handle tv.tv_usec in settimeofday() (#4001)

optional settimeofday()'s callback
fix #1679

cores/esp8266/coredecls.h

@@ -2,8 +2,19 @@
 #ifndef __COREDECLS_H
 #define __COREDECLS_H
 
-extern bool s_bootTimeSet;
+#ifdef __cplusplus
+extern "C" {
+#endif
 
 // TODO: put declarations here, get rid of -Wno-implicit-function-declaration
 
+extern bool timeshift64_is_set;
+
+void tune_timeshift64 (uint64_t now_us);
+void settimeofday_cb (void (*cb)(void));
+
+#ifdef __cplusplus
+}
+#endif
+
 #endif // __COREDECLS_H

cores/esp8266/sntp-lwip2.c

@@ -34,6 +34,7 @@
  * TODOs:
  * settimeofday(): handle tv->tv_usec
  * sntp_mktm_r(): review, fix DST handling (this one is currently untouched from lwip-1.4)
+ * implement adjtime()
  */
 
 #include <lwip/init.h>
@@ -42,6 +43,13 @@
 #include <os_type.h>
 #include "coredecls.h"
 
+static void (*_settimeofday_cb)(void) = NULL;
+
+void settimeofday_cb (void (*cb)(void))
+{
+    _settimeofday_cb = cb;
+}
+
 #if LWIP_VERSION_MAJOR == 1
 
 #include <pgmspace.h>
@@ -58,10 +66,11 @@ int settimeofday(const struct timeval* tv, const struct timezone* tz)
     }
     if (tv) /* after*/
     {
+        // can't call lwip1.4's static sntp_set_system_time()
         os_printf(stod14);
 
         // reset time subsystem
-        s_bootTimeSet = false;
+        timeshift64_is_set = false;
         
         return -1;
     }
@@ -440,11 +449,13 @@ int settimeofday(const struct timeval* tv, const struct timezone* tz)
     }
     if (tv) /* after*/
     {
-        sntp_set_system_time(tv->tv_sec);
-        // XXX FIXME TODO: efficiently use provided tv->tv_sec
-        
         // reset time subsystem
-        s_bootTimeSet = false;
+        tune_timeshift64(tv->tv_sec * 1000000ULL + tv->tv_usec);
+
+        sntp_set_system_time(tv->tv_sec);
+
+        if (_settimeofday_cb)
+            _settimeofday_cb();
     }
     return 0;
 }

cores/esp8266/time.c

@@ -37,22 +37,13 @@ extern uint64_t micros64();
 // time gap in seconds from 01.01.1900 (NTP time) to 01.01.1970 (UNIX time)
 #define DIFF1900TO1970 2208988800UL
 
-bool s_bootTimeSet = false;
-static uint64_t s_bootTime_us = 0;
+bool timeshift64_is_set = false;
+static uint64_t timeshift64 = 0;
 
-// calculate offset used in gettimeofday
-static void ensureBootTimeIsSet()
+void tune_timeshift64 (uint64_t now_us)
 {
-    // Check just a bool flag instead of the full 64-bit s_bootTime for zero.
-    if (!s_bootTimeSet)
-    {
-        time_t now_s = sntp_get_current_timestamp();
-        if (now_s)
-        {
-            s_bootTime_us = now_s * 1000000ULL - micros64();
-            s_bootTimeSet = true;
-        }
-    }
+     timeshift64 = now_us - micros64();
+     timeshift64_is_set = true;
 }
 
 static void setServer(int id, const char* name_or_ip)
@@ -102,8 +93,9 @@ int _gettimeofday_r(struct _reent* unused, struct timeval *tp, void *tzp)
     (void) tzp;
     if (tp)
     {
-        ensureBootTimeIsSet();
-        uint64_t currentTime_us = s_bootTime_us + micros64();
+        if (!timeshift64_is_set)
+            tune_timeshift64(sntp_get_current_timestamp() * 1000000ULL);
+        uint64_t currentTime_us = timeshift64 + micros64();
         tp->tv_sec = currentTime_us / 1000000ULL;
         tp->tv_usec = currentTime_us % 1000000ULL;
     }

libraries/esp8266/examples/NTP-TZ-DST/NTP-TZ-DST.ino

@@ -12,9 +12,10 @@
   This example code is in the public domain.
 */
 
+#include <ESP8266WiFi.h>
 #include <time.h>                       // time() ctime()
 #include <sys/time.h>                   // struct timeval
-#include <ESP8266WiFi.h>
+#include <coredecls.h>                  // settimeofday_cb()
 
 ////////////////////////////////////////////////////////
 
@@ -32,8 +33,19 @@
 #define TZ_SEC          ((TZ)*3600)
 #define DST_SEC         ((DST_MN)*60)
 
+timeval cbtime;			// time set in callback
+bool cbtime_set = false;
+
+void time_is_set (void)
+{
+  gettimeofday(&cbtime, NULL);
+  cbtime_set = true;
+  Serial.println("------------------ settimeofday() was called ------------------");
+}
+
 void setup() {
   Serial.begin(115200);
+  settimeofday_cb(time_is_set);
 
 #if NTP0_OR_LOCAL1
   // local