/* ** $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 #include #include #include "lua.h" #include "lauxlib.h" #include "lualib.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) /* ** Special type equivalent to '(void*)' for functions in gcc ** (to suppress warnings when converting function pointers) */ typedef void (*voidf)(void); /* ** 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 /* ** 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 (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_func(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 /* ** 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)(voidf)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 */ 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_pushstring(L, dft); /* 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, 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, (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, 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, "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); /* iterate over available searchers to find a loader */ for (i = 1; ; i++) { luaL_addstring(&msg, "\n\t"); /* error-message prefix */ if (l_unlikely(lua_rawgeti(L, 3, i) == LUA_TNIL)) { /* no more searchers? */ lua_pop(L, 1); /* remove nil */ luaL_buffsub(&msg, 2); /* remove 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 */ } else { /* no error message */ lua_pop(L, 2); /* remove both returns */ luaL_buffsub(&msg, 2); /* remove prefix */ } } } 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 */ }