misc/liblua/loadlib.c
changeset 2812 0a24853de796
child 3697 d5b30d6373fc
equal deleted inserted replaced
2811:4cad87e11bf6 2812:0a24853de796
       
     1 /*
       
     2 ** $Id: loadlib.c,v 1.52.1.3 2008/08/06 13:29:28 roberto Exp $
       
     3 ** Dynamic library loader for Lua
       
     4 ** See Copyright Notice in lua.h
       
     5 **
       
     6 ** This module contains an implementation of loadlib for Unix systems
       
     7 ** that have dlfcn, an implementation for Darwin (Mac OS X), an
       
     8 ** implementation for Windows, and a stub for other systems.
       
     9 */
       
    10 
       
    11 
       
    12 #include <stdlib.h>
       
    13 #include <string.h>
       
    14 
       
    15 
       
    16 #define loadlib_c
       
    17 #define LUA_LIB
       
    18 
       
    19 #include "lua.h"
       
    20 
       
    21 #include "lauxlib.h"
       
    22 #include "lualib.h"
       
    23 
       
    24 
       
    25 /* prefix for open functions in C libraries */
       
    26 #define LUA_POF		"luaopen_"
       
    27 
       
    28 /* separator for open functions in C libraries */
       
    29 #define LUA_OFSEP	"_"
       
    30 
       
    31 
       
    32 #define LIBPREFIX	"LOADLIB: "
       
    33 
       
    34 #define POF		LUA_POF
       
    35 #define LIB_FAIL	"open"
       
    36 
       
    37 
       
    38 /* error codes for ll_loadfunc */
       
    39 #define ERRLIB		1
       
    40 #define ERRFUNC		2
       
    41 
       
    42 #define setprogdir(L)		((void)0)
       
    43 
       
    44 
       
    45 static void ll_unloadlib (void *lib);
       
    46 static void *ll_load (lua_State *L, const char *path);
       
    47 static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym);
       
    48 
       
    49 
       
    50 
       
    51 #if defined(LUA_DL_DLOPEN)
       
    52 /*
       
    53 ** {========================================================================
       
    54 ** This is an implementation of loadlib based on the dlfcn interface.
       
    55 ** The dlfcn interface is available in Linux, SunOS, Solaris, IRIX, FreeBSD,
       
    56 ** NetBSD, AIX 4.2, HPUX 11, and  probably most other Unix flavors, at least
       
    57 ** as an emulation layer on top of native functions.
       
    58 ** =========================================================================
       
    59 */
       
    60 
       
    61 #include <dlfcn.h>
       
    62 
       
    63 static void ll_unloadlib (void *lib) {
       
    64   dlclose(lib);
       
    65 }
       
    66 
       
    67 
       
    68 static void *ll_load (lua_State *L, const char *path) {
       
    69   void *lib = dlopen(path, RTLD_NOW);
       
    70   if (lib == NULL) lua_pushstring(L, dlerror());
       
    71   return lib;
       
    72 }
       
    73 
       
    74 
       
    75 static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) {
       
    76   lua_CFunction f = (lua_CFunction)dlsym(lib, sym);
       
    77   if (f == NULL) lua_pushstring(L, dlerror());
       
    78   return f;
       
    79 }
       
    80 
       
    81 /* }====================================================== */
       
    82 
       
    83 
       
    84 
       
    85 #elif defined(LUA_DL_DLL)
       
    86 /*
       
    87 ** {======================================================================
       
    88 ** This is an implementation of loadlib for Windows using native functions.
       
    89 ** =======================================================================
       
    90 */
       
    91 
       
    92 #include <windows.h>
       
    93 
       
    94 
       
    95 #undef setprogdir
       
    96 
       
    97 static void setprogdir (lua_State *L) {
       
    98   char buff[MAX_PATH + 1];
       
    99   char *lb;
       
   100   DWORD nsize = sizeof(buff)/sizeof(char);
       
   101   DWORD n = GetModuleFileNameA(NULL, buff, nsize);
       
   102   if (n == 0 || n == nsize || (lb = strrchr(buff, '\\')) == NULL)
       
   103     luaL_error(L, "unable to get ModuleFileName");
       
   104   else {
       
   105     *lb = '\0';
       
   106     luaL_gsub(L, lua_tostring(L, -1), LUA_EXECDIR, buff);
       
   107     lua_remove(L, -2);  /* remove original string */
       
   108   }
       
   109 }
       
   110 
       
   111 
       
   112 static void pusherror (lua_State *L) {
       
   113   int error = GetLastError();
       
   114   char buffer[128];
       
   115   if (FormatMessageA(FORMAT_MESSAGE_IGNORE_INSERTS | FORMAT_MESSAGE_FROM_SYSTEM,
       
   116       NULL, error, 0, buffer, sizeof(buffer), NULL))
       
   117     lua_pushstring(L, buffer);
       
   118   else
       
   119     lua_pushfstring(L, "system error %d\n", error);
       
   120 }
       
   121 
       
   122 static void ll_unloadlib (void *lib) {
       
   123   FreeLibrary((HINSTANCE)lib);
       
   124 }
       
   125 
       
   126 
       
   127 static void *ll_load (lua_State *L, const char *path) {
       
   128   HINSTANCE lib = LoadLibraryA(path);
       
   129   if (lib == NULL) pusherror(L);
       
   130   return lib;
       
   131 }
       
   132 
       
   133 
       
   134 static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) {
       
   135   lua_CFunction f = (lua_CFunction)GetProcAddress((HINSTANCE)lib, sym);
       
   136   if (f == NULL) pusherror(L);
       
   137   return f;
       
   138 }
       
   139 
       
   140 /* }====================================================== */
       
   141 
       
   142 
       
   143 
       
   144 #elif defined(LUA_DL_DYLD)
       
   145 /*
       
   146 ** {======================================================================
       
   147 ** Native Mac OS X / Darwin Implementation
       
   148 ** =======================================================================
       
   149 */
       
   150 
       
   151 #include <mach-o/dyld.h>
       
   152 
       
   153 
       
   154 /* Mac appends a `_' before C function names */
       
   155 #undef POF
       
   156 #define POF	"_" LUA_POF
       
   157 
       
   158 
       
   159 static void pusherror (lua_State *L) {
       
   160   const char *err_str;
       
   161   const char *err_file;
       
   162   NSLinkEditErrors err;
       
   163   int err_num;
       
   164   NSLinkEditError(&err, &err_num, &err_file, &err_str);
       
   165   lua_pushstring(L, err_str);
       
   166 }
       
   167 
       
   168 
       
   169 static const char *errorfromcode (NSObjectFileImageReturnCode ret) {
       
   170   switch (ret) {
       
   171     case NSObjectFileImageInappropriateFile:
       
   172       return "file is not a bundle";
       
   173     case NSObjectFileImageArch:
       
   174       return "library is for wrong CPU type";
       
   175     case NSObjectFileImageFormat:
       
   176       return "bad format";
       
   177     case NSObjectFileImageAccess:
       
   178       return "cannot access file";
       
   179     case NSObjectFileImageFailure:
       
   180     default:
       
   181       return "unable to load library";
       
   182   }
       
   183 }
       
   184 
       
   185 
       
   186 static void ll_unloadlib (void *lib) {
       
   187   NSUnLinkModule((NSModule)lib, NSUNLINKMODULE_OPTION_RESET_LAZY_REFERENCES);
       
   188 }
       
   189 
       
   190 
       
   191 static void *ll_load (lua_State *L, const char *path) {
       
   192   NSObjectFileImage img;
       
   193   NSObjectFileImageReturnCode ret;
       
   194   /* this would be a rare case, but prevents crashing if it happens */
       
   195   if(!_dyld_present()) {
       
   196     lua_pushliteral(L, "dyld not present");
       
   197     return NULL;
       
   198   }
       
   199   ret = NSCreateObjectFileImageFromFile(path, &img);
       
   200   if (ret == NSObjectFileImageSuccess) {
       
   201     NSModule mod = NSLinkModule(img, path, NSLINKMODULE_OPTION_PRIVATE |
       
   202                        NSLINKMODULE_OPTION_RETURN_ON_ERROR);
       
   203     NSDestroyObjectFileImage(img);
       
   204     if (mod == NULL) pusherror(L);
       
   205     return mod;
       
   206   }
       
   207   lua_pushstring(L, errorfromcode(ret));
       
   208   return NULL;
       
   209 }
       
   210 
       
   211 
       
   212 static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) {
       
   213   NSSymbol nss = NSLookupSymbolInModule((NSModule)lib, sym);
       
   214   if (nss == NULL) {
       
   215     lua_pushfstring(L, "symbol " LUA_QS " not found", sym);
       
   216     return NULL;
       
   217   }
       
   218   return (lua_CFunction)NSAddressOfSymbol(nss);
       
   219 }
       
   220 
       
   221 /* }====================================================== */
       
   222 
       
   223 
       
   224 
       
   225 #else
       
   226 /*
       
   227 ** {======================================================
       
   228 ** Fallback for other systems
       
   229 ** =======================================================
       
   230 */
       
   231 
       
   232 #undef LIB_FAIL
       
   233 #define LIB_FAIL	"absent"
       
   234 
       
   235 
       
   236 #define DLMSG	"dynamic libraries not enabled; check your Lua installation"
       
   237 
       
   238 
       
   239 static void ll_unloadlib (void *lib) {
       
   240   (void)lib;  /* to avoid warnings */
       
   241 }
       
   242 
       
   243 
       
   244 static void *ll_load (lua_State *L, const char *path) {
       
   245   (void)path;  /* to avoid warnings */
       
   246   lua_pushliteral(L, DLMSG);
       
   247   return NULL;
       
   248 }
       
   249 
       
   250 
       
   251 static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) {
       
   252   (void)lib; (void)sym;  /* to avoid warnings */
       
   253   lua_pushliteral(L, DLMSG);
       
   254   return NULL;
       
   255 }
       
   256 
       
   257 /* }====================================================== */
       
   258 #endif
       
   259 
       
   260 
       
   261 
       
   262 static void **ll_register (lua_State *L, const char *path) {
       
   263   void **plib;
       
   264   lua_pushfstring(L, "%s%s", LIBPREFIX, path);
       
   265   lua_gettable(L, LUA_REGISTRYINDEX);  /* check library in registry? */
       
   266   if (!lua_isnil(L, -1))  /* is there an entry? */
       
   267     plib = (void **)lua_touserdata(L, -1);
       
   268   else {  /* no entry yet; create one */
       
   269     lua_pop(L, 1);
       
   270     plib = (void **)lua_newuserdata(L, sizeof(const void *));
       
   271     *plib = NULL;
       
   272     luaL_getmetatable(L, "_LOADLIB");
       
   273     lua_setmetatable(L, -2);
       
   274     lua_pushfstring(L, "%s%s", LIBPREFIX, path);
       
   275     lua_pushvalue(L, -2);
       
   276     lua_settable(L, LUA_REGISTRYINDEX);
       
   277   }
       
   278   return plib;
       
   279 }
       
   280 
       
   281 
       
   282 /*
       
   283 ** __gc tag method: calls library's `ll_unloadlib' function with the lib
       
   284 ** handle
       
   285 */
       
   286 static int gctm (lua_State *L) {
       
   287   void **lib = (void **)luaL_checkudata(L, 1, "_LOADLIB");
       
   288   if (*lib) ll_unloadlib(*lib);
       
   289   *lib = NULL;  /* mark library as closed */
       
   290   return 0;
       
   291 }
       
   292 
       
   293 
       
   294 static int ll_loadfunc (lua_State *L, const char *path, const char *sym) {
       
   295   void **reg = ll_register(L, path);
       
   296   if (*reg == NULL) *reg = ll_load(L, path);
       
   297   if (*reg == NULL)
       
   298     return ERRLIB;  /* unable to load library */
       
   299   else {
       
   300     lua_CFunction f = ll_sym(L, *reg, sym);
       
   301     if (f == NULL)
       
   302       return ERRFUNC;  /* unable to find function */
       
   303     lua_pushcfunction(L, f);
       
   304     return 0;  /* return function */
       
   305   }
       
   306 }
       
   307 
       
   308 
       
   309 static int ll_loadlib (lua_State *L) {
       
   310   const char *path = luaL_checkstring(L, 1);
       
   311   const char *init = luaL_checkstring(L, 2);
       
   312   int stat = ll_loadfunc(L, path, init);
       
   313   if (stat == 0)  /* no errors? */
       
   314     return 1;  /* return the loaded function */
       
   315   else {  /* error; error message is on stack top */
       
   316     lua_pushnil(L);
       
   317     lua_insert(L, -2);
       
   318     lua_pushstring(L, (stat == ERRLIB) ?  LIB_FAIL : "init");
       
   319     return 3;  /* return nil, error message, and where */
       
   320   }
       
   321 }
       
   322 
       
   323 
       
   324 
       
   325 /*
       
   326 ** {======================================================
       
   327 ** 'require' function
       
   328 ** =======================================================
       
   329 */
       
   330 
       
   331 
       
   332 static int readable (const char *filename) {
       
   333   FILE *f = fopen(filename, "r");  /* try to open file */
       
   334   if (f == NULL) return 0;  /* open failed */
       
   335   fclose(f);
       
   336   return 1;
       
   337 }
       
   338 
       
   339 
       
   340 static const char *pushnexttemplate (lua_State *L, const char *path) {
       
   341   const char *l;
       
   342   while (*path == *LUA_PATHSEP) path++;  /* skip separators */
       
   343   if (*path == '\0') return NULL;  /* no more templates */
       
   344   l = strchr(path, *LUA_PATHSEP);  /* find next separator */
       
   345   if (l == NULL) l = path + strlen(path);
       
   346   lua_pushlstring(L, path, l - path);  /* template */
       
   347   return l;
       
   348 }
       
   349 
       
   350 
       
   351 static const char *findfile (lua_State *L, const char *name,
       
   352                                            const char *pname) {
       
   353   const char *path;
       
   354   name = luaL_gsub(L, name, ".", LUA_DIRSEP);
       
   355   lua_getfield(L, LUA_ENVIRONINDEX, pname);
       
   356   path = lua_tostring(L, -1);
       
   357   if (path == NULL)
       
   358     luaL_error(L, LUA_QL("package.%s") " must be a string", pname);
       
   359   lua_pushliteral(L, "");  /* error accumulator */
       
   360   while ((path = pushnexttemplate(L, path)) != NULL) {
       
   361     const char *filename;
       
   362     filename = luaL_gsub(L, lua_tostring(L, -1), LUA_PATH_MARK, name);
       
   363     lua_remove(L, -2);  /* remove path template */
       
   364     if (readable(filename))  /* does file exist and is readable? */
       
   365       return filename;  /* return that file name */
       
   366     lua_pushfstring(L, "\n\tno file " LUA_QS, filename);
       
   367     lua_remove(L, -2);  /* remove file name */
       
   368     lua_concat(L, 2);  /* add entry to possible error message */
       
   369   }
       
   370   return NULL;  /* not found */
       
   371 }
       
   372 
       
   373 
       
   374 static void loaderror (lua_State *L, const char *filename) {
       
   375   luaL_error(L, "error loading module " LUA_QS " from file " LUA_QS ":\n\t%s",
       
   376                 lua_tostring(L, 1), filename, lua_tostring(L, -1));
       
   377 }
       
   378 
       
   379 
       
   380 static int loader_Lua (lua_State *L) {
       
   381   const char *filename;
       
   382   const char *name = luaL_checkstring(L, 1);
       
   383   filename = findfile(L, name, "path");
       
   384   if (filename == NULL) return 1;  /* library not found in this path */
       
   385   if (luaL_loadfile(L, filename) != 0)
       
   386     loaderror(L, filename);
       
   387   return 1;  /* library loaded successfully */
       
   388 }
       
   389 
       
   390 
       
   391 static const char *mkfuncname (lua_State *L, const char *modname) {
       
   392   const char *funcname;
       
   393   const char *mark = strchr(modname, *LUA_IGMARK);
       
   394   if (mark) modname = mark + 1;
       
   395   funcname = luaL_gsub(L, modname, ".", LUA_OFSEP);
       
   396   funcname = lua_pushfstring(L, POF"%s", funcname);
       
   397   lua_remove(L, -2);  /* remove 'gsub' result */
       
   398   return funcname;
       
   399 }
       
   400 
       
   401 
       
   402 static int loader_C (lua_State *L) {
       
   403   const char *funcname;
       
   404   const char *name = luaL_checkstring(L, 1);
       
   405   const char *filename = findfile(L, name, "cpath");
       
   406   if (filename == NULL) return 1;  /* library not found in this path */
       
   407   funcname = mkfuncname(L, name);
       
   408   if (ll_loadfunc(L, filename, funcname) != 0)
       
   409     loaderror(L, filename);
       
   410   return 1;  /* library loaded successfully */
       
   411 }
       
   412 
       
   413 
       
   414 static int loader_Croot (lua_State *L) {
       
   415   const char *funcname;
       
   416   const char *filename;
       
   417   const char *name = luaL_checkstring(L, 1);
       
   418   const char *p = strchr(name, '.');
       
   419   int stat;
       
   420   if (p == NULL) return 0;  /* is root */
       
   421   lua_pushlstring(L, name, p - name);
       
   422   filename = findfile(L, lua_tostring(L, -1), "cpath");
       
   423   if (filename == NULL) return 1;  /* root not found */
       
   424   funcname = mkfuncname(L, name);
       
   425   if ((stat = ll_loadfunc(L, filename, funcname)) != 0) {
       
   426     if (stat != ERRFUNC) loaderror(L, filename);  /* real error */
       
   427     lua_pushfstring(L, "\n\tno module " LUA_QS " in file " LUA_QS,
       
   428                        name, filename);
       
   429     return 1;  /* function not found */
       
   430   }
       
   431   return 1;
       
   432 }
       
   433 
       
   434 
       
   435 static int loader_preload (lua_State *L) {
       
   436   const char *name = luaL_checkstring(L, 1);
       
   437   lua_getfield(L, LUA_ENVIRONINDEX, "preload");
       
   438   if (!lua_istable(L, -1))
       
   439     luaL_error(L, LUA_QL("package.preload") " must be a table");
       
   440   lua_getfield(L, -1, name);
       
   441   if (lua_isnil(L, -1))  /* not found? */
       
   442     lua_pushfstring(L, "\n\tno field package.preload['%s']", name);
       
   443   return 1;
       
   444 }
       
   445 
       
   446 
       
   447 static const int sentinel_ = 0;
       
   448 #define sentinel	((void *)&sentinel_)
       
   449 
       
   450 
       
   451 static int ll_require (lua_State *L) {
       
   452   const char *name = luaL_checkstring(L, 1);
       
   453   int i;
       
   454   lua_settop(L, 1);  /* _LOADED table will be at index 2 */
       
   455   lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");
       
   456   lua_getfield(L, 2, name);
       
   457   if (lua_toboolean(L, -1)) {  /* is it there? */
       
   458     if (lua_touserdata(L, -1) == sentinel)  /* check loops */
       
   459       luaL_error(L, "loop or previous error loading module " LUA_QS, name);
       
   460     return 1;  /* package is already loaded */
       
   461   }
       
   462   /* else must load it; iterate over available loaders */
       
   463   lua_getfield(L, LUA_ENVIRONINDEX, "loaders");
       
   464   if (!lua_istable(L, -1))
       
   465     luaL_error(L, LUA_QL("package.loaders") " must be a table");
       
   466   lua_pushliteral(L, "");  /* error message accumulator */
       
   467   for (i=1; ; i++) {
       
   468     lua_rawgeti(L, -2, i);  /* get a loader */
       
   469     if (lua_isnil(L, -1))
       
   470       luaL_error(L, "module " LUA_QS " not found:%s",
       
   471                     name, lua_tostring(L, -2));
       
   472     lua_pushstring(L, name);
       
   473     lua_call(L, 1, 1);  /* call it */
       
   474     if (lua_isfunction(L, -1))  /* did it find module? */
       
   475       break;  /* module loaded successfully */
       
   476     else if (lua_isstring(L, -1))  /* loader returned error message? */
       
   477       lua_concat(L, 2);  /* accumulate it */
       
   478     else
       
   479       lua_pop(L, 1);
       
   480   }
       
   481   lua_pushlightuserdata(L, sentinel);
       
   482   lua_setfield(L, 2, name);  /* _LOADED[name] = sentinel */
       
   483   lua_pushstring(L, name);  /* pass name as argument to module */
       
   484   lua_call(L, 1, 1);  /* run loaded module */
       
   485   if (!lua_isnil(L, -1))  /* non-nil return? */
       
   486     lua_setfield(L, 2, name);  /* _LOADED[name] = returned value */
       
   487   lua_getfield(L, 2, name);
       
   488   if (lua_touserdata(L, -1) == sentinel) {   /* module did not set a value? */
       
   489     lua_pushboolean(L, 1);  /* use true as result */
       
   490     lua_pushvalue(L, -1);  /* extra copy to be returned */
       
   491     lua_setfield(L, 2, name);  /* _LOADED[name] = true */
       
   492   }
       
   493   return 1;
       
   494 }
       
   495 
       
   496 /* }====================================================== */
       
   497 
       
   498 
       
   499 
       
   500 /*
       
   501 ** {======================================================
       
   502 ** 'module' function
       
   503 ** =======================================================
       
   504 */
       
   505   
       
   506 
       
   507 static void setfenv (lua_State *L) {
       
   508   lua_Debug ar;
       
   509   if (lua_getstack(L, 1, &ar) == 0 ||
       
   510       lua_getinfo(L, "f", &ar) == 0 ||  /* get calling function */
       
   511       lua_iscfunction(L, -1))
       
   512     luaL_error(L, LUA_QL("module") " not called from a Lua function");
       
   513   lua_pushvalue(L, -2);
       
   514   lua_setfenv(L, -2);
       
   515   lua_pop(L, 1);
       
   516 }
       
   517 
       
   518 
       
   519 static void dooptions (lua_State *L, int n) {
       
   520   int i;
       
   521   for (i = 2; i <= n; i++) {
       
   522     lua_pushvalue(L, i);  /* get option (a function) */
       
   523     lua_pushvalue(L, -2);  /* module */
       
   524     lua_call(L, 1, 0);
       
   525   }
       
   526 }
       
   527 
       
   528 
       
   529 static void modinit (lua_State *L, const char *modname) {
       
   530   const char *dot;
       
   531   lua_pushvalue(L, -1);
       
   532   lua_setfield(L, -2, "_M");  /* module._M = module */
       
   533   lua_pushstring(L, modname);
       
   534   lua_setfield(L, -2, "_NAME");
       
   535   dot = strrchr(modname, '.');  /* look for last dot in module name */
       
   536   if (dot == NULL) dot = modname;
       
   537   else dot++;
       
   538   /* set _PACKAGE as package name (full module name minus last part) */
       
   539   lua_pushlstring(L, modname, dot - modname);
       
   540   lua_setfield(L, -2, "_PACKAGE");
       
   541 }
       
   542 
       
   543 
       
   544 static int ll_module (lua_State *L) {
       
   545   const char *modname = luaL_checkstring(L, 1);
       
   546   int loaded = lua_gettop(L) + 1;  /* index of _LOADED table */
       
   547   lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");
       
   548   lua_getfield(L, loaded, modname);  /* get _LOADED[modname] */
       
   549   if (!lua_istable(L, -1)) {  /* not found? */
       
   550     lua_pop(L, 1);  /* remove previous result */
       
   551     /* try global variable (and create one if it does not exist) */
       
   552     if (luaL_findtable(L, LUA_GLOBALSINDEX, modname, 1) != NULL)
       
   553       return luaL_error(L, "name conflict for module " LUA_QS, modname);
       
   554     lua_pushvalue(L, -1);
       
   555     lua_setfield(L, loaded, modname);  /* _LOADED[modname] = new table */
       
   556   }
       
   557   /* check whether table already has a _NAME field */
       
   558   lua_getfield(L, -1, "_NAME");
       
   559   if (!lua_isnil(L, -1))  /* is table an initialized module? */
       
   560     lua_pop(L, 1);
       
   561   else {  /* no; initialize it */
       
   562     lua_pop(L, 1);
       
   563     modinit(L, modname);
       
   564   }
       
   565   lua_pushvalue(L, -1);
       
   566   setfenv(L);
       
   567   dooptions(L, loaded - 1);
       
   568   return 0;
       
   569 }
       
   570 
       
   571 
       
   572 static int ll_seeall (lua_State *L) {
       
   573   luaL_checktype(L, 1, LUA_TTABLE);
       
   574   if (!lua_getmetatable(L, 1)) {
       
   575     lua_createtable(L, 0, 1); /* create new metatable */
       
   576     lua_pushvalue(L, -1);
       
   577     lua_setmetatable(L, 1);
       
   578   }
       
   579   lua_pushvalue(L, LUA_GLOBALSINDEX);
       
   580   lua_setfield(L, -2, "__index");  /* mt.__index = _G */
       
   581   return 0;
       
   582 }
       
   583 
       
   584 
       
   585 /* }====================================================== */
       
   586 
       
   587 
       
   588 
       
   589 /* auxiliary mark (for internal use) */
       
   590 #define AUXMARK		"\1"
       
   591 
       
   592 static void setpath (lua_State *L, const char *fieldname, const char *envname,
       
   593                                    const char *def) {
       
   594   const char *path = getenv(envname);
       
   595   if (path == NULL)  /* no environment variable? */
       
   596     lua_pushstring(L, def);  /* use default */
       
   597   else {
       
   598     /* replace ";;" by ";AUXMARK;" and then AUXMARK by default path */
       
   599     path = luaL_gsub(L, path, LUA_PATHSEP LUA_PATHSEP,
       
   600                               LUA_PATHSEP AUXMARK LUA_PATHSEP);
       
   601     luaL_gsub(L, path, AUXMARK, def);
       
   602     lua_remove(L, -2);
       
   603   }
       
   604   setprogdir(L);
       
   605   lua_setfield(L, -2, fieldname);
       
   606 }
       
   607 
       
   608 
       
   609 static const luaL_Reg pk_funcs[] = {
       
   610   {"loadlib", ll_loadlib},
       
   611   {"seeall", ll_seeall},
       
   612   {NULL, NULL}
       
   613 };
       
   614 
       
   615 
       
   616 static const luaL_Reg ll_funcs[] = {
       
   617   {"module", ll_module},
       
   618   {"require", ll_require},
       
   619   {NULL, NULL}
       
   620 };
       
   621 
       
   622 
       
   623 static const lua_CFunction loaders[] =
       
   624   {loader_preload, loader_Lua, loader_C, loader_Croot, NULL};
       
   625 
       
   626 
       
   627 LUALIB_API int luaopen_package (lua_State *L) {
       
   628   int i;
       
   629   /* create new type _LOADLIB */
       
   630   luaL_newmetatable(L, "_LOADLIB");
       
   631   lua_pushcfunction(L, gctm);
       
   632   lua_setfield(L, -2, "__gc");
       
   633   /* create `package' table */
       
   634   luaL_register(L, LUA_LOADLIBNAME, pk_funcs);
       
   635 #if defined(LUA_COMPAT_LOADLIB) 
       
   636   lua_getfield(L, -1, "loadlib");
       
   637   lua_setfield(L, LUA_GLOBALSINDEX, "loadlib");
       
   638 #endif
       
   639   lua_pushvalue(L, -1);
       
   640   lua_replace(L, LUA_ENVIRONINDEX);
       
   641   /* create `loaders' table */
       
   642   lua_createtable(L, 0, sizeof(loaders)/sizeof(loaders[0]) - 1);
       
   643   /* fill it with pre-defined loaders */
       
   644   for (i=0; loaders[i] != NULL; i++) {
       
   645     lua_pushcfunction(L, loaders[i]);
       
   646     lua_rawseti(L, -2, i+1);
       
   647   }
       
   648   lua_setfield(L, -2, "loaders");  /* put it in field `loaders' */
       
   649   setpath(L, "path", LUA_PATH, LUA_PATH_DEFAULT);  /* set field `path' */
       
   650   setpath(L, "cpath", LUA_CPATH, LUA_CPATH_DEFAULT); /* set field `cpath' */
       
   651   /* store config information */
       
   652   lua_pushliteral(L, LUA_DIRSEP "\n" LUA_PATHSEP "\n" LUA_PATH_MARK "\n"
       
   653                      LUA_EXECDIR "\n" LUA_IGMARK);
       
   654   lua_setfield(L, -2, "config");
       
   655   /* set field `loaded' */
       
   656   luaL_findtable(L, LUA_REGISTRYINDEX, "_LOADED", 2);
       
   657   lua_setfield(L, -2, "loaded");
       
   658   /* set field `preload' */
       
   659   lua_newtable(L);
       
   660   lua_setfield(L, -2, "preload");
       
   661   lua_pushvalue(L, LUA_GLOBALSINDEX);
       
   662   luaL_register(L, NULL, ll_funcs);  /* open lib into global table */
       
   663   lua_pop(L, 1);
       
   664   return 1;  /* return 'package' table */
       
   665 }
       
   666