src/lib_package.c

   1 /*
   2 ** Package library.
   3 ** Copyright (C) 2005-2023 Mike Pall. See Copyright Notice in luajit.h
   4 **
   5 ** Major portions taken verbatim or adapted from the Lua interpreter.
   6 ** Copyright (C) 1994-2012 Lua.org, PUC-Rio. See Copyright Notice in lua.h
   7 */
   8
   9 #define lib_package_c
  10 #define LUA_LIB
  11
  12 #include "lua.h"
  13 #include "lauxlib.h"
  14 #include "lualib.h"
  15
  16 #include "lj_obj.h"
  17 #include "lj_err.h"
  18 #include "lj_lib.h"
  19
  20 /* ------------------------------------------------------------------------ */
  21
  22 /* Error codes for ll_loadfunc. */
  23 #define PACKAGE_ERR_LIB         1
  24 #define PACKAGE_ERR_FUNC        2
  25 #define PACKAGE_ERR_LOAD        3
  26
  27 /* Redefined in platform specific part. */
  28 #define PACKAGE_LIB_FAIL        "open"
  29 #define setprogdir(L)           ((void)0)
  30
  31 /* Symbol name prefixes. */
  32 #define SYMPREFIX_CF            "luaopen_%s"
  33 #define SYMPREFIX_BC            "luaJIT_BC_%s"
  34
  35 #if LJ_TARGET_DLOPEN
  36
  37 #include <dlfcn.h>
  38
  39 static void ll_unloadlib(void *lib)
  40 {
  41   dlclose(lib);
  42 }
  43
  44 static void *ll_load(lua_State *L, const char *path, int gl)
  45 {
  46   void *lib = dlopen(path, RTLD_NOW | (gl ? RTLD_GLOBAL : RTLD_LOCAL));
  47   if (lib == NULL) lua_pushstring(L, dlerror());
  48   return lib;
  49 }
  50
  51 static lua_CFunction ll_sym(lua_State *L, void *lib, const char *sym)
  52 {
  53   lua_CFunction f = (lua_CFunction)dlsym(lib, sym);
  54   if (f == NULL) lua_pushstring(L, dlerror());
  55   return f;
  56 }
  57
  58 static const char *ll_bcsym(void *lib, const char *sym)
  59 {
  60 #if defined(RTLD_DEFAULT) && !defined(NO_RTLD_DEFAULT)
  61   if (lib == NULL) lib = RTLD_DEFAULT;
  62 #elif LJ_TARGET_OSX || LJ_TARGET_BSD
  63   if (lib == NULL) lib = (void *)(intptr_t)-2;
  64 #endif
  65   return (const char *)dlsym(lib, sym);
  66 }
  67
  68 #elif LJ_TARGET_WINDOWS
  69
  70 #define WIN32_LEAN_AND_MEAN
  71 #include <windows.h>
  72
  73 #ifndef GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS
  74 #define GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS  4
  75 #define GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT  2
  76 BOOL WINAPI GetModuleHandleExA(DWORD, LPCSTR, HMODULE*);
  77 #endif
  78
  79 #undef setprogdir
  80
  81 static void setprogdir(lua_State *L)
  82 {
  83   char buff[MAX_PATH + 1];
  84   char *lb;
  85   DWORD nsize = sizeof(buff);
  86   DWORD n = GetModuleFileNameA(NULL, buff, nsize);
  87   if (n == 0 || n == nsize || (lb = strrchr(buff, '\\')) == NULL) {
  88     luaL_error(L, "unable to get ModuleFileName");
  89   } else {
  90     *lb = '\0';
  91     luaL_gsub(L, lua_tostring(L, -1), LUA_EXECDIR, buff);
  92     lua_remove(L, -2);  /* remove original string */
  93   }
  94 }
  95
  96 static void pusherror(lua_State *L)
  97 {
  98   DWORD error = GetLastError();
  99   char buffer[128];
 100   if (FormatMessageA(FORMAT_MESSAGE_IGNORE_INSERTS | FORMAT_MESSAGE_FROM_SYSTEM,
 101       NULL, error, 0, buffer, sizeof(buffer), NULL))
 102     lua_pushstring(L, buffer);
 103   else
 104     lua_pushfstring(L, "system error %d\n", error);
 105 }
 106
 107 static void ll_unloadlib(void *lib)
 108 {
 109   FreeLibrary((HINSTANCE)lib);
 110 }
 111
 112 static void *ll_load(lua_State *L, const char *path, int gl)
 113 {
 114   HINSTANCE lib = LoadLibraryA(path);
 115   if (lib == NULL) pusherror(L);
 116   UNUSED(gl);
 117   return lib;
 118 }
 119
 120 static lua_CFunction ll_sym(lua_State *L, void *lib, const char *sym)
 121 {
 122   lua_CFunction f = (lua_CFunction)GetProcAddress((HINSTANCE)lib, sym);
 123   if (f == NULL) pusherror(L);
 124   return f;
 125 }
 126
 127 static const char *ll_bcsym(void *lib, const char *sym)
 128 {
 129   if (lib) {
 130     return (const char *)GetProcAddress((HINSTANCE)lib, sym);
 131   } else {
 132     HINSTANCE h = GetModuleHandleA(NULL);
 133     const char *p = (const char *)GetProcAddress(h, sym);
 134     if (p == NULL && GetModuleHandleExA(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS|GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT,
 135                                         (const char *)ll_bcsym, &h))
 136       p = (const char *)GetProcAddress(h, sym);
 137     return p;
 138   }
 139 }
 140
 141 #else
 142
 143 #undef PACKAGE_LIB_FAIL
 144 #define PACKAGE_LIB_FAIL        "absent"
 145
 146 #define DLMSG   "dynamic libraries not enabled; no support for target OS"
 147
 148 static void ll_unloadlib(void *lib)
 149 {
 150   UNUSED(lib);
 151 }
 152
 153 static void *ll_load(lua_State *L, const char *path, int gl)
 154 {
 155   UNUSED(path); UNUSED(gl);
 156   lua_pushliteral(L, DLMSG);
 157   return NULL;
 158 }
 159
 160 static lua_CFunction ll_sym(lua_State *L, void *lib, const char *sym)
 161 {
 162   UNUSED(lib); UNUSED(sym);
 163   lua_pushliteral(L, DLMSG);
 164   return NULL;
 165 }
 166
 167 static const char *ll_bcsym(void *lib, const char *sym)
 168 {
 169   UNUSED(lib); UNUSED(sym);
 170   return NULL;
 171 }
 172
 173 #endif
 174
 175 /* ------------------------------------------------------------------------ */
 176
 177 static void **ll_register(lua_State *L, const char *path)
 178 {
 179   void **plib;
 180   lua_pushfstring(L, "LOADLIB: %s", path);
 181   lua_gettable(L, LUA_REGISTRYINDEX);  /* check library in registry? */
 182   if (!lua_isnil(L, -1)) {  /* is there an entry? */
 183     plib = (void **)lua_touserdata(L, -1);
 184   } else {  /* no entry yet; create one */
 185     lua_pop(L, 1);
 186     plib = (void **)lua_newuserdata(L, sizeof(void *));
 187     *plib = NULL;
 188     luaL_getmetatable(L, "_LOADLIB");
 189     lua_setmetatable(L, -2);
 190     lua_pushfstring(L, "LOADLIB: %s", path);
 191     lua_pushvalue(L, -2);
 192     lua_settable(L, LUA_REGISTRYINDEX);
 193   }
 194   return plib;
 195 }
 196
 197 static const char *mksymname(lua_State *L, const char *modname,
 198                              const char *prefix)
 199 {
 200   const char *funcname;
 201   const char *mark = strchr(modname, *LUA_IGMARK);
 202   if (mark) modname = mark + 1;
 203   funcname = luaL_gsub(L, modname, ".", "_");
 204   funcname = lua_pushfstring(L, prefix, funcname);
 205   lua_remove(L, -2);  /* remove 'gsub' result */
 206   return funcname;
 207 }
 208
 209 static int ll_loadfunc(lua_State *L, const char *path, const char *name, int r)
 210 {
 211   void **reg;
 212   if (strlen(path) >= 4096) {
 213     lua_pushliteral(L, "path too long");
 214     return PACKAGE_ERR_LIB;
 215   }
 216   reg = ll_register(L, path);
 217   if (*reg == NULL) *reg = ll_load(L, path, (*name == '*'));
 218   if (*reg == NULL) {
 219     return PACKAGE_ERR_LIB;  /* Unable to load library. */
 220   } else if (*name == '*') {  /* Only load library into global namespace. */
 221     lua_pushboolean(L, 1);
 222     return 0;
 223   } else {
 224     const char *sym = r ? name : mksymname(L, name, SYMPREFIX_CF);
 225     lua_CFunction f = ll_sym(L, *reg, sym);
 226     if (f) {
 227       lua_pushcfunction(L, f);
 228       return 0;
 229     }
 230     if (!r) {
 231       const char *bcdata = ll_bcsym(*reg, mksymname(L, name, SYMPREFIX_BC));
 232       lua_pop(L, 1);
 233       if (bcdata) {
 234         if (luaL_loadbuffer(L, bcdata, ~(size_t)0, name) != 0)
 235           return PACKAGE_ERR_LOAD;
 236         return 0;
 237       }
 238     }
 239     return PACKAGE_ERR_FUNC;  /* Unable to find function. */
 240   }
 241 }
 242
 243 static int lj_cf_package_loadlib(lua_State *L)
 244 {
 245   const char *path = luaL_checkstring(L, 1);
 246   const char *init = luaL_checkstring(L, 2);
 247   int st = ll_loadfunc(L, path, init, 1);
 248   if (st == 0) {  /* no errors? */
 249     return 1;  /* return the loaded function */
 250   } else {  /* error; error message is on stack top */
 251     lua_pushnil(L);
 252     lua_insert(L, -2);
 253     lua_pushstring(L, (st == PACKAGE_ERR_LIB) ?  PACKAGE_LIB_FAIL : "init");
 254     return 3;  /* return nil, error message, and where */
 255   }
 256 }
 257
 258 static int lj_cf_package_unloadlib(lua_State *L)
 259 {
 260   void **lib = (void **)luaL_checkudata(L, 1, "_LOADLIB");
 261   if (*lib) ll_unloadlib(*lib);
 262   *lib = NULL;  /* mark library as closed */
 263   return 0;
 264 }
 265
 266 /* ------------------------------------------------------------------------ */
 267
 268 static int readable(const char *filename)
 269 {
 270   FILE *f = fopen(filename, "r");  /* try to open file */
 271   if (f == NULL) return 0;  /* open failed */
 272   fclose(f);
 273   return 1;
 274 }
 275
 276 static const char *pushnexttemplate(lua_State *L, const char *path)
 277 {
 278   const char *l;
 279   while (*path == *LUA_PATHSEP) path++;  /* skip separators */
 280   if (*path == '\0') return NULL;  /* no more templates */
 281   l = strchr(path, *LUA_PATHSEP);  /* find next separator */
 282   if (l == NULL) l = path + strlen(path);
 283   lua_pushlstring(L, path, (size_t)(l - path));  /* template */
 284   return l;
 285 }
 286
 287 static const char *searchpath (lua_State *L, const char *name,
 288                                const char *path, const char *sep,
 289                                const char *dirsep)
 290 {
 291   luaL_Buffer msg;  /* to build error message */
 292   luaL_buffinit(L, &msg);
 293   if (*sep != '\0')  /* non-empty separator? */
 294     name = luaL_gsub(L, name, sep, dirsep);  /* replace it by 'dirsep' */
 295   while ((path = pushnexttemplate(L, path)) != NULL) {
 296     const char *filename = luaL_gsub(L, lua_tostring(L, -1),
 297                                      LUA_PATH_MARK, name);
 298     lua_remove(L, -2);  /* remove path template */
 299     if (readable(filename))  /* does file exist and is readable? */
 300       return filename;  /* return that file name */
 301     lua_pushfstring(L, "\n\tno file " LUA_QS, filename);
 302     lua_remove(L, -2);  /* remove file name */
 303     luaL_addvalue(&msg);  /* concatenate error msg. entry */
 304   }
 305   luaL_pushresult(&msg);  /* create error message */
 306   return NULL;  /* not found */
 307 }
 308
 309 static int lj_cf_package_searchpath(lua_State *L)
 310 {
 311   const char *f = searchpath(L, luaL_checkstring(L, 1),
 312                                 luaL_checkstring(L, 2),
 313                                 luaL_optstring(L, 3, "."),
 314                                 luaL_optstring(L, 4, LUA_DIRSEP));
 315   if (f != NULL) {
 316     return 1;
 317   } else {  /* error message is on top of the stack */
 318     lua_pushnil(L);
 319     lua_insert(L, -2);
 320     return 2;  /* return nil + error message */
 321   }
 322 }
 323
 324 static const char *findfile(lua_State *L, const char *name,
 325                             const char *pname)
 326 {
 327   const char *path;
 328   lua_getfield(L, LUA_ENVIRONINDEX, pname);
 329   path = lua_tostring(L, -1);
 330   if (path == NULL)
 331     luaL_error(L, LUA_QL("package.%s") " must be a string", pname);
 332   return searchpath(L, name, path, ".", LUA_DIRSEP);
 333 }
 334
 335 static void loaderror(lua_State *L, const char *filename)
 336 {
 337   luaL_error(L, "error loading module " LUA_QS " from file " LUA_QS ":\n\t%s",
 338              lua_tostring(L, 1), filename, lua_tostring(L, -1));
 339 }
 340
 341 static int lj_cf_package_loader_lua(lua_State *L)
 342 {
 343   const char *filename;
 344   const char *name = luaL_checkstring(L, 1);
 345   filename = findfile(L, name, "path");
 346   if (filename == NULL) return 1;  /* library not found in this path */
 347   if (luaL_loadfile(L, filename) != 0)
 348     loaderror(L, filename);
 349   return 1;  /* library loaded successfully */
 350 }
 351
 352 static int lj_cf_package_loader_c(lua_State *L)
 353 {
 354   const char *name = luaL_checkstring(L, 1);
 355   const char *filename = findfile(L, name, "cpath");
 356   if (filename == NULL) return 1;  /* library not found in this path */
 357   if (ll_loadfunc(L, filename, name, 0) != 0)
 358     loaderror(L, filename);
 359   return 1;  /* library loaded successfully */
 360 }
 361
 362 static int lj_cf_package_loader_croot(lua_State *L)
 363 {
 364   const char *filename;
 365   const char *name = luaL_checkstring(L, 1);
 366   const char *p = strchr(name, '.');
 367   int st;
 368   if (p == NULL) return 0;  /* is root */
 369   lua_pushlstring(L, name, (size_t)(p - name));
 370   filename = findfile(L, lua_tostring(L, -1), "cpath");
 371   if (filename == NULL) return 1;  /* root not found */
 372   if ((st = ll_loadfunc(L, filename, name, 0)) != 0) {
 373     if (st != PACKAGE_ERR_FUNC) loaderror(L, filename);  /* real error */
 374     lua_pushfstring(L, "\n\tno module " LUA_QS " in file " LUA_QS,
 375                     name, filename);
 376     return 1;  /* function not found */
 377   }
 378   return 1;
 379 }
 380
 381 static int lj_cf_package_loader_preload(lua_State *L)
 382 {
 383   const char *name = luaL_checkstring(L, 1);
 384   lua_getfield(L, LUA_ENVIRONINDEX, "preload");
 385   if (!lua_istable(L, -1))
 386     luaL_error(L, LUA_QL("package.preload") " must be a table");
 387   lua_getfield(L, -1, name);
 388   if (lua_isnil(L, -1)) {  /* Not found? */
 389     const char *bcname = mksymname(L, name, SYMPREFIX_BC);
 390     const char *bcdata = ll_bcsym(NULL, bcname);
 391     if (bcdata == NULL || luaL_loadbuffer(L, bcdata, ~(size_t)0, name) != 0)
 392       lua_pushfstring(L, "\n\tno field package.preload['%s']", name);
 393   }
 394   return 1;
 395 }
 396
 397 /* ------------------------------------------------------------------------ */
 398
 399 static const int sentinel_ = 0;
 400 #define sentinel        ((void *)&sentinel_)
 401
 402 static int lj_cf_package_require(lua_State *L)
 403 {
 404   const char *name = luaL_checkstring(L, 1);
 405   int i;
 406   lua_settop(L, 1);  /* _LOADED table will be at index 2 */
 407   lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");
 408   lua_getfield(L, 2, name);
 409   if (lua_toboolean(L, -1)) {  /* is it there? */
 410     if (lua_touserdata(L, -1) == sentinel)  /* check loops */
 411       luaL_error(L, "loop or previous error loading module " LUA_QS, name);
 412     return 1;  /* package is already loaded */
 413   }
 414   /* else must load it; iterate over available loaders */
 415   lua_getfield(L, LUA_ENVIRONINDEX, "loaders");
 416   if (!lua_istable(L, -1))
 417     luaL_error(L, LUA_QL("package.loaders") " must be a table");
 418   lua_pushliteral(L, "");  /* error message accumulator */
 419   for (i = 1; ; i++) {
 420     lua_rawgeti(L, -2, i);  /* get a loader */
 421     if (lua_isnil(L, -1))
 422       luaL_error(L, "module " LUA_QS " not found:%s",
 423                  name, lua_tostring(L, -2));
 424     lua_pushstring(L, name);
 425     lua_call(L, 1, 1);  /* call it */
 426     if (lua_isfunction(L, -1))  /* did it find module? */
 427       break;  /* module loaded successfully */
 428     else if (lua_isstring(L, -1))  /* loader returned error message? */
 429       lua_concat(L, 2);  /* accumulate it */
 430     else
 431       lua_pop(L, 1);
 432   }
 433   lua_pushlightuserdata(L, sentinel);
 434   lua_setfield(L, 2, name);  /* _LOADED[name] = sentinel */
 435   lua_pushstring(L, name);  /* pass name as argument to module */
 436   lua_call(L, 1, 1);  /* run loaded module */
 437   if (!lua_isnil(L, -1))  /* non-nil return? */
 438     lua_setfield(L, 2, name);  /* _LOADED[name] = returned value */
 439   lua_getfield(L, 2, name);
 440   if (lua_touserdata(L, -1) == sentinel) {   /* module did not set a value? */
 441     lua_pushboolean(L, 1);  /* use true as result */
 442     lua_pushvalue(L, -1);  /* extra copy to be returned */
 443     lua_setfield(L, 2, name);  /* _LOADED[name] = true */
 444   }
 445   lj_lib_checkfpu(L);
 446   return 1;
 447 }
 448
 449 /* ------------------------------------------------------------------------ */
 450
 451 static void setfenv(lua_State *L)
 452 {
 453   lua_Debug ar;
 454   if (lua_getstack(L, 1, &ar) == 0 ||
 455       lua_getinfo(L, "f", &ar) == 0 ||  /* get calling function */
 456       lua_iscfunction(L, -1))
 457     luaL_error(L, LUA_QL("module") " not called from a Lua function");
 458   lua_pushvalue(L, -2);
 459   lua_setfenv(L, -2);
 460   lua_pop(L, 1);
 461 }
 462
 463 static void dooptions(lua_State *L, int n)
 464 {
 465   int i;
 466   for (i = 2; i <= n; i++) {
 467     lua_pushvalue(L, i);  /* get option (a function) */
 468     lua_pushvalue(L, -2);  /* module */
 469     lua_call(L, 1, 0);
 470   }
 471 }
 472
 473 static void modinit(lua_State *L, const char *modname)
 474 {
 475   const char *dot;
 476   lua_pushvalue(L, -1);
 477   lua_setfield(L, -2, "_M");  /* module._M = module */
 478   lua_pushstring(L, modname);
 479   lua_setfield(L, -2, "_NAME");
 480   dot = strrchr(modname, '.');  /* look for last dot in module name */
 481   if (dot == NULL) dot = modname; else dot++;
 482   /* set _PACKAGE as package name (full module name minus last part) */
 483   lua_pushlstring(L, modname, (size_t)(dot - modname));
 484   lua_setfield(L, -2, "_PACKAGE");
 485 }
 486
 487 static int lj_cf_package_module(lua_State *L)
 488 {
 489   const char *modname = luaL_checkstring(L, 1);
 490   int loaded = lua_gettop(L) + 1;  /* index of _LOADED table */
 491   lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");
 492   lua_getfield(L, loaded, modname);  /* get _LOADED[modname] */
 493   if (!lua_istable(L, -1)) {  /* not found? */
 494     lua_pop(L, 1);  /* remove previous result */
 495     /* try global variable (and create one if it does not exist) */
 496     if (luaL_findtable(L, LUA_GLOBALSINDEX, modname, 1) != NULL)
 497       lj_err_callerv(L, LJ_ERR_BADMODN, modname);
 498     lua_pushvalue(L, -1);
 499     lua_setfield(L, loaded, modname);  /* _LOADED[modname] = new table */
 500   }
 501   /* check whether table already has a _NAME field */
 502   lua_getfield(L, -1, "_NAME");
 503   if (!lua_isnil(L, -1)) {  /* is table an initialized module? */
 504     lua_pop(L, 1);
 505   } else {  /* no; initialize it */
 506     lua_pop(L, 1);
 507     modinit(L, modname);
 508   }
 509   lua_pushvalue(L, -1);
 510   setfenv(L);
 511   dooptions(L, loaded - 1);
 512   return 0;
 513 }
 514
 515 static int lj_cf_package_seeall(lua_State *L)
 516 {
 517   luaL_checktype(L, 1, LUA_TTABLE);
 518   if (!lua_getmetatable(L, 1)) {
 519     lua_createtable(L, 0, 1); /* create new metatable */
 520     lua_pushvalue(L, -1);
 521     lua_setmetatable(L, 1);
 522   }
 523   lua_pushvalue(L, LUA_GLOBALSINDEX);
 524   lua_setfield(L, -2, "__index");  /* mt.__index = _G */
 525   return 0;
 526 }
 527
 528 /* ------------------------------------------------------------------------ */
 529
 530 #define AUXMARK         "\1"
 531
 532 static void setpath(lua_State *L, const char *fieldname, const char *envname,
 533                     const char *def, int noenv)
 534 {
 535 #if LJ_TARGET_CONSOLE
 536   const char *path = NULL;
 537   UNUSED(envname);
 538 #else
 539   const char *path = getenv(envname);
 540 #endif
 541   if (path == NULL || noenv) {
 542     lua_pushstring(L, def);
 543   } else {
 544     path = luaL_gsub(L, path, LUA_PATHSEP LUA_PATHSEP,
 545                               LUA_PATHSEP AUXMARK LUA_PATHSEP);
 546     luaL_gsub(L, path, AUXMARK, def);
 547     lua_remove(L, -2);
 548   }
 549   setprogdir(L);
 550   lua_setfield(L, -2, fieldname);
 551 }
 552
 553 static const luaL_Reg package_lib[] = {
 554   { "loadlib",  lj_cf_package_loadlib },
 555   { "searchpath",  lj_cf_package_searchpath },
 556   { "seeall",   lj_cf_package_seeall },
 557   { NULL, NULL }
 558 };
 559
 560 static const luaL_Reg package_global[] = {
 561   { "module",   lj_cf_package_module },
 562   { "require",  lj_cf_package_require },
 563   { NULL, NULL }
 564 };
 565
 566 static const lua_CFunction package_loaders[] =
 567 {
 568   lj_cf_package_loader_preload,
 569   lj_cf_package_loader_lua,
 570   lj_cf_package_loader_c,
 571   lj_cf_package_loader_croot,
 572   NULL
 573 };
 574
 575 LUALIB_API int luaopen_package(lua_State *L)
 576 {
 577   int i;
 578   int noenv;
 579   luaL_newmetatable(L, "_LOADLIB");
 580   lj_lib_pushcf(L, lj_cf_package_unloadlib, 1);
 581   lua_setfield(L, -2, "__gc");
 582   luaL_register(L, LUA_LOADLIBNAME, package_lib);
 583   lua_pushvalue(L, -1);
 584   lua_replace(L, LUA_ENVIRONINDEX);
 585   lua_createtable(L, sizeof(package_loaders)/sizeof(package_loaders[0])-1, 0);
 586   for (i = 0; package_loaders[i] != NULL; i++) {
 587     lj_lib_pushcf(L, package_loaders[i], 1);
 588     lua_rawseti(L, -2, i+1);
 589   }
 590   lua_setfield(L, -2, "loaders");
 591   lua_getfield(L, LUA_REGISTRYINDEX, "LUA_NOENV");
 592   noenv = lua_toboolean(L, -1);
 593   lua_pop(L, 1);
 594   setpath(L, "path", LUA_PATH, LUA_PATH_DEFAULT, noenv);
 595   setpath(L, "cpath", LUA_CPATH, LUA_CPATH_DEFAULT, noenv);
 596   lua_pushliteral(L, LUA_PATH_CONFIG);
 597   lua_setfield(L, -2, "config");
 598   luaL_findtable(L, LUA_REGISTRYINDEX, "_LOADED", 16);
 599   lua_setfield(L, -2, "loaded");
 600   luaL_findtable(L, LUA_REGISTRYINDEX, "_PRELOAD", 4);
 601   lua_setfield(L, -2, "preload");
 602   lua_pushvalue(L, LUA_GLOBALSINDEX);
 603   luaL_register(L, NULL, package_global);
 604   lua_pop(L, 1);
 605   return 1;
 606 }
 607