/src/middleware/lua/loadlib.c

  1/*
  2** $Id: loadlib.c,v 1.52.1.3 2008/08/06 13:29:28 roberto Exp $
  3** Dynamic library loader for Lua
  4** See Copyright Notice in lua.h
  5**
  6** This module contains an implementation of loadlib for Unix systems
  7** that have dlfcn, an implementation for Darwin (Mac OS X), an
  8** implementation for Windows, and a stub for other systems.
  9*/
 10
 11
 12#include <stdlib.h>
 13#include <string.h>
 14
 15
 16#define loadlib_c
 17#define LUA_LIB
 18
 19#include "lua.h"
 20
 21#include "lauxlib.h"
 22#include "lualib.h"
 23
 24
 25/* prefix for open functions in C libraries */
 26#define LUA_POF		"luaopen_"
 27
 28/* separator for open functions in C libraries */
 29#define LUA_OFSEP	"_"
 30
 31
 32#define LIBPREFIX	"LOADLIB: "
 33
 34#define POF		LUA_POF
 35#define LIB_FAIL	"open"
 36
 37
 38/* error codes for ll_loadfunc */
 39#define ERRLIB		1
 40#define ERRFUNC		2
 41
 42#define setprogdir(L)		((void)0)
 43
 44
 45static void ll_unloadlib (void *lib);
 46static void *ll_load (lua_State *L, const char *path);
 47static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym);
 48
 49
 50
 51#if defined(LUA_DL_DLOPEN)
 52/*
 53** {========================================================================
 54** This is an implementation of loadlib based on the dlfcn interface.
 55** The dlfcn interface is available in Linux, SunOS, Solaris, IRIX, FreeBSD,
 56** NetBSD, AIX 4.2, HPUX 11, and  probably most other Unix flavors, at least
 57** as an emulation layer on top of native functions.
 58** =========================================================================
 59*/
 60
 61#include <dlfcn.h>
 62
 63static void ll_unloadlib (void *lib) {
 64  dlclose(lib);
 65}
 66
 67
 68static void *ll_load (lua_State *L, const char *path) {
 69  void *lib = dlopen(path, RTLD_NOW);
 70  if (lib == NULL) lua_pushstring(L, dlerror());
 71  return lib;
 72}
 73
 74
 75static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) {
 76  lua_CFunction f = (lua_CFunction)dlsym(lib, sym);
 77  if (f == NULL) lua_pushstring(L, dlerror());
 78  return f;
 79}
 80
 81/* }====================================================== */
 82
 83
 84
 85#elif defined(LUA_DL_DLL)
 86/*
 87** {======================================================================
 88** This is an implementation of loadlib for Windows using native functions.
 89** =======================================================================
 90*/
 91
 92#include <windows.h>
 93
 94
 95#undef setprogdir
 96
 97static void setprogdir (lua_State *L) {
 98  char buff[MAX_PATH + 1];
 99  char *lb;
100  DWORD nsize = sizeof(buff)/sizeof(char);
101  DWORD n = GetModuleFileNameA(NULL, buff, nsize);
102  if (n == 0 || n == nsize || (lb = strrchr(buff, '\\')) == NULL)
103    luaL_error(L, "unable to get ModuleFileName");
104  else {
105    *lb = '\0';
106    luaL_gsub(L, lua_tostring(L, -1), LUA_EXECDIR, buff);
107    lua_remove(L, -2);  /* remove original string */
108  }
109}
110
111
112static void pusherror (lua_State *L) {
113  int error = GetLastError();
114  char buffer[128];
115  if (FormatMessageA(FORMAT_MESSAGE_IGNORE_INSERTS | FORMAT_MESSAGE_FROM_SYSTEM,
116      NULL, error, 0, buffer, sizeof(buffer), NULL))
117    lua_pushstring(L, buffer);
118  else
119    lua_pushfstring(L, "system error %d\n", error);
120}
121
122static void ll_unloadlib (void *lib) {
123  FreeLibrary((HINSTANCE)lib);
124}
125
126
127static void *ll_load (lua_State *L, const char *path) {
128  HINSTANCE lib = LoadLibraryA(path);
129  if (lib == NULL) pusherror(L);
130  return lib;
131}
132
133
134static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) {
135  lua_CFunction f = (lua_CFunction)GetProcAddress((HINSTANCE)lib, sym);
136  if (f == NULL) pusherror(L);
137  return f;
138}
139
140/* }====================================================== */
141
142
143
144#elif defined(LUA_DL_DYLD)
145/*
146** {======================================================================
147** Native Mac OS X / Darwin Implementation
148** =======================================================================
149*/
150
151#include <mach-o/dyld.h>
152
153
154/* Mac appends a `_' before C function names */
155#undef POF
156#define POF	"_" LUA_POF
157
158
159static void pusherror (lua_State *L) {
160  const char *err_str;
161  const char *err_file;
162  NSLinkEditErrors err;
163  int err_num;
164  NSLinkEditError(&err, &err_num, &err_file, &err_str);
165  lua_pushstring(L, err_str);
166}
167
168
169static const char *errorfromcode (NSObjectFileImageReturnCode ret) {
170  switch (ret) {
171    case NSObjectFileImageInappropriateFile:
172      return "file is not a bundle";
173    case NSObjectFileImageArch:
174      return "library is for wrong CPU type";
175    case NSObjectFileImageFormat:
176      return "bad format";
177    case NSObjectFileImageAccess:
178      return "cannot access file";
179    case NSObjectFileImageFailure:
180    default:
181      return "unable to load library";
182  }
183}
184
185
186static void ll_unloadlib (void *lib) {
187  NSUnLinkModule((NSModule)lib, NSUNLINKMODULE_OPTION_RESET_LAZY_REFERENCES);
188}
189
190
191static void *ll_load (lua_State *L, const char *path) {
192  NSObjectFileImage img;
193  NSObjectFileImageReturnCode ret;
194  /* this would be a rare case, but prevents crashing if it happens */
195  if(!_dyld_present()) {
196    lua_pushliteral(L, "dyld not present");
197    return NULL;
198  }
199  ret = NSCreateObjectFileImageFromFile(path, &img);
200  if (ret == NSObjectFileImageSuccess) {
201    NSModule mod = NSLinkModule(img, path, NSLINKMODULE_OPTION_PRIVATE |
202                       NSLINKMODULE_OPTION_RETURN_ON_ERROR);
203    NSDestroyObjectFileImage(img);
204    if (mod == NULL) pusherror(L);
205    return mod;
206  }
207  lua_pushstring(L, errorfromcode(ret));
208  return NULL;
209}
210
211
212static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) {
213  NSSymbol nss = NSLookupSymbolInModule((NSModule)lib, sym);
214  if (nss == NULL) {
215    lua_pushfstring(L, "symbol " LUA_QS " not found", sym);
216    return NULL;
217  }
218  return (lua_CFunction)NSAddressOfSymbol(nss);
219}
220
221/* }====================================================== */
222
223
224
225#else
226/*
227** {======================================================
228** Fallback for other systems
229** =======================================================
230*/
231
232#undef LIB_FAIL
233#define LIB_FAIL	"absent"
234
235
236#define DLMSG	"dynamic libraries not enabled; check your Lua installation"
237
238
239static void ll_unloadlib (void *lib) {
240  (void)lib;  /* to avoid warnings */
241}
242
243
244static void *ll_load (lua_State *L, const char *path) {
245  (void)path;  /* to avoid warnings */
246  lua_pushliteral(L, DLMSG);
247  return NULL;
248}
249
250
251static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) {
252  (void)lib; (void)sym;  /* to avoid warnings */
253  lua_pushliteral(L, DLMSG);
254  return NULL;
255}
256
257/* }====================================================== */
258#endif
259
260
261
262static void **ll_register (lua_State *L, const char *path) {
263  void **plib;
264  lua_pushfstring(L, "%s%s", LIBPREFIX, path);
265  lua_gettable(L, LUA_REGISTRYINDEX);  /* check library in registry? */
266  if (!lua_isnil(L, -1))  /* is there an entry? */
267    plib = (void **)lua_touserdata(L, -1);
268  else {  /* no entry yet; create one */
269    lua_pop(L, 1);
270    plib = (void **)lua_newuserdata(L, sizeof(const void *));
271    *plib = NULL;
272    luaL_getmetatable(L, "_LOADLIB");
273    lua_setmetatable(L, -2);
274    lua_pushfstring(L, "%s%s", LIBPREFIX, path);
275    lua_pushvalue(L, -2);
276    lua_settable(L, LUA_REGISTRYINDEX);
277  }
278  return plib;
279}
280
281
282/*
283** __gc tag method: calls library's `ll_unloadlib' function with the lib
284** handle
285*/
286static int gctm (lua_State *L) {
287  void **lib = (void **)luaL_checkudata(L, 1, "_LOADLIB");
288  if (*lib) ll_unloadlib(*lib);
289  *lib = NULL;  /* mark library as closed */
290  return 0;
291}
292
293
294static int ll_loadfunc (lua_State *L, const char *path, const char *sym) {
295  void **reg = ll_register(L, path);
296  if (*reg == NULL) *reg = ll_load(L, path);
297  if (*reg == NULL)
298    return ERRLIB;  /* unable to load library */
299  else {
300    lua_CFunction f = ll_sym(L, *reg, sym);
301    if (f == NULL)
302      return ERRFUNC;  /* unable to find function */
303    lua_pushcfunction(L, f);
304    return 0;  /* return function */
305  }
306}
307
308
309static int ll_loadlib (lua_State *L) {
310  const char *path = luaL_checkstring(L, 1);
311  const char *init = luaL_checkstring(L, 2);
312  int stat = ll_loadfunc(L, path, init);
313  if (stat == 0)  /* no errors? */
314    return 1;  /* return the loaded function */
315  else {  /* error; error message is on stack top */
316    lua_pushnil(L);
317    lua_insert(L, -2);
318    lua_pushstring(L, (stat == ERRLIB) ?  LIB_FAIL : "init");
319    return 3;  /* return nil, error message, and where */
320  }
321}
322
323
324
325/*
326** {======================================================
327** 'require' function
328** =======================================================
329*/
330
331
332static int readable (const char *filename) {
333  FILE *f = fopen(filename, "r");  /* try to open file */
334  if (f == NULL) return 0;  /* open failed */
335  fclose(f);
336  return 1;
337}
338
339
340static const char *pushnexttemplate (lua_State *L, const char *path) {
341  const char *l;
342  while (*path == *LUA_PATHSEP) path++;  /* skip separators */
343  if (*path == '\0') return NULL;  /* no more templates */
344  l = strchr(path, *LUA_PATHSEP);  /* find next separator */
345  if (l == NULL) l = path + strlen(path);
346  lua_pushlstring(L, path, l - path);  /* template */
347  return l;
348}
349
350
351static const char *findfile (lua_State *L, const char *name,
352                                           const char *pname) {
353  const char *path;
354  name = luaL_gsub(L, name, ".", LUA_DIRSEP);
355  lua_getfield(L, LUA_ENVIRONINDEX, pname);
356  path = lua_tostring(L, -1);
357  if (path == NULL)
358    luaL_error(L, LUA_QL("package.%s") " must be a string", pname);
359  lua_pushliteral(L, "");  /* error accumulator */
360  while ((path = pushnexttemplate(L, path)) != NULL) {
361    const char *filename;
362    filename = luaL_gsub(L, lua_tostring(L, -1), LUA_PATH_MARK, name);
363    lua_remove(L, -2);  /* remove path template */
364    if (readable(filename))  /* does file exist and is readable? */
365      return filename;  /* return that file name */
366    lua_pushfstring(L, "\n\tno file " LUA_QS, filename);
367    lua_remove(L, -2);  /* remove file name */
368    lua_concat(L, 2);  /* add entry to possible error message */
369  }
370  return NULL;  /* not found */
371}
372
373
374static void loaderror (lua_State *L, const char *filename) {
375  luaL_error(L, "error loading module " LUA_QS " from file " LUA_QS ":\n\t%s",
376                lua_tostring(L, 1), filename, lua_tostring(L, -1));
377}
378
379
380static int loader_Lua (lua_State *L) {
381  const char *filename;
382  const char *name = luaL_checkstring(L, 1);
383  filename = findfile(L, name, "path");
384  if (filename == NULL) return 1;  /* library not found in this path */
385  if (luaL_loadfile(L, filename) != 0)
386    loaderror(L, filename);
387  return 1;  /* library loaded successfully */
388}
389
390
391static const char *mkfuncname (lua_State *L, const char *modname) {
392  const char *funcname;
393  const char *mark = strchr(modname, *LUA_IGMARK);
394  if (mark) modname = mark + 1;
395  funcname = luaL_gsub(L, modname, ".", LUA_OFSEP);
396  funcname = lua_pushfstring(L, POF"%s", funcname);
397  lua_remove(L, -2);  /* remove 'gsub' result */
398  return funcname;
399}
400
401
402static int loader_C (lua_State *L) {
403  const char *funcname;
404  const char *name = luaL_checkstring(L, 1);
405  const char *filename = findfile(L, name, "cpath");
406  if (filename == NULL) return 1;  /* library not found in this path */
407  funcname = mkfuncname(L, name);
408  if (ll_loadfunc(L, filename, funcname) != 0)
409    loaderror(L, filename);
410  return 1;  /* library loaded successfully */
411}
412
413
414static int loader_Croot (lua_State *L) {
415  const char *funcname;
416  const char *filename;
417  const char *name = luaL_checkstring(L, 1);
418  const char *p = strchr(name, '.');
419  int stat;
420  if (p == NULL) return 0;  /* is root */
421  lua_pushlstring(L, name, p - name);
422  filename = findfile(L, lua_tostring(L, -1), "cpath");
423  if (filename == NULL) return 1;  /* root not found */
424  funcname = mkfuncname(L, name);
425  if ((stat = ll_loadfunc(L, filename, funcname)) != 0) {
426    if (stat != ERRFUNC) loaderror(L, filename);  /* real error */
427    lua_pushfstring(L, "\n\tno module " LUA_QS " in file " LUA_QS,
428                       name, filename);
429    return 1;  /* function not found */
430  }
431  return 1;
432}
433
434
435static int loader_preload (lua_State *L) {
436  const char *name = luaL_checkstring(L, 1);
437  lua_getfield(L, LUA_ENVIRONINDEX, "preload");
438  if (!lua_istable(L, -1))
439    luaL_error(L, LUA_QL("package.preload") " must be a table");
440  lua_getfield(L, -1, name);
441  if (lua_isnil(L, -1))  /* not found? */
442    lua_pushfstring(L, "\n\tno field package.preload['%s']", name);
443  return 1;
444}
445
446
447static const int sentinel_ = 0;
448#define sentinel	((void *)&sentinel_)
449
450
451static int ll_require (lua_State *L) {
452  const char *name = luaL_checkstring(L, 1);
453  int i;
454  lua_settop(L, 1);  /* _LOADED table will be at index 2 */
455  lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");
456  lua_getfield(L, 2, name);
457  if (lua_toboolean(L, -1)) {  /* is it there? */
458    if (lua_touserdata(L, -1) == sentinel)  /* check loops */
459      luaL_error(L, "loop or previous error loading module " LUA_QS, name);
460    return 1;  /* package is already loaded */
461  }
462  /* else must load it; iterate over available loaders */
463  lua_getfield(L, LUA_ENVIRONINDEX, "loaders");
464  if (!lua_istable(L, -1))
465    luaL_error(L, LUA_QL("package.loaders") " must be a table");
466  lua_pushliteral(L, "");  /* error message accumulator */
467  for (i=1; ; i++) {
468    lua_rawgeti(L, -2, i);  /* get a loader */
469    if (lua_isnil(L, -1))
470      luaL_error(L, "module " LUA_QS " not found:%s",
471                    name, lua_tostring(L, -2));
472    lua_pushstring(L, name);
473    lua_call(L, 1, 1);  /* call it */
474    if (lua_isfunction(L, -1))  /* did it find module? */
475      break;  /* module loaded successfully */
476    else if (lua_isstring(L, -1))  /* loader returned error message? */
477      lua_concat(L, 2);  /* accumulate it */
478    else
479      lua_pop(L, 1);
480  }
481  lua_pushlightuserdata(L, sentinel);
482  lua_setfield(L, 2, name);  /* _LOADED[name] = sentinel */
483  lua_pushstring(L, name);  /* pass name as argument to module */
484  lua_call(L, 1, 1);  /* run loaded module */
485  if (!lua_isnil(L, -1))  /* non-nil return? */
486    lua_setfield(L, 2, name);  /* _LOADED[name] = returned value */
487  lua_getfield(L, 2, name);
488  if (lua_touserdata(L, -1) == sentinel) {   /* module did not set a value? */
489    lua_pushboolean(L, 1);  /* use true as result */
490    lua_pushvalue(L, -1);  /* extra copy to be returned */
491    lua_setfield(L, 2, name);  /* _LOADED[name] = true */
492  }
493  return 1;
494}
495
496/* }====================================================== */
497
498
499
500/*
501** {======================================================
502** 'module' function
503** =======================================================
504*/
505  
506
507static void setfenv (lua_State *L) {
508  lua_Debug ar;
509  if (lua_getstack(L, 1, &ar) == 0 ||
510      lua_getinfo(L, "f", &ar) == 0 ||  /* get calling function */
511      lua_iscfunction(L, -1))
512    luaL_error(L, LUA_QL("module") " not called from a Lua function");
513  lua_pushvalue(L, -2);
514  lua_setfenv(L, -2);
515  lua_pop(L, 1);
516}
517
518
519static void dooptions (lua_State *L, int n) {
520  int i;
521  for (i = 2; i <= n; i++) {
522    lua_pushvalue(L, i);  /* get option (a function) */
523    lua_pushvalue(L, -2);  /* module */
524    lua_call(L, 1, 0);
525  }
526}
527
528
529static void modinit (lua_State *L, const char *modname) {
530  const char *dot;
531  lua_pushvalue(L, -1);
532  lua_setfield(L, -2, "_M");  /* module._M = module */
533  lua_pushstring(L, modname);
534  lua_setfield(L, -2, "_NAME");
535  dot = strrchr(modname, '.');  /* look for last dot in module name */
536  if (dot == NULL) dot = modname;
537  else dot++;
538  /* set _PACKAGE as package name (full module name minus last part) */
539  lua_pushlstring(L, modname, dot - modname);
540  lua_setfield(L, -2, "_PACKAGE");
541}
542
543
544static int ll_module (lua_State *L) {
545  const char *modname = luaL_checkstring(L, 1);
546  int loaded = lua_gettop(L) + 1;  /* index of _LOADED table */
547  lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");
548  lua_getfield(L, loaded, modname);  /* get _LOADED[modname] */
549  if (!lua_istable(L, -1)) {  /* not found? */
550    lua_pop(L, 1);  /* remove previous result */
551    /* try global variable (and create one if it does not exist) */
552    if (luaL_findtable(L, LUA_GLOBALSINDEX, modname, 1) != NULL)
553      return luaL_error(L, "name conflict for module " LUA_QS, modname);
554    lua_pushvalue(L, -1);
555    lua_setfield(L, loaded, modname);  /* _LOADED[modname] = new table */
556  }
557  /* check whether table already has a _NAME field */
558  lua_getfield(L, -1, "_NAME");
559  if (!lua_isnil(L, -1))  /* is table an initialized module? */
560    lua_pop(L, 1);
561  else {  /* no; initialize it */
562    lua_pop(L, 1);
563    modinit(L, modname);
564  }
565  lua_pushvalue(L, -1);
566  setfenv(L);
567  dooptions(L, loaded - 1);
568  return 0;
569}
570
571
572static int ll_seeall (lua_State *L) {
573  luaL_checktype(L, 1, LUA_TTABLE);
574  if (!lua_getmetatable(L, 1)) {
575    lua_createtable(L, 0, 1); /* create new metatable */
576    lua_pushvalue(L, -1);
577    lua_setmetatable(L, 1);
578  }
579  lua_pushvalue(L, LUA_GLOBALSINDEX);
580  lua_setfield(L, -2, "__index");  /* mt.__index = _G */
581  return 0;
582}
583
584
585/* }====================================================== */
586
587
588
589/* auxiliary mark (for internal use) */
590#define AUXMARK		"\1"
591
592static void setpath (lua_State *L, const char *fieldname, const char *envname,
593                                   const char *def) {
594  const char *path = getenv(envname);
595  if (path == NULL)  /* no environment variable? */
596    lua_pushstring(L, def);  /* use default */
597  else {
598    /* replace ";;" by ";AUXMARK;" and then AUXMARK by default path */
599    path = luaL_gsub(L, path, LUA_PATHSEP LUA_PATHSEP,
600                              LUA_PATHSEP AUXMARK LUA_PATHSEP);
601    luaL_gsub(L, path, AUXMARK, def);
602    lua_remove(L, -2);
603  }
604  setprogdir(L);
605  lua_setfield(L, -2, fieldname);
606}
607
608
609static const luaL_Reg pk_funcs[] = {
610  {"loadlib", ll_loadlib},
611  {"seeall", ll_seeall},
612  {NULL, NULL}
613};
614
615
616static const luaL_Reg ll_funcs[] = {
617  {"module", ll_module},
618  {"require", ll_require},
619  {NULL, NULL}
620};
621
622
623static const lua_CFunction loaders[] =
624  {loader_preload, loader_Lua, loader_C, loader_Croot, NULL};
625
626
627LUALIB_API int luaopen_package (lua_State *L) {
628  int i;
629  /* create new type _LOADLIB */
630  luaL_newmetatable(L, "_LOADLIB");
631  lua_pushcfunction(L, gctm);
632  lua_setfield(L, -2, "__gc");
633  /* create `package' table */
634  luaL_register(L, LUA_LOADLIBNAME, pk_funcs);
635#if defined(LUA_COMPAT_LOADLIB) 
636  lua_getfield(L, -1, "loadlib");
637  lua_setfield(L, LUA_GLOBALSINDEX, "loadlib");
638#endif
639  lua_pushvalue(L, -1);
640  lua_replace(L, LUA_ENVIRONINDEX);
641  /* create `loaders' table */
642  lua_createtable(L, 0, sizeof(loaders)/sizeof(loaders[0]) - 1);
643  /* fill it with pre-defined loaders */
644  for (i=0; loaders[i] != NULL; i++) {
645    lua_pushcfunction(L, loaders[i]);
646    lua_rawseti(L, -2, i+1);
647  }
648  lua_setfield(L, -2, "loaders");  /* put it in field `loaders' */
649  setpath(L, "path", LUA_PATH, LUA_PATH_DEFAULT);  /* set field `path' */
650  setpath(L, "cpath", LUA_CPATH, LUA_CPATH_DEFAULT); /* set field `cpath' */
651  /* store config information */
652  lua_pushliteral(L, LUA_DIRSEP "\n" LUA_PATHSEP "\n" LUA_PATH_MARK "\n"
653                     LUA_EXECDIR "\n" LUA_IGMARK);
654  lua_setfield(L, -2, "config");
655  /* set field `loaded' */
656  luaL_findtable(L, LUA_REGISTRYINDEX, "_LOADED", 2);
657  lua_setfield(L, -2, "loaded");
658  /* set field `preload' */
659  lua_newtable(L);
660  lua_setfield(L, -2, "preload");
661  lua_pushvalue(L, LUA_GLOBALSINDEX);
662  luaL_register(L, NULL, ll_funcs);  /* open lib into global table */
663  lua_pop(L, 1);
664  return 1;  /* return 'package' table */
665}
666