fv, session->driver.sirf.driverstate);
-#ifdef NTPSHM_ENABLE
+#ifdef TIMESERVICE_ENABLE
     session->driver.sirf.time_seen = 0;
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMESERVICE_ENABLE */
     gpsd_report(session->context->debug, LOG_DATA,
 		"SiRF: FV MID 0x06: subtype='%s' mask={DEVICEID}\n",
 		session->subtype);
@@ -577,7 +577,7 @@ static gps_mask_t sirf_msg_svinfo(struct gps_device_t *session,
 		&& session->driver.sirf.dgps_source == SIRF_DGPS_SOURCE_SBAS)
 	    session->gpsdata.used[session->gpsdata.satellites_used++] = prn;
     }
-#ifdef NTPSHM_ENABLE
+#ifdef TIMESERVICE_ENABLE
     if (st < 3) {
 	gpsd_report(session->context->debug, LOG_PROG,
 		    "SiRF: NTPD not enough satellites seen: %d\n", st);
@@ -589,15 +589,15 @@ static gps_mask_t sirf_msg_svinfo(struct gps_device_t *session,
 		    session->gpsdata.skyview_time,
 		    session->context->leap_seconds);
     }
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMESERVICE_ENABLE */
     gpsd_report(session->context->debug, LOG_DATA,
 		"SiRF: MTD 0x04: visible=%d mask={SATELLITE}\n",
 		session->gpsdata.satellites_visible);
     return SATELLITE_SET;
 }
 
-#ifdef NTPSHM_ENABLE
-static double sirf_ntp_offset(struct gps_device_t *session)
+#ifdef TIMESERVICE_ENABLE
+static double sirf_time_offset(struct gps_device_t *session)
 /* return NTP time-offset fudge factor for this device */
 {
     double retval = NAN;
@@ -650,7 +650,7 @@ static double sirf_ntp_offset(struct gps_device_t *session)
 
     return retval;
 }
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMESERVICE_ENABLE */
 
 static gps_mask_t sirf_msg_navsol(struct gps_device_t *session,
 				  unsigned char *buf, size_t len)
@@ -695,7 +695,7 @@ static gps_mask_t sirf_msg_navsol(struct gps_device_t *session,
     /* byte 21 is "mode 2", not clear how to interpret that */
     session->newdata.time = gpsd_gpstime_resolve(session,
 	(unsigned short)getbes16(buf, 22), (double)getbeu32(buf, 24) * 1e-2);
-#ifdef NTPSHM_ENABLE
+#ifdef TIMESERVICE_ENABLE
     if (session->newdata.mode <= MODE_NO_FIX) {
 	gpsd_report(session->context->debug, LOG_PROG,
 		    "SiRF: NTPD no fix, mode: %d\n",
@@ -706,7 +706,7 @@ static gps_mask_t sirf_msg_navsol(struct gps_device_t *session,
 		    session->driver.sirf.time_seen,
 		    session->newdata.time, session->context->leap_seconds);
     }
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMESERVICE_ENABLE */
     /* fix quality data */
     session->gpsdata.dop.hdop = (double)getub(buf, 20) / 5.0;
     mask |=
@@ -846,7 +846,7 @@ static gps_mask_t sirf_msg_geodetic(struct gps_device_t *session,
 	gpsd_report(session->context->debug, LOG_PROG,
 		    "SiRF: GND 0x29 UTC: %lf\n",
 		    session->newdata.time);
-#ifdef NTPSHM_ENABLE
+#ifdef TIMESERVICE_ENABLE
 	if (session->newdata.mode <= MODE_NO_FIX) {
 	    gpsd_report(session->context->debug, LOG_PROG,
 			"SiRF: NTPD no fix, mode: $d\n",
@@ -864,7 +864,7 @@ static gps_mask_t sirf_msg_geodetic(struct gps_device_t *session,
 	    mask |= PPSTIME_IS;
 	}
 
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMESERVICE_ENABLE */
 	/* skip 4 bytes of satellite map */
 	session->newdata.altitude = getbes32(buf, 35) * 1e-2;
 	/* skip 1 byte of map datum */
@@ -979,7 +979,7 @@ static gps_mask_t sirf_msg_ublox(struct gps_device_t *session,
 	/*@ -compdef */
 	session->newdata.time = (timestamp_t)mkgmtime(&unpacked_date) + subseconds;
 	/*@ +compdef */
-#ifdef NTPSHM_ENABLE
+#ifdef TIMESERVICE_ENABLE
 	if (0 == (session->driver.sirf.time_seen & TIME_SEEN_UTC_2)) {
 	    gpsd_report(session->context->debug, LOG_RAW,
 			"SiRF: NTPD just SEEN_UTC_2\n");
@@ -988,7 +988,7 @@ static gps_mask_t sirf_msg_ublox(struct gps_device_t *session,
 		    "SiRF: NTPD valid time MID 0x62, seen=0x%02x\n",
 		    session->driver.sirf.time_seen);
 	session->driver.sirf.time_seen |= TIME_SEEN_UTC_2;
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMESERVICE_ENABLE */
 	session->context->valid |= LEAP_SECOND_VALID;
     }
 
@@ -1034,7 +1034,7 @@ static gps_mask_t sirf_msg_ppstime(struct gps_device_t *session,
 	/*@ +compdef */
 	session->context->leap_seconds = (int)getbeu16(buf, 8);
 	session->context->valid |= LEAP_SECOND_VALID;
-#ifdef NTPSHM_ENABLE
+#ifdef TIMESERVICE_ENABLE
 	if (0 == (session->driver.sirf.time_seen & TIME_SEEN_UTC_2)) {
 	    gpsd_report(session->context->debug, LOG_RAW,
 			"SiRF: NTPD just SEEN_UTC_2\n");
@@ -1044,7 +1044,7 @@ static gps_mask_t sirf_msg_ppstime(struct gps_device_t *session,
 		    session->driver.sirf.time_seen,
 		    session->context->leap_seconds);
 	session->driver.sirf.time_seen |= TIME_SEEN_UTC_2;
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMESERVICE_ENABLE */
 	mask |= TIME_SET;
 	if ( 3 <= session->gpsdata.satellites_visible ) {
 	    mask |= PPSTIME_IS;
@@ -1385,8 +1385,8 @@ const struct gps_type_t sirf_binary =
 #ifdef CONTROLSEND_ENABLE
     .control_send   = sirf_control_send,/* how to send a control string */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = sirf_ntp_offset,
+#ifdef TIMESERVICE_ENABLE
+    .time_offset     = sirf_time_offset,
 #endif /* NTP_SHM_ENABLE */
 };
 /* *INDENT-ON* */
diff --git a/driver_superstar2.c b/driver_superstar2.c
index 31a8658c..d98fa697 100644
--- a/driver_superstar2.c
+++ b/driver_superstar2.c
@@ -575,9 +575,9 @@ const struct gps_type_t superstar2_binary = {
     /* Control string sender - should provide checksum and trailer */
     .control_send	= superstar2_control_send,
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,		/* no method for NTP fudge factor */
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    .time_offset     = NULL,		/* no method for NTP fudge factor */
+#endif /* ENABLE ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* defined(SUPERSTAR2_ENABLE) && defined(BINARY_ENABLE) */
diff --git a/driver_tsip.c b/driver_tsip.c
index 087dfccf..ddc79395 100644
--- a/driver_tsip.c
+++ b/driver_tsip.c
@@ -1151,13 +1151,13 @@ static void tsip_mode(struct gps_device_t *session, int mode)
 }
 #endif /* RECONFIGURE_ENABLE */
 
-#ifdef NTPSHM_ENABLE
-static double tsip_ntp_offset(struct gps_device_t *session UNUSED)
+#ifdef TIMESERVICE_ENABLE
+static double tsip_time_offset(struct gps_device_t *session UNUSED)
 {
     /* FIX-ME: is a constant offset right here? */
     return 0.075;
 }
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMESERVICE_ENABLE */
 
 void configuration_packets_generic(struct gps_device_t *session)
 /* configure generic Trimble TSIP device to a known state */
@@ -1274,9 +1274,9 @@ const struct gps_type_t tsip_binary =
 #ifdef CONTROLSEND_ENABLE
     .control_send   = tsip_control_send,/* how to send commands */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = tsip_ntp_offset,
-#endif /* NTPSHM_ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    .time_offset     = tsip_time_offset,
+#endif /* TIMESERVICE_ENABLE */
 };
 /* *INDENT-ON* */
 
diff --git a/driver_ubx.c b/driver_ubx.c
index d1bda91d..a8f414c1 100644
--- a/driver_ubx.c
+++ b/driver_ubx.c
@@ -840,9 +840,9 @@ const struct gps_type_t ubx_binary = {
 #ifdef CONTROLSEND_ENABLE
     .control_send     = ubx_control_send,	/* no control sender yet */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,		/* no method for NTP fudge factor */
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    .time_offset     = NULL,		/* no method for NTP fudge factor */
+#endif /* ENABLE ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* defined(UBX_ENABLE) && defined(BINARY_ENABLE) */
diff --git a/driver_zodiac.c b/driver_zodiac.c
index 296dbece..5ab969a1 100644
--- a/driver_zodiac.c
+++ b/driver_zodiac.c
@@ -445,8 +445,8 @@ static bool zodiac_speed_switch(struct gps_device_t *session,
 }
 #endif /* RECONFIGURE_ENABLE */
 
-#ifdef NTPSHM_ENABLE
-static double zodiac_ntp_offset(struct gps_device_t *session UNUSED)
+#ifdef TIMESERVICE_ENABLE
+static double zodiac_time_offset(struct gps_device_t *session UNUSED)
 {
     /* Removing/changing the magic number below is likely to disturb
      * the handling of the 1pps signal from the gps device. The regression
@@ -454,7 +454,7 @@ static double zodiac_ntp_offset(struct gps_device_t *session UNUSED)
      * with the 1pps signal active is required. */
     return 1.1;
 }
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMESERVICE_ENABLE */
 
 /* this is everything we export */
 /* *INDENT-OFF* */
@@ -479,9 +479,9 @@ const struct gps_type_t zodiac_binary =
 #ifdef CONTROLSEND_ENABLE
     .control_send   = zodiac_control_send,	/* for gpsctl and friends */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = zodiac_ntp_offset,	/* compute NTO fudge factor */
-#endif /* NTPSHM_ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    .time_offset     = zodiac_time_offset,	/* compute NTO fudge factor */
+#endif /* TIMESERVICE_ENABLE */
 };
 /* *INDENT-ON* */
 
diff --git a/drivers.c b/drivers.c
index e55d8790..52d130bf 100644
--- a/drivers.c
+++ b/drivers.c
@@ -101,9 +101,9 @@ const struct gps_type_t unknown = {
 #ifdef CONTROLSEND_ENABLE
     .control_send   = NULL,		/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,		/* no method for NTP fudge factor */
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    .time_offset     = NULL,		/* no method for NTP fudge factor */
+#endif /* ENABLE ENABLE */
 };
 /* *INDENT-ON* */
 
@@ -265,9 +265,9 @@ const struct gps_type_t nmea = {
 #ifdef CONTROLSEND_ENABLE
     .control_send   = nmea_write,	/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,		/* no method for NTP fudge factor */
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    .time_offset     = NULL,		/* no method for NTP fudge factor */
+#endif /* ENABLE ENABLE */
 };
 /* *INDENT-ON* */
 
@@ -366,9 +366,9 @@ const struct gps_type_t garmin = {
 #ifdef CONTROLSEND_ENABLE
     .control_send   = nmea_write,	/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,		/* no method for NTP fudge factor */
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    .time_offset     = NULL,		/* no method for NTP fudge factor */
+#endif /* ENABLE ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* GARMIN_ENABLE && NMEA_ENABLE */
@@ -428,9 +428,9 @@ const struct gps_type_t ashtech = {
 #ifdef CONTROLSEND_ENABLE
     .control_send   = nmea_write,	/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,		/* no method for NTP fudge factor */
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    .time_offset     = NULL,		/* no method for NTP fudge factor */
+#endif /* ENABLE ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* ASHTECH_ENABLE */
@@ -479,9 +479,9 @@ const struct gps_type_t fv18 = {
 #ifdef CONTROLSEND_ENABLE
     .control_send   = nmea_write,	/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,		/* no method for NTP fudge factor */
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    .time_offset     = NULL,		/* no method for NTP fudge factor */
+#endif /* ENABLE ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* FV18_ENABLE */
@@ -533,9 +533,9 @@ const struct gps_type_t gpsclock = {
 #ifdef CONTROLSEND_ENABLE
     .control_send   = nmea_write,	/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,		/* no method for NTP fudge factor */
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    .time_offset     = NULL,		/* no method for NTP fudge factor */
+#endif /* ENABLE ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* GPSCLOCK_ENABLE */
@@ -588,9 +588,9 @@ static const struct gps_type_t tripmate = {
 #ifdef CONTROLSEND_ENABLE
     .control_send  = nmea_write,	/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,		/* no method for NTP fudge factor */
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    .time_offset     = NULL,		/* no method for NTP fudge factor */
+#endif /* ENABLE ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* TRIPMATE_ENABLE */
@@ -639,9 +639,9 @@ static const struct gps_type_t earthmate = {
 #ifdef CONTROLSEND_ENABLE
     .control_send  = nmea_write,	/* never actually used. */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,		/* no method for NTP fudge factor */
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    .time_offset     = NULL,		/* no method for NTP fudge factor */
+#endif /* ENABLE ENABLE */
 };
 /*@ -redef @*/
 /* *INDENT-ON* */
@@ -762,9 +762,9 @@ const struct gps_type_t trueNorth = {
 #ifdef CONTROLSEND_ENABLE
     .control_send   = tnt_control_send,	/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    .time_offset     = NULL,
+#endif /* ENABLE ENABLE */
 };
 /* *INDENT-ON* */
 #endif
@@ -840,9 +840,9 @@ static const struct gps_type_t oceanServer = {
 #ifdef CONTROLSEND_ENABLE
     .control_send   = nmea_write,	/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    .time_offset     = NULL,
+#endif /* ENABLE ENABLE */
 };
 /* *INDENT-ON* */
 #endif
@@ -907,9 +907,9 @@ static const struct gps_type_t fury = {
 #ifdef CONTROLSEND_ENABLE
     .control_send   = nmea_write,	/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    .time_offset     = NULL,
+#endif /* ENABLE ENABLE */
 };
 /* *INDENT-ON* */
 
@@ -961,9 +961,9 @@ static const struct gps_type_t rtcm104v2 = {
 #ifdef CONTROLSEND_ENABLE
     .control_send   = NULL,		/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    .time_offset     = NULL,
+#endif /* ENABLE ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* RTCM104V2_ENABLE */
@@ -1007,9 +1007,9 @@ static const struct gps_type_t rtcm104v3 = {
 #ifdef CONTROLSEND_ENABLE
     .control_send   = NULL,		/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    .time_offset     = NULL,
+#endif /* ENABLE ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* RTCM104V3_ENABLE */
@@ -1042,9 +1042,9 @@ static const struct gps_type_t garmintxt = {
 #ifdef CONTROLSEND_ENABLE
     .control_send   = NULL,		/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    .time_offset     = NULL,
+#endif /* ENABLE ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* GARMINTXT_ENABLE */
@@ -1130,9 +1130,9 @@ const struct gps_type_t mtk3301 = {
 #ifdef CONTROLSEND_ENABLE
     .control_send   = nmea_write,	/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    .time_offset     = NULL,
+#endif /* ENABLE ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* MTK3301_ENABLE */
@@ -1368,9 +1368,9 @@ const struct gps_type_t aivdm = {
 #ifdef CONTROLSEND_ENABLE
     .control_send     = NULL,		/* no control sender */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,		/* no NTP communication */
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    .time_offset     = NULL,		/* no NTP communication */
+#endif /* ENABLE ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* AIVDM_ENABLE */
@@ -1466,9 +1466,9 @@ const struct gps_type_t json_passthrough = {
 #ifdef CONTROLSEND_ENABLE
     .control_send   = NULL,		/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,		/* no method for NTP fudge factor */
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    .time_offset     = NULL,		/* no method for NTP fudge factor */
+#endif /* ENABLE ENABLE */
 };
 /* *INDENT-ON* */
 
diff --git a/gpscap.ini b/gpscap.ini
index 533150e4..8c2bc308 100644
--- a/gpscap.ini
+++ b/gpscap.ini
@@ -24,7 +24,7 @@
 # usbchip      = USB I/O chipset
 # pps	       = supports pulse-per-second precision time reporting
 # pps_accuracy = claimed PPS accuracy
-# ntp_offset   = NTP offset
+# time_offset   = NTP offset
 # configurable = can the device be bricked by speed changes?
 # tested       = last gpsd tested, or "regression" if we have a test load
 # nmea	       = NMEA version this emits, if known
@@ -871,7 +871,7 @@ nmea = 2.0 and 2.3
 packaging = mouse
 pps = True
 pps_accuracy = 1us
-ntp_offset = 0.125s
+time_offset = 0.125s
 submitter = Gary E. Miller <gem@rellim.com>
 techdoc = http://www.garmin.com/manuals/GPS18_TechnicalSpecification.pdf
 tested = 2.5
@@ -1162,7 +1162,7 @@ nmea = 3.01
 packaging = mouse
 pps = True
 pps_accuracy = 50ns
-ntp_offset = ?
+time_offset = ?
 rating = excellent
 submitter = Gary E. Miller <gem@rellim.com>, Tony Hain <tony@tndh.net>
 techdoc = http://www.usglobalsat.com/p-58-mr-350p-bulkhead.aspx
@@ -1425,7 +1425,7 @@ firmware = 2.18
 interfaces = RS-232
 pps = True
 pps_accuracy = 50ns
-ntp_offset = ?
+time_offset = ?
 model = FireFly-1A and FireFly-II GPSDO
 notes = Uses uBlox Antaris 5 with Kick Start and Super Sense, 
         soon movingto uBlox-6.  Defective \r\r\n string terminations
@@ -1530,7 +1530,7 @@ tested = regression
 rating = good
 pps = True
 pps_accuracy = 250ns
-ntp_offset = ?
+time_offset = ?
 submitter = Chris Kuethe <chris.kuethe@gmail.com>
 notes = Receiver comes up in silent mode, you may need to use ashctl to turn
       on a default set of messages. Tested with firmware BQ00 and BQ04.
@@ -1565,7 +1565,7 @@ tested = 2.20
 nmea = 2.2
 pps = True
 pps_accuracy = 50ns
-ntp_offset = ?
+time_offset = ?
 rating = good
 discontinued = True
 submitter = Wojciech Kazubski <wk@ire.pw.edu.pl>
@@ -1612,7 +1612,7 @@ interfaces = USB
 tested = 3.9
 pps = True
 pps_accuracy = 1ms
-ntp_offset = ?
+time_offset = ?
 rating = excellent
 submitter = Eric S. Raymond <esr@thyrsus.com>.
 notes = Also known as the Macx-1, this is the USB variant of the
@@ -2266,7 +2266,7 @@ engine = Colossus RF ASIC, IO-C33 (Epson C33 RISC)
 interfaces = USB,RS-232
 pps = True
 pps_accuracy = 50ns
-ntp_offset = 0.675s
+time_offset = 0.675s
 usbchip = CP2102
 tested = regression
 rating = good
@@ -2332,7 +2332,7 @@ interfaces = USB,UART
 tested = regression
 pps = True
 pps_accuracy = 50ns
-ntp_offset = ?
+time_offset = ?
 submitter = Chris Kuethe <chris.kuethe@gmail.com>
 
 [EVK-5H-0]
@@ -2355,7 +2355,7 @@ date = 2011-02-02
 interfaces = TTL
 pps = True
 pps_accuracy = 50ns
-ntp_offset = ?
+time_offset = ?
 location = Adelaide, AU, 34.9S, 138.6E
 model = LEA 5Q
 notes = Sample contains GPGST (pseudorange noise statistics).
@@ -2379,7 +2379,7 @@ model = EVK-6H-0
 packaging = other
 rating = excellent
 pps_accuracy = 50ns
-ntp_offset = ?
+time_offset = ?
 submitter = Eric S. Raymond <esr@thyrsus.com>
 techdoc = http://www.u-blox.com/images/downloads/Product_Docs/u-blox6_ReceiverDescriptionProtocolSpec_%28GPS.G6-SW-10018%29.pdf
 vendor = uBlox
diff --git a/gpscap.py b/gpscap.py
index b00f46c7..423cea17 100644
--- a/gpscap.py
+++ b/gpscap.py
@@ -139,13 +139,13 @@ class GPSDictionary(ConfigParser.RawConfigParser):
                     nmea = self.get(dev, "nmea")
                 ofp.write("<td>%s</td>\n" % nmea)
                 if self.has_option(dev, "pps") and self.get(dev, "pps") == "True":
-                    pps_accuracy = ntp_offset = ""
+                    pps_accuracy = time_offset = ""
                     if self.has_option(dev, "pps_accuracy"):
                         pps_accuracy = self.get(dev, "pps_accuracy")
-                    if self.has_option(dev, "ntp_offset"):
-                        ntp_offset = self.get(dev, "ntp_offset")
-                    if pps_accuracy and ntp_offset:
-                        ofp.write("<td>%s<br>%s</td>\n" % (pps_accuracy, ntp_offset))
+                    if self.has_option(dev, "time_offset"):
+                        time_offset = self.get(dev, "time_offset")
+                    if pps_accuracy and time_offset:
+                        ofp.write("<td>%s<br>%s</td>\n" % (pps_accuracy, time_offset))
                     else:
                         ofp.write("<td>?<br>\n")
                 else:
diff --git a/gpsd.c b/gpsd.c
index f31d07eb..8c1e1bf1 100644
--- a/gpsd.c
+++ b/gpsd.c
@@ -223,6 +223,9 @@ static void typelist(void)
 #if defined(NTPSHM_ENABLE)
     (void)printf("# NTPSHM for NTPd enabled.\n");
 #endif
+#if defined(CHRONY_ENABLE)
+    (void)printf("# Chrony support enabled.\n");
+#endif
 #if defined(PPS_ENABLE)
     (void)printf("# PPS enabled.\n");
 #endif
@@ -663,9 +666,9 @@ static void deactivate_device(struct gps_device_t *device)
 	adjust_max_fd(device->gpsdata.gps_fd, false);
 #if defined(PPS_ENABLE) && defined(TIOCMIWAIT)
 #endif /* defined(PPS_ENABLE) && defined(TIOCMIWAIT) */
-#ifdef NTPSHM_ENABLE
+#ifdef TIMESERVICE_ENABLE
 	ntpd_link_deactivate(device);
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMESERVICE_ENABLE */
 	gpsd_deactivate(device);
     }
 }
@@ -717,7 +720,7 @@ bool gpsd_add_device(const char *device_name, bool flag_nowait)
     for (devp = devices; devp < devices + MAXDEVICES; devp++)
 	if (!allocated_device(devp)) {
 	    gpsd_init(devp, &context, device_name);
-#ifdef NTPSHM_ENABLE
+#ifdef TIMESERVICE_ENABLE
 	    /*
 	     * Now is the right time to grab the shared memory segment(s)
 	     * to communicate the navigation message derived and (possibly)
@@ -732,7 +735,7 @@ bool gpsd_add_device(const char *device_name, bool flag_nowait)
 			"NTPD ntpd_link_activate: %d\n",
 			(int)devp->shmindex >= 0);
 
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMESERVICE_ENABLE */
 	    gpsd_report(context.debug, LOG_INF,
 			"stashing device %s at slot %d\n",
 			device_name, (int)(devp - devices));
@@ -1508,7 +1511,7 @@ static void all_reports(struct gps_device_t *device, gps_mask_t changed)
     }
 
 
-#ifdef NTPSHM_ENABLE
+#ifdef TIMESERVICE_ENABLE
     /*
      * Time is eligible for shipping to NTPD if the driver has
      * asserted PPSTIME_IS at any point in the current cycle.
@@ -1536,14 +1539,14 @@ static void all_reports(struct gps_device_t *device, gps_mask_t changed)
 	//gpsd_report(context.debug, LOG_PROG, "NTP: Got one\n");
 	/* assume zero when there's no offset method */
 	if (device->device_type == NULL
-	    || device->device_type->ntp_offset == NULL)
+	    || device->device_type->time_offset == NULL)
 	    offset = 0.0;
 	else
-	    offset = device->device_type->ntp_offset(device);
+	    offset = device->device_type->time_offset(device);
 	(void)ntpshm_put(device, device->newdata.time, offset);
 	device->last_fixtime = device->newdata.time;
     }
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMESERVICE_ENABLE */
 
     /*
      * If no reliable end of cycle, must report every time
@@ -1946,7 +1949,7 @@ int main(int argc, char *argv[])
     gpsd_report(context.debug, LOG_INF, "listening on port %s\n", gpsd_service);
 #endif /* SOCKET_EXPORT_ENABLE */
 
-#ifdef NTPSHM_ENABLE
+#ifdef TIMESERVICE_ENABLE
     if (getuid() == 0) {
 	errno = 0;
 	// nice() can ONLY succeed when run as root!
@@ -1960,7 +1963,7 @@ int main(int argc, char *argv[])
      * to use segments 0 and 1.
      */
     (void)ntpshm_init(&context);
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMESERVICE_ENABLE */
 
 #if defined(DBUS_EXPORT_ENABLE) && !defined(S_SPLINT_S)
     /* we need to connect to dbus as root */
diff --git a/gpsd.h-tail b/gpsd.h-tail
index a11bcac3..2ff8b5e8 100644
--- a/gpsd.h-tail
+++ b/gpsd.h-tail
@@ -36,6 +36,10 @@
 #include <sys/timepps.h>
 #endif
 
+#if defined(ENABLE_NTPSHM) || defined(ENABLE_CHRONY)
+#define TIMESERVICE_ENABLE
+#endif
+
 #ifdef _WIN32
 typedef unsigned int speed_t;
 #endif
@@ -239,12 +243,14 @@ struct gps_context_t {
     double gps_tow;                     /* GPS time of week, actually 19 bits */
     int century;			/* for NMEA-only devices without ZDA */
     int rollovers;			/* rollovers since start of run */
-#ifdef NTPSHM_ENABLE
+#ifdef TIMESERVICE_ENABLE
     int leap_notify;			/* notification state from subframe */
 #define LEAP_NOWARNING  0x0     /* normal, no leap second warning */
 #define LEAP_ADDSECOND  0x1     /* last minute of day has 60 seconds */
 #define LEAP_DELSECOND  0x2     /* last minute of day has 59 seconds */
 #define LEAP_NOTINSYNC  0x3     /* overload, clock is free running */
+#endif /* TIMESERVICE_ENABLE */
+#ifdef NTPSHM_ENABLE
     bool enable_ntpshm;
     /* we need the volatile here to tell the C compiler not to
      * 'optimize' as 'dead code' the writes to SHM */
@@ -348,9 +354,9 @@ struct gps_type_t {
 #ifdef CONTROLSEND_ENABLE
     /*@null@*/ssize_t (*control_send)(struct gps_device_t *session, char *buf, size_t buflen);
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    /*@null@*/double (*ntp_offset)(struct gps_device_t *session);
-#endif /* NTPSHM_ENABLE */
+#ifdef TIMESERVICE_ENABLE
+    /*@null@*/double (*time_offset)(struct gps_device_t *session);
+#endif /* TIMESERVICE_ENABLE */
 };
 
 /*
@@ -471,7 +477,6 @@ struct gps_device_t {
 #if defined(HAVE_SYS_TIMEPPS_H)
     pps_handle_t kernelpps_handle;
 #endif /* defined(HAVE_SYS_TIMEPPS_H) */
-    int chronyfd;			/* for talking to chrony */
     /*@null@*/ void (*thread_init_hook)(struct gps_device_t *);
     /*@null@*/ void (*thread_error_hook)(struct gps_device_t *);
     /*@null@*/ char *(*thread_report_hook)(struct gps_device_t *,
@@ -480,6 +485,9 @@ struct gps_device_t {
 					   double);
     /*@null@*/ void (*thread_wrap_hook)(struct gps_device_t *);
 #endif /* PPS_ENABLE */
+#ifdef CHRONY_ENABLE
+    int chronyfd;			/* for talking to chrony */
+#endif /* CHRONY_ENABLE */
     double mag_var;			/* magnetic variation in degrees */
     bool back_to_nmea;			/* back to NMEA on revert? */
     char msgbuf[MAX_PACKET_LENGTH*2+1];	/* command message buffer for sends */
diff --git a/libgpsd_core.c b/libgpsd_core.c
index aa4f4b7a..c30b3dcf 100644
--- a/libgpsd_core.c
+++ b/libgpsd_core.c
@@ -231,15 +231,17 @@ void gps_context_init(struct gps_context_t *context)
 	.gps_tow        = 0,
 	.century	= 0,
 	.rollovers      = 0,
-#ifdef NTPSHM_ENABLE
+#ifdef TIMESERVICE_ENABLE
 	.leap_notify    = LEAP_NOWARNING,
+#endif /* TIMESERVICE_ENABLE */
+#ifdef NTPSHM_ENABLE
 	.enable_ntpshm  = false,
 	.shmTime	= {0},
 	.shmTimeInuse   = {0},
+#endif /* NTPSHM_ENABLE */
 # ifdef PPS_ENABLE
 	.pps_hook       = NULL,
 # endif /* PPS_ENABLE */
-#endif /* NTPSHM_ENABLE */
 #ifdef SHM_EXPORT_ENABLE
 	.shmexport      = NULL,
 #endif /* SHM_EXPORT_ENABLE */
diff --git a/subframe.c b/subframe.c
index 25097428..d776b59f 100644
--- a/subframe.c
+++ b/subframe.c
@@ -728,7 +728,7 @@ gps_mask_t gpsd_interpret_subframe(struct gps_device_t *session,
 			    subp->sub4_18.leap, subp->sub4_18.WNlsf,
 			    subp->sub4_18.DN, subp->sub4_18.lsf);
 
-#ifdef NTPSHM_ENABLE
+#ifdef TIMESERVICE_ENABLE
 		/* IS-GPS-200 Revision E, paragraph 20.3.3.5.2.4 */
 		if (((session->context->gps_week % 256) == (unsigned short)subp->sub4_18.WNlsf) &&
 		    /* notify the leap seconds correction in the end of current day */
@@ -742,7 +742,7 @@ gps_mask_t gpsd_interpret_subframe(struct gps_device_t *session,
 			session->context->leap_notify = LEAP_NOWARNING;
 		} else
 		   session->context->leap_notify = LEAP_NOWARNING;
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMESERVICE_ENABLE */
 
 		session->context->leap_seconds = (int)subp->sub4_18.leap;
 		session->context->valid |= LEAP_SECOND_VALID;
diff --git a/ntpshm.c b/timeexport.c
index 5fe96af3..c2067860 100644
--- a/ntpshm.c
+++ b/timeexport.c
@@ -1,5 +1,5 @@
 /*
- * ntpshm.c - put time information in SHM segment for xntpd, or to chrony
+ * timeexport.c - put time information in SHM segment for xntpd, or to chrony
  *
  * struct shmTime and getShmTime from file in the xntp distribution:
  *	sht.c - Testprogram for shared memory refclock
@@ -23,7 +23,7 @@
 
 #include "gpsd.h"
 
-#ifdef NTPSHM_ENABLE
+#ifdef TIMESERVICE_ENABLE
 #include <sys/time.h>
 #include <sys/ipc.h>
 #include <sys/shm.h>
@@ -89,7 +89,7 @@ struct shmTime
  * to debug, try looking at the live segments this way
  *
  *  ipcs -m
- * 
+ *
  * results  should look like this:
  * ------ Shared Memory Segments --------
  *  key        shmid      owner      perms      bytes      nattch     status
@@ -340,7 +340,7 @@ static int ntpshm_pps(struct gps_device_t *session, struct timeval *actual_tv,
     /*@-type@*//* splint is confused about struct timespec */
     gpsd_report(session->context->debug, LOG_RAW,
 		"PPS ntpshm_pps %lu.%03lu @ %lu.%09lu, preci %d\n",
-		(unsigned long)actual_tv->tv_sec, 
+		(unsigned long)actual_tv->tv_sec,
 		(unsigned long)actual_tv->tv_usec,
 		(unsigned long)ts->tv_sec, (unsigned long)ts->tv_nsec,
 		precision);
@@ -363,6 +363,7 @@ struct sock_sample {
 static void init_hook(struct gps_device_t *session)
 /* for chrony SOCK interface, which allows nSec timekeeping */
 {
+#ifdef CHRONY_ENABLE
     /* open the chrony socket */
     char chrony_path[PATH_MAX];
 
@@ -392,6 +393,7 @@ static void init_hook(struct gps_device_t *session)
 	    gpsd_report(session->context->debug, LOG_RAW,
 			"PPS using chrony socket: %s\n", chrony_path);
     }
+#endif /* CHRONY_ENABLE */
 }
 /*@+mustfreefresh@*/
 
@@ -411,7 +413,7 @@ static void chrony_send(struct gps_device_t *session,
     sample.leap = session->context->leap_notify;
     sample.magic = SOCK_MAGIC;
     sample.tv = *actual_tv; /* structure copy */
-    sample.offset = offset; 
+    sample.offset = offset;
 
     (void)send(session->chronyfd, &sample, sizeof (sample), 0);
 }
@@ -423,8 +425,8 @@ static void wrap_hook(struct gps_device_t *session)
 }
 
 static /*@observer@*/ char *report_hook(struct gps_device_t *session,
-			struct timeval *actual_tv, 
-			struct timespec *ts, 
+			struct timeval *actual_tv,
+			struct timespec *ts,
 			double edge_offset)
 /* ship the time of a PPS event to ntpd and/or chrony */
 {
@@ -501,5 +503,5 @@ void ntpd_link_activate(struct gps_device_t *session)
     }
 }
 
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMESERVICE_ENABLE */
 /* end */
diff --git a/www/writing-a-driver.xml b/www/writing-a-driver.xml
index ab624354..1145fcfa 100644
--- a/www/writing-a-driver.xml
+++ b/www/writing-a-driver.xml
@@ -15,6 +15,14 @@
 
 <revhistory>
    <revision>
+      <revnumber>1.12</revnumber>
+      <date>30 Oct 2013</date>
+      <authorinitials>er</authorinitials>
+      <revremark>
+	 Updated by esr; ntp_offset becomes time_offset
+      </revremark>
+   </revision>
+   <revision>
       <revnumber>1.11</revnumber>
       <date>19 Jan 2011</date>
       <authorinitials>er</authorinitials>
@@ -745,11 +753,12 @@ possible, assemble your packet in
 gpsmon to display the control messages it sends for you.</para>
 
 <!-- added by ESR, 2009 -->
-<para><structfield>.ntp_offset</structfield> points to code to compute
-an offset to be added, additionally to that in
-<filename>ntp.conf</filename> (if any) when shipping time notifications
-to NTP. If multiple sentences set TIME_IS, this will differ by
-sentence type; it should differ by baud rare, as well. </para>
+<para><structfield>.timr_offset</structfield> points to code to
+compute an offset to be added, additionally to that in
+<filename>ntp.conf</filename> (if any) when shipping time
+notifications to NTP, or the equivalent configuration file for
+chrony. If multiple sentences set TIME_IS, this will differ by
+sentence type; it should differ by baud rate, as well. </para>
 
 </sect1>