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1/*
2** $Id: loadlib.c,v 1.52 2006/04/10 18:27:23 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 "lauxlib.h"
20#include "lobject.h"
21#include "lua.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 POFLUA_POF
35#define LIB_FAIL"open"
36
37
38/* error codes for ll_loadfunc */
39#define ERRLIB1
40#define ERRFUNC2
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 = GetModuleFileName(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 (FormatMessage(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 = LoadLibrary(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_pushstring(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 if (readable(filename)) /* does file exist and is readable? */
364 return filename; /* return that file name */
365 lua_pop(L, 2); /* remove path template and file name */
366 luaO_pushfstring(L, "\n\tno file " LUA_QS, filename);
367 lua_concat(L, 2);
368 }
369 return NULL; /* not found */
370}
371
372
373static void loaderror (lua_State *L, const char *filename) {
374 luaL_error(L, "error loading module " LUA_QS " from file " LUA_QS ":\n\t%s",
375 lua_tostring(L, 1), filename, lua_tostring(L, -1));
376}
377
378
379static int loader_Lua (lua_State *L) {
380 const char *filename;
381 const char *name = luaL_checkstring(L, 1);
382 filename = findfile(L, name, "path");
383 if (filename == NULL) return 1; /* library not found in this path */
384 if (luaL_loadfile(L, filename) != 0)
385 loaderror(L, filename);
386 return 1; /* library loaded successfully */
387}
388
389
390static const char *mkfuncname (lua_State *L, const char *modname) {
391 const char *funcname;
392 const char *mark = strchr(modname, *LUA_IGMARK);
393 if (mark) modname = mark + 1;
394 funcname = luaL_gsub(L, modname, ".", LUA_OFSEP);
395 funcname = lua_pushfstring(L, POF"%s", funcname);
396 lua_remove(L, -2); /* remove 'gsub' result */
397 return funcname;
398}
399
400
401static int loader_C (lua_State *L) {
402 const char *funcname;
403 const char *name = luaL_checkstring(L, 1);
404 const char *filename = findfile(L, name, "cpath");
405 if (filename == NULL) return 1; /* library not found in this path */
406 funcname = mkfuncname(L, name);
407 if (ll_loadfunc(L, filename, funcname) != 0)
408 loaderror(L, filename);
409 return 1; /* library loaded successfully */
410}
411
412
413static int loader_Croot (lua_State *L) {
414 const char *funcname;
415 const char *filename;
416 const char *name = luaL_checkstring(L, 1);
417 const char *p = strchr(name, '.');
418 int stat;
419 if (p == NULL) return 0; /* is root */
420 lua_pushlstring(L, name, p - name);
421 filename = findfile(L, lua_tostring(L, -1), "cpath");
422 if (filename == NULL) return 1; /* root not found */
423 funcname = mkfuncname(L, name);
424 if ((stat = ll_loadfunc(L, filename, funcname)) != 0) {
425 if (stat != ERRFUNC) loaderror(L, filename); /* real error */
426 luaO_pushfstring(L, "\n\tno module " LUA_QS " in file " LUA_QS,
427 name, filename);
428 return 1; /* function not found */
429 }
430 return 1;
431}
432
433
434static int loader_preload (lua_State *L) {
435 const char *name = luaL_checkstring(L, 1);
436 lua_getfield(L, LUA_ENVIRONINDEX, "preload");
437 if (!lua_istable(L, -1))
438 luaL_error(L, LUA_QL("package.preload") " must be a table");
439 lua_getfield(L, -1, name);
440 if (lua_isnil(L, -1)) /* not found? */
441 luaO_pushfstring(L, "\n\tno field package.preload['%s']", name);
442 return 1;
443}
444
445
446static const int sentinel_ = 0;
447#define sentinel((void *)&sentinel_)
448
449
450static int ll_require (lua_State *L) {
451 const char *name = luaL_checkstring(L, 1);
452 int i;
453 lua_settop(L, 1); /* _LOADED table will be at index 2 */
454 lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");
455 lua_getfield(L, 2, name);
456 if (lua_toboolean(L, -1)) { /* is it there? */
457 if (lua_touserdata(L, -1) == sentinel) /* check loops */
458 luaL_error(L, "loop or previous error loading module " LUA_QS, name);
459 return 1; /* package is already loaded */
460 }
461 /* else must load it; iterate over available loaders */
462 lua_getfield(L, LUA_ENVIRONINDEX, "loaders");
463 if (!lua_istable(L, -1))
464 luaL_error(L, LUA_QL("package.loaders") " must be a table");
465 lua_pushstring(L, ""); /* error message accumulator */
466 for (i=1; ; i++) {
467 lua_rawgeti(L, -2, i); /* get a loader */
468 if (lua_isnil(L, -1))
469 luaL_error(L, "module " LUA_QS " not found:%s",
470 name, lua_tostring(L, -2));
471 lua_pushstring(L, name);
472 lua_call(L, 1, 1); /* call it */
473 if (lua_isfunction(L, -1)) /* did it find module? */
474 break; /* module loaded successfully */
475 else if (lua_isstring(L, -1)) /* loader returned error message? */
476 lua_concat(L, 2); /* accumulate it */
477 else
478 lua_pop(L, 1);
479 }
480 lua_pushlightuserdata(L, sentinel);
481 lua_setfield(L, 2, name); /* _LOADED[name] = sentinel */
482 lua_pushstring(L, name); /* pass name as argument to module */
483 lua_call(L, 1, 1); /* run loaded module */
484 if (!lua_isnil(L, -1)) /* non-nil return? */
485 lua_setfield(L, 2, name); /* _LOADED[name] = returned value */
486 lua_getfield(L, 2, name);
487 if (lua_touserdata(L, -1) == sentinel) { /* module did not set a value? */
488 lua_pushboolean(L, 1); /* use true as result */
489 lua_pushvalue(L, -1); /* extra copy to be returned */
490 lua_setfield(L, 2, name); /* _LOADED[name] = true */
491 }
492 return 1;
493}
494
495/* }====================================================== */
496
497
498
499/*
500** {======================================================
501** 'module' function
502** =======================================================
503*/
504
505
506static void setfenv (lua_State *L) {
507 lua_Debug ar;
508 lua_getstack(L, 1, &ar);
509 lua_getinfo(L, "f", &ar);
510 lua_pushvalue(L, -2);
511 lua_setfenv(L, -2);
512 lua_pop(L, 1);
513}
514
515
516static void dooptions (lua_State *L, int n) {
517 int i;
518 for (i = 2; i <= n; i++) {
519 lua_pushvalue(L, i); /* get option (a function) */
520 lua_pushvalue(L, -2); /* module */
521 lua_call(L, 1, 0);
522 }
523}
524
525
526static void modinit (lua_State *L, const char *modname) {
527 const char *dot;
528 lua_pushvalue(L, -1);
529 lua_setfield(L, -2, "_M"); /* module._M = module */
530 lua_pushstring(L, modname);
531 lua_setfield(L, -2, "_NAME");
532 dot = strrchr(modname, '.'); /* look for last dot in module name */
533 if (dot == NULL) dot = modname;
534 else dot++;
535 /* set _PACKAGE as package name (full module name minus last part) */
536 lua_pushlstring(L, modname, dot - modname);
537 lua_setfield(L, -2, "_PACKAGE");
538}
539
540
541static int ll_module (lua_State *L) {
542 const char *modname = luaL_checkstring(L, 1);
543 int loaded = lua_gettop(L) + 1; /* index of _LOADED table */
544 lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");
545 lua_getfield(L, loaded, modname); /* get _LOADED[modname] */
546 if (!lua_istable(L, -1)) { /* not found? */
547 lua_pop(L, 1); /* remove previous result */
548 /* try global variable (and create one if it does not exist) */
549 if (luaL_findtable(L, LUA_GLOBALSINDEX, modname, 1) != NULL)
550 return luaL_error(L, "name conflict for module " LUA_QS, modname);
551 lua_pushvalue(L, -1);
552 lua_setfield(L, loaded, modname); /* _LOADED[modname] = new table */
553 }
554 /* check whether table already has a _NAME field */
555 lua_getfield(L, -1, "_NAME");
556 if (!lua_isnil(L, -1)) /* is table an initialized module? */
557 lua_pop(L, 1);
558 else { /* no; initialize it */
559 lua_pop(L, 1);
560 modinit(L, modname);
561 }
562 lua_pushvalue(L, -1);
563 setfenv(L);
564 dooptions(L, loaded - 1);
565 return 0;
566}
567
568
569static int ll_seeall (lua_State *L) {
570 luaL_checktype(L, 1, LUA_TTABLE);
571 if (!lua_getmetatable(L, 1)) {
572 lua_createtable(L, 0, 1); /* create new metatable */
573 lua_pushvalue(L, -1);
574 lua_setmetatable(L, 1);
575 }
576 lua_pushvalue(L, LUA_GLOBALSINDEX);
577 lua_setfield(L, -2, "__index"); /* mt.__index = _G */
578 return 0;
579}
580
581
582/* }====================================================== */
583
584
585
586/* auxiliary mark (for internal use) */
587#define AUXMARK"\1"
588
589static void setpath (lua_State *L, const char *fieldname, const char *envname,
590 const char *def) {
591 const char *path = getenv(envname);
592 if (path == NULL) /* no environment variable? */
593 lua_pushstring(L, def); /* use default */
594 else {
595 /* replace ";;" by ";AUXMARK;" and then AUXMARK by default path */
596 path = luaL_gsub(L, path, LUA_PATHSEP LUA_PATHSEP,
597 LUA_PATHSEP AUXMARK LUA_PATHSEP);
598 luaL_gsub(L, path, AUXMARK, def);
599 lua_remove(L, -2);
600 }
601 setprogdir(L);
602 lua_setfield(L, -2, fieldname);
603}
604
605
606static const luaL_Reg pk_funcs[] = {
607 {"loadlib", ll_loadlib},
608 {"seeall", ll_seeall},
609 {NULL, NULL}
610};
611
612
613static const luaL_Reg ll_funcs[] = {
614 {"module", ll_module},
615 {"require", ll_require},
616 {NULL, NULL}
617};
618
619
620static const lua_CFunction loaders[] =
621 {loader_preload, loader_Lua, loader_C, loader_Croot, NULL};
622
623
624LUALIB_API int luaopen_package (lua_State *L) {
625 int i;
626 /* create new type _LOADLIB */
627 luaL_newmetatable(L, "_LOADLIB");
628 lua_pushcfunction(L, gctm);
629 lua_setfield(L, -2, "__gc");
630 /* create `package' table */
631 luaL_register(L, LUA_LOADLIBNAME, pk_funcs);
632#if defined(LUA_COMPAT_LOADLIB)
633 lua_getfield(L, -1, "loadlib");
634 lua_setfield(L, LUA_GLOBALSINDEX, "loadlib");
635#endif
636 lua_pushvalue(L, -1);
637 lua_replace(L, LUA_ENVIRONINDEX);
638 /* create `loaders' table */
639 lua_createtable(L, 0, sizeof(loaders)/sizeof(loaders[0]) - 1);
640 /* fill it with pre-defined loaders */
641 for (i=0; loaders[i] != NULL; i++) {
642 lua_pushcfunction(L, loaders[i]);
643 lua_rawseti(L, -2, i+1);
644 }
645 lua_setfield(L, -2, "loaders"); /* put it in field `loaders' */
646 setpath(L, "path", LUA_PATH, LUA_PATH_DEFAULT); /* set field `path' */
647 setpath(L, "cpath", LUA_CPATH, LUA_CPATH_DEFAULT); /* set field `cpath' */
648 /* store config information */
649 lua_pushstring(L, LUA_DIRSEP "\n" LUA_PATHSEP "\n" LUA_PATH_MARK "\n"
650 LUA_EXECDIR "\n" LUA_IGMARK);
651 lua_setfield(L, -2, "config");
652 /* set field `loaded' */
653 luaL_findtable(L, LUA_REGISTRYINDEX, "_LOADED", 2);
654 lua_setfield(L, -2, "loaded");
655 /* set field `preload' */
656 lua_newtable(L);
657 lua_setfield(L, -2, "preload");
658 lua_pushvalue(L, LUA_GLOBALSINDEX);
659 luaL_register(L, NULL, ll_funcs); /* open lib into global table */
660 lua_pop(L, 1);
661 return 1; /* return 'package' table */
662}
663

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