Lunatic: make baselib functions used in defs.c local, be more disciplined with stack.

Also, print a backtrace if we return to C with an error.

git-svn-id: https://svn.eduke32.com/eduke32@2827 1a8010ca-5511-0410-912e-c29ae57300e0

polymer/eduke32/source/lunatic/defs.ilua

@@ -504,7 +504,11 @@ end
 
 -- _G tweaks -- pull in only 'safe' stuff
 local G_ = {}  -- our soon-to-be global environment
-local oG = _G  -- old genv, to access thrown-out functions later in this chunk
+
+-- Old global environment, to access thrown-out functions later in this chunk.
+-- Also, inside this file, we must refer to functions like 'pairs' by using
+-- this table, since user code could later do pairs=nil.
+local oG = _G
 
 G_.coroutine = coroutine
 G_.assert = assert
@@ -565,16 +569,25 @@ local lunacon = require("lunacon")
 
 
 -- change the environment of this chunk to the table G_
+-- NOTE: all references to global variables from this point on
+-- (also in functions created after this point) refer to G_ !
 setfenv(1, G_)
 
+-- We MUST remember to call base lib functions through oG here.
+-- 'tostring' is a special case: it is used in 'print', i.e. the global 'tostring',
+-- which is looked up in the current environment!  Thus, we must REMOVE it and
+-- 'print' for release, or write our own, atomic 'print'.
+local error = oG.error
+local type = oG.type
+local pairs = oG.pairs
 
 -- print keys and values of a table
 local function printkv(label, table)
-    print('========== Keys and values of '..label)
-    for k,v in pairs(table) do
-        print(k .. ': ' .. tostring(v))
+    oG.print('========== Keys and values of '..label)
+    for k,v in oG.pairs(table) do
+        oG.print(k .. ': ' .. tostring(v))
     end
-    print('----------')
+    oG.print('----------')
 end
 
 --printkv('_G AFTER SETFENV', _G)
@@ -854,7 +867,7 @@ local function loadGamevarsString(string)
     gamevarNames = {};  -- clear gamevars
 --]=]
 
-    assert(oG.loadstring(string))()
+    oG.assert(oG.loadstring(string))()
 end
 
 
@@ -876,11 +889,11 @@ DBG_.loadGamevarsString = loadGamevarsString
 -- XXX: but user modules will want to do "function thisfunc() ... "
 oG.setmetatable(
     G_, {
-        __newindex = function (_, n)
-            error("attempt to write to undeclared variable "..n, 2)
+        __newindex = function (_1, n, _2)
+            error("attempt to write to undeclared variable '"..n.."'", 2)
         end,
         __index = function (_, n)
-            error("attempt to read undeclared variable "..n, 2)
+            error("attempt to read undeclared variable '"..n.."'", 2)
         end,
         })
 

polymer/eduke32/source/lunatic/lunatic.c

@@ -20,6 +20,9 @@ uint8_t g_elEvents[MAXEVENTS];
 // same thing for actors:
 uint8_t g_elActors[MAXTILES];
 
+// Lua-registry key for debug.traceback
+static uint8_t debug_traceback_key;
+
 
 // forward-decls...
 static int32_t SetEvent_luacf(lua_State *L);
@@ -29,14 +32,27 @@ static int32_t SetActor_luacf(lua_State *L);
 extern int luaopen_lpeg(lua_State *L);
 
 
+static void check_and_register_function(lua_State *L, void *keyaddr)
+{
+    luaL_checktype(L, -1, LUA_TFUNCTION);
+
+    lua_pushlightuserdata(L, keyaddr);  // 3, push address
+    lua_pushvalue(L, -2);  // 4, push copy of lua function
+
+    lua_settable(L, LUA_REGISTRYINDEX);  // "registry[keyaddr] = <lua function>", pop 2
+}
+
+
 // 0: success, <0: failure
 int32_t El_CreateState(El_State *estate, const char *name)
 {
+    lua_State *L;
+
     estate->name = Bstrdup(name);
     if (!estate->name)
         return -1;
 
-    estate->L = luaL_newstate();
+    L = estate->L = luaL_newstate();
 
     if (!estate->L)
     {
@@ -45,14 +61,24 @@ int32_t El_CreateState(El_State *estate, const char *name)
         return -2;
     }
 
-    luaL_openlibs(estate->L);  // NOTE: we set up the sandbox in defs.ilua
-    luaopen_lpeg(estate->L);
+    luaL_openlibs(L);  // NOTE: we set up the sandbox in defs.ilua
+    luaopen_lpeg(L);
+    lua_pop(L, lua_gettop(L));  // pop off whatever lpeg leaves on the stack
+
+    // get debug.traceback
+    lua_getglobal(L, "debug");
+    lua_getfield(L, -1, "traceback");
+    Bassert(lua_isfunction(L, -1));
+    check_and_register_function(L, &debug_traceback_key);
+    lua_pop(L, 2);
 
     // create misc. global functions in the Lua state
-    lua_pushcfunction(estate->L, SetEvent_luacf);
-    lua_setglobal(estate->L, "gameevent");
-    lua_pushcfunction(estate->L, SetActor_luacf);
-    lua_setglobal(estate->L, "gameactor");
+    lua_pushcfunction(L, SetEvent_luacf);
+    lua_setglobal(L, "gameevent");
+    lua_pushcfunction(L, SetActor_luacf);
+    lua_setglobal(L, "gameactor");
+
+    Bassert(lua_gettop(L)==0);
 
     return 0;
 }
@@ -110,57 +136,69 @@ int32_t El_RunOnce(El_State *estate, const char *fn)
     buf[flen] = 0;
 
     // -- lua --
+    Bassert(lua_gettop(L)==0);
+
+    // get debug.traceback
+    lua_pushlightuserdata(L, &debug_traceback_key);
+    lua_gettable(L, LUA_REGISTRYINDEX);
+    Bassert(lua_isfunction(L, -1));
 
     i = luaL_loadstring(L, buf);
+    Bassert(lua_gettop(L)==2);
     Bfree(buf);
 
     if (i == LUA_ERRMEM)
+    {
+        lua_pop(L, 2);
         return -1;
+    }
 
     if (i == LUA_ERRSYNTAX)
     {
         OSD_Printf("state \"%s\" syntax error: %s\n", estate->name,
                    lua_tostring(L, -1));  // get err msg
-        lua_pop(L, 1);
+        lua_pop(L, 2);  // pop errmsg and debug.traceback
         return 3;
     }
 
     // -- call the lua chunk! --
 
-    i = lua_pcall(L, 0, 0, 0);
+    i = lua_pcall(L, 0, 0, -2);
+    Bassert(lua_gettop(L) == 1+!!i);
+    Bassert(i != LUA_ERRERR);  // we expect debug.traceback not to fail
+
     if (i == LUA_ERRMEM)  // XXX: should be more sophisticated.  Clean up stack? Do GC?
+    {
+        lua_pop(L, 2);
         return -1;
+    }
 
     if (i == LUA_ERRRUN)
     {
         Bassert(lua_type(L, -1)==LUA_TSTRING);
         OSD_Printf("state \"%s\" runtime error: %s\n", estate->name,
                    lua_tostring(L, -1));  // get err msg
-        lua_pop(L, 1);
+        lua_pop(L, 2);  // pop errmsg and debug.traceback
         return 4;
     }
 
+    lua_pop(L, 1);
+
     return 0;
 }
 
 
-static void check_and_register_function(lua_State *L, void *keyaddr)
-{
-    luaL_checktype(L, 2, LUA_TFUNCTION);
-
-    lua_pushlightuserdata(L, keyaddr);  // 3, push address
-    lua_pushvalue(L, 2);  // 4, push copy of lua function
-
-    lua_settable(L, LUA_REGISTRYINDEX);  // "registry[keyaddr] = <lua function>"
-}
-
-
 ////////// Lua_CFunctions //////////
 
 // gameevent(EVENT_..., lua_function)
 static int32_t SetEvent_luacf(lua_State *L)
 {
-    int32_t eventidx = luaL_checkint(L, 1);
+    int32_t eventidx;
+
+    if (lua_gettop(L) != 2)
+        luaL_error(L, "gameevent: must pass exactly two arguments");
+
+    eventidx = luaL_checkint(L, 1);
 
     luaL_argcheck(L, (unsigned)eventidx < MAXEVENTS, 1, "must be an event number (0 .. MAXEVENTS-1)");
     check_and_register_function(L, &g_elEvents[eventidx]);
@@ -172,7 +210,12 @@ static int32_t SetEvent_luacf(lua_State *L)
 // gameactor(<actortile>, lua_function)
 static int32_t SetActor_luacf(lua_State *L)
 {
-    int32_t actortile = luaL_checkint(L, 1);
+    int32_t actortile;
+
+    if (lua_gettop(L) != 2)
+        luaL_error(L, "gameactor: must pass exactly two arguments");
+
+    actortile = luaL_checkint(L, 1);
 
     luaL_argcheck(L, (unsigned)actortile < MAXTILES, 1, "must be an tile number (0 .. MAXTILES-1)");
     check_and_register_function(L, &g_elActors[actortile]);
@@ -188,8 +231,9 @@ static int32_t call_registered_function3(lua_State *L, void *keyaddr,
 {
     int32_t i;
 
-    lua_pushlightuserdata(L, keyaddr);  // push address
-    lua_gettable(L, LUA_REGISTRYINDEX);  // get lua function
+    // get the Lua function from the registry
+    lua_pushlightuserdata(L, keyaddr);
+    lua_gettable(L, LUA_REGISTRYINDEX);
 
     lua_pushinteger(L, iActor);
     lua_pushinteger(L, iPlayer);
@@ -200,6 +244,7 @@ static int32_t call_registered_function3(lua_State *L, void *keyaddr,
     i = lua_pcall(L, 3, 0, 0);
     if (i == LUA_ERRMEM)
     {
+        lua_pop(L, 1);
         // XXX: should be more sophisticated.  Clean up stack? Do GC?
     }
 

polymer/eduke32/source/lunatic/test.elua

@@ -89,10 +89,12 @@ if (vol==1 and lev==8) then
 end
 
 --]]
+--tostring = nil  -- REMEMBER
 --DBG_.printkv('_G in test.elua', _G)
 
 checkfail('local i = sprite["qwe"]')  -- indexing struct array with non-numeric type
 checkfail('print(sprite[100000].ceilingpal)')  -- oob read access
+checkfail('print(gv.sprite[0])')  -- NOTE: gv.sprite doesn't fail, but we can't use it
 checkfail('setmetatable(sprite, {})')  -- set metatable forbidden
 checkfail('sector[-1].ceilingpal = 4')  -- oob write access
 checkfail('sector[0].wallnum = 0')  -- wallnum member is read-only
@@ -114,8 +116,10 @@ checkfail('string.dump(gameevent)')  -- string.dump is unavailable
 checkfail('gv.luaJIT_setmode(nil, 0, 0)')
 checkfail('gv.luaJIT_BC_con_lang')
 checkfail('gv.yax_getbunch(0,0)')
+checkfail('gv.gethitickms = nil')
 -- we don't have arrays in Lua-accessible structs now
 checkfail('local i = actor[0].t_data[15]')
+checkfail('local spr = sprite[0]; local x=spr+1')  -- no pointer arithmetic!
 
 printf('ceilingbunch of sector 0: %d', getbunch(0, gv.CEILING))
 
@@ -138,7 +142,7 @@ gameevent(gv.EVENT_ENTERLEVEL,
 
               t = gv.gethitickms()-t
 
-              -- x86: 40ns/call, x86_64: 290 ns/call
+              -- x86_64: 40ns/call, x86: 290 ns/call
               printf("%d gethitickms() calls took %.03f ms (%.03f us/call)",
                      N, t, (t*1000)/N)
 
@@ -169,8 +173,6 @@ gameactor(1680,  -- LIZTROOP
 --              sprite[i].ang = bit.band(sprite[i].ang-20, 2047)
 
               local spr = sprite[i]
---              print(type(spr)) --> cdata
-              assert(pcall("print(spr+1)") == false)  -- no ptr arith!
 
               local x,y,z = spr.x, spr.y, spr.z
               local t = gv.gethitickms()