Lua fix reader bug in lzio

When loading a file, Lua may call the reader function again after it
returned end of input

https://www.lua.org/bugs.html#5.1.5-2

Change-Id: Ic2f4d727705a0b8f48ce792f6a9f7af25a503037

1 files changed, 6 insertions, 1 deletions

diff --git a/apps/plugins/lua/lzio.c b/apps/plugins/lua/lzio.c
index 293edd59b0..54d5ec4741 100644
--- a/apps/plugins/lua/lzio.c
+++ b/apps/plugins/lua/lzio.c
@@ -22,10 +22,15 @@ int luaZ_fill (ZIO *z) {
   size_t size;
   lua_State *L = z->L;
   const char *buff;
+  if (!z->reader)
+    return EOZ;
   lua_unlock(L);
   buff = z->reader(L, z->data, &size);
   lua_lock(L);
-  if (buff == NULL || size == 0) return EOZ;
+  if (buff == NULL || size == 0) {
+    z->reader = NULL;  /* avoid calling reader function next time */
+    return EOZ;
+  }
   z->n = size - 1;
   z->p = buff;
   return char2int(*(z->p++));