[core] adjust time jump detection (fixes #3123)

adjust time jump detection to handle when server.max-workers is non-zero

x-ref:
  "child exit causes time jump false positive when server.max-workers is non-zero"
  https://redmine.lighttpd.net/issues/3123

src/server.c

@@ -247,18 +247,21 @@ server_monotonic_secs (void)
 }
 
 static unix_time64_t
-server_epoch_secs (server * const srv)
+server_epoch_secs (server * const srv, unix_time64_t mono_ts_delta)
 {
     const unix_time64_t cur_ts = log_epoch_secs;
     const unix_time64_t new_ts = TIME64_CAST(time(NULL));
+    const unix_time64_t new_ts_adj = new_ts - mono_ts_delta;
     /* attempt to detect large clock jump */
-    if (new_ts < cur_ts || new_ts - cur_ts > 300) { /*(5 mins)*/
+    if (new_ts_adj < cur_ts || new_ts_adj - cur_ts > 300) { /*(5 mins)*/
         log_error(srv->errh, __FILE__, __LINE__,
           "warning: clock jumped %lld secs",
-          (long long)((int64_t)new_ts - (int64_t)cur_ts));
+          (long long)((int64_t)new_ts_adj - (int64_t)cur_ts));
         int delta =                             /*(30 mins default)*/
           config_feature_int(srv, "server.clock-jump-restart", 1800);
-        if (delta && (new_ts > cur_ts ? new_ts-cur_ts : cur_ts-new_ts) > delta){
+        if (delta && (new_ts_adj > cur_ts
+                      ? new_ts_adj-cur_ts
+                      : cur_ts-new_ts_adj) > delta) {
             log_error(srv->errh, __FILE__, __LINE__,
               "attempting graceful restart in < ~5 seconds, else hard restart");
             srv->graceful_expire_ts = log_monotonic_secs + 5;
@@ -1613,10 +1616,12 @@ static int server_main_setup (server * const srv, int argc, char **argv) {
 				}
 			} else {
 				int status;
+				unix_time64_t mono_ts;
 
 				if (-1 != (pid = fdevent_waitpid_intr(-1, &status))) {
+					mono_ts = log_monotonic_secs;
 					log_monotonic_secs = server_monotonic_secs();
-					log_epoch_secs = server_epoch_secs(srv);
+					log_epoch_secs = server_epoch_secs(srv, log_monotonic_secs - mono_ts);
 					if (plugins_call_handle_waitpid(srv, pid, status) != HANDLER_GO_ON) {
 						if (!timer) alarm((timer = 5));
 						continue;
@@ -1640,8 +1645,9 @@ static int server_main_setup (server * const srv, int argc, char **argv) {
 				} else {
 					switch (errno) {
 					case EINTR:
+						mono_ts = log_monotonic_secs;
 						log_monotonic_secs = server_monotonic_secs();
-						log_epoch_secs = server_epoch_secs(srv);
+						log_epoch_secs = server_epoch_secs(srv, log_monotonic_secs - mono_ts);
 						/**
 						 * if we receive a SIGHUP we have to close our logs ourself as we don't 
 						 * have the mainloop who can help us here
@@ -1840,7 +1846,7 @@ static void server_handle_sigalrm (server * const srv, unix_time64_t mono_ts, un
 				plugins_call_handle_trigger(srv);
 
 				log_monotonic_secs = mono_ts;
-				log_epoch_secs = server_epoch_secs(srv);
+				log_epoch_secs = server_epoch_secs(srv, 0);
 
 				/* check idle time limit, if enabled */
 				if (idle_limit && idle_limit < mono_ts - last_active_ts && !graceful_shutdown) {
@@ -1923,7 +1929,7 @@ __attribute_hot__
 __attribute_noinline__
 static void server_main_loop (server * const srv) {
 	unix_time64_t last_active_ts = server_monotonic_secs();
-	log_epoch_secs = server_epoch_secs(srv);
+	log_epoch_secs = server_epoch_secs(srv, 0);
 
 	while (!srv_shutdown) {