Add nanoseconds to time logging and change date-time format to RFC3339.

fixes #1873 @30m

src/common/log.c

@@ -14,11 +14,19 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#define _POSIX_C_SOURCE 199506L
+#define _BSD_SOURCE
 #include <config.h>
 #include <stdarg.h>
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
+#include <unistd.h>
+#if defined(_POSIX_TIMERS) && _POSIX_TIMERS > 0
+#include <time.h>
+#else
+#include <sys/time.h>
+#endif
 
 #include "common/log.h"
 #include "common/lists.h"
@@ -212,14 +220,22 @@ static int _log_msg(logsrc_t src, int level, const char *msg)
 	/* Prefix date and time. */
 	char tstr[128] = {0};
 	int tlen = 0;
-	time_t t = time(NULL);
-	struct tm *lt = localtime(&t);
-	if (lt != NULL) {
+	struct tm lt;
+	struct timespec ts;
+#if defined(_POSIX_TIMERS) && _POSIX_TIMERS > 0
+	clock_gettime(CLOCK_REALTIME, &ts);
+#else	
+	struct timeval tv;
+	gettimeofday(&tv, NULL);
+	ts.tv_sec = tv.tv_sec;
+	ts.tv_nsec = tv.tv_usec * 1000;
+#endif
+	if (localtime_r(&ts.tv_sec, &lt) != NULL) {
 		tlen = strftime(tstr, sizeof(tstr) - 1,
-		                "%d-%m-%Y %H:%M:%S", lt);
+				"%Y-%m-%dT%H:%M:%S", &lt);
 		if (tlen > 0) {
-			tstr[tlen] = ' ';
-			tstr[tlen + 1] = '\0';
+			char pm = (lt.tm_gmtoff > 0)?'+':'-';
+			snprintf(tstr+tlen, 128-tlen-1, ".%.9lu%c%.2u:%.2u ", (unsigned long)ts.tv_nsec, pm, (unsigned int)lt.tm_gmtoff/3600, (unsigned int)(lt.tm_gmtoff/60)%60);
 		}
 	}