loadlib.c
(5.3.6)
/*
** $Id: loadlib.c,v 1.130.1.1 2017/04/19 17:20:42 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.
*/
#define loadlib_c
#define LUA_LIB
#include "lprefix.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "lua.h"
#include "lauxlib.h"
#include "lualib.h"
/*
** LUA_IGMARK is a mark to ignore all before it when building the
** luaopen_ function name.
*/
#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 "_"
/*
** unique key for table in the registry that keeps handles
** for all loaded C libraries
*/
static const int CLIBS = 0;
#define LIB_FAIL "open"
#define setprogdir(L) ((void)0)
/*
** system-dependent functions
*/
/*
** unload library 'lib'
*/
static void lsys_unloadlib (void *lib);
/*
** load C library in file 'path'. If 'seeglb', load with all names in
** the library global.
** Returns the library; in case of error, returns NULL plus an
** error string in the stack.
*/
static void *lsys_load (lua_State *L, const char *path, int seeglb);
/*
** Try to find a function named 'sym' in library 'lib'.
** Returns the function; in case of error, returns NULL plus an
** error string in the stack.
*/
static lua_CFunction lsys_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 <dlfcn.h>
/*
** Macro to convert pointer-to-void* to pointer-to-function. This cast
** is undefined according to ISO C, but POSIX assumes that it works.
** (The '__extension__' in gnu compilers is only to avoid warnings.)
*/
#if defined(__GNUC__)
#define cast_func(p) (__extension__ (lua_CFunction)(p))
#else
#define cast_func(p) ((lua_CFunction)(p))
#endif
static void lsys_unloadlib (void *lib) {
dlclose(lib);
}
static void *lsys_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 lsys_sym (lua_State *L, void *lib, const char *sym) {
lua_CFunction f = cast_func(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>
/*
** optional flags for LoadLibraryEx
*/
#if !defined(LUA_LLE_FLAGS)
#define LUA_LLE_FLAGS 0
#endif
#undef setprogdir
/*
** Replace in the path (on the top of the stack) any occurrence
** of LUA_EXEC_DIR with the executable's path.
*/
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); /* get exec. name */
if (n == 0 || n == nsize || (lb = strrchr(buff, '\\')) == NULL)
luaL_error(L, "unable to get ModuleFileName");
else {
*lb = '\0'; /* cut name on the last '\\' to get the path */
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 lsys_unloadlib (void *lib) {
FreeLibrary((HMODULE)lib);
}
static void *lsys_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 lsys_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 lsys_unloadlib (void *lib) {
(void)(lib); /* not used */
}
static void *lsys_load (lua_State *L, const char *path, int seeglb) {
(void)(path); (void)(seeglb); /* not used */
lua_pushliteral(L, DLMSG);
return NULL;
}
static lua_CFunction lsys_sym (lua_State *L, void *lib, const char *sym) {
(void)(lib); (void)(sym); /* not used */
lua_pushliteral(L, DLMSG);
return NULL;
}
/* }====================================================== */
#endif /* } */
/*
** {==================================================================
** Set Paths
** ===================================================================
*/
/*
** LUA_PATH_VAR and LUA_CPATH_VAR are the names of the environment
** variables that Lua check to set its paths.
*/
#if !defined(LUA_PATH_VAR)
#define LUA_PATH_VAR "LUA_PATH"
#endif
#if !defined(LUA_CPATH_VAR)
#define LUA_CPATH_VAR "LUA_CPATH"
#endif
#define AUXMARK "\1" /* auxiliary mark */
/*
** 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;
}
/*
** Set a path
*/
static void setpath (lua_State *L, const char *fieldname,
const char *envname,
const char *dft) {
const char *nver = lua_pushfstring(L, "%s%s", envname, LUA_VERSUFFIX);
const char *path = getenv(nver); /* use versioned name */
if (path == NULL) /* no environment variable? */
path = getenv(envname); /* try unversioned name */
if (path == NULL || noenv(L)) /* no environment variable? */
lua_pushstring(L, dft); /* 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, dft);
lua_remove(L, -2); /* remove result from 1st 'gsub' */
}
setprogdir(L);
lua_setfield(L, -3, fieldname); /* package[fieldname] = path value */
lua_pop(L, 1); /* pop versioned variable name */
}
/* }================================================================== */
/*
** return registry.CLIBS[path]
*/
static void *checkclib (lua_State *L, const char *path) {
void *plib;
lua_rawgetp(L, LUA_REGISTRYINDEX, &CLIBS);
lua_getfield(L, -1, path);
plib = lua_touserdata(L, -1); /* plib = CLIBS[path] */
lua_pop(L, 2); /* pop CLIBS table and 'plib' */
return plib;
}
/*
** registry.CLIBS[path] = plib -- for queries
** registry.CLIBS[#CLIBS + 1] = plib -- also keep a list of all libraries
*/
static void addtoclib (lua_State *L, const char *path, void *plib) {
lua_rawgetp(L, LUA_REGISTRYINDEX, &CLIBS);
lua_pushlightuserdata(L, plib);
lua_pushvalue(L, -1);
lua_setfield(L, -3, path); /* CLIBS[path] = plib */
lua_rawseti(L, -2, luaL_len(L, -2) + 1); /* CLIBS[#CLIBS + 1] = plib */
lua_pop(L, 1); /* pop CLIBS table */
}
/*
** __gc tag method for CLIBS table: calls 'lsys_unloadlib' for all lib
** handles in list CLIBS
*/
static int gctm (lua_State *L) {
lua_Integer n = luaL_len(L, 1);
for (; n >= 1; n--) { /* for each handle, in reverse order */
lua_rawgeti(L, 1, n); /* get handle CLIBS[n] */
lsys_unloadlib(lua_touserdata(L, -1));
lua_pop(L, 1); /* pop handle */
}
return 0;
}
/* error codes for 'lookforfunc' */
#define ERRLIB 1
#define ERRFUNC 2
/*
** Look for a C function named 'sym' in a dynamically loaded library
** 'path'.
** First, check whether the library is already loaded; if not, try
** to load it.
** Then, if 'sym' is '*', return true (as library has been loaded).
** Otherwise, look for symbol 'sym' in the library and push a
** C function with that symbol.
** Return 0 and 'true' or a function in the stack; in case of
** errors, return an error code and an error message in the stack.
*/
static int lookforfunc (lua_State *L, const char *path, const char *sym) {
void *reg = checkclib(L, path); /* check loaded C libraries */
if (reg == NULL) { /* must load library? */
reg = lsys_load(L, path, *sym == '*'); /* global symbols if 'sym'=='*' */
if (reg == NULL) return ERRLIB; /* unable to load library */
addtoclib(L, path, reg);
}
if (*sym == '*') { /* loading only library (no function)? */
lua_pushboolean(L, 1); /* return 'true' */
return 0; /* no errors */
}
else {
lua_CFunction f = lsys_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 = lookforfunc(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 '%s'", 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, "'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 '%s' from file '%s':\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);
}
/*
** Try to find a load function for module 'modname' at file 'filename'.
** First, change '.' to '_' in 'modname'; then, if 'modname' has
** the form X-Y (that is, it has an "ignore mark"), build a function
** name "luaopen_X" and look for it. (For compatibility, if that
** fails, it also tries "luaopen_Y".) If there is no ignore mark,
** look for a function named "luaopen_modname".
*/
static int loadfunc (lua_State *L, const char *filename, const char *modname) {
const char *openfunc;
const char *mark;
modname = luaL_gsub(L, modname, ".", LUA_OFSEP);
mark = strchr(modname, *LUA_IGMARK);
if (mark) {
int stat;
openfunc = lua_pushlstring(L, modname, mark - modname);
openfunc = lua_pushfstring(L, LUA_POF"%s", openfunc);
stat = lookforfunc(L, filename, openfunc);
if (stat != ERRFUNC) return stat;
modname = mark + 1; /* else go ahead and try old-style name */
}
openfunc = lua_pushfstring(L, LUA_POF"%s", modname);
return lookforfunc(L, filename, openfunc);
}
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 '%s' in file '%s'", 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, LUA_PRELOAD_TABLE);
if (lua_getfield(L, -1, name) == LUA_TNIL) /* 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);
/* push 'package.searchers' to index 3 in the stack */
if (lua_getfield(L, lua_upvalueindex(1), "searchers") != LUA_TTABLE)
luaL_error(L, "'package.searchers' must be a table");
/* iterate over available searchers to find a loader */
for (i = 1; ; i++) {
if (lua_rawgeti(L, 3, i) == LUA_TNIL) { /* no more searchers? */
lua_pop(L, 1); /* remove nil */
luaL_pushresult(&msg); /* create error message */
luaL_error(L, "module '%s' 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, LUA_LOADED_TABLE);
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 */
if (lua_getfield(L, 2, name) == LUA_TNIL) { /* module set no 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, "'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 */
if (lua_getfield(L, -1, "_NAME") != LUA_TNIL)
lua_pop(L, 1); /* table is an initialized module */
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
/* }====================================================== */
static const luaL_Reg pk_funcs[] = {
{"loadlib", ll_loadlib},
{"searchpath", ll_searchpath},
#if defined(LUA_COMPAT_MODULE)
{"seeall", ll_seeall},
#endif
/* placeholders */
{"preload", NULL},
{"cpath", NULL},
{"path", NULL},
{"searchers", NULL},
{"loaded", NULL},
{NULL, NULL}
};
static const luaL_Reg ll_funcs[] = {
#if defined(LUA_COMPAT_MODULE)
{"module", ll_module},
#endif
{"require", ll_require},
{NULL, NULL}
};
static void createsearcherstable (lua_State *L) {
static const lua_CFunction searchers[] =
{searcher_preload, searcher_Lua, searcher_C, searcher_Croot, NULL};
int i;
/* create 'searchers' table */
lua_createtable(L, sizeof(searchers)/sizeof(searchers[0]) - 1, 0);
/* fill it with predefined 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' */
}
/*
** create table CLIBS to keep track of loaded C libraries,
** setting a finalizer to close all libraries when closing state.
*/
static void createclibstable (lua_State *L) {
lua_newtable(L); /* create CLIBS table */
lua_createtable(L, 0, 1); /* create metatable for CLIBS */
lua_pushcfunction(L, gctm);
lua_setfield(L, -2, "__gc"); /* set finalizer for CLIBS table */
lua_setmetatable(L, -2);
lua_rawsetp(L, LUA_REGISTRYINDEX, &CLIBS); /* set CLIBS table in registry */
}
LUAMOD_API int luaopen_package (lua_State *L) {
createclibstable(L);
luaL_newlib(L, pk_funcs); /* create 'package' table */
createsearcherstable(L);
/* set paths */
setpath(L, "path", LUA_PATH_VAR, LUA_PATH_DEFAULT);
setpath(L, "cpath", LUA_CPATH_VAR, 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, LUA_LOADED_TABLE);
lua_setfield(L, -2, "loaded");
/* set field 'preload' */
luaL_getsubtable(L, LUA_REGISTRYINDEX, LUA_PRELOAD_TABLE);
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 */
}