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 #if LJ_TARGET_UWP
  80 void *LJ_WIN_LOADLIBA(const char *path)
  81 {
  82   DWORD err = GetLastError();
  83   wchar_t wpath[256];
  84   HANDLE lib = NULL;
  85   if (MultiByteToWideChar(CP_ACP, 0, path, -1, wpath, 256) > 0) {
  86     lib = LoadPackagedLibrary(wpath, 0);
  87   }
  88   SetLastError(err);
  89   return lib;
  90 }
  91 #endif
  92
  93 #undef setprogdir
  94
  95 static void setprogdir(lua_State *L)
  96 {
  97   char buff[MAX_PATH + 1];
  98   char *lb;
  99   DWORD nsize = sizeof(buff);
 100   DWORD n = GetModuleFileNameA(NULL, buff, nsize);
 101   if (n == 0 || n == nsize || (lb = strrchr(buff, '\\')) == NULL) {
 102     luaL_error(L, "unable to get ModuleFileName");
 103   } else {
 104     *lb = '\0';
 105     luaL_gsub(L, lua_tostring(L, -1), LUA_EXECDIR, buff);
 106     lua_remove(L, -2);  /* remove original string */
 107   }
 108 }
 109
 110 static void pusherror(lua_State *L)
 111 {
 112   DWORD error = GetLastError();
 113 #if LJ_TARGET_XBOXONE
 114   wchar_t wbuffer[128];
 115   char buffer[128*2];
 116   if (FormatMessageW(FORMAT_MESSAGE_IGNORE_INSERTS | FORMAT_MESSAGE_FROM_SYSTEM,
 117       NULL, error, 0, wbuffer, sizeof(wbuffer)/sizeof(wchar_t), NULL) &&
 118       WideCharToMultiByte(CP_ACP, 0, wbuffer, 128, buffer, 128*2, NULL, NULL))
 119 #else
 120   char buffer[128];
 121   if (FormatMessageA(FORMAT_MESSAGE_IGNORE_INSERTS | FORMAT_MESSAGE_FROM_SYSTEM,
 122       NULL, error, 0, buffer, sizeof(buffer), NULL))
 123 #endif
 124     lua_pushstring(L, buffer);
 125   else
 126     lua_pushfstring(L, "system error %d\n", error);
 127 }
 128
 129 static void ll_unloadlib(void *lib)
 130 {
 131   FreeLibrary((HINSTANCE)lib);
 132 }
 133
 134 static void *ll_load(lua_State *L, const char *path, int gl)
 135 {
 136   HINSTANCE lib = LJ_WIN_LOADLIBA(path);
 137   if (lib == NULL) pusherror(L);
 138   UNUSED(gl);
 139   return lib;
 140 }
 141
 142 static lua_CFunction ll_sym(lua_State *L, void *lib, const char *sym)
 143 {
 144   lua_CFunction f = (lua_CFunction)GetProcAddress((HINSTANCE)lib, sym);
 145   if (f == NULL) pusherror(L);
 146   return f;
 147 }
 148
 149 #if LJ_TARGET_UWP
 150 EXTERN_C IMAGE_DOS_HEADER __ImageBase;
 151 #endif
 152
 153 static const char *ll_bcsym(void *lib, const char *sym)
 154 {
 155   if (lib) {
 156     return (const char *)GetProcAddress((HINSTANCE)lib, sym);
 157   } else {
 158 #if LJ_TARGET_UWP
 159     return (const char *)GetProcAddress((HINSTANCE)&__ImageBase, sym);
 160 #else
 161     HINSTANCE h = GetModuleHandleA(NULL);
 162     const char *p = (const char *)GetProcAddress(h, sym);
 163     if (p == NULL && GetModuleHandleExA(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS|GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT,
 164                                         (const char *)ll_bcsym, &h))
 165       p = (const char *)GetProcAddress(h, sym);
 166     return p;
 167 #endif
 168   }
 169 }
 170
 171 #else
 172
 173 #undef PACKAGE_LIB_FAIL
 174 #define PACKAGE_LIB_FAIL        "absent"
 175
 176 #define DLMSG   "dynamic libraries not enabled; no support for target OS"
 177
 178 static void ll_unloadlib(void *lib)
 179 {
 180   UNUSED(lib);
 181 }
 182
 183 static void *ll_load(lua_State *L, const char *path, int gl)
 184 {
 185   UNUSED(path); UNUSED(gl);
 186   lua_pushliteral(L, DLMSG);
 187   return NULL;
 188 }
 189
 190 static lua_CFunction ll_sym(lua_State *L, void *lib, const char *sym)
 191 {
 192   UNUSED(lib); UNUSED(sym);
 193   lua_pushliteral(L, DLMSG);
 194   return NULL;
 195 }
 196
 197 static const char *ll_bcsym(void *lib, const char *sym)
 198 {
 199   UNUSED(lib); UNUSED(sym);
 200   return NULL;
 201 }
 202
 203 #endif
 204
 205 /* ------------------------------------------------------------------------ */
 206
 207 static void **ll_register(lua_State *L, const char *path)
 208 {
 209   void **plib;
 210   lua_pushfstring(L, "LOADLIB: %s", path);
 211   lua_gettable(L, LUA_REGISTRYINDEX);  /* check library in registry? */
 212   if (!lua_isnil(L, -1)) {  /* is there an entry? */
 213     plib = (void **)lua_touserdata(L, -1);
 214   } else {  /* no entry yet; create one */
 215     lua_pop(L, 1);
 216     plib = (void **)lua_newuserdata(L, sizeof(void *));
 217     *plib = NULL;
 218     luaL_setmetatable(L, "_LOADLIB");
 219     lua_pushfstring(L, "LOADLIB: %s", path);
 220     lua_pushvalue(L, -2);
 221     lua_settable(L, LUA_REGISTRYINDEX);
 222   }
 223   return plib;
 224 }
 225
 226 static const char *mksymname(lua_State *L, const char *modname,
 227                              const char *prefix)
 228 {
 229   const char *funcname;
 230   const char *mark = strchr(modname, *LUA_IGMARK);
 231   if (mark) modname = mark + 1;
 232   funcname = luaL_gsub(L, modname, ".", "_");
 233   funcname = lua_pushfstring(L, prefix, funcname);
 234   lua_remove(L, -2);  /* remove 'gsub' result */
 235   return funcname;
 236 }
 237
 238 static int ll_loadfunc(lua_State *L, const char *path, const char *name, int r)
 239 {
 240   void **reg;
 241   if (strlen(path) >= 4096) {
 242     lua_pushliteral(L, "path too long");
 243     return PACKAGE_ERR_LIB;
 244   }
 245   reg = ll_register(L, path);
 246   if (*reg == NULL) *reg = ll_load(L, path, (*name == '*'));
 247   if (*reg == NULL) {
 248     return PACKAGE_ERR_LIB;  /* Unable to load library. */
 249   } else if (*name == '*') {  /* Only load library into global namespace. */
 250     lua_pushboolean(L, 1);
 251     return 0;
 252   } else {
 253     const char *sym = r ? name : mksymname(L, name, SYMPREFIX_CF);
 254     lua_CFunction f = ll_sym(L, *reg, sym);
 255     if (f) {
 256       lua_pushcfunction(L, f);
 257       return 0;
 258     }
 259     if (!r) {
 260       const char *bcdata = ll_bcsym(*reg, mksymname(L, name, SYMPREFIX_BC));
 261       lua_pop(L, 1);
 262       if (bcdata) {
 263         if (luaL_loadbuffer(L, bcdata, ~(size_t)0, name) != 0)
 264           return PACKAGE_ERR_LOAD;
 265         return 0;
 266       }
 267     }
 268     return PACKAGE_ERR_FUNC;  /* Unable to find function. */
 269   }
 270 }
 271
 272 static int lj_cf_package_loadlib(lua_State *L)
 273 {
 274   const char *path = luaL_checkstring(L, 1);
 275   const char *init = luaL_checkstring(L, 2);
 276   int st = ll_loadfunc(L, path, init, 1);
 277   if (st == 0) {  /* no errors? */
 278     return 1;  /* return the loaded function */
 279   } else {  /* error; error message is on stack top */
 280     lua_pushnil(L);
 281     lua_insert(L, -2);
 282     lua_pushstring(L, (st == PACKAGE_ERR_LIB) ?  PACKAGE_LIB_FAIL : "init");
 283     return 3;  /* return nil, error message, and where */
 284   }
 285 }
 286
 287 static int lj_cf_package_unloadlib(lua_State *L)
 288 {
 289   void **lib = (void **)luaL_checkudata(L, 1, "_LOADLIB");
 290   if (*lib) ll_unloadlib(*lib);
 291   *lib = NULL;  /* mark library as closed */
 292   return 0;
 293 }
 294
 295 /* ------------------------------------------------------------------------ */
 296
 297 static int readable(const char *filename)
 298 {
 299   FILE *f = fopen(filename, "r");  /* try to open file */
 300   if (f == NULL) return 0;  /* open failed */
 301   fclose(f);
 302   return 1;
 303 }
 304
 305 static const char *pushnexttemplate(lua_State *L, const char *path)
 306 {
 307   const char *l;
 308   while (*path == *LUA_PATHSEP) path++;  /* skip separators */
 309   if (*path == '\0') return NULL;  /* no more templates */
 310   l = strchr(path, *LUA_PATHSEP);  /* find next separator */
 311   if (l == NULL) l = path + strlen(path);
 312   lua_pushlstring(L, path, (size_t)(l - path));  /* template */
 313   return l;
 314 }
 315
 316 static const char *searchpath (lua_State *L, const char *name,
 317                                const char *path, const char *sep,
 318                                const char *dirsep)
 319 {
 320   luaL_Buffer msg;  /* to build error message */
 321   luaL_buffinit(L, &msg);
 322   if (*sep != '\0')  /* non-empty separator? */
 323     name = luaL_gsub(L, name, sep, dirsep);  /* replace it by 'dirsep' */
 324   while ((path = pushnexttemplate(L, path)) != NULL) {
 325     const char *filename = luaL_gsub(L, lua_tostring(L, -1),
 326                                      LUA_PATH_MARK, name);
 327     lua_remove(L, -2);  /* remove path template */
 328     if (readable(filename))  /* does file exist and is readable? */
 329       return filename;  /* return that file name */
 330     lua_pushfstring(L, "\n\tno file " LUA_QS, filename);
 331     lua_remove(L, -2);  /* remove file name */
 332     luaL_addvalue(&msg);  /* concatenate error msg. entry */
 333   }
 334   luaL_pushresult(&msg);  /* create error message */
 335   return NULL;  /* not found */
 336 }
 337
 338 static int lj_cf_package_searchpath(lua_State *L)
 339 {
 340   const char *f = searchpath(L, luaL_checkstring(L, 1),
 341                                 luaL_checkstring(L, 2),
 342                                 luaL_optstring(L, 3, "."),
 343                                 luaL_optstring(L, 4, LUA_DIRSEP));
 344   if (f != NULL) {
 345     return 1;
 346   } else {  /* error message is on top of the stack */
 347     lua_pushnil(L);
 348     lua_insert(L, -2);
 349     return 2;  /* return nil + error message */
 350   }
 351 }
 352
 353 static const char *findfile(lua_State *L, const char *name,
 354                             const char *pname)
 355 {
 356   const char *path;
 357   lua_getfield(L, LUA_ENVIRONINDEX, pname);
 358   path = lua_tostring(L, -1);
 359   if (path == NULL)
 360     luaL_error(L, LUA_QL("package.%s") " must be a string", pname);
 361   return searchpath(L, name, path, ".", LUA_DIRSEP);
 362 }
 363
 364 static void loaderror(lua_State *L, const char *filename)
 365 {
 366   luaL_error(L, "error loading module " LUA_QS " from file " LUA_QS ":\n\t%s",
 367              lua_tostring(L, 1), filename, lua_tostring(L, -1));
 368 }
 369
 370 static int lj_cf_package_loader_lua(lua_State *L)
 371 {
 372   const char *filename;
 373   const char *name = luaL_checkstring(L, 1);
 374   filename = findfile(L, name, "path");
 375   if (filename == NULL) return 1;  /* library not found in this path */
 376   if (luaL_loadfile(L, filename) != 0)
 377     loaderror(L, filename);
 378   return 1;  /* library loaded successfully */
 379 }
 380
 381 static int lj_cf_package_loader_c(lua_State *L)
 382 {
 383   const char *name = luaL_checkstring(L, 1);
 384   const char *filename = findfile(L, name, "cpath");
 385   if (filename == NULL) return 1;  /* library not found in this path */
 386   if (ll_loadfunc(L, filename, name, 0) != 0)
 387     loaderror(L, filename);
 388   return 1;  /* library loaded successfully */
 389 }
 390
 391 static int lj_cf_package_loader_croot(lua_State *L)
 392 {
 393   const char *filename;
 394   const char *name = luaL_checkstring(L, 1);
 395   const char *p = strchr(name, '.');
 396   int st;
 397   if (p == NULL) return 0;  /* is root */
 398   lua_pushlstring(L, name, (size_t)(p - name));
 399   filename = findfile(L, lua_tostring(L, -1), "cpath");
 400   if (filename == NULL) return 1;  /* root not found */
 401   if ((st = ll_loadfunc(L, filename, name, 0)) != 0) {
 402     if (st != PACKAGE_ERR_FUNC) loaderror(L, filename);  /* real error */
 403     lua_pushfstring(L, "\n\tno module " LUA_QS " in file " LUA_QS,
 404                     name, filename);
 405     return 1;  /* function not found */
 406   }
 407   return 1;
 408 }
 409
 410 static int lj_cf_package_loader_preload(lua_State *L)
 411 {
 412   const char *name = luaL_checkstring(L, 1);
 413   lua_getfield(L, LUA_ENVIRONINDEX, "preload");
 414   if (!lua_istable(L, -1))
 415     luaL_error(L, LUA_QL("package.preload") " must be a table");
 416   lua_getfield(L, -1, name);
 417   if (lua_isnil(L, -1)) {  /* Not found? */
 418     const char *bcname = mksymname(L, name, SYMPREFIX_BC);
 419     const char *bcdata = ll_bcsym(NULL, bcname);
 420     if (bcdata == NULL || luaL_loadbuffer(L, bcdata, ~(size_t)0, name) != 0)
 421       lua_pushfstring(L, "\n\tno field package.preload['%s']", name);
 422   }
 423   return 1;
 424 }
 425
 426 /* ------------------------------------------------------------------------ */
 427
 428 #define KEY_SENTINEL    (U64x(80000000,00000000)|'s')
 429
 430 static int lj_cf_package_require(lua_State *L)
 431 {
 432   const char *name = luaL_checkstring(L, 1);
 433   int i;
 434   lua_settop(L, 1);  /* _LOADED table will be at index 2 */
 435   lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");
 436   lua_getfield(L, 2, name);
 437   if (lua_toboolean(L, -1)) {  /* is it there? */
 438     if ((L->top-1)->u64 == KEY_SENTINEL)  /* check loops */
 439       luaL_error(L, "loop or previous error loading module " LUA_QS, name);
 440     return 1;  /* package is already loaded */
 441   }
 442   /* else must load it; iterate over available loaders */
 443   lua_getfield(L, LUA_ENVIRONINDEX, "loaders");
 444   if (!lua_istable(L, -1))
 445     luaL_error(L, LUA_QL("package.loaders") " must be a table");
 446   lua_pushliteral(L, "");  /* error message accumulator */
 447   for (i = 1; ; i++) {
 448     lua_rawgeti(L, -2, i);  /* get a loader */
 449     if (lua_isnil(L, -1))
 450       luaL_error(L, "module " LUA_QS " not found:%s",
 451                  name, lua_tostring(L, -2));
 452     lua_pushstring(L, name);
 453     lua_call(L, 1, 1);  /* call it */
 454     if (lua_isfunction(L, -1))  /* did it find module? */
 455       break;  /* module loaded successfully */
 456     else if (lua_isstring(L, -1))  /* loader returned error message? */
 457       lua_concat(L, 2);  /* accumulate it */
 458     else
 459       lua_pop(L, 1);
 460   }
 461   (L->top++)->u64 = KEY_SENTINEL;
 462   lua_setfield(L, 2, name);  /* _LOADED[name] = sentinel */
 463   lua_pushstring(L, name);  /* pass name as argument to module */
 464   lua_call(L, 1, 1);  /* run loaded module */
 465   if (!lua_isnil(L, -1))  /* non-nil return? */
 466     lua_setfield(L, 2, name);  /* _LOADED[name] = returned value */
 467   lua_getfield(L, 2, name);
 468   if ((L->top-1)->u64 == KEY_SENTINEL) {   /* module did not set a value? */
 469     lua_pushboolean(L, 1);  /* use true as result */
 470     lua_pushvalue(L, -1);  /* extra copy to be returned */
 471     lua_setfield(L, 2, name);  /* _LOADED[name] = true */
 472   }
 473   lj_lib_checkfpu(L);
 474   return 1;
 475 }
 476
 477 /* ------------------------------------------------------------------------ */
 478
 479 static void setfenv(lua_State *L)
 480 {
 481   lua_Debug ar;
 482   if (lua_getstack(L, 1, &ar) == 0 ||
 483       lua_getinfo(L, "f", &ar) == 0 ||  /* get calling function */
 484       lua_iscfunction(L, -1))
 485     luaL_error(L, LUA_QL("module") " not called from a Lua function");
 486   lua_pushvalue(L, -2);
 487   lua_setfenv(L, -2);
 488   lua_pop(L, 1);
 489 }
 490
 491 static void dooptions(lua_State *L, int n)
 492 {
 493   int i;
 494   for (i = 2; i <= n; i++) {
 495     lua_pushvalue(L, i);  /* get option (a function) */
 496     lua_pushvalue(L, -2);  /* module */
 497     lua_call(L, 1, 0);
 498   }
 499 }
 500
 501 static void modinit(lua_State *L, const char *modname)
 502 {
 503   const char *dot;
 504   lua_pushvalue(L, -1);
 505   lua_setfield(L, -2, "_M");  /* module._M = module */
 506   lua_pushstring(L, modname);
 507   lua_setfield(L, -2, "_NAME");
 508   dot = strrchr(modname, '.');  /* look for last dot in module name */
 509   if (dot == NULL) dot = modname; else dot++;
 510   /* set _PACKAGE as package name (full module name minus last part) */
 511   lua_pushlstring(L, modname, (size_t)(dot - modname));
 512   lua_setfield(L, -2, "_PACKAGE");
 513 }
 514
 515 static int lj_cf_package_module(lua_State *L)
 516 {
 517   const char *modname = luaL_checkstring(L, 1);
 518   int lastarg = (int)(L->top - L->base);
 519   luaL_pushmodule(L, modname, 1);
 520   lua_getfield(L, -1, "_NAME");
 521   if (!lua_isnil(L, -1)) {  /* Module already initialized? */
 522     lua_pop(L, 1);
 523   } else {
 524     lua_pop(L, 1);
 525     modinit(L, modname);
 526   }
 527   lua_pushvalue(L, -1);
 528   setfenv(L);
 529   dooptions(L, lastarg);
 530   return LJ_52;
 531 }
 532
 533 static int lj_cf_package_seeall(lua_State *L)
 534 {
 535   luaL_checktype(L, 1, LUA_TTABLE);
 536   if (!lua_getmetatable(L, 1)) {
 537     lua_createtable(L, 0, 1); /* create new metatable */
 538     lua_pushvalue(L, -1);
 539     lua_setmetatable(L, 1);
 540   }
 541   lua_pushvalue(L, LUA_GLOBALSINDEX);
 542   lua_setfield(L, -2, "__index");  /* mt.__index = _G */
 543   return 0;
 544 }
 545
 546 /* ------------------------------------------------------------------------ */
 547
 548 #define AUXMARK         "\1"
 549
 550 static void setpath(lua_State *L, const char *fieldname, const char *envname,
 551                     const char *def, int noenv)
 552 {
 553 #if LJ_TARGET_CONSOLE
 554   const char *path = NULL;
 555   UNUSED(envname);
 556 #else
 557   const char *path = getenv(envname);
 558 #endif
 559   if (path == NULL || noenv) {
 560     lua_pushstring(L, def);
 561   } else {
 562     path = luaL_gsub(L, path, LUA_PATHSEP LUA_PATHSEP,
 563                               LUA_PATHSEP AUXMARK LUA_PATHSEP);
 564     luaL_gsub(L, path, AUXMARK, def);
 565     lua_remove(L, -2);
 566   }
 567   setprogdir(L);
 568   lua_setfield(L, -2, fieldname);
 569 }
 570
 571 static const luaL_Reg package_lib[] = {
 572   { "loadlib",  lj_cf_package_loadlib },
 573   { "searchpath",  lj_cf_package_searchpath },
 574   { "seeall",   lj_cf_package_seeall },
 575   { NULL, NULL }
 576 };
 577
 578 static const luaL_Reg package_global[] = {
 579   { "module",   lj_cf_package_module },
 580   { "require",  lj_cf_package_require },
 581   { NULL, NULL }
 582 };
 583
 584 static const lua_CFunction package_loaders[] =
 585 {
 586   lj_cf_package_loader_preload,
 587   lj_cf_package_loader_lua,
 588   lj_cf_package_loader_c,
 589   lj_cf_package_loader_croot,
 590   NULL
 591 };
 592
 593 LUALIB_API int luaopen_package(lua_State *L)
 594 {
 595   int i;
 596   int noenv;
 597   luaL_newmetatable(L, "_LOADLIB");
 598   lj_lib_pushcf(L, lj_cf_package_unloadlib, 1);
 599   lua_setfield(L, -2, "__gc");
 600   luaL_register(L, LUA_LOADLIBNAME, package_lib);
 601   lua_copy(L, -1, LUA_ENVIRONINDEX);
 602   lua_createtable(L, sizeof(package_loaders)/sizeof(package_loaders[0])-1, 0);
 603   for (i = 0; package_loaders[i] != NULL; i++) {
 604     lj_lib_pushcf(L, package_loaders[i], 1);
 605     lua_rawseti(L, -2, i+1);
 606   }
 607 #if LJ_52
 608   lua_pushvalue(L, -1);
 609   lua_setfield(L, -3, "searchers");
 610 #endif
 611   lua_setfield(L, -2, "loaders");
 612   lua_getfield(L, LUA_REGISTRYINDEX, "LUA_NOENV");
 613   noenv = lua_toboolean(L, -1);
 614   lua_pop(L, 1);
 615   setpath(L, "path", LUA_PATH, LUA_PATH_DEFAULT, noenv);
 616   setpath(L, "cpath", LUA_CPATH, LUA_CPATH_DEFAULT, noenv);
 617   lua_pushliteral(L, LUA_PATH_CONFIG);
 618   lua_setfield(L, -2, "config");
 619   luaL_findtable(L, LUA_REGISTRYINDEX, "_LOADED", 16);
 620   lua_setfield(L, -2, "loaded");
 621   luaL_findtable(L, LUA_REGISTRYINDEX, "_PRELOAD", 4);
 622   lua_setfield(L, -2, "preload");
 623   lua_pushvalue(L, LUA_GLOBALSINDEX);
 624   luaL_register(L, NULL, package_global);
 625   lua_pop(L, 1);
 626   return 1;
 627 }
 628