lua: prepare for Lua 5.2

Adjust code for Lua 5.2 and keep compatibility with Lua 5.1.

Signed-off-by: Natanael Copa <ncopa@alpinelinux.org>
Acked-by: Dwight Engen <dwight.engen@oracle.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>

src/lua-lxc/core.c

@@ -25,9 +25,15 @@
 #define _GNU_SOURCE
 #include <lua.h>
 #include <lauxlib.h>
+#include <assert.h>
 #include <string.h>
 #include <lxc/lxccontainer.h>
 
+#if LUA_VERSION_NUM < 502
+#define luaL_newlib(L,l) (lua_newtable(L), luaL_register(L,NULL,l))
+#define luaL_setfuncs(L,l,n) (assert(n==0), luaL_register(L,NULL,l))
+#endif
+
 #ifdef NO_CHECK_UDATA
 #define checkudata(L,i,tname)	lua_touserdata(L, i)
 #else
@@ -389,7 +395,7 @@ static int lxc_lib_uninit(lua_State *L) {
 LUALIB_API int luaopen_lxc_core(lua_State *L) {
     /* this is where we would initialize liblxc.so if we needed to */
 
-    luaL_register(L, "lxc", lxc_lib_methods);
+    luaL_newlib(L, lxc_lib_methods);
 
     lua_newuserdata(L, 0);
     lua_newtable(L);  /* metatable */
@@ -401,12 +407,12 @@ LUALIB_API int luaopen_lxc_core(lua_State *L) {
     lua_rawset(L, -3);
 
     luaL_newmetatable(L, CONTAINER_TYPENAME);
+    luaL_setfuncs(L, lxc_container_methods, 0);
     lua_pushvalue(L, -1);  /* push metatable */
     lua_pushstring(L, "__gc");
     lua_pushcfunction(L, container_gc);
     lua_settable(L, -3);
     lua_setfield(L, -2, "__index");  /* metatable.__index = metatable */
-    luaL_register(L, NULL, lxc_container_methods);
     lua_pop(L, 1);
     return 1;
 }

src/lua-lxc/lxc.lua

@@ -32,6 +32,11 @@ local lxc_path
 local cgroup_path
 local log_level = 3
 
+-- lua 5.1 compat
+if table.unpack == nil then
+    table.unpack = unpack
+end
+
 -- the following two functions can be useful for debugging
 function printf(...)
     local function wrapper(...) io.write(string.format(...)) end
@@ -286,7 +291,7 @@ function container:stat_get_ints(controller, item, coords)
 	    table.insert(result, val)
 	end
     end
-    return unpack(result)
+    return table.unpack(result)
 end
 
 -- read an integer from a cgroup file
@@ -324,17 +329,6 @@ function container:stat_match_get_int(controller, item, match, column)
     return val
 end
 
-function stats_clear(stat)
-    stat.mem_used      = 0
-    stat.mem_limit     = 0
-    stat.memsw_used    = 0
-    stat.memsw_limit   = 0
-    stat.cpu_use_nanos = 0
-    stat.cpu_use_user  = 0
-    stat.cpu_use_sys   = 0
-    stat.blkio         = 0
-end
-
 function container:stats_get(total)
     local stat = {}
     stat.mem_used      = self:stat_get_int("memory",  "memory.usage_in_bytes")
@@ -359,10 +353,21 @@ function container:stats_get(total)
     return stat
 end
 
+local M = { container = container }
 
+function M.stats_clear(stat)
+    stat.mem_used      = 0
+    stat.mem_limit     = 0
+    stat.memsw_used    = 0
+    stat.memsw_limit   = 0
+    stat.cpu_use_nanos = 0
+    stat.cpu_use_user  = 0
+    stat.cpu_use_sys   = 0
+    stat.blkio         = 0
+end
 
 -- return configured containers found in LXC_PATH directory
-function containers_configured(names_only)
+function M.containers_configured(names_only)
     local containers = {}
 
     for dir in lfs.dir(lxc_path) do
@@ -390,7 +395,7 @@ function containers_configured(names_only)
 end
 
 -- return running containers found in cgroup fs
-function containers_running(names_only)
+function M.containers_running(names_only)
     local containers = {}
     local attr
 
@@ -426,3 +431,5 @@ end
 
 lxc_path = core.default_config_path_get()
 cgroup_path = cgroup_path_get()
+
+return M