summaryrefslogtreecommitdiffstats
path: root/deps/lua/src/loadlib.c
blob: 6158c5353df2fd0bd385ea7de725738f28d8ba51 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
/*
** $Id: loadlib.c,v 1.52.1.4 2009/09/09 13:17:16 roberto Exp $
** 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 Darwin (Mac OS X), an
** implementation for Windows, and a stub for other systems.
*/


#include <stdlib.h>
#include <string.h>


#define loadlib_c
#define LUA_LIB

#include "lua.h"

#include "lauxlib.h"
#include "lualib.h"


/* prefix for open functions in C libraries */
#define LUA_POF		"luaopen_"

/* separator for open functions in C libraries */
#define LUA_OFSEP	"_"


#define LIBPREFIX	"LOADLIB: "

#define POF		LUA_POF
#define LIB_FAIL	"open"


/* error codes for ll_loadfunc */
#define ERRLIB		1
#define ERRFUNC		2

#define setprogdir(L)		((void)0)


static void ll_unloadlib (void *lib);
static void *ll_load (lua_State *L, const char *path);
static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym);



#if defined(LUA_DL_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 <dlfcn.h>

static void ll_unloadlib (void *lib) {
  dlclose(lib);
}


static void *ll_load (lua_State *L, const char *path) {
  void *lib = dlopen(path, RTLD_NOW);
  if (lib == NULL) lua_pushstring(L, dlerror());
  return lib;
}


static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) {
  lua_CFunction f = (lua_CFunction)dlsym(lib, sym);
  if (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 <windows.h>


#undef setprogdir

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);
  if (n == 0 || n == nsize || (lb = strrchr(buff, '\\')) == NULL)
    luaL_error(L, "unable to get ModuleFileName");
  else {
    *lb = '\0';
    luaL_gsub(L, lua_tostring(L, -1), LUA_EXECDIR, 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), NULL))
    lua_pushstring(L, buffer);
  else
    lua_pushfstring(L, "system error %d\n", error);
}

static void ll_unloadlib (void *lib) {
  FreeLibrary((HINSTANCE)lib);
}


static void *ll_load (lua_State *L, const char *path) {
  HINSTANCE lib = LoadLibraryA(path);
  if (lib == NULL) pusherror(L);
  return lib;
}


static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) {
  lua_CFunction f = (lua_CFunction)GetProcAddress((HINSTANCE)lib, sym);
  if (f == NULL) pusherror(L);
  return f;
}

/* }====================================================== */



#elif defined(LUA_DL_DYLD)
/*
** {======================================================================
** Native Mac OS X / Darwin Implementation
** =======================================================================
*/

#include <mach-o/dyld.h>


/* Mac appends a `_' before C function names */
#undef POF
#define POF	"_" LUA_POF


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 const char *errorfromcode (NSObjectFileImageReturnCode ret) {
  switch (ret) {
    case NSObjectFileImageInappropriateFile:
      return "file is not a bundle";
    case NSObjectFileImageArch:
      return "library is for wrong CPU type";
    case NSObjectFileImageFormat:
      return "bad format";
    case NSObjectFileImageAccess:
      return "cannot access file";
    case NSObjectFileImageFailure:
    default:
      return "unable to load library";
  }
}


static void ll_unloadlib (void *lib) {
  NSUnLinkModule((NSModule)lib, NSUNLINKMODULE_OPTION_RESET_LAZY_REFERENCES);
}


static void *ll_load (lua_State *L, const char *path) {
  NSObjectFileImage img;
  NSObjectFileImageReturnCode ret;
  /* this would be a rare case, but prevents crashing if it happens */
  if(!_dyld_present()) {
    lua_pushliteral(L, "dyld not present");
    return NULL;
  }
  ret = NSCreateObjectFileImageFromFile(path, &img);
  if (ret == NSObjectFileImageSuccess) {
    NSModule mod = NSLinkModule(img, path, NSLINKMODULE_OPTION_PRIVATE |
                       NSLINKMODULE_OPTION_RETURN_ON_ERROR);
    NSDestroyObjectFileImage(img);
    if (mod == NULL) pusherror(L);
    return mod;
  }
  lua_pushstring(L, errorfromcode(ret));
  return NULL;
}


static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) {
  NSSymbol nss = NSLookupSymbolInModule((NSModule)lib, sym);
  if (nss == NULL) {
    lua_pushfstring(L, "symbol " LUA_QS " not found", sym);
    return NULL;
  }
  return (lua_CFunction)NSAddressOfSymbol(nss);
}

/* }====================================================== */



#else
/*
** {======================================================
** Fallback for other systems
** =======================================================
*/

#undef LIB_FAIL
#define LIB_FAIL	"absent"


#define DLMSG	"dynamic libraries not enabled; check your Lua installation"


static void ll_unloadlib (void *lib) {
  (void)lib;  /* to avoid warnings */
}


static void *ll_load (lua_State *L, const char *path) {
  (void)path;  /* to avoid warnings */
  lua_pushliteral(L, DLMSG);
  return NULL;
}


static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) {
  (void)lib; (void)sym;  /* to avoid warnings */
  lua_pushliteral(L, DLMSG);
  return NULL;
}

/* }====================================================== */
#endif



static void **ll_register (lua_State *L, const char *path) {
  void **plib;
  lua_pushfstring(L, "%s%s", LIBPREFIX, path);
  lua_gettable(L, LUA_REGISTRYINDEX);  /* check library in registry? */
  if (!lua_isnil(L, -1))  /* is there an entry? */
    plib = (void **)lua_touserdata(L, -1);
  else {  /* no entry yet; create one */
    lua_pop(L, 1);
    plib = (void **)lua_newuserdata(L, sizeof(const void *));
    *plib = NULL;
    luaL_getmetatable(L, "_LOADLIB");
    lua_setmetatable(L, -2);
    lua_pushfstring(L, "%s%s", LIBPREFIX, path);
    lua_pushvalue(L, -2);
    lua_settable(L, LUA_REGISTRYINDEX);
  }
  return plib;
}


/*
** __gc tag method: calls library's `ll_unloadlib' function with the lib
** handle
*/
static int gctm (lua_State *L) {
  void **lib = (void **)luaL_checkudata(L, 1, "_LOADLIB");
  if (*lib) ll_unloadlib(*lib);
  *lib = NULL;  /* mark library as closed */
  return 0;
}


static int ll_loadfunc (lua_State *L, const char *path, const char *sym) {
  void **reg = ll_register(L, path);
  if (*reg == NULL) *reg = ll_load(L, path);
  if (*reg == NULL)
    return ERRLIB;  /* unable to load library */
  else {
    lua_CFunction f = ll_sym(L, *reg, sym);
    if (f == NULL)
      return ERRFUNC;  /* unable to find function */
    lua_pushcfunction(L, f);
    return 0;  /* return function */
  }
}


static int ll_loadlib (lua_State *L) {
  const char *path = luaL_checkstring(L, 1);
  const char *init = luaL_checkstring(L, 2);
  int stat = ll_loadfunc(L, path, init);
  if (stat == 0)  /* no errors? */
    return 1;  /* return the loaded function */
  else {  /* error; error message is on stack top */
    lua_pushnil(L);
    lua_insert(L, -2);
    lua_pushstring(L, (stat == ERRLIB) ?  LIB_FAIL : "init");
    return 3;  /* return nil, 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;
}


static const char *pushnexttemplate (lua_State *L, const char *path) {
  const char *l;
  while (*path == *LUA_PATHSEP) path++;  /* skip separators */
  if (*path == '\0') return NULL;  /* no more templates */
  l = strchr(path, *LUA_PATHSEP);  /* find next separator */
  if (l == NULL) l = path + strlen(path);
  lua_pushlstring(L, path, l - path);  /* template */
  return l;
}


static const char *findfile (lua_State *L, const char *name,
                                           const char *pname) {
  const char *path;
  name = luaL_gsub(L, name, ".", LUA_DIRSEP);
  lua_getfield(L, LUA_ENVIRONINDEX, pname);
  path = lua_tostring(L, -1);
  if (path == NULL)
    luaL_error(L, LUA_QL("package.%s") " must be a string", pname);
  lua_pushliteral(L, "");  /* error accumulator */
  while ((path = pushnexttemplate(L, path)) != NULL) {
    const char *filename;
    filename = luaL_gsub(L, lua_tostring(L, -1), LUA_PATH_MARK, name);
    lua_remove(L, -2);  /* remove path template */
    if (readable(filename))  /* does file exist and is readable? */
      return filename;  /* return that file name */
    lua_pushfstring(L, "\n\tno file " LUA_QS, filename);
    lua_remove(L, -2);  /* remove file name */
    lua_concat(L, 2);  /* add entry to possible error message */
  }
  return NULL;  /* not found */
}


static void loaderror (lua_State *L, const char *filename) {
  luaL_error(L, "error loading module " LUA_QS " from file " LUA_QS ":\n\t%s",
                lua_tostring(L, 1), filename, lua_tostring(L, -1));
}


static int loader_Lua (lua_State *L) {
  const char *filename;
  const char *name = luaL_checkstring(L, 1);
  filename = findfile(L, name, "path");
  if (filename == NULL) return 1;  /* library not found in this path */
  if (luaL_loadfile(L, filename) != 0)
    loaderror(L, filename);
  return 1;  /* library loaded successfully */
}


static const char *mkfuncname (lua_State *L, const char *modname) {
  const char *funcname;
  const char *mark = strchr(modname, *LUA_IGMARK);
  if (mark) modname = mark + 1;
  funcname = luaL_gsub(L, modname, ".", LUA_OFSEP);
  funcname = lua_pushfstring(L, POF"%s", funcname);
  lua_remove(L, -2);  /* remove 'gsub' result */
  return funcname;
}


static int loader_C (lua_State *L) {
  const char *funcname;
  const char *name = luaL_checkstring(L, 1);
  const char *filename = findfile(L, name, "cpath");
  if (filename == NULL) return 1;  /* library not found in this path */
  funcname = mkfuncname(L, name);
  if (ll_loadfunc(L, filename, funcname) != 0)
    loaderror(L, filename);
  return 1;  /* library loaded successfully */
}


static int loader_Croot (lua_State *L) {
  const char *funcname;
  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");
  if (filename == NULL) return 1;  /* root not found */
  funcname = mkfuncname(L, name);
  if ((stat = ll_loadfunc(L, filename, funcname)) != 0) {
    if (stat != ERRFUNC) loaderror(L, filename);  /* real error */
    lua_pushfstring(L, "\n\tno module " LUA_QS " in file " LUA_QS,
                       name, filename);
    return 1;  /* function not found */
  }
  return 1;
}


static int loader_preload (lua_State *L) {
  const char *name = luaL_checkstring(L, 1);
  lua_getfield(L, LUA_ENVIRONINDEX, "preload");
  if (!lua_istable(L, -1))
    luaL_error(L, LUA_QL("package.preload") " must be a table");
  lua_getfield(L, -1, name);
  if (lua_isnil(L, -1))  /* not found? */
    lua_pushfstring(L, "\n\tno field package.preload['%s']", name);
  return 1;
}


static const int sentinel_ = 0;
#define sentinel	((void *)&sentinel_)


static int ll_require (lua_State *L) {
  const char *name = luaL_checkstring(L, 1);
  int i;
  lua_settop(L, 1);  /* _LOADED table will be at index 2 */
  lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");
  lua_getfield(L, 2, name);
  if (lua_toboolean(L, -1)) {  /* is it there? */
    if (lua_touserdata(L, -1) == sentinel)  /* check loops */
      luaL_error(L, "loop or previous error loading module " LUA_QS, name);
    return 1;  /* package is already loaded */
  }
  /* else must load it; iterate over available loaders */
  lua_getfield(L, LUA_ENVIRONINDEX, "loaders");
  if (!lua_istable(L, -1))
    luaL_error(L, LUA_QL("package.loaders") " must be a table");
  lua_pushliteral(L, "");  /* error message accumulator */
  for (i=1; ; i++) {
    lua_rawgeti(L, -2, i);  /* get a loader */
    if (lua_isnil(L, -1))
      luaL_error(L, "module " LUA_QS " not found:%s",
                    name, lua_tostring(L, -2));
    lua_pushstring(L, name);
    lua_call(L, 1, 1);  /* call it */
    if (lua_isfunction(L, -1))  /* did it find module? */
      break;  /* module loaded successfully */
    else if (lua_isstring(L, -1))  /* loader returned error message? */
      lua_concat(L, 2);  /* accumulate it */
    else
      lua_pop(L, 1);
  }
  lua_pushlightuserdata(L, sentinel);
  lua_setfield(L, 2, name);  /* _LOADED[name] = sentinel */
  lua_pushstring(L, name);  /* 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);  /* _LOADED[name] = returned value */
  lua_getfield(L, 2, name);
  if (lua_touserdata(L, -1) == sentinel) {   /* module did not set a value? */
    lua_pushboolean(L, 1);  /* use true as result */
    lua_pushvalue(L, -1);  /* extra copy to be returned */
    lua_setfield(L, 2, name);  /* _LOADED[name] = true */
  }
  return 1;
}

/* }====================================================== */



/*
** {======================================================
** 'module' function
** =======================================================
*/
  

static void setfenv (lua_State *L) {
  lua_Debug ar;
  if (lua_getstack(L, 1, &ar) == 0 ||
      lua_getinfo(L, "f", &ar) == 0 ||  /* get calling function */
      lua_iscfunction(L, -1))
    luaL_error(L, LUA_QL("module") " not called from a Lua function");
  lua_pushvalue(L, -2);
  lua_setfenv(L, -2);
  lua_pop(L, 1);
}


static void dooptions (lua_State *L, int n) {
  int i;
  for (i = 2; i <= n; i++) {
    lua_pushvalue(L, i);  /* get option (a function) */
    lua_pushvalue(L, -2);  /* module */
    lua_call(L, 1, 0);
  }
}


static void modinit (lua_State *L, const char *modname) {
  const char *dot;
  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");
}


static int ll_module (lua_State *L) {
  const char *modname = luaL_checkstring(L, 1);
  int loaded = lua_gettop(L) + 1;  /* index of _LOADED table */
  lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");
  lua_getfield(L, loaded, modname);  /* get _LOADED[modname] */
  if (!lua_istable(L, -1)) {  /* not found? */
    lua_pop(L, 1);  /* remove previous result */
    /* try global variable (and create one if it does not exist) */
    if (luaL_findtable(L, LUA_GLOBALSINDEX, modname, 1) != NULL)
      return luaL_error(L, "name conflict for module " LUA_QS, modname);
    lua_pushvalue(L, -1);
    lua_setfield(L, loaded, modname);  /* _LOADED[modname] = new table */
  }
  /* 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);
    modinit(L, modname);
  }
  lua_pushvalue(L, -1);
  setfenv(L);
  dooptions(L, loaded - 1);
  return 0;
}


static int ll_seeall (lua_State *L) {
  luaL_checktype(L, 1, LUA_TTABLE);
  if (!lua_getmetatable(L, 1)) {
    lua_createtable(L, 0, 1); /* create new metatable */
    lua_pushvalue(L, -1);
    lua_setmetatable(L, 1);
  }
  lua_pushvalue(L, LUA_GLOBALSINDEX);
  lua_setfield(L, -2, "__index");  /* mt.__index = _G */
  return 0;
}


/* }====================================================== */



/* auxiliary mark (for internal use) */
#define AUXMARK		"\1"

static void setpath (lua_State *L, const char *fieldname, const char *envname,
                                   const char *def) {
  const char *path = getenv(envname);
  if (path == NULL)  /* no environment variable? */
    lua_pushstring(L, def);  /* use default */
  else {
    /* replace ";;" by ";AUXMARK;" and then AUXMARK by default path */
    path = luaL_gsub(L, path, LUA_PATHSEP LUA_PATHSEP,
                              LUA_PATHSEP AUXMARK LUA_PATHSEP);
    luaL_gsub(L, path, AUXMARK, def);
    lua_remove(L, -2);
  }
  setprogdir(L);
  lua_setfield(L, -2, fieldname);
}


static const luaL_Reg pk_funcs[] = {
  {"loadlib", ll_loadlib},
  {"seeall", ll_seeall},
  {NULL, NULL}
};


static const luaL_Reg ll_funcs[] = {
  {"module", ll_module},
  {"require", ll_require},
  {NULL, NULL}
};


static const lua_CFunction loaders[] =
  {loader_preload, loader_Lua, loader_C, loader_Croot, NULL};


LUALIB_API int luaopen_package (lua_State *L) {
  int i;
  /* create new type _LOADLIB */
  luaL_newmetatable(L, "_LOADLIB");
  lua_pushcfunction(L, gctm);
  lua_setfield(L, -2, "__gc");
  /* create `package' table */
  luaL_register(L, LUA_LOADLIBNAME, pk_funcs);
#if defined(LUA_COMPAT_LOADLIB) 
  lua_getfield(L, -1, "loadlib");
  lua_setfield(L, LUA_GLOBALSINDEX, "loadlib");
#endif
  lua_pushvalue(L, -1);
  lua_replace(L, LUA_ENVIRONINDEX);
  /* create `loaders' table */
  lua_createtable(L, sizeof(loaders)/sizeof(loaders[0]) - 1, 0);
  /* fill it with pre-defined loaders */
  for (i=0; loaders[i] != NULL; i++) {
    lua_pushcfunction(L, loaders[i]);
    lua_rawseti(L, -2, i+1);
  }
  lua_setfield(L, -2, "loaders");  /* put it in field `loaders' */
  setpath(L, "path", LUA_PATH, LUA_PATH_DEFAULT);  /* set field `path' */
  setpath(L, "cpath", LUA_CPATH, LUA_CPATH_DEFAULT); /* set field `cpath' */
  /* store config information */
  lua_pushliteral(L, LUA_DIRSEP "\n" LUA_PATHSEP "\n" LUA_PATH_MARK "\n"
                     LUA_EXECDIR "\n" LUA_IGMARK);
  lua_setfield(L, -2, "config");
  /* set field `loaded' */
  luaL_findtable(L, LUA_REGISTRYINDEX, "_LOADED", 2);
  lua_setfield(L, -2, "loaded");
  /* set field `preload' */
  lua_newtable(L);
  lua_setfield(L, -2, "preload");
  lua_pushvalue(L, LUA_GLOBALSINDEX);
  luaL_register(L, NULL, ll_funcs);  /* open lib into global table */
  lua_pop(L, 1);
  return 1;  /* return 'package' table */
}