nfqws,tpws: r/o open instead of stat() for list file check

nfq/helpers.c

@@ -9,6 +9,7 @@
 #include <ctype.h>
 #include <sys/stat.h>
 #include <libgen.h>
+#include <fcntl.h>
 
 int unique_size_t(size_t *pu, int ct)
 {
@@ -313,6 +314,17 @@ bool file_mod_signature(const char *filename, file_mod_sig *ms)
 	return true;
 }
 
+bool file_open_test(const char *filename, int flags)
+{
+	int fd = open(filename,flags);
+	if (fd>=0)
+	{
+		close(fd);
+		return true;
+	}
+	return false;
+}
+
 bool pf_in_range(uint16_t port, const port_filter *pf)
 {
 	return port && (((!pf->from && !pf->to) || (port>=pf->from && port<=pf->to)) ^ pf->neg);