/* ** $Id: loadlib.c,v 1.6 2004/04/30 20:13:38 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" #undef LOADLIB #ifdef USE_DLOPEN #define LOADLIB /* * 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 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) { lua_pushlightuserdata(L,lib); lua_pushcclosure(L,f,1); 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; } #endif /* ** In Windows, default is to use dll; otherwise, default is not to use dll */ #ifndef USE_DLL #ifdef _WIN32 #define USE_DLL 1 #else #define USE_DLL 0 #endif #endif #if USE_DLL #define LOADLIB /* * This is an implementation of loadlib for Windows using native functions. */ #include 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) { lua_pushlightuserdata(L,lib); lua_pushcclosure(L,f,1); return 1; } } lua_pushnil(L); pusherror(L); lua_pushstring(L,(lib!=NULL) ? "init" : "open"); if (lib!=NULL) FreeLibrary(lib); return 3; } #endif /* Native Mac OS X / Darwin Implementation */ #ifdef USE_DYLD #define LOADLIB #include static int loadlib (lua_State *L) { const char * err_str; const char * err_file; NSLinkEditErrors err; int err_num; 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); lua_pushlightuserdata(L,(void *)lib); lua_pushcclosure(L,f,1); return 1; } } /* else an error ocurred */ NSLinkEditError(&err, &err_num, &err_file, &err_str); lua_pushnil(L); lua_pushstring(L, err_str); lua_pushstring(L, (lib != NULL) ? "init" : "open"); /* Can't unload image */ return 3; } #endif #ifndef LOADLIB /* Fallback for other systems */ /* ** Those systems support dlopen, so they should have defined USE_DLOPEN. ** The default (no)implementation gives them a special error message. */ #if defined(linux) || defined(sun) || defined(sgi) || defined(BSD) || defined(_WIN32) #define LOADLIB "`loadlib' not installed (check your Lua configuration)" #else #define LOADLIB "`loadlib' not supported" #endif static int loadlib(lua_State *L) { lua_pushnil(L); lua_pushliteral(L,LOADLIB); lua_pushliteral(L,"absent"); return 3; } #endif LUALIB_API int luaopen_loadlib (lua_State *L) { 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 * * Mac OS X/Darwin * http://www.opendarwin.org/projects/dlcompat/ * * GLIB has wrapper code for BeOS, OS2, Unix and Windows * http://cvs.gnome.org/lxr/source/glib/gmodule/ * */