/* ** $Id: loadlib.c,v 1.7 2004/10/07 17:27:20 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. */ #define loadlib_c #define LUA_LIB #include "lua.h" #include "lauxlib.h" #include "lualib.h" 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=luaL_checkstring(L,1); const char *init=luaL_checkstring(L,2); 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 1; } } /* else return appropriate error messages */ lua_pushnil(L); lua_pushstring(L,dlerror()); lua_pushstring(L,(lib!=NULL) ? "init" : "open"); if (lib!=NULL) dlclose(lib); return 3; } #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=luaL_checkstring(L,1); const char *init=luaL_checkstring(L,2); 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 1; } } lua_pushnil(L); pusherror(L); lua_pushstring(L,(lib!=NULL) ? "init" : "open"); if (lib!=NULL) FreeLibrary(lib); return 3; } /* 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=luaL_checkstring(L,1); const char *init=luaL_checkstring(L,2); const struct mach_header *lib; /* this would be a rare case, but prevents crashing if it happens */ if(!_dyld_present()) { lua_pushnil(L); lua_pushstring(L,"dyld not present."); lua_pushstring(L,"absent"); return 3; } 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 1; } } /* else an error ocurred */ lua_pushnil(L); pusherror(L); lua_pushstring(L, (lib != NULL) ? "init" : "open"); /* Can't unload image */ return 3; } #else /* Fallback for other systems */ #define freelib(lib) ((void)lib) static int loadlib(lua_State *L) { registerlib(L, NULL); /* to avoid warnings */ lua_pushnil(L); lua_pushliteral(L,"`loadlib' not supported"); lua_pushliteral(L,"absent"); return 3; } #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; } LUALIB_API int luaopen_loadlib (lua_State *L) { luaL_newmetatable(L, "_LOADLIB"); lua_pushcfunction(L, gctm); lua_setfield(L, -2, "__gc"); lua_register(L,"loadlib",loadlib); return 0; } /* * 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/ * */