Resolved forgotten fprintf and error message when compiled zone file is empty.

src/knot/zone/zone-load.c

@@ -66,8 +66,8 @@ static inline int fread_safe_from_file(void *dst,
 {
 	int rc = fread(dst, size, n, fp);
 	if (rc != n) {
-		fprintf(stderr, "fread: invalid read %d (expected %zu)\n", rc,
-			n);
+		dbg_zload("fread_safe_from_file: invalid read %d (exp. %zu)\n",
+			  rc, n);
 	}
 
 	return rc == n;
@@ -856,6 +856,15 @@ int knot_zload_open(zloader_t **dst, const char *filename)
 
 		return KNOT_EFEWDATA; // No such file or directory (POSIX.1)
 	}
+	
+	/* Calculate file size. */
+	fseek(f, 0L, SEEK_END);
+	size_t file_size = ftell(f);
+	fseek(f, 0L, SEEK_SET);
+	if (file_size < MAGIC_LENGTH) {
+		fclose(f);
+		return KNOT_EFEWDATA;
+	}
 
 	/* Calculate CRC and compare with filename.crc file */
 	unsigned long crc_calculated = calculate_crc(f);