/*
** $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 setprogdir

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_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_POF


static 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;
}

/* }====================================================== */
#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);
   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 */
 fclose(f);
 return 1;
}


static const char *pushnexttemplate (lua_State *L, const char *path) {
 const char *l;
 while (*path == *LUA_PATHSEP) path++;  /* skip separators */
 if (*path == '\0') return NULL;  /* no more templates */
 l = strchr(path, *LUA_PATHSEP);  /* find next separator */
 if (l == NULL) l = path + strlen(path);
 lua_pushlstring(L, path, l - path);  /* template */
 return l;
}


static const char *findfile (lua_State *L, const char *name,
                                          const char *pname) {
 const char *path;
 name = luaL_gsub(L, name, ".", LUA_DIRSEP);
 lua_getfield(L, LUA_ENVIRONINDEX, pname);
 path = lua_tostring(L, -1);
 if (path == NULL)
   luaL_error(L, LUA_QL("package.%s") " must be a string", pname);
 lua_pushliteral(L, "");  /* error accumulator */
 while ((path = pushnexttemplate(L, path)) != NULL) {
   const char *filename;
   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 */
   lua_concat(L, 2);  /* add entry to possible error message */
 }
 return NULL;  /* not found */
}


static void loaderror (lua_State *L, const char *filename) {
 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 loader_Lua (lua_State *L) {
 const char *filename;
 const char *name = luaL_checkstring(L, 1);
 filename = findfile(L, name, "path");
 if (filename == NULL) return 1;  /* library not found in this path */
 if (luaL_loadfile(L, filename) != 0)
   loaderror(L, filename);
 return 1;  /* library loaded successfully */
}


static const char *mkfuncname (lua_State *L, const char *modname) {
 const char *funcname;
 const char *mark = strchr(modname, *LUA_IGMARK);
 if (mark) modname = mark + 1;
 funcname = luaL_gsub(L, modname, ".", LUA_OFSEP);
 funcname = lua_pushfstring(L, POF"%s", funcname);
 lua_remove(L, -2);  /* remove 'gsub' result */
 return funcname;
}


static int loader_C (lua_State *L) {
 const char *funcname;
 const char *name = luaL_checkstring(L, 1);
 const char *filename = findfile(L, name, "cpath");
 if (filename == NULL) return 1;  /* library not found in this path */
 funcname = mkfuncname(L, name);
 if (ll_loadfunc(L, filename, funcname) != 0)
   loaderror(L, filename);
 return 1;  /* library loaded successfully */
}

int loader_C_luatex (lua_State *L, const char *name, const char *filename) {
 const char *funcname;
 funcname = mkfuncname(L, name);
 if (ll_loadfunc(L, filename, funcname) != 0)
   loaderror(L, filename);
 return 1;  /* library loaded successfully */
}


static int loader_Croot (lua_State *L) {
 const char *funcname;
 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");
 if (filename == NULL) return 1;  /* root not found */
 funcname = mkfuncname(L, name);
 if ((stat = ll_loadfunc(L, filename, funcname)) != 0) {
   if (stat != ERRFUNC) loaderror(L, filename);  /* real error */
   lua_pushfstring(L, "\n\tno module " LUA_QS " in file " LUA_QS,
                      name, filename);
   return 1;  /* function not found */
 }
 return 1;
}

int loader_Call_luatex (lua_State *L, const char *name, const char *filename) {
 const char *funcname;
 int stat;
 if (filename == NULL) return 1;  /* root not found */
 funcname = mkfuncname(L, name);
 if ((stat = ll_loadfunc(L, filename, funcname)) != 0) {
   if (stat != ERRFUNC) loaderror(L, filename);  /* real error */
   lua_pushfstring(L, "\n\tno module " LUA_QS " in file " LUA_QS,
                      name, filename);
   return 1;  /* function not found */
 }
 return 1;  /* library loaded successfully */
}



static int loader_preload (lua_State *L) {
 const char *name = luaL_checkstring(L, 1);
 lua_getfield(L, LUA_ENVIRONINDEX, "preload");
 if (!lua_istable(L, -1))
   luaL_error(L, LUA_QL("package.preload") " must be a table");
 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 const int sentinel_ = 0;
#define sentinel        ((void *)&sentinel_)


static int ll_require (lua_State *L) {
 const char *name = luaL_checkstring(L, 1);
 int i;
 lua_settop(L, 1);  /* _LOADED table will be at index 2 */
 lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");
 lua_getfield(L, 2, name);
 if (lua_toboolean(L, -1)) {  /* is it there? */
   if (lua_touserdata(L, -1) == sentinel)  /* check loops */
     luaL_error(L, "loop or previous error loading module " LUA_QS, name);
   return 1;  /* package is already loaded */
 }
 /* else must load it; iterate over available loaders */
 lua_getfield(L, LUA_ENVIRONINDEX, "loaders");
 if (!lua_istable(L, -1))
   luaL_error(L, LUA_QL("package.loaders") " must be a table");
 lua_pushliteral(L, "");  /* error message accumulator */
 for (i=1; ; i++) {
   lua_rawgeti(L, -2, i);  /* get a loader */
   if (lua_isnil(L, -1))
     luaL_error(L, "module " LUA_QS " not found:%s",
                   name, lua_tostring(L, -2));
   lua_pushstring(L, name);
   lua_call(L, 1, 1);  /* call it */
   if (lua_isfunction(L, -1))  /* did it find module? */
     break;  /* module loaded successfully */
   else if (lua_isstring(L, -1))  /* loader returned error message? */
     lua_concat(L, 2);  /* accumulate it */
   else
     lua_pop(L, 1);
 }
 lua_pushlightuserdata(L, sentinel);
 lua_setfield(L, 2, name);  /* _LOADED[name] = sentinel */
 lua_pushstring(L, name);  /* pass name as argument to module */
 lua_call(L, 1, 1);  /* run loaded 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_touserdata(L, -1) == sentinel) {   /* 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
** =======================================================
*/


static void setfenv (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);
 lua_setfenv(L, -2);
 lua_pop(L, 1);
}


static void dooptions (lua_State *L, int n) {
 int i;
 for (i = 2; i <= n; i++) {
   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 loaded = lua_gettop(L) + 1;  /* index of _LOADED table */
 lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");
 lua_getfield(L, loaded, modname);  /* get _LOADED[modname] */
 if (!lua_istable(L, -1)) {  /* not found? */
   lua_pop(L, 1);  /* remove previous result */
   /* try global variable (and create one if it does not exist) */
   if (luaL_findtable(L, LUA_GLOBALSINDEX, modname, 1) != NULL)
     return luaL_error(L, "name conflict for module " LUA_QS, modname);
   lua_pushvalue(L, -1);
   lua_setfield(L, loaded, modname);  /* _LOADED[modname] = new 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);
 setfenv(L);
 dooptions(L, loaded - 1);
 return 0;
}


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_pushvalue(L, LUA_GLOBALSINDEX);
 lua_setfield(L, -2, "__index");  /* mt.__index = _G */
 return 0;
}


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



/* auxiliary mark (for internal use) */
#define AUXMARK         "\1"

static void setpath (lua_State *L, const char *fieldname, const char *envname,
                                  const char *def) {
 const char *path = getenv(envname);
 if (path == NULL)  /* 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_PATHSEP LUA_PATHSEP,
                             LUA_PATHSEP AUXMARK LUA_PATHSEP);
   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},
 {"seeall", ll_seeall},
 {NULL, NULL}
};


static const luaL_Reg ll_funcs[] = {
 {"module", ll_module},
 {"require", ll_require},
 {NULL, NULL}
};


static const lua_CFunction loaders[] =
 {loader_preload, loader_Lua, loader_C, loader_Croot, NULL};


LUALIB_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_register(L, LUA_LOADLIBNAME, pk_funcs);
#if defined(LUA_COMPAT_LOADLIB)
 lua_getfield(L, -1, "loadlib");
 lua_setfield(L, LUA_GLOBALSINDEX, "loadlib");
#endif
 lua_pushvalue(L, -1);
 lua_replace(L, LUA_ENVIRONINDEX);
 /* create `loaders' table */
 lua_createtable(L, 0, sizeof(loaders)/sizeof(loaders[0]) - 1);
 /* fill it with pre-defined loaders */
 for (i=0; loaders[i] != NULL; i++) {
   lua_pushcfunction(L, loaders[i]);
   lua_rawseti(L, -2, i+1);
 }
 lua_setfield(L, -2, "loaders");  /* put it in field `loaders' */
 setpath(L, "path", LUA_PATH, LUA_PATH_DEFAULT);  /* set field `path' */
 setpath(L, "cpath", LUA_CPATH, LUA_CPATH_DEFAULT); /* set field `cpath' */
 /* store config information */
 lua_pushliteral(L, LUA_DIRSEP "\n" LUA_PATHSEP "\n" LUA_PATH_MARK "\n"
                    LUA_EXECDIR "\n" LUA_IGMARK);
 lua_setfield(L, -2, "config");
 /* set field `loaded' */
 luaL_findtable(L, LUA_REGISTRYINDEX, "_LOADED", 2);
 lua_setfield(L, -2, "loaded");
 /* set field `preload' */
 lua_newtable(L);
 lua_setfield(L, -2, "preload");
 lua_pushvalue(L, LUA_GLOBALSINDEX);
 luaL_register(L, NULL, ll_funcs);  /* open lib into global table */
 lua_pop(L, 1);
 return 1;  /* return 'package' table */
}

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