/* ** $Id: loadlib.c,v 1.12 2004/12/13 12:14:21 roberto Exp roberto $ ** Dynamic library loader for Lua ** See Copyright Notice in lua.h * * This Lua library exports a single function, called loadlib, which * is called from Lua as loadlib(lib,init), where lib is the full * name of the library to be loaded (including the complete path) and * init is the name of a function to be called after the library is * loaded. Typically, this function will register other functions, thus * making the complete library available to Lua. The init function is * *not* automatically called by loadlib. Instead, loadlib returns the * init function as a Lua function that the client can call when it * thinks is appropriate. In the case of errors, loadlib returns nil and * two strings describing the error. The first string is supplied by * the operating system; it should be informative and useful for error * messages. The second string is "open", "init", or "absent" to identify * the error and is meant to be used for making decisions without having * to look into the first string (whose format is system-dependent). * 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. See * the list at the end of this file for some links to available * implementations of dlfcn and interfaces to other native dynamic * loaders on top of which loadlib could be implemented. */ #include #include #define loadlib_c #define LUA_LIB #include "lua.h" #include "lauxlib.h" #include "lualib.h" #define ERR_OPEN 1 #define ERR_FUNCTION 2 #define ERR_ABSENT 3 static void registerlib (lua_State *L, const void *lib); #if defined(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 #define freelib dlclose static int loadlib(lua_State *L, const char *path, const char *init) { void *lib=dlopen(path,RTLD_NOW); if (lib != NULL) { lua_CFunction f=(lua_CFunction) dlsym(lib,init); if (f != NULL) { registerlib(L, lib); lua_pushcfunction(L,f); return 0; } } /* else return appropriate error message */ lua_pushstring(L,dlerror()); if (lib != NULL) { dlclose(lib); return ERR_FUNCTION; /* error loading function */ } else return ERR_OPEN; /* error loading library */ } #elif defined(USE_DLL) /* * This is an implementation of loadlib for Windows using native functions. */ #include #define freelib(lib) FreeLibrary((HINSTANCE)lib) static void pusherror(lua_State *L) { int error = GetLastError(); char buffer[128]; if (FormatMessage(FORMAT_MESSAGE_IGNORE_INSERTS | FORMAT_MESSAGE_FROM_SYSTEM, 0, error, 0, buffer, sizeof(buffer), 0)) lua_pushstring(L,buffer); else lua_pushfstring(L, "system error %d\n", error); } static int loadlib (lua_State *L, const char *path, const char *init) { HINSTANCE lib = LoadLibrary(path); if (lib != NULL) { lua_CFunction f = (lua_CFunction)GetProcAddress(lib, init); if (f != NULL) { registerlib(L, lib); lua_pushcfunction(L, f); return 0; } } pusherror(L); if (lib != NULL) { FreeLibrary(lib); return ERR_OPEN; } else return ERR_FUNCTION; } /* Native Mac OS X / Darwin Implementation */ #elif defined(USE_DYLD) #include /* Mach cannot unload images (?) */ #define freelib(lib) ((void)lib) 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 int loadlib (lua_State *L, const char *path, const char *init) { const struct mach_header *lib; /* this would be a rare case, but prevents crashing if it happens */ if(!_dyld_present()) { lua_pushstring(L, "dyld not present."); return ERR_OPEN; } lib = NSAddImage(path, NSADDIMAGE_OPTION_RETURN_ON_ERROR); if(lib != NULL) { NSSymbol init_sym = NSLookupSymbolInImage(lib, init, NSLOOKUPSYMBOLINIMAGE_OPTION_BIND | NSLOOKUPSYMBOLINIMAGE_OPTION_RETURN_ON_ERROR); if(init_sym != NULL) { lua_CFunction f = (lua_CFunction)NSAddressOfSymbol(init_sym); registerlib(L, lib); lua_pushcfunction(L, f); return 0; } } /* else an error ocurred */ pusherror(L); /* Can't unload image */ return (lib != NULL) ? ERR_FUNCTION : ERR_OPEN; } #else /* Fallback for other systems */ #define freelib(lib) ((void)lib) static int loadlib (lua_State *L, const char *path, const char *init) { (void)path; (void)init; (void)®isterlib; /* to avoid warnings */ lua_pushliteral(L,"`loadlib' not supported"); return ERR_ABSENT; } #endif /* ** common code for all implementations: put a library into the registry ** so that, when Lua closes its state, the library's __gc metamethod ** will be called to unload the library. */ static void registerlib (lua_State *L, const void *lib) { const void **plib = (const void **)lua_newuserdata(L, sizeof(const void *)); *plib = lib; luaL_getmetatable(L, "_LOADLIB"); lua_setmetatable(L, -2); lua_pushboolean(L, 1); lua_settable(L, LUA_REGISTRYINDEX); /* registry[lib] = true */ } /* ** __gc tag method: calls library's `freelib' function with the lib ** handle */ static int gctm (lua_State *L) { void *lib = *(void **)luaL_checkudata(L, 1, "_LOADLIB"); freelib(lib); return 0; } static int ll_loadlib (lua_State *L) { static const char *const errcodes[] = {NULL, "open", "init", "absent"}; const char *path = luaL_checkstring(L, 1); const char *init = luaL_checkstring(L, 2); int res = loadlib(L,path,init); if (res == 0) /* no error? */ return 1; /* function is at stack top */ else { /* error */ lua_pushnil(L); lua_insert(L, -2); /* insert nil before error message */ lua_pushstring(L, errcodes[res]); return 3; } } /* ** {====================================================== ** `require' and `module' functions ** ======================================================= */ static const char *loadLua (lua_State *L, const char *fname, const char *name) { const char *path; /* try first `LUA_PATH' for compatibility */ lua_getglobal(L, "LUA_PATH"); path = lua_tostring(L, -1); if (!path) { lua_pop(L, 1); luaL_getfield(L, LUA_GLOBALSINDEX, "package.path"); path = lua_tostring(L, -1); } if (path == NULL) luaL_error(L, "`package.path' must be a string"); fname = luaL_searchpath(L, fname, path); if (fname == NULL) return path; /* library not found in this path */ if (luaL_loadfile(L, fname) != 0) luaL_error(L, "error loading package `%s' (%s)", name, lua_tostring(L, -1)); return NULL; /* library loaded successfully */ } static const char *loadC (lua_State *L, const char *fname, const char *name) { const char *path; const char *funcname; luaL_getfield(L, LUA_GLOBALSINDEX, "package.cpath"); path = lua_tostring(L, -1); if (path == NULL) luaL_error(L, "`package.cpath' must be a string"); fname = luaL_searchpath(L, fname, path); if (fname == NULL) return path; /* library not found in this path */ funcname = luaL_gsub(L, name, ".", LUA_OFSEP); funcname = lua_pushfstring(L, "%s%s", LUA_POF, funcname); if (loadlib(L, fname, funcname) != 0) luaL_error(L, "error loading package `%s' (%s)", name, lua_tostring(L, -1)); return NULL; /* library loaded successfully */ } static int ll_require (lua_State *L) { const char *name = luaL_checkstring(L, 1); lua_settop(L, 1); lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED"); lua_getfield(L, 2, name); if (lua_toboolean(L, -1)) /* is it there? */ return 1; /* package is already loaded; return its result */ /* else must load it; first mark it as loaded */ lua_pushboolean(L, 1); lua_setfield(L, 2, name); /* _LOADED[name] = true */ /* check whether it is preloaded */ lua_getfield(L, LUA_REGISTRYINDEX, "_PRELOAD"); lua_getfield(L, -1, name); if (lua_isnil(L, -1)) { /* no preload function for that module? */ const char *fname = luaL_gsub(L, name, ".", LUA_DIRSEP); const char *cpath = loadC(L, fname, name); /* try a C module */ if (cpath) { /* not found? */ const char *path = loadLua(L, fname, name); /* try a Lua module */ if (path) { /* yet not found? */ lua_pushnil(L); lua_setfield(L, 2, name); /* unmark _LOADED[name] */ return luaL_error(L, "package `%s' not found\n" " cpath: %s\n path: %s", name, cpath, path); } } } lua_pushvalue(L, 1); /* 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); /* update _LOADED[name] with returned value */ lua_getfield(L, 2, name); /* return _LOADED[name] */ return 1; } static void setfenv (lua_State *L) { lua_Debug ar; lua_getstack(L, 1, &ar); lua_getinfo(L, "f", &ar); lua_pushvalue(L, -2); lua_setfenv(L, -2); } static int ll_module (lua_State *L) { const char *modname = luaL_checkstring(L, 1); const char *dot; lua_settop(L, 1); lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED"); /* try to find given table */ luaL_getfield(L, LUA_GLOBALSINDEX, modname); if (lua_isnil(L, -1)) { /* not found? */ lua_pop(L, 1); /* remove previous result */ lua_newtable(L); /* create it */ /* register it with given name */ lua_pushvalue(L, -1); luaL_setfield(L, LUA_GLOBALSINDEX, modname); } else if (!lua_istable(L, -1)) return luaL_error(L, "name conflict for module `%s'", modname); /* 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); lua_newtable(L); /* create new metatable */ lua_pushvalue(L, LUA_GLOBALSINDEX); lua_setfield(L, -2, "__index"); /* mt.__index = _G */ lua_setmetatable(L, -2); 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"); } lua_pushvalue(L, -1); lua_setfield(L, 2, modname); /* _LOADED[modname] = new table */ setfenv(L); return 0; } /* }====================================================== */ static const luaL_reg ll_funcs[] = { {"loadlib", ll_loadlib}, {"require", ll_require}, {"module", ll_module}, {NULL, NULL} }; LUALIB_API int luaopen_loadlib (lua_State *L) { const char *path; /* create new type _LOADLIB */ luaL_newmetatable(L, "_LOADLIB"); lua_pushcfunction(L, gctm); lua_setfield(L, -2, "__gc"); /* create `package' table */ lua_newtable(L); lua_pushvalue(L, -1); lua_setglobal(L, "package"); /* set field `path' */ path = getenv(LUA_PATH); if (path == NULL) path = LUA_PATH_DEFAULT; lua_pushstring(L, path); lua_setfield(L, -2, "path"); /* set field `cpath' */ path = getenv(LUA_CPATH); if (path == NULL) path = LUA_CPATH_DEFAULT; lua_pushstring(L, path); lua_setfield(L, -2, "cpath"); /* set field `loaded' */ lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED"); lua_setfield(L, -2, "loaded"); /* set field `preload' */ lua_getfield(L, LUA_REGISTRYINDEX, "_PRELOAD"); lua_setfield(L, -2, "preload"); lua_pushvalue(L, LUA_GLOBALSINDEX); luaL_openlib(L, NULL, ll_funcs, 0); /* open lib into global table */ return 1; } /* * Here are some links to available implementations of dlfcn and * interfaces to other native dynamic loaders on top of which loadlib * could be implemented. Please send contributions and corrections to us. * * AIX * Starting with AIX 4.2, dlfcn is included in the base OS. * There is also an emulation package available. * http://www.faqs.org/faqs/aix-faq/part4/section-21.html * * HPUX * HPUX 11 has dlfcn. For HPUX 10 use shl_*. * http://www.geda.seul.org/mailinglist/geda-dev37/msg00094.html * http://www.stat.umn.edu/~luke/xls/projects/dlbasics/dlbasics.html * * Macintosh, Windows * http://www.stat.umn.edu/~luke/xls/projects/dlbasics/dlbasics.html * * GLIB has wrapper code for BeOS, OS2, Unix and Windows * http://cvs.gnome.org/lxr/source/glib/gmodule/ * */