Cope with failure to get a single block template more gracefully

src/generator.c

@@ -59,8 +59,7 @@ retry:
 			free(s);
 			clear_gbtbase(&gbt);
 		}
-	}
-	if (!strncasecmp(buf, "getbest", 7)) {
+	} else if (!strncasecmp(buf, "getbest", 7)) {
 		if (!get_bestblockhash(cs, hash)) {
 			LOGWARNING("No best block hash support from %s:%s",
 				   cs->url, cs->port);
@@ -68,8 +67,7 @@ retry:
 		} else {
 			send_unix_msg(sockd, hash);
 		}
-	}
-	if (!strncasecmp(buf, "getlast", 7)) {
+	} else if (!strncasecmp(buf, "getlast", 7)) {
 		int height = get_blockcount(cs);
 
 		if (height == -1)

src/stratifier.c

@@ -279,12 +279,17 @@ static void update_base(ckpool_t *ckp)
 	json_t *val;
 	char *buf;
 
-	wb = ckzalloc(sizeof(workbase_t));
 	buf = send_recv_proc(&ckp->generator, "getbase");
 	if (unlikely(!buf)) {
 		LOGWARNING("Failed to get base from generator in update_base");
 		return;
 	}
+	if (unlikely(!strncasecmp(buf, "failed", 6))) {
+		LOGWARNING("Generator returned failure in update_base");
+		return;
+	}
+
+	wb = ckzalloc(sizeof(workbase_t));
 	val = json_loads(buf, 0, NULL);
 	dealloc(buf);
 
@@ -679,8 +684,11 @@ static void add_submit(stratum_instance_t *client, int diff)
 		return;
 
 	optimal = dsps * 3;
-	if (optimal <= 1 && client->diff == 1)
+	if (optimal <= 1) {
+		if (client->diff == 1)
 			return;
+		optimal = 1;
+	}
 
 	ck_rlock(&workbase_lock);
 	next_blockid = workbase_id + 1;