/*** $Id: loadlib.c,v 1.52.1.3 2008/08/06 13:29:28 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 Darwin (Mac OS X), an** implementation for Windows, and a stub for other systems.*/#include <stdlib.h>#include <string.h>#define loadlib_c#define LUA_LIB#include "lua.h"#include "lauxlib.h"#include "lualib.h"/* 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)static void ll_unloadlib (void *lib);static void *ll_load (lua_State *L, const char *path);static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym);#if defined(LUA_DL_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 <dlfcn.h>static void ll_unloadlib (void *lib) {  dlclose(lib);}static void *ll_load (lua_State *L, const char *path) {  void *lib = dlopen(path, RTLD_NOW);  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.** =======================================================================*/#include <windows.h>#undef setprogdirstatic 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_EXECDIR, 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), NULL))    lua_pushstring(L, buffer);  else    lua_pushfstring(L, "system error %d\n", error);}static void ll_unloadlib (void *lib) {  FreeLibrary((HINSTANCE)lib);}static void *ll_load (lua_State *L, const char *path) {  HINSTANCE lib = LoadLibraryA(path);  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((HINSTANCE)lib, sym);  if (f == NULL) pusherror(L);  return f;}/* }====================================================== */#elif defined(LUA_DL_DYLD)/*** {======================================================================** Native Mac OS X / Darwin Implementation** =======================================================================*/#include <mach-o/dyld.h>/* Mac appends a `_' before C function names */#undef POF#define POF	"_" LUA_POFstatic void pusherror (lua_State *L) {  const char *err_str;  const char *err_file;  NSLinkEditErrors err;  int err_num;  NSLinkEditError(&err, &err_num, &err_file, &err_str);  lua_pushstring(L, err_str);}static const char *errorfromcode (NSObjectFileImageReturnCode ret) {  switch (ret) {    case NSObjectFileImageInappropriateFile:      return "file is not a bundle";    case NSObjectFileImageArch:      return "library is for wrong CPU type";    case NSObjectFileImageFormat:      return "bad format";    case NSObjectFileImageAccess:      return "cannot access file";    case NSObjectFileImageFailure:    default:      return "unable to load library";  }}static void ll_unloadlib (void *lib) {  NSUnLinkModule((NSModule)lib, NSUNLINKMODULE_OPTION_RESET_LAZY_REFERENCES);}static void *ll_load (lua_State *L, const char *path) {  NSObjectFileImage img;  NSObjectFileImageReturnCode ret;  /* this would be a rare case, but prevents crashing if it happens */  if(!_dyld_present()) {    lua_pushliteral(L, "dyld not present");    return NULL;  }  ret = NSCreateObjectFileImageFromFile(path, &img);  if (ret == NSObjectFileImageSuccess) {    NSModule mod = NSLinkModule(img, path, NSLINKMODULE_OPTION_PRIVATE |                       NSLINKMODULE_OPTION_RETURN_ON_ERROR);    NSDestroyObjectFileImage(img);    if (mod == NULL) pusherror(L);    return mod;  }  lua_pushstring(L, errorfromcode(ret));  return NULL;}static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) {  NSSymbol nss = NSLookupSymbolInModule((NSModule)lib, sym);  if (nss == NULL) {    lua_pushfstring(L, "symbol " LUA_QS " not found", sym);    return NULL;  }  return (lua_CFunction)NSAddressOfSymbol(nss);}/* }====================================================== */#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;  /* to avoid warnings */}static void *ll_load (lua_State *L, const char *path) {  (void)path;  /* to avoid warnings */  lua_pushliteral(L, DLMSG);  return NULL;}static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) {  (void)lib; (void)sym;  /* to avoid warnings */  lua_pushliteral(L, DLMSG);  return NULL;}/* }====================================================== */#endifstatic 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);    plib = (void **)lua_newuserdata(L, sizeof(const void *));    *plib = NULL;    luaL_getmetatable(L, "_LOADLIB");    lua_setmetatable(L, -2);    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);  if (*reg == NULL)    return ERRLIB;  /* unable to load library */  else {    lua_CFunction f = ll_sym(L, *reg, sym);    if (f == NULL)      return ERRFUNC;  /* unable to find function */    lua_pushcfunction(L, f);    return 0;  /* return function */  }}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 */