src/lib_package.c

   1 /*
   2 ** Package library.
   3 ** Copyright (C) 2005-2012 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)
  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 #ifndef WINVER
  72 #define WINVER 0x0500
  73 #endif
  74 #include <windows.h>
  75
  76 #ifndef GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS
  77 #define GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS  4
  78 #define GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT  2
  79 BOOL WINAPI GetModuleHandleExA(DWORD, LPCSTR, HMODULE*);
  80 #endif
  81
  82 #undef setprogdir
  83
  84 static void setprogdir(lua_State *L)
  85 {
  86   char buff[MAX_PATH + 1];
  87   char *lb;
  88   DWORD nsize = sizeof(buff);
  89   DWORD n = GetModuleFileNameA(NULL, buff, nsize);
  90   if (n == 0 || n == nsize || (lb = strrchr(buff, '\\')) == NULL) {
  91     luaL_error(L, "unable to get ModuleFileName");
  92   } else {
  93     *lb = '\0';
  94     luaL_gsub(L, lua_tostring(L, -1), LUA_EXECDIR, buff);
  95     lua_remove(L, -2);  /* remove original string */
  96   }
  97 }
  98
  99 static void pusherror(lua_State *L)
 100 {
 101   DWORD error = GetLastError();
 102   char buffer[128];
 103   if (FormatMessageA(FORMAT_MESSAGE_IGNORE_INSERTS | FORMAT_MESSAGE_FROM_SYSTEM,
 104       NULL, error, 0, buffer, sizeof(buffer), NULL))
 105     lua_pushstring(L, buffer);
 106   else
 107     lua_pushfstring(L, "system error %d\n", error);
 108 }
 109
 110 static void ll_unloadlib(void *lib)
 111 {
 112   FreeLibrary((HINSTANCE)lib);
 113 }
 114
 115 static void *ll_load(lua_State *L, const char *path, int gl)
 116 {
 117   HINSTANCE lib = LoadLibraryA(path);
 118   if (lib == NULL) pusherror(L);
 119   UNUSED(gl);
 120   return lib;
 121 }
 122
 123 static lua_CFunction ll_sym(lua_State *L, void *lib, const char *sym)
 124 {
 125   lua_CFunction f = (lua_CFunction)GetProcAddress((HINSTANCE)lib, sym);
 126   if (f == NULL) pusherror(L);
 127   return f;
 128 }
 129
 130 static const char *ll_bcsym(void *lib, const char *sym)
 131 {
 132   if (lib) {
 133     return (const char *)GetProcAddress((HINSTANCE)lib, sym);
 134   } else {
 135     HINSTANCE h = GetModuleHandleA(NULL);
 136     const char *p = (const char *)GetProcAddress(h, sym);
 137     if (p == NULL && GetModuleHandleExA(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS|GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT,
 138                                         (const char *)ll_bcsym, &h))
 139       p = (const char *)GetProcAddress(h, sym);
 140     return p;
 141   }
 142 }
 143
 144 #else
 145
 146 #undef PACKAGE_LIB_FAIL
 147 #define PACKAGE_LIB_FAIL        "absent"
 148
 149 #define DLMSG   "dynamic libraries not enabled; no support for target OS"
 150
 151 static void ll_unloadlib(void *lib)
 152 {
 153   UNUSED(lib);
 154 }
 155
 156 static void *ll_load(lua_State *L, const char *path, int gl)
 157 {
 158   UNUSED(path); UNUSED(gl);
 159   lua_pushliteral(L, DLMSG);
 160   return NULL;
 161 }
 162
 163 static lua_CFunction ll_sym(lua_State *L, void *lib, const char *sym)
 164 {
 165   UNUSED(lib); UNUSED(sym);
 166   lua_pushliteral(L, DLMSG);
 167   return NULL;
 168 }
 169
 170 static const char *ll_bcsym(void *lib, const char *sym)
 171 {
 172   UNUSED(lib); UNUSED(sym);
 173   return NULL;
 174 }
 175
 176 #endif
 177
 178 /* ------------------------------------------------------------------------ */
 179
 180 static void **ll_register(lua_State *L, const char *path)
 181 {
 182   void **plib;
 183   lua_pushfstring(L, "LOADLIB: %s", path);
 184   lua_gettable(L, LUA_REGISTRYINDEX);  /* check library in registry? */
 185   if (!lua_isnil(L, -1)) {  /* is there an entry? */
 186     plib = (void **)lua_touserdata(L, -1);
 187   } else {  /* no entry yet; create one */
 188     lua_pop(L, 1);
 189     plib = (void **)lua_newuserdata(L, sizeof(void *));
 190     *plib = NULL;
 191     luaL_getmetatable(L, "_LOADLIB");
 192     lua_setmetatable(L, -2);
 193     lua_pushfstring(L, "LOADLIB: %s", path);
 194     lua_pushvalue(L, -2);
 195     lua_settable(L, LUA_REGISTRYINDEX);
 196   }
 197   return plib;
 198 }
 199
 200 static const char *mksymname(lua_State *L, const char *modname,
 201                              const char *prefix)
 202 {
 203   const char *funcname;
 204   const char *mark = strchr(modname, *LUA_IGMARK);
 205   if (mark) modname = mark + 1;
 206   funcname = luaL_gsub(L, modname, ".", "_");
 207   funcname = lua_pushfstring(L, prefix, funcname);
 208   lua_remove(L, -2);  /* remove 'gsub' result */
 209   return funcname;
 210 }
 211
 212 static int ll_loadfunc(lua_State *L, const char *path, const char *name, int r)
 213 {
 214   void **reg = ll_register(L, path);
 215   if (*reg == NULL) *reg = ll_load(L, path, (*name == '*'));
 216   if (*reg == NULL) {
 217     return PACKAGE_ERR_LIB;  /* Unable to load library. */
 218   } else if (*name == '*') {  /* Only load library into global namespace. */
 219     lua_pushboolean(L, 1);
 220     return 0;
 221   } else {
 222     const char *sym = r ? name : mksymname(L, name, SYMPREFIX_CF);
 223     lua_CFunction f = ll_sym(L, *reg, sym);
 224     if (f) {
 225       lua_pushcfunction(L, f);
 226       return 0;
 227     }
 228     if (!r) {
 229       const char *bcdata = ll_bcsym(*reg, mksymname(L, name, SYMPREFIX_BC));
 230       lua_pop(L, 1);
 231       if (bcdata) {
 232         if (luaL_loadbuffer(L, bcdata, ~(size_t)0, name) != 0)
 233           return PACKAGE_ERR_LOAD;
 234         return 0;
 235       }
 236     }
 237     return PACKAGE_ERR_FUNC;  /* Unable to find function. */
 238   }
 239 }
 240
 241 static int lj_cf_package_loadlib(lua_State *L)
 242 {
 243   const char *path = luaL_checkstring(L, 1);
 244   const char *init = luaL_checkstring(L, 2);
 245   int st = ll_loadfunc(L, path, init, 1);
 246   if (st == 0) {  /* no errors? */
 247     return 1;  /* return the loaded function */
 248   } else {  /* error; error message is on stack top */
 249     lua_pushnil(L);
 250     lua_insert(L, -2);
 251     lua_pushstring(L, (st == PACKAGE_ERR_LIB) ?  PACKAGE_LIB_FAIL : "init");
 252     return 3;  /* return nil, error message, and where */
 253   }
 254 }
 255
 256 static int lj_cf_package_unloadlib(lua_State *L)
 257 {
 258   void **lib = (void **)luaL_checkudata(L, 1, "_LOADLIB");
 259   if (*lib) ll_unloadlib(*lib);
 260   *lib = NULL;  /* mark library as closed */
 261   return 0;
 262 }
 263
 264 /* ------------------------------------------------------------------------ */
 265
 266 static int readable(const char *filename)
 267 {
 268   FILE *f = fopen(filename, "r");  /* try to open file */
 269   if (f == NULL) return 0;  /* open failed */
 270   fclose(f);
 271   return 1;
 272 }
 273
 274 static const char *pushnexttemplate(lua_State *L, const char *path)
 275 {
 276   const char *l;
 277   while (*path == *LUA_PATHSEP) path++;  /* skip separators */
 278   if (*path == '\0') return NULL;  /* no more templates */
 279   l = strchr(path, *LUA_PATHSEP);  /* find next separator */
 280   if (l == NULL) l = path + strlen(path);
 281   lua_pushlstring(L, path, (size_t)(l - path));  /* template */
 282   return l;
 283 }
 284
 285 static const char *searchpath (lua_State *L, const char *name,
 286                                const char *path, const char *sep,
 287                                const char *dirsep)
 288 {
 289   luaL_Buffer msg;  /* to build error message */
 290   luaL_buffinit(L, &msg);
 291   if (*sep != '\0')  /* non-empty separator? */
 292     name = luaL_gsub(L, name, sep, dirsep);  /* replace it by 'dirsep' */
 293   while ((path = pushnexttemplate(L, path)) != NULL) {
 294     const char *filename = luaL_gsub(L, lua_tostring(L, -1),
 295                                      LUA_PATH_MARK, name);
 296     lua_remove(L, -2);  /* remove path template */
 297     if (readable(filename))  /* does file exist and is readable? */
 298       return filename;  /* return that file name */
 299     lua_pushfstring(L, "\n\tno file " LUA_QS, filename);
 300     lua_remove(L, -2);  /* remove file name */
 301     luaL_addvalue(&msg);  /* concatenate error msg. entry */
 302   }
 303   luaL_pushresult(&msg);  /* create error message */
 304   return NULL;  /* not found */
 305 }
 306
 307 static int lj_cf_package_searchpath(lua_State *L)
 308 {
 309   const char *f = searchpath(L, luaL_checkstring(L, 1),
 310                                 luaL_checkstring(L, 2),
 311                                 luaL_optstring(L, 3, "."),
 312                                 luaL_optstring(L, 4, LUA_DIRSEP));
 313   if (f != NULL) {
 314     return 1;
 315   } else {  /* error message is on top of the stack */
 316     lua_pushnil(L);
 317     lua_insert(L, -2);
 318     return 2;  /* return nil + error message */
 319   }
 320 }
 321
 322 static const char *findfile(lua_State *L, const char *name,
 323                             const char *pname)
 324 {
 325   const char *path;
 326   lua_getfield(L, LUA_ENVIRONINDEX, pname);
 327   path = lua_tostring(L, -1);
 328   if (path == NULL)
 329     luaL_error(L, LUA_QL("package.%s") " must be a string", pname);
 330   return searchpath(L, name, path, ".", LUA_DIRSEP);
 331 }
 332
 333 static void loaderror(lua_State *L, const char *filename)
 334 {
 335   luaL_error(L, "error loading module " LUA_QS " from file " LUA_QS ":\n\t%s",
 336              lua_tostring(L, 1), filename, lua_tostring(L, -1));
 337 }
 338
 339 static int lj_cf_package_loader_lua(lua_State *L)
 340 {
 341   const char *filename;
 342   const char *name = luaL_checkstring(L, 1);
 343   filename = findfile(L, name, "path");
 344   if (filename == NULL) return 1;  /* library not found in this path */
 345   if (luaL_loadfile(L, filename) != 0)
 346     loaderror(L, filename);
 347   return 1;  /* library loaded successfully */
 348 }
 349
 350 static int lj_cf_package_loader_c(lua_State *L)
 351 {
 352   const char *name = luaL_checkstring(L, 1);
 353   const char *filename = findfile(L, name, "cpath");
 354   if (filename == NULL) return 1;  /* library not found in this path */
 355   if (ll_loadfunc(L, filename, name, 0) != 0)
 356     loaderror(L, filename);
 357   return 1;  /* library loaded successfully */
 358 }
 359
 360 static int lj_cf_package_loader_croot(lua_State *L)
 361 {
 362   const char *filename;
 363   const char *name = luaL_checkstring(L, 1);
 364   const char *p = strchr(name, '.');
 365   int st;
 366   if (p == NULL) return 0;  /* is root */
 367   lua_pushlstring(L, name, (size_t)(p - name));
 368   filename = findfile(L, lua_tostring(L, -1), "cpath");
 369   if (filename == NULL) return 1;  /* root not found */
 370   if ((st = ll_loadfunc(L, filename, name, 0)) != 0) {
 371     if (st != PACKAGE_ERR_FUNC) loaderror(L, filename);  /* real error */
 372     lua_pushfstring(L, "\n\tno module " LUA_QS " in file " LUA_QS,
 373                     name, filename);
 374     return 1;  /* function not found */
 375   }
 376   return 1;
 377 }
 378
 379 static int lj_cf_package_loader_preload(lua_State *L)
 380 {
 381   const char *name = luaL_checkstring(L, 1);
 382   lua_getfield(L, LUA_ENVIRONINDEX, "preload");
 383   if (!lua_istable(L, -1))
 384     luaL_error(L, LUA_QL("package.preload") " must be a table");
 385   lua_getfield(L, -1, name);
 386   if (lua_isnil(L, -1)) {  /* Not found? */
 387     const char *bcname = mksymname(L, name, SYMPREFIX_BC);
 388     const char *bcdata = ll_bcsym(NULL, bcname);
 389     if (bcdata == NULL || luaL_loadbuffer(L, bcdata, ~(size_t)0, name) != 0)
 390       lua_pushfstring(L, "\n\tno field package.preload['%s']", name);
 391   }
 392   return 1;
 393 }
 394
 395 /* ------------------------------------------------------------------------ */
 396
 397 static const int sentinel_ = 0;
 398 #define sentinel        ((void *)&sentinel_)
 399
 400 static int lj_cf_package_require(lua_State *L)
 401 {
 402   const char *name = luaL_checkstring(L, 1);
 403   int i;
 404   lua_settop(L, 1);  /* _LOADED table will be at index 2 */
 405   lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");
 406   lua_getfield(L, 2, name);
 407   if (lua_toboolean(L, -1)) {  /* is it there? */
 408     if (lua_touserdata(L, -1) == sentinel)  /* check loops */
 409       luaL_error(L, "loop or previous error loading module " LUA_QS, name);
 410     return 1;  /* package is already loaded */
 411   }
 412   /* else must load it; iterate over available loaders */
 413   lua_getfield(L, LUA_ENVIRONINDEX, "loaders");
 414   if (!lua_istable(L, -1))
 415     luaL_error(L, LUA_QL("package.loaders") " must be a table");
 416   lua_pushliteral(L, "");  /* error message accumulator */
 417   for (i = 1; ; i++) {
 418     lua_rawgeti(L, -2, i);  /* get a loader */
 419     if (lua_isnil(L, -1))
 420       luaL_error(L, "module " LUA_QS " not found:%s",
 421                  name, lua_tostring(L, -2));
 422     lua_pushstring(L, name);
 423     lua_call(L, 1, 1);  /* call it */
 424     if (lua_isfunction(L, -1))  /* did it find module? */
 425       break;  /* module loaded successfully */
 426     else if (lua_isstring(L, -1))  /* loader returned error message? */
 427       lua_concat(L, 2);  /* accumulate it */
 428     else
 429       lua_pop(L, 1);
 430   }
 431   lua_pushlightuserdata(L, sentinel);
 432   lua_setfield(L, 2, name);  /* _LOADED[name] = sentinel */
 433   lua_pushstring(L, name);  /* pass name as argument to module */
 434   lua_call(L, 1, 1);  /* run loaded module */
 435   if (!lua_isnil(L, -1))  /* non-nil return? */
 436     lua_setfield(L, 2, name);  /* _LOADED[name] = returned value */
 437   lua_getfield(L, 2, name);
 438   if (lua_touserdata(L, -1) == sentinel) {   /* module did not set a value? */
 439     lua_pushboolean(L, 1);  /* use true as result */
 440     lua_pushvalue(L, -1);  /* extra copy to be returned */
 441     lua_setfield(L, 2, name);  /* _LOADED[name] = true */
 442   }
 443   lj_lib_checkfpu(L);
 444   return 1;
 445 }
 446
 447 /* ------------------------------------------------------------------------ */
 448
 449 static void setfenv(lua_State *L)
 450 {
 451   lua_Debug ar;
 452   if (lua_getstack(L, 1, &ar) == 0 ||
 453       lua_getinfo(L, "f", &ar) == 0 ||  /* get calling function */
 454       lua_iscfunction(L, -1))
 455     luaL_error(L, LUA_QL("module") " not called from a Lua function");
 456   lua_pushvalue(L, -2);
 457   lua_setfenv(L, -2);
 458   lua_pop(L, 1);
 459 }
 460
 461 static void dooptions(lua_State *L, int n)
 462 {
 463   int i;
 464   for (i = 2; i <= n; i++) {
 465     lua_pushvalue(L, i);  /* get option (a function) */
 466     lua_pushvalue(L, -2);  /* module */
 467     lua_call(L, 1, 0);
 468   }
 469 }
 470
 471 static void modinit(lua_State *L, const char *modname)
 472 {
 473   const char *dot;
 474   lua_pushvalue(L, -1);
 475   lua_setfield(L, -2, "_M");  /* module._M = module */
 476   lua_pushstring(L, modname);
 477   lua_setfield(L, -2, "_NAME");
 478   dot = strrchr(modname, '.');  /* look for last dot in module name */
 479   if (dot == NULL) dot = modname; else dot++;
 480   /* set _PACKAGE as package name (full module name minus last part) */
 481   lua_pushlstring(L, modname, (size_t)(dot - modname));
 482   lua_setfield(L, -2, "_PACKAGE");
 483 }
 484
 485 static int lj_cf_package_module(lua_State *L)
 486 {
 487   const char *modname = luaL_checkstring(L, 1);
 488   int loaded = lua_gettop(L) + 1;  /* index of _LOADED table */
 489   lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");
 490   lua_getfield(L, loaded, modname);  /* get _LOADED[modname] */
 491   if (!lua_istable(L, -1)) {  /* not found? */
 492     lua_pop(L, 1);  /* remove previous result */
 493     /* try global variable (and create one if it does not exist) */
 494     if (luaL_findtable(L, LUA_GLOBALSINDEX, modname, 1) != NULL)
 495       lj_err_callerv(L, LJ_ERR_BADMODN, modname);
 496     lua_pushvalue(L, -1);
 497     lua_setfield(L, loaded, modname);  /* _LOADED[modname] = new table */
 498   }
 499   /* check whether table already has a _NAME field */
 500   lua_getfield(L, -1, "_NAME");
 501   if (!lua_isnil(L, -1)) {  /* is table an initialized module? */
 502     lua_pop(L, 1);
 503   } else {  /* no; initialize it */
 504     lua_pop(L, 1);
 505     modinit(L, modname);
 506   }
 507   lua_pushvalue(L, -1);
 508   setfenv(L);
 509   dooptions(L, loaded - 1);
 510   return 0;
 511 }
 512
 513 static int lj_cf_package_seeall(lua_State *L)
 514 {
 515   luaL_checktype(L, 1, LUA_TTABLE);
 516   if (!lua_getmetatable(L, 1)) {
 517     lua_createtable(L, 0, 1); /* create new metatable */
 518     lua_pushvalue(L, -1);
 519     lua_setmetatable(L, 1);
 520   }
 521   lua_pushvalue(L, LUA_GLOBALSINDEX);
 522   lua_setfield(L, -2, "__index");  /* mt.__index = _G */
 523   return 0;
 524 }
 525
 526 /* ------------------------------------------------------------------------ */
 527
 528 #define AUXMARK         "\1"
 529
 530 static void setpath(lua_State *L, const char *fieldname, const char *envname,
 531                     const char *def, int noenv)
 532 {
 533 #if LJ_TARGET_CONSOLE
 534   const char *path = NULL;
 535   UNUSED(envname);
 536 #else
 537   const char *path = getenv(envname);
 538 #endif
 539   if (path == NULL || noenv) {
 540     lua_pushstring(L, def);
 541   } else {
 542     path = luaL_gsub(L, path, LUA_PATHSEP LUA_PATHSEP,
 543                               LUA_PATHSEP AUXMARK LUA_PATHSEP);
 544     luaL_gsub(L, path, AUXMARK, def);
 545     lua_remove(L, -2);
 546   }
 547   setprogdir(L);
 548   lua_setfield(L, -2, fieldname);
 549 }
 550
 551 static const luaL_Reg package_lib[] = {
 552   { "loadlib",  lj_cf_package_loadlib },
 553   { "searchpath",  lj_cf_package_searchpath },
 554   { "seeall",   lj_cf_package_seeall },
 555   { NULL, NULL }
 556 };
 557
 558 static const luaL_Reg package_global[] = {
 559   { "module",   lj_cf_package_module },
 560   { "require",  lj_cf_package_require },
 561   { NULL, NULL }
 562 };
 563
 564 static const lua_CFunction package_loaders[] =
 565 {
 566   lj_cf_package_loader_preload,
 567   lj_cf_package_loader_lua,
 568   lj_cf_package_loader_c,
 569   lj_cf_package_loader_croot,
 570   NULL
 571 };
 572
 573 LUALIB_API int luaopen_package(lua_State *L)
 574 {
 575   int i;
 576   int noenv;
 577   luaL_newmetatable(L, "_LOADLIB");
 578   lj_lib_pushcf(L, lj_cf_package_unloadlib, 1);
 579   lua_setfield(L, -2, "__gc");
 580   luaL_register(L, LUA_LOADLIBNAME, package_lib);
 581   lua_pushvalue(L, -1);
 582   lua_replace(L, LUA_ENVIRONINDEX);
 583   lua_createtable(L, sizeof(package_loaders)/sizeof(package_loaders[0])-1, 0);
 584   for (i = 0; package_loaders[i] != NULL; i++) {
 585     lj_lib_pushcf(L, package_loaders[i], 1);
 586     lua_rawseti(L, -2, i+1);
 587   }
 588   lua_setfield(L, -2, "loaders");
 589   lua_getfield(L, LUA_REGISTRYINDEX, "LUA_NOENV");
 590   noenv = lua_toboolean(L, -1);
 591   lua_pop(L, 1);
 592   setpath(L, "path", LUA_PATH, LUA_PATH_DEFAULT, noenv);
 593   setpath(L, "cpath", LUA_CPATH, LUA_CPATH_DEFAULT, noenv);
 594   lua_pushliteral(L, LUA_PATH_CONFIG);
 595   lua_setfield(L, -2, "config");
 596   luaL_findtable(L, LUA_REGISTRYINDEX, "_LOADED", 16);
 597   lua_setfield(L, -2, "loaded");
 598   luaL_findtable(L, LUA_REGISTRYINDEX, "_PRELOAD", 4);
 599   lua_setfield(L, -2, "preload");
 600   lua_pushvalue(L, LUA_GLOBALSINDEX);
 601   luaL_register(L, NULL, package_global);
 602   lua_pop(L, 1);
 603   return 1;
 604 }
 605