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  1. /*
  2. ** $Id: loadlib.c,v 1.111.1.1 2013/04/12 18:48:47 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 Windows, and a stub for other
  8. ** systems.
  9. */
  10.  
  11.  
  12. /*
  13. ** if needed, includes windows header before everything else
  14. */
  15. #if defined(_WIN32)
  16. #include <windows.h>
  17. #endif
  18.  
  19.  
  20. #include <stdlib.h>
  21. #include <string.h>
  22.  
  23.  
  24. #define loadlib_c
  25. #define LUA_LIB
  26.  
  27. #include "lua.h"
  28.  
  29. #include "lauxlib.h"
  30. #include "lualib.h"
  31.  
  32.  
  33. /*
  34. ** LUA_PATH and LUA_CPATH are the names of the environment
  35. ** variables that Lua check to set its paths.
  36. */
  37. #if !defined(LUA_PATH)
  38. #define LUA_PATH        "LUA_PATH"
  39. #endif
  40.  
  41. #if !defined(LUA_CPATH)
  42. #define LUA_CPATH       "LUA_CPATH"
  43. #endif
  44.  
  45. #define LUA_PATHSUFFIX          "_" LUA_VERSION_MAJOR "_" LUA_VERSION_MINOR
  46.  
  47. #define LUA_PATHVERSION         LUA_PATH LUA_PATHSUFFIX
  48. #define LUA_CPATHVERSION        LUA_CPATH LUA_PATHSUFFIX
  49.  
  50. /*
  51. ** LUA_PATH_SEP is the character that separates templates in a path.
  52. ** LUA_PATH_MARK is the string that marks the substitution points in a
  53. ** template.
  54. ** LUA_EXEC_DIR in a Windows path is replaced by the executable's
  55. ** directory.
  56. ** LUA_IGMARK is a mark to ignore all before it when building the
  57. ** luaopen_ function name.
  58. */
  59. #if !defined (LUA_PATH_SEP)
  60. #define LUA_PATH_SEP            ";"
  61. #endif
  62. #if !defined (LUA_PATH_MARK)
  63. #define LUA_PATH_MARK           "?"
  64. #endif
  65. #if !defined (LUA_EXEC_DIR)
  66. #define LUA_EXEC_DIR            "!"
  67. #endif
  68. #if !defined (LUA_IGMARK)
  69. #define LUA_IGMARK              "-"
  70. #endif
  71.  
  72.  
  73. /*
  74. ** LUA_CSUBSEP is the character that replaces dots in submodule names
  75. ** when searching for a C loader.
  76. ** LUA_LSUBSEP is the character that replaces dots in submodule names
  77. ** when searching for a Lua loader.
  78. */
  79. #if !defined(LUA_CSUBSEP)
  80. #define LUA_CSUBSEP             LUA_DIRSEP
  81. #endif
  82.  
  83. #if !defined(LUA_LSUBSEP)
  84. #define LUA_LSUBSEP             LUA_DIRSEP
  85. #endif
  86.  
  87.  
  88. /* prefix for open functions in C libraries */
  89. #define LUA_POF         "luaopen_"
  90.  
  91. /* separator for open functions in C libraries */
  92. #define LUA_OFSEP       "_"
  93.  
  94.  
  95. /* table (in the registry) that keeps handles for all loaded C libraries */
  96. #define CLIBS           "_CLIBS"
  97.  
  98. #define LIB_FAIL        "open"
  99.  
  100.  
  101. /* error codes for ll_loadfunc */
  102. #define ERRLIB          1
  103. #define ERRFUNC         2
  104.  
  105. #define setprogdir(L)           ((void)0)
  106.  
  107.  
  108. /*
  109. ** system-dependent functions
  110. */
  111. static void ll_unloadlib (void *lib);
  112. static void *ll_load (lua_State *L, const char *path, int seeglb);
  113. static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym);
  114.  
  115.  
  116.  
  117. #if defined(LUA_USE_DLOPEN)
  118. /*
  119. ** {========================================================================
  120. ** This is an implementation of loadlib based on the dlfcn interface.
  121. ** The dlfcn interface is available in Linux, SunOS, Solaris, IRIX, FreeBSD,
  122. ** NetBSD, AIX 4.2, HPUX 11, and  probably most other Unix flavors, at least
  123. ** as an emulation layer on top of native functions.
  124. ** =========================================================================
  125. */
  126.  
  127. #include <dlfcn.h>
  128.  
  129. static void ll_unloadlib (void *lib) {
  130.   dlclose(lib);
  131. }
  132.  
  133.  
  134. static void *ll_load (lua_State *L, const char *path, int seeglb) {
  135.   void *lib = dlopen(path, RTLD_NOW | (seeglb ? RTLD_GLOBAL : RTLD_LOCAL));
  136.   if (lib == NULL) lua_pushstring(L, dlerror());
  137.   return lib;
  138. }
  139.  
  140.  
  141. static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) {
  142.   lua_CFunction f = (lua_CFunction)dlsym(lib, sym);
  143.   if (f == NULL) lua_pushstring(L, dlerror());
  144.   return f;
  145. }
  146.  
  147. /* }====================================================== */
  148.  
  149.  
  150.  
  151. #elif defined(LUA_DL_DLL)
  152. /*
  153. ** {======================================================================
  154. ** This is an implementation of loadlib for Windows using native functions.
  155. ** =======================================================================
  156. */
  157.  
  158. #undef setprogdir
  159.  
  160. /*
  161. ** optional flags for LoadLibraryEx
  162. */
  163. #if !defined(LUA_LLE_FLAGS)
  164. #define LUA_LLE_FLAGS   0
  165. #endif
  166.  
  167.  
  168. static void setprogdir (lua_State *L) {
  169.   char buff[MAX_PATH + 1];
  170.   char *lb;
  171.   DWORD nsize = sizeof(buff)/sizeof(char);
  172.   DWORD n = GetModuleFileNameA(NULL, buff, nsize);
  173.   if (n == 0 || n == nsize || (lb = strrchr(buff, '\\')) == NULL)
  174.     luaL_error(L, "unable to get ModuleFileName");
  175.   else {
  176.     *lb = '\0';
  177.     luaL_gsub(L, lua_tostring(L, -1), LUA_EXEC_DIR, buff);
  178.     lua_remove(L, -2);  /* remove original string */
  179.   }
  180. }
  181.  
  182.  
  183. static void pusherror (lua_State *L) {
  184.   int error = GetLastError();
  185.   char buffer[128];
  186.   if (FormatMessageA(FORMAT_MESSAGE_IGNORE_INSERTS | FORMAT_MESSAGE_FROM_SYSTEM,
  187.       NULL, error, 0, buffer, sizeof(buffer)/sizeof(char), NULL))
  188.     lua_pushstring(L, buffer);
  189.   else
  190.     lua_pushfstring(L, "system error %d\n", error);
  191. }
  192.  
  193. static void ll_unloadlib (void *lib) {
  194.   FreeLibrary((HMODULE)lib);
  195. }
  196.  
  197.  
  198. static void *ll_load (lua_State *L, const char *path, int seeglb) {
  199.   HMODULE lib = LoadLibraryExA(path, NULL, LUA_LLE_FLAGS);
  200.   (void)(seeglb);  /* not used: symbols are 'global' by default */
  201.   if (lib == NULL) pusherror(L);
  202.   return lib;
  203. }
  204.  
  205.  
  206. static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) {
  207.   lua_CFunction f = (lua_CFunction)GetProcAddress((HMODULE)lib, sym);
  208.   if (f == NULL) pusherror(L);
  209.   return f;
  210. }
  211.  
  212. /* }====================================================== */
  213.  
  214.  
  215. #else
  216. /*
  217. ** {======================================================
  218. ** Fallback for other systems
  219. ** =======================================================
  220. */
  221.  
  222. #undef LIB_FAIL
  223. #define LIB_FAIL        "absent"
  224.  
  225.  
  226. #define DLMSG   "dynamic libraries not enabled; check your Lua installation"
  227.  
  228.  
  229. static void ll_unloadlib (void *lib) {
  230.   (void)(lib);  /* not used */
  231. }
  232.  
  233.  
  234. static void *ll_load (lua_State *L, const char *path, int seeglb) {
  235.   (void)(path); (void)(seeglb);  /* not used */
  236.   lua_pushliteral(L, DLMSG);
  237.   return NULL;
  238. }
  239.  
  240.  
  241. static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) {
  242.   (void)(lib); (void)(sym);  /* not used */
  243.   lua_pushliteral(L, DLMSG);
  244.   return NULL;
  245. }
  246.  
  247. /* }====================================================== */
  248. #endif
  249.  
  250.  
  251. static void *ll_checkclib (lua_State *L, const char *path) {
  252.   void *plib;
  253.   lua_getfield(L, LUA_REGISTRYINDEX, CLIBS);
  254.   lua_getfield(L, -1, path);
  255.   plib = lua_touserdata(L, -1);  /* plib = CLIBS[path] */
  256.   lua_pop(L, 2);  /* pop CLIBS table and 'plib' */
  257.   return plib;
  258. }
  259.  
  260.  
  261. static void ll_addtoclib (lua_State *L, const char *path, void *plib) {
  262.   lua_getfield(L, LUA_REGISTRYINDEX, CLIBS);
  263.   lua_pushlightuserdata(L, plib);
  264.   lua_pushvalue(L, -1);
  265.   lua_setfield(L, -3, path);  /* CLIBS[path] = plib */
  266.   lua_rawseti(L, -2, luaL_len(L, -2) + 1);  /* CLIBS[#CLIBS + 1] = plib */
  267.   lua_pop(L, 1);  /* pop CLIBS table */
  268. }
  269.  
  270.  
  271. /*
  272. ** __gc tag method for CLIBS table: calls 'll_unloadlib' for all lib
  273. ** handles in list CLIBS
  274. */
  275. static int gctm (lua_State *L) {
  276.   int n = luaL_len(L, 1);
  277.   for (; n >= 1; n--) {  /* for each handle, in reverse order */
  278.     lua_rawgeti(L, 1, n);  /* get handle CLIBS[n] */
  279.     ll_unloadlib(lua_touserdata(L, -1));
  280.     lua_pop(L, 1);  /* pop handle */
  281.   }
  282.   return 0;
  283. }
  284.  
  285.  
  286. static int ll_loadfunc (lua_State *L, const char *path, const char *sym) {
  287.   void *reg = ll_checkclib(L, path);  /* check loaded C libraries */
  288.   if (reg == NULL) {  /* must load library? */
  289.     reg = ll_load(L, path, *sym == '*');
  290.     if (reg == NULL) return ERRLIB;  /* unable to load library */
  291.     ll_addtoclib(L, path, reg);
  292.   }
  293.   if (*sym == '*') {  /* loading only library (no function)? */
  294.     lua_pushboolean(L, 1);  /* return 'true' */
  295.     return 0;  /* no errors */
  296.   }
  297.   else {
  298.     lua_CFunction f = ll_sym(L, reg, sym);
  299.     if (f == NULL)
  300.       return ERRFUNC;  /* unable to find function */
  301.     lua_pushcfunction(L, f);  /* else create new function */
  302.     return 0;  /* no errors */
  303.   }
  304. }
  305.  
  306.  
  307. static int ll_loadlib (lua_State *L) {
  308.   const char *path = luaL_checkstring(L, 1);
  309.   const char *init = luaL_checkstring(L, 2);
  310.   int stat = ll_loadfunc(L, path, init);
  311.   if (stat == 0)  /* no errors? */
  312.     return 1;  /* return the loaded function */
  313.   else {  /* error; error message is on stack top */
  314.     lua_pushnil(L);
  315.     lua_insert(L, -2);
  316.     lua_pushstring(L, (stat == ERRLIB) ?  LIB_FAIL : "init");
  317.     return 3;  /* return nil, error message, and where */
  318.   }
  319. }
  320.  
  321.  
  322.  
  323. /*
  324. ** {======================================================
  325. ** 'require' function
  326. ** =======================================================
  327. */
  328.  
  329.  
  330. static int readable (const char *filename) {
  331.   FILE *f = fopen(filename, "r");  /* try to open file */
  332.   if (f == NULL) return 0;  /* open failed */
  333.   fclose(f);
  334.   return 1;
  335. }
  336.  
  337.  
  338. static const char *pushnexttemplate (lua_State *L, const char *path) {
  339.   const char *l;
  340.   while (*path == *LUA_PATH_SEP) path++;  /* skip separators */
  341.   if (*path == '\0') return NULL;  /* no more templates */
  342.   l = strchr(path, *LUA_PATH_SEP);  /* find next separator */
  343.   if (l == NULL) l = path + strlen(path);
  344.   lua_pushlstring(L, path, l - path);  /* template */
  345.   return l;
  346. }
  347.  
  348.  
  349. static const char *searchpath (lua_State *L, const char *name,
  350.                                              const char *path,
  351.                                              const char *sep,
  352.                                              const char *dirsep) {
  353.   luaL_Buffer msg;  /* to build error message */
  354.   luaL_buffinit(L, &msg);
  355.   if (*sep != '\0')  /* non-empty separator? */
  356.     name = luaL_gsub(L, name, sep, dirsep);  /* replace it by 'dirsep' */
  357.   while ((path = pushnexttemplate(L, path)) != NULL) {
  358.     const char *filename = luaL_gsub(L, lua_tostring(L, -1),
  359.                                      LUA_PATH_MARK, name);
  360.     lua_remove(L, -2);  /* remove path template */
  361.     if (readable(filename))  /* does file exist and is readable? */
  362.       return filename;  /* return that file name */
  363.     lua_pushfstring(L, "\n\tno file " LUA_QS, filename);
  364.     lua_remove(L, -2);  /* remove file name */
  365.     luaL_addvalue(&msg);  /* concatenate error msg. entry */
  366.   }
  367.   luaL_pushresult(&msg);  /* create error message */
  368.   return NULL;  /* not found */
  369. }
  370.  
  371.  
  372. static int ll_searchpath (lua_State *L) {
  373.   const char *f = searchpath(L, luaL_checkstring(L, 1),
  374.                                 luaL_checkstring(L, 2),
  375.                                 luaL_optstring(L, 3, "."),
  376.                                 luaL_optstring(L, 4, LUA_DIRSEP));
  377.   if (f != NULL) return 1;
  378.   else {  /* error message is on top of the stack */
  379.     lua_pushnil(L);
  380.     lua_insert(L, -2);
  381.     return 2;  /* return nil + error message */
  382.   }
  383. }
  384.  
  385.  
  386. static const char *findfile (lua_State *L, const char *name,
  387.                                            const char *pname,
  388.                                            const char *dirsep) {
  389.   const char *path;
  390.   lua_getfield(L, lua_upvalueindex(1), pname);
  391.   path = lua_tostring(L, -1);
  392.   if (path == NULL)
  393.     luaL_error(L, LUA_QL("package.%s") " must be a string", pname);
  394.   return searchpath(L, name, path, ".", dirsep);
  395. }
  396.  
  397.  
  398. static int checkload (lua_State *L, int stat, const char *filename) {
  399.   if (stat) {  /* module loaded successfully? */
  400.     lua_pushstring(L, filename);  /* will be 2nd argument to module */
  401.     return 2;  /* return open function and file name */
  402.   }
  403.   else
  404.     return luaL_error(L, "error loading module " LUA_QS
  405.                          " from file " LUA_QS ":\n\t%s",
  406.                           lua_tostring(L, 1), filename, lua_tostring(L, -1));
  407. }
  408.  
  409.  
  410. static int searcher_Lua (lua_State *L) {
  411.   const char *filename;
  412.   const char *name = luaL_checkstring(L, 1);
  413.   filename = findfile(L, name, "path", LUA_LSUBSEP);
  414.   if (filename == NULL) return 1;  /* module not found in this path */
  415.   return checkload(L, (luaL_loadfile(L, filename) == LUA_OK), filename);
  416. }
  417.  
  418.  
  419. static int loadfunc (lua_State *L, const char *filename, const char *modname) {
  420.   const char *funcname;
  421.   const char *mark;
  422.   modname = luaL_gsub(L, modname, ".", LUA_OFSEP);
  423.   mark = strchr(modname, *LUA_IGMARK);
  424.   if (mark) {
  425.     int stat;
  426.     funcname = lua_pushlstring(L, modname, mark - modname);
  427.     funcname = lua_pushfstring(L, LUA_POF"%s", funcname);
  428.     stat = ll_loadfunc(L, filename, funcname);
  429.     if (stat != ERRFUNC) return stat;
  430.     modname = mark + 1;  /* else go ahead and try old-style name */
  431.   }
  432.   funcname = lua_pushfstring(L, LUA_POF"%s", modname);
  433.   return ll_loadfunc(L, filename, funcname);
  434. }
  435.  
  436.  
  437. static int searcher_C (lua_State *L) {
  438.   const char *name = luaL_checkstring(L, 1);
  439.   const char *filename = findfile(L, name, "cpath", LUA_CSUBSEP);
  440.   if (filename == NULL) return 1;  /* module not found in this path */
  441.   return checkload(L, (loadfunc(L, filename, name) == 0), filename);
  442. }
  443.  
  444.  
  445. static int searcher_Croot (lua_State *L) {
  446.   const char *filename;
  447.   const char *name = luaL_checkstring(L, 1);
  448.   const char *p = strchr(name, '.');
  449.   int stat;
  450.   if (p == NULL) return 0;  /* is root */
  451.   lua_pushlstring(L, name, p - name);
  452.   filename = findfile(L, lua_tostring(L, -1), "cpath", LUA_CSUBSEP);
  453.   if (filename == NULL) return 1;  /* root not found */
  454.   if ((stat = loadfunc(L, filename, name)) != 0) {
  455.     if (stat != ERRFUNC)
  456.       return checkload(L, 0, filename);  /* real error */
  457.     else {  /* open function not found */
  458.       lua_pushfstring(L, "\n\tno module " LUA_QS " in file " LUA_QS,
  459.                          name, filename);
  460.       return 1;
  461.     }
  462.   }
  463.   lua_pushstring(L, filename);  /* will be 2nd argument to module */
  464.   return 2;
  465. }
  466.  
  467.  
  468. static int searcher_preload (lua_State *L) {
  469.   const char *name = luaL_checkstring(L, 1);
  470.   lua_getfield(L, LUA_REGISTRYINDEX, "_PRELOAD");
  471.   lua_getfield(L, -1, name);
  472.   if (lua_isnil(L, -1))  /* not found? */
  473.     lua_pushfstring(L, "\n\tno field package.preload['%s']", name);
  474.   return 1;
  475. }
  476.  
  477.  
  478. static void findloader (lua_State *L, const char *name) {
  479.   int i;
  480.   luaL_Buffer msg;  /* to build error message */
  481.   luaL_buffinit(L, &msg);
  482.   lua_getfield(L, lua_upvalueindex(1), "searchers");  /* will be at index 3 */
  483.   if (!lua_istable(L, 3))
  484.     luaL_error(L, LUA_QL("package.searchers") " must be a table");
  485.   /*  iterate over available searchers to find a loader */
  486.   for (i = 1; ; i++) {
  487.     lua_rawgeti(L, 3, i);  /* get a searcher */
  488.     if (lua_isnil(L, -1)) {  /* no more searchers? */
  489.       lua_pop(L, 1);  /* remove nil */
  490.       luaL_pushresult(&msg);  /* create error message */
  491.       luaL_error(L, "module " LUA_QS " not found:%s",
  492.                     name, lua_tostring(L, -1));
  493.     }
  494.     lua_pushstring(L, name);
  495.     lua_call(L, 1, 2);  /* call it */
  496.     if (lua_isfunction(L, -2))  /* did it find a loader? */
  497.       return;  /* module loader found */
  498.     else if (lua_isstring(L, -2)) {  /* searcher returned error message? */
  499.       lua_pop(L, 1);  /* remove extra return */
  500.       luaL_addvalue(&msg);  /* concatenate error message */
  501.     }
  502.     else
  503.       lua_pop(L, 2);  /* remove both returns */
  504.   }
  505. }
  506.  
  507.  
  508. static int ll_require (lua_State *L) {
  509.   const char *name = luaL_checkstring(L, 1);
  510.   lua_settop(L, 1);  /* _LOADED table will be at index 2 */
  511.   lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");
  512.   lua_getfield(L, 2, name);  /* _LOADED[name] */
  513.   if (lua_toboolean(L, -1))  /* is it there? */
  514.     return 1;  /* package is already loaded */
  515.   /* else must load package */
  516.   lua_pop(L, 1);  /* remove 'getfield' result */
  517.   findloader(L, name);
  518.   lua_pushstring(L, name);  /* pass name as argument to module loader */
  519.   lua_insert(L, -2);  /* name is 1st argument (before search data) */
  520.   lua_call(L, 2, 1);  /* run loader to load module */
  521.   if (!lua_isnil(L, -1))  /* non-nil return? */
  522.     lua_setfield(L, 2, name);  /* _LOADED[name] = returned value */
  523.   lua_getfield(L, 2, name);
  524.   if (lua_isnil(L, -1)) {   /* module did not set a value? */
  525.     lua_pushboolean(L, 1);  /* use true as result */
  526.     lua_pushvalue(L, -1);  /* extra copy to be returned */
  527.     lua_setfield(L, 2, name);  /* _LOADED[name] = true */
  528.   }
  529.   return 1;
  530. }
  531.  
  532. /* }====================================================== */
  533.  
  534.  
  535.  
  536. /*
  537. ** {======================================================
  538. ** 'module' function
  539. ** =======================================================
  540. */
  541. #if defined(LUA_COMPAT_MODULE)
  542.  
  543. /*
  544. ** changes the environment variable of calling function
  545. */
  546. static void set_env (lua_State *L) {
  547.   lua_Debug ar;
  548.   if (lua_getstack(L, 1, &ar) == 0 ||
  549.       lua_getinfo(L, "f", &ar) == 0 ||  /* get calling function */
  550.       lua_iscfunction(L, -1))
  551.     luaL_error(L, LUA_QL("module") " not called from a Lua function");
  552.   lua_pushvalue(L, -2);  /* copy new environment table to top */
  553.   lua_setupvalue(L, -2, 1);
  554.   lua_pop(L, 1);  /* remove function */
  555. }
  556.  
  557.  
  558. static void dooptions (lua_State *L, int n) {
  559.   int i;
  560.   for (i = 2; i <= n; i++) {
  561.     if (lua_isfunction(L, i)) {  /* avoid 'calling' extra info. */
  562.       lua_pushvalue(L, i);  /* get option (a function) */
  563.       lua_pushvalue(L, -2);  /* module */
  564.       lua_call(L, 1, 0);
  565.     }
  566.   }
  567. }
  568.  
  569.  
  570. static void modinit (lua_State *L, const char *modname) {
  571.   const char *dot;
  572.   lua_pushvalue(L, -1);
  573.   lua_setfield(L, -2, "_M");  /* module._M = module */
  574.   lua_pushstring(L, modname);
  575.   lua_setfield(L, -2, "_NAME");
  576.   dot = strrchr(modname, '.');  /* look for last dot in module name */
  577.   if (dot == NULL) dot = modname;
  578.   else dot++;
  579.   /* set _PACKAGE as package name (full module name minus last part) */
  580.   lua_pushlstring(L, modname, dot - modname);
  581.   lua_setfield(L, -2, "_PACKAGE");
  582. }
  583.  
  584.  
  585. static int ll_module (lua_State *L) {
  586.   const char *modname = luaL_checkstring(L, 1);
  587.   int lastarg = lua_gettop(L);  /* last parameter */
  588.   luaL_pushmodule(L, modname, 1);  /* get/create module table */
  589.   /* check whether table already has a _NAME field */
  590.   lua_getfield(L, -1, "_NAME");
  591.   if (!lua_isnil(L, -1))  /* is table an initialized module? */
  592.     lua_pop(L, 1);
  593.   else {  /* no; initialize it */
  594.     lua_pop(L, 1);
  595.     modinit(L, modname);
  596.   }
  597.   lua_pushvalue(L, -1);
  598.   set_env(L);
  599.   dooptions(L, lastarg);
  600.   return 1;
  601. }
  602.  
  603.  
  604. static int ll_seeall (lua_State *L) {
  605.   luaL_checktype(L, 1, LUA_TTABLE);
  606.   if (!lua_getmetatable(L, 1)) {
  607.     lua_createtable(L, 0, 1); /* create new metatable */
  608.     lua_pushvalue(L, -1);
  609.     lua_setmetatable(L, 1);
  610.   }
  611.   lua_pushglobaltable(L);
  612.   lua_setfield(L, -2, "__index");  /* mt.__index = _G */
  613.   return 0;
  614. }
  615.  
  616. #endif
  617. /* }====================================================== */
  618.  
  619.  
  620.  
  621. /* auxiliary mark (for internal use) */
  622. #define AUXMARK         "\1"
  623.  
  624.  
  625. /*
  626. ** return registry.LUA_NOENV as a boolean
  627. */
  628. static int noenv (lua_State *L) {
  629.   int b;
  630.   lua_getfield(L, LUA_REGISTRYINDEX, "LUA_NOENV");
  631.   b = lua_toboolean(L, -1);
  632.   lua_pop(L, 1);  /* remove value */
  633.   return b;
  634. }
  635.  
  636.  
  637. static void setpath (lua_State *L, const char *fieldname, const char *envname1,
  638.                                    const char *envname2, const char *def) {
  639.   const char *path = getenv(envname1);
  640.   if (path == NULL)  /* no environment variable? */
  641.     path = getenv(envname2);  /* try alternative name */
  642.   if (path == NULL || noenv(L))  /* no environment variable? */
  643.     lua_pushstring(L, def);  /* use default */
  644.   else {
  645.     /* replace ";;" by ";AUXMARK;" and then AUXMARK by default path */
  646.     path = luaL_gsub(L, path, LUA_PATH_SEP LUA_PATH_SEP,
  647.                               LUA_PATH_SEP AUXMARK LUA_PATH_SEP);
  648.     luaL_gsub(L, path, AUXMARK, def);
  649.     lua_remove(L, -2);
  650.   }
  651.   setprogdir(L);
  652.   lua_setfield(L, -2, fieldname);
  653. }
  654.  
  655.  
  656. static const luaL_Reg pk_funcs[] = {
  657.   {"loadlib", ll_loadlib},
  658.   {"searchpath", ll_searchpath},
  659. #if defined(LUA_COMPAT_MODULE)
  660.   {"seeall", ll_seeall},
  661. #endif
  662.   {NULL, NULL}
  663. };
  664.  
  665.  
  666. static const luaL_Reg ll_funcs[] = {
  667. #if defined(LUA_COMPAT_MODULE)
  668.   {"module", ll_module},
  669. #endif
  670.   {"require", ll_require},
  671.   {NULL, NULL}
  672. };
  673.  
  674.  
  675. static void createsearcherstable (lua_State *L) {
  676.   static const lua_CFunction searchers[] =
  677.     {searcher_preload, searcher_Lua, searcher_C, searcher_Croot, NULL};
  678.   int i;
  679.   /* create 'searchers' table */
  680.   lua_createtable(L, sizeof(searchers)/sizeof(searchers[0]) - 1, 0);
  681.   /* fill it with pre-defined searchers */
  682.   for (i=0; searchers[i] != NULL; i++) {
  683.     lua_pushvalue(L, -2);  /* set 'package' as upvalue for all searchers */
  684.     lua_pushcclosure(L, searchers[i], 1);
  685.     lua_rawseti(L, -2, i+1);
  686.   }
  687. }
  688.  
  689.  
  690. LUAMOD_API int luaopen_package (lua_State *L) {
  691.   /* create table CLIBS to keep track of loaded C libraries */
  692.   luaL_getsubtable(L, LUA_REGISTRYINDEX, CLIBS);
  693.   lua_createtable(L, 0, 1);  /* metatable for CLIBS */
  694.   lua_pushcfunction(L, gctm);
  695.   lua_setfield(L, -2, "__gc");  /* set finalizer for CLIBS table */
  696.   lua_setmetatable(L, -2);
  697.   /* create `package' table */
  698.   luaL_newlib(L, pk_funcs);
  699.   createsearcherstable(L);
  700. #if defined(LUA_COMPAT_LOADERS)
  701.   lua_pushvalue(L, -1);  /* make a copy of 'searchers' table */
  702.   lua_setfield(L, -3, "loaders");  /* put it in field `loaders' */
  703. #endif
  704.   lua_setfield(L, -2, "searchers");  /* put it in field 'searchers' */
  705.   /* set field 'path' */
  706.   setpath(L, "path", LUA_PATHVERSION, LUA_PATH, LUA_PATH_DEFAULT);
  707.   /* set field 'cpath' */
  708.   setpath(L, "cpath", LUA_CPATHVERSION, LUA_CPATH, LUA_CPATH_DEFAULT);
  709.   /* store config information */
  710.   lua_pushliteral(L, LUA_DIRSEP "\n" LUA_PATH_SEP "\n" LUA_PATH_MARK "\n"
  711.                      LUA_EXEC_DIR "\n" LUA_IGMARK "\n");
  712.   lua_setfield(L, -2, "config");
  713.   /* set field `loaded' */
  714.   luaL_getsubtable(L, LUA_REGISTRYINDEX, "_LOADED");
  715.   lua_setfield(L, -2, "loaded");
  716.   /* set field `preload' */
  717.   luaL_getsubtable(L, LUA_REGISTRYINDEX, "_PRELOAD");
  718.   lua_setfield(L, -2, "preload");
  719.   lua_pushglobaltable(L);
  720.   lua_pushvalue(L, -2);  /* set 'package' as upvalue for next lib */
  721.   luaL_setfuncs(L, ll_funcs, 1);  /* open lib into global table */
  722.   lua_pop(L, 1);  /* pop global table */
  723.   return 1;  /* return 'package' table */
  724. }
  725.  
  726.