Report status of the time drift

Author: pascal-fb-martin

hc_clock.c

@@ -56,12 +56,15 @@
 
 #include "houseclock.h"
 #include "hc_clock.h"
+#include "hc_db.h"
 
 static int clockPrecision;
 static int clockShowDrift = 0;
 
 static int clockSynchronized = 0;
 
+static int *hc_clock_drift_db = 0;
+
 const char *hc_clock_help (int level) {
 
     static const char *clockHelp[] = {
@@ -87,6 +90,14 @@ void hc_clock_initialize (int argc, const char **argv) {
     clockPrecision = atoi(precision_option);
 
     clockSynchronized = 0;
+
+    i = hc_db_new (HC_CLOCK_DRIFT, sizeof(int), 120);
+    if (i != 0) {
+        fprintf (stderr, "cannot create %s: %s\n", HC_CLOCK_DRIFT, strerror(i));
+        exit (1);
+    }
+    hc_clock_drift_db = (int *) hc_db_get (HC_CLOCK_DRIFT);
+    for (i = 0; i < 120; ++i) hc_clock_drift_db[i] = 0;
 }
 
 void hc_clock_synchronize(const struct timeval *gps,
@@ -97,8 +108,10 @@ void hc_clock_synchronize(const struct timeval *gps,
 
     time_t absdrift = (drift < 0)? (0 - drift) : drift;
 
+    if (hc_clock_drift_db) hc_clock_drift_db[local->tv_sec%120] = (int)drift;
+
     if (clockShowDrift || hc_test_mode()) {
-        printf ("%8.3f\n", drift/1000.0);
+        printf ("[%d]=%8.3f\n", local->tv_sec%120, drift/1000.0);
         return;
     }
 

hc_clock.h

@@ -27,3 +27,7 @@ void hc_clock_synchronize  (const struct timeval *gps,
                             const struct timeval *local, int latency);
 int  hc_clock_synchronized (void);
 
+/* Live database.
+ */
+#define HC_CLOCK_DRIFT "ClockDrift"
+

hc_http.c

@@ -37,6 +37,7 @@
 #include "houseclock.h"
 #include "hc_db.h"
 #include "hc_nmea.h"
+#include "hc_clock.h"
 #include "hc_http.h"
 
 #include "echttp.h"
@@ -51,19 +52,53 @@ static void hc_background (int fd, int mode) {
 
 static const char *hc_http_status (const char *method, const char *uri,
                                    const char *data, int length) {
-    static char buffer[1024];
+    static char buffer[8192];
+    static char *driftbuffer;
+    static int   driftbuffersize;
     static hc_nmea_status *status_db = 0;
+    static int *drift_db = 0;
+    static int drift_count;
     char latitude[20];
     char longitude[20];
 
     if (status_db == 0) {
+        status_db = (hc_nmea_status *) hc_db_get (HC_NMEA_STATUS);
+        if (status_db == 0) {
+            echttp_error (503, "Service Temporarily Unavailable");
+            return "";
+        }
         if (hc_db_get_count (HC_NMEA_STATUS) != 1
             || hc_db_get_size (HC_NMEA_STATUS) != sizeof(hc_nmea_status)) {
             fprintf (stderr, "wrong data structure for table %s\n",
                      HC_NMEA_STATUS);
             exit (1);
         }
-        status_db = (hc_nmea_status *) hc_db_get (HC_NMEA_STATUS);
+    }
+
+    if (drift_db == 0) {
+        drift_db = (int *) hc_db_get (HC_CLOCK_DRIFT);
+        if (drift_db == 0) {
+            echttp_error (503, "Service Temporarily Unavailable");
+            return "";
+        }
+        drift_count = hc_db_get_count (HC_CLOCK_DRIFT);
+        if (hc_db_get_size (HC_CLOCK_DRIFT) != sizeof(int)) {
+            fprintf (stderr, "wrong data structure for table %s\n",
+                     HC_CLOCK_DRIFT);
+            exit (1);
+        }
+        driftbuffersize = drift_count * 12;
+        driftbuffer = malloc(driftbuffersize);
+    }
+
+    snprintf (driftbuffer, driftbuffersize, "%d", drift_db[0]);
+    int room = driftbuffersize - strlen(driftbuffer);
+    char *p = driftbuffer + (driftbuffersize-room);
+    int i;
+    for (i = 1; i < drift_count; ++i) {
+        snprintf (p, room, ",%d", drift_db[i]);
+        room -= strlen(p);
+        p = driftbuffer + (driftbuffersize-room);
     }
 
     // This conversion is not made when decoding the NMEA stream to avoid
@@ -77,7 +112,8 @@ static const char *hc_http_status (const char *method, const char *uri,
     snprintf (buffer, sizeof(buffer),
               "{\"gps\":{\"fix\":%s"
               ",\"time\":[%c%c,%c%c,%c%c],\"date\":[%d,%c%c,%c%c]"
-              ",\"latitude\":%s,\"longitude\":%s,\"timestamp\":%zd.%03d}}",
+              ",\"latitude\":%s,\"longitude\":%s,\"timestamp\":%zd.%03d}"
+              ",\"clock\":{\"drift\":[%s]}}",
               status_db->fix?"true":"false",
               status_db->time[0], status_db->time[1],
               status_db->time[2], status_db->time[3],
@@ -87,7 +123,8 @@ static const char *hc_http_status (const char *method, const char *uri,
               status_db->date[0], status_db->date[1],
               latitude, longitude,
               (size_t) (status_db->timestamp.tv_sec),
-              status_db->timestamp.tv_usec/1000);
+              status_db->timestamp.tv_usec/1000,
+              driftbuffer);
     echttp_content_type_json();
     return buffer;
 }