Log an error upon read failure of dsts.ini and don't write changes back

Part of potential fix (or work-around) for issue #791

src/sbbs3/logon.cpp

@@ -652,12 +652,15 @@ uint sbbs_t::logonstats()
 				continue;
 			}
 
-			fread_dstats(dsts, &stats);
+			if(!fread_dstats(dsts, &stats)) {
+				errormsg(WHERE, ERR_READ, "dsts.ini", i);
+			} else {
 				stats.date = time(NULL);
 				fwrite_cstats(csts, &stats);
 				fclose_cstats(csts);
 				rolloverstats(&stats);
 				fwrite_dstats(dsts, &stats, __FUNCTION__);
+			}
 			fclose_dstats(dsts);
 		} 
 	}
@@ -677,10 +680,13 @@ uint sbbs_t::logonstats()
 			errormsg(WHERE, ERR_OPEN, "dsts.ini", i);
 			return(0L); 
 		}
-		fread_dstats(fp, &stats);
+		if(!fread_dstats(fp, &stats)) {
+			errormsg(WHERE, ERR_READ, "dsts.ini", i);
+		} else {
 			stats.today.logons++;
 			stats.total.logons++;
 			fwrite_dstats(fp, &stats, __FUNCTION__);
+		}
 		fclose_dstats(fp);
 	}
 

src/sbbs3/main.cpp

@@ -4379,7 +4379,9 @@ void sbbs_t::logoffstats()
 		FILE* fp = fopen_dstats(&cfg, i ? 0 : cfg.node_num, /* for_write: */true);
 		if(fp == NULL)
 			continue;
-		if(fread_dstats(fp, &stats)) {
+		if(!fread_dstats(fp, &stats)) {
+			errormsg(WHERE, ERR_READ, "dsts.ini", i);
+		} else {
 			stats.total.timeon += minutes_used;
 			stats.today.timeon += minutes_used;
 			fwrite_dstats(fp, &stats, __FUNCTION__);