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lua/loadlib.c

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/*
** $Id: loadlib.c $
** 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"
#include "llimits.h"
/*
** 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 "_"
/*
** key for table in the registry that keeps handles
** for all loaded C libraries
*/
static const char *const CLIBS = "_CLIBS";
#define LIB_FAIL "open"
#define setprogdir(L) ((void)0)
/* cast void* to a Lua function */
#define cast_Lfunc(p) cast(lua_CFunction, cast_func(p))
/*
** 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,
** which is available in all POSIX systems.
** =========================================================================
*/
#include <dlfcn.h>
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 (l_unlikely(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_Lfunc(dlsym(lib, sym));
if (l_unlikely(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 = cast_Lfunc(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
/*
** 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. (If using the default path, assume it is a string
** literal in C and create it as an external string.)
*/
static void setpath (lua_State *L, const char *fieldname,
const char *envname,
const char *dft) {
const char *dftmark;
const char *nver = lua_pushfstring(L, "%s%s", envname, LUA_VERSUFFIX);
const char *path = getenv(nver); /* try versioned name */
if (path == NULL) /* no versioned environment variable? */
path = getenv(envname); /* try unversioned name */
if (path == NULL || noenv(L)) /* no environment variable? */
lua_pushextlstring(L, dft, strlen(dft), NULL, NULL); /* use default */
else if ((dftmark = strstr(path, LUA_PATH_SEP LUA_PATH_SEP)) == NULL)
lua_pushstring(L, path); /* nothing to change */
else { /* path contains a ";;": insert default path in its place */
size_t len = strlen(path);
luaL_Buffer b;
luaL_buffinit(L, &b);
if (path < dftmark) { /* is there a prefix before ';;'? */
luaL_addlstring(&b, path, ct_diff2sz(dftmark - path)); /* add it */
luaL_addchar(&b, *LUA_PATH_SEP);
}
luaL_addstring(&b, dft); /* add default */
if (dftmark < path + len - 2) { /* is there a suffix after ';;'? */
luaL_addchar(&b, *LUA_PATH_SEP);
luaL_addlstring(&b, dftmark + 2, ct_diff2sz((path + len - 2) - dftmark));
}
luaL_pushresult(&b);
}
setprogdir(L);
lua_setfield(L, -3, fieldname); /* package[fieldname] = path value */
lua_pop(L, 1); /* pop versioned variable name ('nver') */
}
/* }================================================================== */
/*
** return registry.CLIBS[path]
*/
static void *checkclib (lua_State *L, const char *path) {
void *plib;
lua_getfield(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_getfield(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 (l_likely(stat == 0)) /* no errors? */
return 1; /* return the loaded function */
else { /* error; error message is on stack top */
luaL_pushfail(L);
lua_insert(L, -2);
lua_pushstring(L, (stat == ERRLIB) ? LIB_FAIL : "init");
return 3; /* return fail, 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;
}
/*
** Get the next name in '*path' = 'name1;name2;name3;...', changing
** the ending ';' to '\0' to create a zero-terminated string. Return
** NULL when list ends.
*/
static const char *getnextfilename (char **path, char *end) {
char *sep;
char *name = *path;
if (name == end)
return NULL; /* no more names */
else if (*name == '\0') { /* from previous iteration? */
*name = *LUA_PATH_SEP; /* restore separator */
name++; /* skip it */
}
sep = strchr(name, *LUA_PATH_SEP); /* find next separator */
if (sep == NULL) /* separator not found? */
sep = end; /* name goes until the end */
*sep = '\0'; /* finish file name */
*path = sep; /* will start next search from here */
return name;
}
/*
** Given a path such as ";blabla.so;blublu.so", pushes the string
**
** no file 'blabla.so'
** no file 'blublu.so'
*/
static void pusherrornotfound (lua_State *L, const char *path) {
luaL_Buffer b;
luaL_buffinit(L, &b);
luaL_addstring(&b, "no file '");
luaL_addgsub(&b, path, LUA_PATH_SEP, "'\n\tno file '");
luaL_addstring(&b, "'");
luaL_pushresult(&b);
}
static const char *searchpath (lua_State *L, const char *name,
const char *path,
const char *sep,
const char *dirsep) {
luaL_Buffer buff;
char *pathname; /* path with name inserted */
char *endpathname; /* its end */
const char *filename;
/* separator is non-empty and appears in 'name'? */
if (*sep != '\0' && strchr(name, *sep) != NULL)
name = luaL_gsub(L, name, sep, dirsep); /* replace it by 'dirsep' */
luaL_buffinit(L, &buff);
/* add path to the buffer, replacing marks ('?') with the file name */
luaL_addgsub(&buff, path, LUA_PATH_MARK, name);
luaL_addchar(&buff, '\0');
pathname = luaL_buffaddr(&buff); /* writable list of file names */
endpathname = pathname + luaL_bufflen(&buff) - 1;
while ((filename = getnextfilename(&pathname, endpathname)) != NULL) {
if (readable(filename)) /* does file exist and is readable? */
return lua_pushstring(L, filename); /* save and return name */
}
luaL_pushresult(&buff); /* push path to create error message */
pusherrornotfound(L, lua_tostring(L, -1)); /* 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 */
luaL_pushfail(L);
lua_insert(L, -2);
return 2; /* return fail + 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 (l_unlikely(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 (l_likely(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, ct_diff2sz(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, ct_diff2sz(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, "no 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, "no field package.preload['%s']", name);
return 1;
}
else {
lua_pushliteral(L, ":preload:");
return 2;
}
}
static void findloader (lua_State *L, const char *name) {
int i;
luaL_Buffer msg; /* to build error message */
/* push 'package.searchers' to index 3 in the stack */
if (l_unlikely(lua_getfield(L, lua_upvalueindex(1), "searchers")
!= LUA_TTABLE))
luaL_error(L, "'package.searchers' must be a table");
luaL_buffinit(L, &msg);
luaL_addstring(&msg, "\n\t"); /* error-message prefix for first message */
/* iterate over available searchers to find a loader */
for (i = 1; ; i++) {
if (l_unlikely(lua_rawgeti(L, 3, i) == LUA_TNIL)) { /* no more searchers? */
lua_pop(L, 1); /* remove nil */
luaL_buffsub(&msg, 2); /* remove last prefix */
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 */
luaL_addstring(&msg, "\n\t"); /* prefix for next message */
}
else /* no error message */
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_rotate(L, -2, 1); /* function <-> loader data */
lua_pushvalue(L, 1); /* name is 1st argument to module loader */
lua_pushvalue(L, -3); /* loader data is 2nd argument */
/* stack: ...; loader data; loader function; mod. name; loader data */
lua_call(L, 2, 1); /* run loader to load module */
/* stack: ...; loader data; result from loader */
if (!lua_isnil(L, -1)) /* non-nil return? */
lua_setfield(L, 2, name); /* LOADED[name] = returned value */
else
lua_pop(L, 1); /* pop nil */
if (lua_getfield(L, 2, name) == LUA_TNIL) { /* module set no value? */
lua_pushboolean(L, 1); /* use true as result */
lua_copy(L, -1, -2); /* replace loader result */
lua_setfield(L, 2, name); /* LOADED[name] = true */
}
lua_rotate(L, -2, 1); /* loader data <-> module result */
return 2; /* return module result and loader data */
}
/* }====================================================== */
static const luaL_Reg pk_funcs[] = {
{"loadlib", ll_loadlib},
{"searchpath", ll_searchpath},
/* placeholders */
{"preload", NULL},
{"cpath", NULL},
{"path", NULL},
{"searchers", NULL},
{"loaded", NULL},
{NULL, NULL}
};
static const luaL_Reg ll_funcs[] = {
{"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);
}
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) {
luaL_getsubtable(L, LUA_REGISTRYINDEX, CLIBS); /* 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);
}
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 */
}
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