Synchronizing system time to the transponder time is now done using adjtime() in order to avoid discontinuities

3 files changed, 30 insertions, 11 deletions

diff --git a/CONTRIBUTORS b/CONTRIBUTORS
index 0c37f847..1cbe7e08 100644
--- a/CONTRIBUTORS
+++ b/CONTRIBUTORS
@@ -2731,6 +2731,8 @@ Manuel Reimer <Manuel.Reimer@gmx.de>
  contains only the address of the local host
  for a patch that was used as a base for making editing marks be updated every 10
  seconds during replay
+ for suggesting to synchronize system time to the transponder time using adjtime() in
+ order to avoid discontinuities
 
 Rene van den Braken <rene@vandenbraken.name>
  for reporting a bug in writing the PCR pid into the PMT in
diff --git a/HISTORY b/HISTORY
index e457499c..2cccde92 100644
--- a/HISTORY
+++ b/HISTORY
@@ -7339,7 +7339,7 @@ Video Disk Recorder Revision History
 - Modified editing marks are now written to disk whenever the replay progress display
   gets hidden (thanks to Christoph Haubrich).
 
-2012-12-03: Version 1.7.33
+2012-12-04: Version 1.7.33
 
 - In order to be able to play TS recordings from other sources, in which there is
   more than one PMT PID in the PAT, 'int cPatPmtParser::PatPmt(void)' has been changed
@@ -7366,3 +7366,6 @@ Video Disk Recorder Revision History
 - Fixed some spellings in osd.h and svdrp.c (thanks to Ville Skyttä).
 - Fixed handling lowercase polarization characters in channel definitions if no DiSEqC
   is used (reported by Mike Hay, actual bug pointed out by Stefan Huelswitt).
+- Synchronizing system time to the transponder time is now done using adjtime() in order
+  to avoid discontinuities (suggested by Manuel Reimer). If the time difference is more
+  than 10 seconds, stime() is still used to do the initial sync.
diff --git a/eit.c b/eit.c
index a236b896..dc63cce8 100644
--- a/eit.c
+++ b/eit.c
@@ -8,10 +8,11 @@
  * Robert Schneider <Robert.Schneider@web.de> and Rolf Hakenes <hakenes@hippomi.de>.
  * Adapted to 'libsi' for VDR 1.3.0 by Marcel Wiesweg <marcel.wiesweg@gmx.de>.
  *
- * $Id: eit.c 2.21 2012/08/25 11:13:00 kls Exp $
+ * $Id: eit.c 2.22 2012/12/04 09:33:20 kls Exp $
  */
 
 #include "eit.h"
+#include <sys/time.h>
 #include "epg.h"
 #include "i18n.h"
 #include "libsi/section.h"
@@ -313,35 +314,48 @@ cEIT::cEIT(cSchedules *Schedules, int Source, u_char Tid, const u_char *Data, bo
 
 // --- cTDT ------------------------------------------------------------------
 
+#define MAX_TIME_DIFF   1 // number of seconds the local time may differ from dvb time before making any corrections
+#define MAX_ADJ_DIFF   10 // number of seconds the local time may differ from dvb time to allow smooth adjustment
+#define ADJ_DELTA     300 // number of seconds between calls for smooth time adjustment
+
 class cTDT : public SI::TDT {
 private:
   static cMutex mutex;
-  static int lastDiff;
+  static time_t lastAdj;
 public:
   cTDT(const u_char *Data);
   };
 
 cMutex cTDT::mutex;
-int cTDT::lastDiff = 0;
+time_t cTDT::lastAdj = 0;
 
 cTDT::cTDT(const u_char *Data)
 :SI::TDT(Data, false)
 {
   CheckParse();
 
-  time_t sattim = getTime();
+  time_t dvbtim = getTime();
   time_t loctim = time(NULL);
 
-  int diff = abs(sattim - loctim);
-  if (diff > 2) {
+  int diff = dvbtim - loctim;
+  if (abs(diff) > MAX_TIME_DIFF) {
      mutex.Lock();
-     if (abs(diff - lastDiff) < 3) {
-        if (stime(&sattim) == 0)
-           isyslog("system time changed from %s (%ld) to %s (%ld)", *TimeToString(loctim), loctim, *TimeToString(sattim), sattim);
+     if (abs(diff) > MAX_ADJ_DIFF) {
+        if (stime(&dvbtim) == 0)
+           isyslog("system time changed from %s (%ld) to %s (%ld)", *TimeToString(loctim), loctim, *TimeToString(dvbtim), dvbtim);
         else
            esyslog("ERROR while setting system time: %m");
         }
-     lastDiff = diff;
+     else if (time(NULL) - lastAdj > ADJ_DELTA) {
+        lastAdj = time(NULL);
+        timeval delta;
+        delta.tv_sec = diff;
+        delta.tv_usec = 0;
+        if (adjtime(&delta, NULL) == 0)
+           isyslog("system time adjustment initiated from %s (%ld) to %s (%ld)", *TimeToString(loctim), loctim, *TimeToString(dvbtim), dvbtim);
+        else
+           esyslog("ERROR while adjusting system time: %m");
+        }
      mutex.Unlock();
      }
 }