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/*

** $Id: loadlib.c,v 1.108 2011/12/12 16:34:03 roberto Exp $

** Dynamic library loader for Lua

** See Copyright Notice in lua.h

**

** This module contains an implementation of loadlib for Unix systems

** that have dlfcn, an implementation for Windows, and a stub for other

** systems.

*/

/*

** if needed, includes windows header before everything else

*/

#if defined(_WIN32)

#include 

#endif

#include 

#include 

#define loadlib_c

#define LUA_LIB

#include "lua.h"

#include "lauxlib.h"

#include "lualib.h"

/*

** LUA_PATH and LUA_CPATH are the names of the environment

** variables that Lua check to set its paths.

*/

#if !defined(LUA_PATH)

#define LUA_PATH	"LUA_PATH"

#endif

#if !defined(LUA_CPATH)

#define LUA_CPATH	"LUA_CPATH"

#endif

#define LUA_PATHSUFFIX		"_" LUA_VERSION_MAJOR "_" LUA_VERSION_MINOR

#define LUA_PATHVERSION		LUA_PATH LUA_PATHSUFFIX

#define LUA_CPATHVERSION	LUA_CPATH LUA_PATHSUFFIX

/*

** LUA_PATH_SEP is the character that separates templates in a path.

** LUA_PATH_MARK is the string that marks the substitution points in a

** template.

** LUA_EXEC_DIR in a Windows path is replaced by the executable's

** directory.

** LUA_IGMARK is a mark to ignore all before it when building the

** luaopen_ function name.

*/

#if !defined (LUA_PATH_SEP)

#define LUA_PATH_SEP		";"

#endif

#if !defined (LUA_PATH_MARK)

#define LUA_PATH_MARK		"?"

#endif

#if !defined (LUA_EXEC_DIR)

#define LUA_EXEC_DIR		"!"

#endif

#if !defined (LUA_IGMARK)

#define LUA_IGMARK		"-"

#endif

/*

** LUA_CSUBSEP is the character that replaces dots in submodule names

** when searching for a C loader.

** LUA_LSUBSEP is the character that replaces dots in submodule names

** when searching for a Lua loader.

*/

#if !defined(LUA_CSUBSEP)

#define LUA_CSUBSEP		LUA_DIRSEP

#endif

#if !defined(LUA_LSUBSEP)

#define LUA_LSUBSEP		LUA_DIRSEP

#endif

/* prefix for open functions in C libraries */

#define LUA_POF		"luaopen_"

/* separator for open functions in C libraries */

#define LUA_OFSEP	"_"

#define LIBPREFIX	"LOADLIB: "

#define POF		LUA_POF

#define LIB_FAIL	"open"

/* error codes for ll_loadfunc */

#define ERRLIB		1

#define ERRFUNC		2

#define setprogdir(L)		((void)0)

/*

** system-dependent functions

*/

static void ll_unloadlib (void *lib);

static void *ll_load (lua_State *L, const char *path, int seeglb);

static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym);

#if defined(LUA_USE_DLOPEN)

/*

** {========================================================================

** This is an implementation of loadlib based on the dlfcn interface.

** The dlfcn interface is available in Linux, SunOS, Solaris, IRIX, FreeBSD,

** NetBSD, AIX 4.2, HPUX 11, and  probably most other Unix flavors, at least

** as an emulation layer on top of native functions.

** =========================================================================

*/

#include 

static void ll_unloadlib (void *lib) {

  dlclose(lib);

}

static void *ll_load (lua_State *L, const char *path, int seeglb) {

  void *lib = dlopen(path, RTLD_NOW | (seeglb ? RTLD_GLOBAL : RTLD_LOCAL));

  if (lib == NULL) lua_pushstring(L, dlerror());

  return lib;

}

static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) {

  lua_CFunction f = (lua_CFunction)dlsym(lib, sym);

  if (f == NULL) lua_pushstring(L, dlerror());

  return f;

}

/* }====================================================== */

#elif defined(LUA_DL_DLL)

/*

** {======================================================================

** This is an implementation of loadlib for Windows using native functions.

** =======================================================================

*/

#undef setprogdir

/*

** optional flags for LoadLibraryEx

*/

#if !defined(LUA_LLE_FLAGS)

#define LUA_LLE_FLAGS	0

#endif

static void setprogdir (lua_State *L) {

  char buff[MAX_PATH + 1];

  char *lb;

  DWORD nsize = sizeof(buff)/sizeof(char);

  DWORD n = GetModuleFileNameA(NULL, buff, nsize);

  if (n == 0 || n == nsize || (lb = strrchr(buff, '\\')) == NULL)

    luaL_error(L, "unable to get ModuleFileName");

  else {

    *lb = '\0';

    luaL_gsub(L, lua_tostring(L, -1), LUA_EXEC_DIR, buff);

    lua_remove(L, -2);  /* remove original string */

  }

}

static void pusherror (lua_State *L) {

  int error = GetLastError();

  char buffer[128];

  if (FormatMessageA(FORMAT_MESSAGE_IGNORE_INSERTS | FORMAT_MESSAGE_FROM_SYSTEM,

      NULL, error, 0, buffer, sizeof(buffer)/sizeof(char), NULL))

    lua_pushstring(L, buffer);

  else

    lua_pushfstring(L, "system error %d\n", error);

}

static void ll_unloadlib (void *lib) {

  FreeLibrary((HMODULE)lib);

}

static void *ll_load (lua_State *L, const char *path, int seeglb) {

  HMODULE lib = LoadLibraryExA(path, NULL, LUA_LLE_FLAGS);

  (void)(seeglb);  /* not used: symbols are 'global' by default */

  if (lib == NULL) pusherror(L);

  return lib;

}

static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) {

  lua_CFunction f = (lua_CFunction)GetProcAddress((HMODULE)lib, sym);

  if (f == NULL) pusherror(L);

  return f;

}

/* }====================================================== */

#else

/*

** {======================================================

** Fallback for other systems

** =======================================================

*/

#undef LIB_FAIL

#define LIB_FAIL	"absent"

#define DLMSG	"dynamic libraries not enabled; check your Lua installation"

static void ll_unloadlib (void *lib) {

  (void)(lib);  /* not used */

}

static void *ll_load (lua_State *L, const char *path, int seeglb) {

  (void)(path); (void)(seeglb);  /* not used */

  lua_pushliteral(L, DLMSG);

  return NULL;

}

static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) {

  (void)(lib); (void)(sym);  /* not used */

  lua_pushliteral(L, DLMSG);

  return NULL;

}

/* }====================================================== */

#endif

static void **ll_register (lua_State *L, const char *path) {

  void **plib;

  lua_pushfstring(L, "%s%s", LIBPREFIX, path);

  lua_gettable(L, LUA_REGISTRYINDEX);  /* check library in registry? */

  if (!lua_isnil(L, -1))  /* is there an entry? */

    plib = (void **)lua_touserdata(L, -1);

  else {  /* no entry yet; create one */

    lua_pop(L, 1);  /* remove result from gettable */

    plib = (void **)lua_newuserdata(L, sizeof(const void *));

    *plib = NULL;

    luaL_setmetatable(L, "_LOADLIB");

    lua_pushfstring(L, "%s%s", LIBPREFIX, path);

    lua_pushvalue(L, -2);

    lua_settable(L, LUA_REGISTRYINDEX);

  }

  return plib;

}

/*

** __gc tag method: calls library's `ll_unloadlib' function with the lib

** handle

*/

static int gctm (lua_State *L) {

  void **lib = (void **)luaL_checkudata(L, 1, "_LOADLIB");

  if (*lib) ll_unloadlib(*lib);

  *lib = NULL;  /* mark library as closed */

  return 0;

}

static int ll_loadfunc (lua_State *L, const char *path, const char *sym) {

  void **reg = ll_register(L, path);

  if (*reg == NULL) *reg = ll_load(L, path, *sym == '*');

  if (*reg == NULL) return ERRLIB;  /* unable to load library */

  if (*sym == '*') {  /* loading only library (no function)? */

    lua_pushboolean(L, 1);  /* return 'true' */

    return 0;  /* no errors */

  }

  else {

    lua_CFunction f = ll_sym(L, *reg, sym);

    if (f == NULL)

      return ERRFUNC;  /* unable to find function */

    lua_pushcfunction(L, f);  /* else create new function */

    return 0;  /* no errors */

  }

}

static int ll_loadlib (lua_State *L) {

  const char *path = luaL_checkstring(L, 1);

  const char *init = luaL_checkstring(L, 2);

  int stat = ll_loadfunc(L, path, init);

  if (stat == 0)  /* no errors? */

    return 1;  /* return the loaded function */

  else {  /* error; error message is on stack top */

    lua_pushnil(L);

    lua_insert(L, -2);

    lua_pushstring(L, (stat == ERRLIB) ?  LIB_FAIL : "init");

    return 3;  /* return nil, error message, and where */

  }

}

/*

** {======================================================

** 'require' function

** =======================================================

*/

static int readable (const char *filename) {

  FILE *f = fopen(filename, "r");  /* try to open file */

  if (f == NULL) return 0;  /* open failed */

  fclose(f);

  return 1;

}

static const char *pushnexttemplate (lua_State *L, const char *path) {

  const char *l;

  while (*path == *LUA_PATH_SEP) path++;  /* skip separators */

  if (*path == '\0') return NULL;  /* no more templates */

  l = strchr(path, *LUA_PATH_SEP);  /* find next separator */

  if (l == NULL) l = path + strlen(path);

  lua_pushlstring(L, path, l - path);  /* template */

  return l;

}

static const char *searchpath (lua_State *L, const char *name,

                                             const char *path,

                                             const char *sep,

                                             const char *dirsep) {

  luaL_Buffer msg;  /* to build error message */

  luaL_buffinit(L, &msg);

  if (*sep != '\0')  /* non-empty separator? */

    name = luaL_gsub(L, name, sep, dirsep);  /* replace it by 'dirsep' */

  while ((path = pushnexttemplate(L, path)) != NULL) {

    const char *filename = luaL_gsub(L, lua_tostring(L, -1),

                                     LUA_PATH_MARK, name);

    lua_remove(L, -2);  /* remove path template */

    if (readable(filename))  /* does file exist and is readable? */

      return filename;  /* return that file name */

    lua_pushfstring(L, "\n\tno file " LUA_QS, filename);

    lua_remove(L, -2);  /* remove file name */

    luaL_addvalue(&msg);  /* concatenate error msg. entry */

  }

  luaL_pushresult(&msg);  /* create error message */

  return NULL;  /* not found */

}

static int ll_searchpath (lua_State *L) {

  const char *f = searchpath(L, luaL_checkstring(L, 1),

                                luaL_checkstring(L, 2),

                                luaL_optstring(L, 3, "."),

                                luaL_optstring(L, 4, LUA_DIRSEP));

  if (f != NULL) return 1;

  else {  /* error message is on top of the stack */

    lua_pushnil(L);

    lua_insert(L, -2);

    return 2;  /* return nil + error message */

  }

}

static const char *findfile (lua_State *L, const char *name,

                                           const char *pname,

                                           const char *dirsep) {

  const char *path;

  lua_getfield(L, lua_upvalueindex(1), pname);

  path = lua_tostring(L, -1);

  if (path == NULL)

    luaL_error(L, LUA_QL("package.%s") " must be a string", pname);

  return searchpath(L, name, path, ".", dirsep);

}

static int checkload (lua_State *L, int stat, const char *filename) {

  if (stat) {  /* module loaded successfully? */

    lua_pushstring(L, filename);  /* will be 2nd argument to module */

    return 2;  /* return open function and file name */

  }

  else

    return luaL_error(L, "error loading module " LUA_QS

                         " from file " LUA_QS ":\n\t%s",

                          lua_tostring(L, 1), filename, lua_tostring(L, -1));

}

static int searcher_Lua (lua_State *L) {

  const char *filename;

  const char *name = luaL_checkstring(L, 1);

  filename = findfile(L, name, "path", LUA_LSUBSEP);

  if (filename == NULL) return 1;  /* module not found in this path */

  return checkload(L, (luaL_loadfile(L, filename) == LUA_OK), filename);

}

static int loadfunc (lua_State *L, const char *filename, const char *modname) {

  const char *funcname;

  const char *mark;

  modname = luaL_gsub(L, modname, ".", LUA_OFSEP);

  mark = strchr(modname, *LUA_IGMARK);

  if (mark) {

    int stat;

    funcname = lua_pushlstring(L, modname, mark - modname);

    funcname = lua_pushfstring(L, POF"%s", funcname);

    stat = ll_loadfunc(L, filename, funcname);

    if (stat != ERRFUNC) return stat;

    modname = mark + 1;  /* else go ahead and try old-style name */

  }

  funcname = lua_pushfstring(L, POF"%s", modname);

  return ll_loadfunc(L, filename, funcname);

}

static int searcher_C (lua_State *L) {

  const char *name = luaL_checkstring(L, 1);

  const char *filename = findfile(L, name, "cpath", LUA_CSUBSEP);

  if (filename == NULL) return 1;  /* module not found in this path */

  return checkload(L, (loadfunc(L, filename, name) == 0), filename);

}

static int searcher_Croot (lua_State *L) {

  const char *filename;

  const char *name = luaL_checkstring(L, 1);

  const char *p = strchr(name, '.');

  int stat;

  if (p == NULL) return 0;  /* is root */

  lua_pushlstring(L, name, p - name);

  filename = findfile(L, lua_tostring(L, -1), "cpath", LUA_CSUBSEP);

  if (filename == NULL) return 1;  /* root not found */

  if ((stat = loadfunc(L, filename, name)) != 0) {

    if (stat != ERRFUNC)

      return checkload(L, 0, filename);  /* real error */

    else {  /* open function not found */

      lua_pushfstring(L, "\n\tno module " LUA_QS " in file " LUA_QS,

                         name, filename);

      return 1;

    }

  }

  lua_pushstring(L, filename);  /* will be 2nd argument to module */

  return 2;

}

static int searcher_preload (lua_State *L) {

  const char *name = luaL_checkstring(L, 1);

  lua_getfield(L, LUA_REGISTRYINDEX, "_PRELOAD");

  lua_getfield(L, -1, name);

  if (lua_isnil(L, -1))  /* not found? */

    lua_pushfstring(L, "\n\tno field package.preload['%s']", name);

  return 1;

}

static void findloader (lua_State *L, const char *name) {

  int i;

  luaL_Buffer msg;  /* to build error message */

  luaL_buffinit(L, &msg);

  lua_getfield(L, lua_upvalueindex(1), "searchers");  /* will be at index 3 */

  if (!lua_istable(L, 3))

    luaL_error(L, LUA_QL("package.searchers") " must be a table");

  /*  iterate over available seachers to find a loader */

  for (i = 1; ; i++) {

    lua_rawgeti(L, 3, i);  /* get a seacher */

    if (lua_isnil(L, -1)) {  /* no more searchers? */

      lua_pop(L, 1);  /* remove nil */

      luaL_pushresult(&msg);  /* create error message */

      luaL_error(L, "module " LUA_QS " not found:%s",

                    name, lua_tostring(L, -1));

    }

    lua_pushstring(L, name);

    lua_call(L, 1, 2);  /* call it */

    if (lua_isfunction(L, -2))  /* did it find a loader? */

      return;  /* module loader found */

    else if (lua_isstring(L, -2)) {  /* searcher returned error message? */

      lua_pop(L, 1);  /* remove extra return */

      luaL_addvalue(&msg);  /* concatenate error message */

    }

    else

      lua_pop(L, 2);  /* remove both returns */

  }

}

static int ll_require (lua_State *L) {

  const char *name = luaL_checkstring(L, 1);

  lua_settop(L, 1);  /* _LOADED table will be at index 2 */

  lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");

  lua_getfield(L, 2, name);  /* _LOADED[name] */

  if (lua_toboolean(L, -1))  /* is it there? */

    return 1;  /* package is already loaded */

  /* else must load package */

  lua_pop(L, 1);  /* remove 'getfield' result */

  findloader(L, name);

  lua_pushstring(L, name);  /* pass name as argument to module loader */

  lua_insert(L, -2);  /* name is 1st argument (before search data) */

  lua_call(L, 2, 1);  /* run loader to load module */

  if (!lua_isnil(L, -1))  /* non-nil return? */

    lua_setfield(L, 2, name);  /* _LOADED[name] = returned value */

  lua_getfield(L, 2, name);

  if (lua_isnil(L, -1)) {   /* module did not set a value? */

    lua_pushboolean(L, 1);  /* use true as result */

    lua_pushvalue(L, -1);  /* extra copy to be returned */

    lua_setfield(L, 2, name);  /* _LOADED[name] = true */

  }

  return 1;

}

/* }====================================================== */

/*

** {======================================================

** 'module' function

** =======================================================

*/

#if defined(LUA_COMPAT_MODULE)

/*

** changes the environment variable of calling function

*/

static void set_env (lua_State *L) {

  lua_Debug ar;

  if (lua_getstack(L, 1, &ar) == 0 ||

      lua_getinfo(L, "f", &ar) == 0 ||  /* get calling function */

      lua_iscfunction(L, -1))

    luaL_error(L, LUA_QL("module") " not called from a Lua function");

  lua_pushvalue(L, -2);  /* copy new environment table to top */

  lua_setupvalue(L, -2, 1);

  lua_pop(L, 1);  /* remove function */

}

static void dooptions (lua_State *L, int n) {

  int i;

  for (i = 2; i <= n; i++) {

    if (lua_isfunction(L, i)) {  /* avoid 'calling' extra info. */

      lua_pushvalue(L, i);  /* get option (a function) */

      lua_pushvalue(L, -2);  /* module */

      lua_call(L, 1, 0);

    }

  }

}

static void modinit (lua_State *L, const char *modname) {

  const char *dot;

  lua_pushvalue(L, -1);

  lua_setfield(L, -2, "_M");  /* module._M = module */

  lua_pushstring(L, modname);

  lua_setfield(L, -2, "_NAME");

  dot = strrchr(modname, '.');  /* look for last dot in module name */

  if (dot == NULL) dot = modname;

  else dot++;

  /* set _PACKAGE as package name (full module name minus last part) */

  lua_pushlstring(L, modname, dot - modname);

  lua_setfield(L, -2, "_PACKAGE");

}

static int ll_module (lua_State *L) {

  const char *modname = luaL_checkstring(L, 1);

  int lastarg = lua_gettop(L);  /* last parameter */

  luaL_pushmodule(L, modname, 1);  /* get/create module table */

  /* check whether table already has a _NAME field */

  lua_getfield(L, -1, "_NAME");

  if (!lua_isnil(L, -1))  /* is table an initialized module? */

    lua_pop(L, 1);

  else {  /* no; initialize it */

    lua_pop(L, 1);

    modinit(L, modname);

  }

  lua_pushvalue(L, -1);

  set_env(L);

  dooptions(L, lastarg);

  return 1;

}

static int ll_seeall (lua_State *L) {

  luaL_checktype(L, 1, LUA_TTABLE);

  if (!lua_getmetatable(L, 1)) {

    lua_createtable(L, 0, 1); /* create new metatable */

    lua_pushvalue(L, -1);

    lua_setmetatable(L, 1);

  }

  lua_pushglobaltable(L);

  lua_setfield(L, -2, "__index");  /* mt.__index = _G */

  return 0;

}

#endif

/* }====================================================== */

/* auxiliary mark (for internal use) */

#define AUXMARK		"\1"

/*

** return registry.LUA_NOENV as a boolean

*/

static int noenv (lua_State *L) {

  int b;

  lua_getfield(L, LUA_REGISTRYINDEX, "LUA_NOENV");

  b = lua_toboolean(L, -1);

  lua_pop(L, 1);  /* remove value */

  return b;

}

static void setpath (lua_State *L, const char *fieldname, const char *envname1,

                                   const char *envname2, const char *def) {

  const char *path = getenv(envname1);

  if (path == NULL)  /* no environment variable? */

    path = getenv(envname2);  /* try alternative name */

  if (path == NULL || noenv(L))  /* no environment variable? */

    lua_pushstring(L, def);  /* use default */

  else {

    /* replace ";;" by ";AUXMARK;" and then AUXMARK by default path */

    path = luaL_gsub(L, path, LUA_PATH_SEP LUA_PATH_SEP,

                              LUA_PATH_SEP AUXMARK LUA_PATH_SEP);

    luaL_gsub(L, path, AUXMARK, def);

    lua_remove(L, -2);

  }

  setprogdir(L);

  lua_setfield(L, -2, fieldname);

}

static const luaL_Reg pk_funcs[] = {

  {"loadlib", ll_loadlib},

  {"searchpath", ll_searchpath},

#if defined(LUA_COMPAT_MODULE)

  {"seeall", ll_seeall},

#endif

  {NULL, NULL}

};

static const luaL_Reg ll_funcs[] = {

#if defined(LUA_COMPAT_MODULE)

  {"module", ll_module},

#endif

  {"require", ll_require},

  {NULL, NULL}

};

static const lua_CFunction searchers[] =

  {searcher_preload, searcher_Lua, searcher_C, searcher_Croot, NULL};

LUAMOD_API int luaopen_package (lua_State *L) {

  int i;

  /* create new type _LOADLIB */

  luaL_newmetatable(L, "_LOADLIB");

  lua_pushcfunction(L, gctm);

  lua_setfield(L, -2, "__gc");

  /* create `package' table */

  luaL_newlib(L, pk_funcs);

  /* create 'searchers' table */

  lua_createtable(L, sizeof(searchers)/sizeof(searchers[0]) - 1, 0);

  /* fill it with pre-defined searchers */

  for (i=0; searchers[i] != NULL; i++) {

    lua_pushvalue(L, -2);  /* set 'package' as upvalue for all searchers */

    lua_pushcclosure(L, searchers[i], 1);

    lua_rawseti(L, -2, i+1);

  }

#if defined(LUA_COMPAT_LOADERS)

  lua_pushvalue(L, -1);  /* make a copy of 'searchers' table */

  lua_setfield(L, -3, "loaders");  /* put it in field `loaders' */

#endif

  lua_setfield(L, -2, "searchers");  /* put it in field 'searchers' */

  /* set field 'path' */

  setpath(L, "path", LUA_PATHVERSION, LUA_PATH, LUA_PATH_DEFAULT);

  /* set field 'cpath' */

  setpath(L, "cpath", LUA_CPATHVERSION, LUA_CPATH, LUA_CPATH_DEFAULT);

  /* store config information */

  lua_pushliteral(L, LUA_DIRSEP "\n" LUA_PATH_SEP "\n" LUA_PATH_MARK "\n"

                     LUA_EXEC_DIR "\n" LUA_IGMARK "\n");

  lua_setfield(L, -2, "config");

  /* set field `loaded' */

  luaL_getsubtable(L, LUA_REGISTRYINDEX, "_LOADED");

  lua_setfield(L, -2, "loaded");

  /* set field `preload' */

  luaL_getsubtable(L, LUA_REGISTRYINDEX, "_PRELOAD");

  lua_setfield(L, -2, "preload");

  lua_pushglobaltable(L);

  lua_pushvalue(L, -2);  /* set 'package' as upvalue for next lib */

  luaL_setfuncs(L, ll_funcs, 1);  /* open lib into global table */

  lua_pop(L, 1);  /* pop global table */

  return 1;  /* return 'package' table */

}