From edfe1a5fdef2f672637db3b0c048bb82fa245acd Mon Sep 17 00:00:00 2001
From: Enyby <enyby@yandex.ru>
Date: Sun, 13 Oct 2019 06:16:21 +0300
Subject: [PATCH] Add check for io.popen modes.

---
 src/core/org/luaj/vm2/lib/IoLib.java | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/core/org/luaj/vm2/lib/IoLib.java b/src/core/org/luaj/vm2/lib/IoLib.java
index d49c2551..98c220b5 100644
--- a/src/core/org/luaj/vm2/lib/IoLib.java
+++ b/src/core/org/luaj/vm2/lib/IoLib.java
@@ -386,6 +386,7 @@ public class IoLib extends TwoArgFunction {
 
 	// io.popen(prog, [mode]) -> file
 	public Varargs _io_popen(String prog, String mode) throws IOException {
+		if (!"r".equals(mode) && !"w".equals(mode)) argerror(2, "invalid value: '" + mode + "'; must be one of 'r' or 'w'");
 		return openProgram(prog, mode);
 	}