1 /*
2 ** $Id: loadlib.c,v 1.130.1.1 2017/04/19 17:20:42 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 Windows, and a stub for other
8 ** systems.
9 */
10 
11 #define loadlib_c
12 #define LUA_LIB
13 
14 #include "lprefix.h"
15 
16 
17 #include <stdio.h>
18 #include <stdlib.h>
19 #include <string.h>
20 
21 #include "lua.h"
22 
23 #include "lauxlib.h"
24 #include "lualib.h"
25 
26 
27 /*
28 ** LUA_IGMARK is a mark to ignore all before it when building the
29 ** luaopen_ function name.
30 */
31 #if !defined (LUA_IGMARK)
32 #define LUA_IGMARK		"-"
33 #endif
34 
35 
36 /*
37 ** LUA_CSUBSEP is the character that replaces dots in submodule names
38 ** when searching for a C loader.
39 ** LUA_LSUBSEP is the character that replaces dots in submodule names
40 ** when searching for a Lua loader.
41 */
42 #if !defined(LUA_CSUBSEP)
43 #define LUA_CSUBSEP		LUA_DIRSEP
44 #endif
45 
46 #if !defined(LUA_LSUBSEP)
47 #define LUA_LSUBSEP		LUA_DIRSEP
48 #endif
49 
50 
51 /* prefix for open functions in C libraries */
52 #define LUA_POF		"luaopen_"
53 
54 /* separator for open functions in C libraries */
55 #define LUA_OFSEP	"_"
56 
57 
58 /*
59 ** unique key for table in the registry that keeps handles
60 ** for all loaded C libraries
61 */
62 static const int CLIBS = 0;
63 
64 #define LIB_FAIL	"open"
65 
66 
67 #define setprogdir(L)           ((void)0)
68 
69 
70 /*
71 ** system-dependent functions
72 */
73 
74 /*
75 ** unload library 'lib'
76 */
77 static void lsys_unloadlib (void *lib);
78 
79 /*
80 ** load C library in file 'path'. If 'seeglb', load with all names in
81 ** the library global.
82 ** Returns the library; in case of error, returns NULL plus an
83 ** error string in the stack.
84 */
85 static void *lsys_load (lua_State *L, const char *path, int seeglb);
86 
87 /*
88 ** Try to find a function named 'sym' in library 'lib'.
89 ** Returns the function; in case of error, returns NULL plus an
90 ** error string in the stack.
91 */
92 static lua_CFunction lsys_sym (lua_State *L, void *lib, const char *sym);
93 
94 
95 
96 
97 #if defined(LUA_USE_DLOPEN)	/* { */
98 /*
99 ** {========================================================================
100 ** This is an implementation of loadlib based on the dlfcn interface.
101 ** The dlfcn interface is available in Linux, SunOS, Solaris, IRIX, FreeBSD,
102 ** NetBSD, AIX 4.2, HPUX 11, and  probably most other Unix flavors, at least
103 ** as an emulation layer on top of native functions.
104 ** =========================================================================
105 */
106 
107 #include <dlfcn.h>
108 
109 /*
110 ** Macro to convert pointer-to-void* to pointer-to-function. This cast
111 ** is undefined according to ISO C, but POSIX assumes that it works.
112 ** (The '__extension__' in gnu compilers is only to avoid warnings.)
113 */
114 #if defined(__GNUC__)
115 #define cast_func(p) (__extension__ (lua_CFunction)(p))
116 #else
117 #define cast_func(p) ((lua_CFunction)(p))
118 #endif
119 
120 
lsys_unloadlib(void * lib)121 static void lsys_unloadlib (void *lib) {
122   dlclose(lib);
123 }
124 
125 
lsys_load(lua_State * L,const char * path,int seeglb)126 static void *lsys_load (lua_State *L, const char *path, int seeglb) {
127   void *lib = dlopen(path, RTLD_NOW | (seeglb ? RTLD_GLOBAL : RTLD_LOCAL));
128   if (lib == NULL) lua_pushstring(L, dlerror());
129   return lib;
130 }
131 
132 
lsys_sym(lua_State * L,void * lib,const char * sym)133 static lua_CFunction lsys_sym (lua_State *L, void *lib, const char *sym) {
134   lua_CFunction f = cast_func(dlsym(lib, sym));
135   if (f == NULL) lua_pushstring(L, dlerror());
136   return f;
137 }
138 
139 /* }====================================================== */
140 
141 
142 
143 #elif defined(LUA_DL_DLL)	/* }{ */
144 /*
145 ** {======================================================================
146 ** This is an implementation of loadlib for Windows using native functions.
147 ** =======================================================================
148 */
149 
150 #include <windows.h>
151 
152 
153 /*
154 ** optional flags for LoadLibraryEx
155 */
156 #if !defined(LUA_LLE_FLAGS)
157 #define LUA_LLE_FLAGS	0
158 #endif
159 
160 
161 #undef setprogdir
162 
163 
164 /*
165 ** Replace in the path (on the top of the stack) any occurrence
166 ** of LUA_EXEC_DIR with the executable's path.
167 */
setprogdir(lua_State * L)168 static void setprogdir (lua_State *L) {
169   char buff[MAX_PATH + 1];
170   char *lb;
171   DWORD nsize = sizeof(buff)/sizeof(char);
172   DWORD n = GetModuleFileNameA(NULL, buff, nsize);  /* get exec. name */
173   if (n == 0 || n == nsize || (lb = strrchr(buff, '\\')) == NULL)
174     luaL_error(L, "unable to get ModuleFileName");
175   else {
176     *lb = '\0';  /* cut name on the last '\\' to get the path */
177     luaL_gsub(L, lua_tostring(L, -1), LUA_EXEC_DIR, buff);
178     lua_remove(L, -2);  /* remove original string */
179   }
180 }
181 
182 
183 
184 
pusherror(lua_State * L)185 static void pusherror (lua_State *L) {
186   int error = GetLastError();
187   char buffer[128];
188   if (FormatMessageA(FORMAT_MESSAGE_IGNORE_INSERTS | FORMAT_MESSAGE_FROM_SYSTEM,
189       NULL, error, 0, buffer, sizeof(buffer)/sizeof(char), NULL))
190     lua_pushstring(L, buffer);
191   else
192     lua_pushfstring(L, "system error %d\n", error);
193 }
194 
lsys_unloadlib(void * lib)195 static void lsys_unloadlib (void *lib) {
196   FreeLibrary((HMODULE)lib);
197 }
198 
199 
lsys_load(lua_State * L,const char * path,int seeglb)200 static void *lsys_load (lua_State *L, const char *path, int seeglb) {
201   HMODULE lib = LoadLibraryExA(path, NULL, LUA_LLE_FLAGS);
202   (void)(seeglb);  /* not used: symbols are 'global' by default */
203   if (lib == NULL) pusherror(L);
204   return lib;
205 }
206 
207 
lsys_sym(lua_State * L,void * lib,const char * sym)208 static lua_CFunction lsys_sym (lua_State *L, void *lib, const char *sym) {
209   lua_CFunction f = (lua_CFunction)GetProcAddress((HMODULE)lib, sym);
210   if (f == NULL) pusherror(L);
211   return f;
212 }
213 
214 /* }====================================================== */
215 
216 
217 #else				/* }{ */
218 /*
219 ** {======================================================
220 ** Fallback for other systems
221 ** =======================================================
222 */
223 
224 #undef LIB_FAIL
225 #define LIB_FAIL	"absent"
226 
227 
228 #define DLMSG	"dynamic libraries not enabled; check your Lua installation"
229 
230 
lsys_unloadlib(void * lib)231 static void lsys_unloadlib (void *lib) {
232   (void)(lib);  /* not used */
233 }
234 
235 
lsys_load(lua_State * L,const char * path,int seeglb)236 static void *lsys_load (lua_State *L, const char *path, int seeglb) {
237   (void)(path); (void)(seeglb);  /* not used */
238   lua_pushliteral(L, DLMSG);
239   return NULL;
240 }
241 
242 
lsys_sym(lua_State * L,void * lib,const char * sym)243 static lua_CFunction lsys_sym (lua_State *L, void *lib, const char *sym) {
244   (void)(lib); (void)(sym);  /* not used */
245   lua_pushliteral(L, DLMSG);
246   return NULL;
247 }
248 
249 /* }====================================================== */
250 #endif				/* } */
251 
252 
253 /*
254 ** {==================================================================
255 ** Set Paths
256 ** ===================================================================
257 */
258 
259 /*
260 ** LUA_PATH_VAR and LUA_CPATH_VAR are the names of the environment
261 ** variables that Lua check to set its paths.
262 */
263 #if !defined(LUA_PATH_VAR)
264 #define LUA_PATH_VAR    "LUA_PATH"
265 #endif
266 
267 #if !defined(LUA_CPATH_VAR)
268 #define LUA_CPATH_VAR   "LUA_CPATH"
269 #endif
270 
271 
272 #define AUXMARK         "\1"	/* auxiliary mark */
273 
274 
275 /*
276 ** return registry.LUA_NOENV as a boolean
277 */
noenv(lua_State * L)278 static int noenv (lua_State *L) {
279   int b;
280   lua_getfield(L, LUA_REGISTRYINDEX, "LUA_NOENV");
281   b = lua_toboolean(L, -1);
282   lua_pop(L, 1);  /* remove value */
283   return b;
284 }
285 
286 
287 /*
288 ** Set a path
289 */
setpath(lua_State * L,const char * fieldname,const char * envname,const char * dft)290 static void setpath (lua_State *L, const char *fieldname,
291                                    const char *envname,
292                                    const char *dft) {
293   const char *nver = lua_pushfstring(L, "%s%s", envname, LUA_VERSUFFIX);
294   const char *path = getenv(nver);  /* use versioned name */
295   if (path == NULL)  /* no environment variable? */
296     path = getenv(envname);  /* try unversioned name */
297   if (path == NULL || noenv(L))  /* no environment variable? */
298     lua_pushstring(L, dft);  /* use default */
299   else {
300     /* replace ";;" by ";AUXMARK;" and then AUXMARK by default path */
301     path = luaL_gsub(L, path, LUA_PATH_SEP LUA_PATH_SEP,
302                               LUA_PATH_SEP AUXMARK LUA_PATH_SEP);
303     luaL_gsub(L, path, AUXMARK, dft);
304     lua_remove(L, -2); /* remove result from 1st 'gsub' */
305   }
306   setprogdir(L);
307   lua_setfield(L, -3, fieldname);  /* package[fieldname] = path value */
308   lua_pop(L, 1);  /* pop versioned variable name */
309 }
310 
311 /* }================================================================== */
312 
313 
314 /*
315 ** return registry.CLIBS[path]
316 */
checkclib(lua_State * L,const char * path)317 static void *checkclib (lua_State *L, const char *path) {
318   void *plib;
319   lua_rawgetp(L, LUA_REGISTRYINDEX, &CLIBS);
320   lua_getfield(L, -1, path);
321   plib = lua_touserdata(L, -1);  /* plib = CLIBS[path] */
322   lua_pop(L, 2);  /* pop CLIBS table and 'plib' */
323   return plib;
324 }
325 
326 
327 /*
328 ** registry.CLIBS[path] = plib        -- for queries
329 ** registry.CLIBS[#CLIBS + 1] = plib  -- also keep a list of all libraries
330 */
addtoclib(lua_State * L,const char * path,void * plib)331 static void addtoclib (lua_State *L, const char *path, void *plib) {
332   lua_rawgetp(L, LUA_REGISTRYINDEX, &CLIBS);
333   lua_pushlightuserdata(L, plib);
334   lua_pushvalue(L, -1);
335   lua_setfield(L, -3, path);  /* CLIBS[path] = plib */
336   lua_rawseti(L, -2, luaL_len(L, -2) + 1);  /* CLIBS[#CLIBS + 1] = plib */
337   lua_pop(L, 1);  /* pop CLIBS table */
338 }
339 
340 
341 /*
342 ** __gc tag method for CLIBS table: calls 'lsys_unloadlib' for all lib
343 ** handles in list CLIBS
344 */
gctm(lua_State * L)345 static int gctm (lua_State *L) {
346   lua_Integer n = luaL_len(L, 1);
347   for (; n >= 1; n--) {  /* for each handle, in reverse order */
348     lua_rawgeti(L, 1, n);  /* get handle CLIBS[n] */
349     lsys_unloadlib(lua_touserdata(L, -1));
350     lua_pop(L, 1);  /* pop handle */
351   }
352   return 0;
353 }
354 
355 
356 
357 /* error codes for 'lookforfunc' */
358 #define ERRLIB		1
359 #define ERRFUNC		2
360 
361 /*
362 ** Look for a C function named 'sym' in a dynamically loaded library
363 ** 'path'.
364 ** First, check whether the library is already loaded; if not, try
365 ** to load it.
366 ** Then, if 'sym' is '*', return true (as library has been loaded).
367 ** Otherwise, look for symbol 'sym' in the library and push a
368 ** C function with that symbol.
369 ** Return 0 and 'true' or a function in the stack; in case of
370 ** errors, return an error code and an error message in the stack.
371 */
lookforfunc(lua_State * L,const char * path,const char * sym)372 static int lookforfunc (lua_State *L, const char *path, const char *sym) {
373   void *reg = checkclib(L, path);  /* check loaded C libraries */
374   if (reg == NULL) {  /* must load library? */
375     reg = lsys_load(L, path, *sym == '*');  /* global symbols if 'sym'=='*' */
376     if (reg == NULL) return ERRLIB;  /* unable to load library */
377     addtoclib(L, path, reg);
378   }
379   if (*sym == '*') {  /* loading only library (no function)? */
380     lua_pushboolean(L, 1);  /* return 'true' */
381     return 0;  /* no errors */
382   }
383   else {
384     lua_CFunction f = lsys_sym(L, reg, sym);
385     if (f == NULL)
386       return ERRFUNC;  /* unable to find function */
387     lua_pushcfunction(L, f);  /* else create new function */
388     return 0;  /* no errors */
389   }
390 }
391 
392 
ll_loadlib(lua_State * L)393 static int ll_loadlib (lua_State *L) {
394   const char *path = luaL_checkstring(L, 1);
395   const char *init = luaL_checkstring(L, 2);
396   int stat = lookforfunc(L, path, init);
397   if (stat == 0)  /* no errors? */
398     return 1;  /* return the loaded function */
399   else {  /* error; error message is on stack top */
400     lua_pushnil(L);
401     lua_insert(L, -2);
402     lua_pushstring(L, (stat == ERRLIB) ?  LIB_FAIL : "init");
403     return 3;  /* return nil, error message, and where */
404   }
405 }
406 
407 
408 
409 /*
410 ** {======================================================
411 ** 'require' function
412 ** =======================================================
413 */
414 
415 
readable(const char * filename)416 static int readable (const char *filename) {
417   FILE *f = fopen(filename, "r");  /* try to open file */
418   if (f == NULL) return 0;  /* open failed */
419   fclose(f);
420   return 1;
421 }
422 
423 
pushnexttemplate(lua_State * L,const char * path)424 static const char *pushnexttemplate (lua_State *L, const char *path) {
425   const char *l;
426   while (*path == *LUA_PATH_SEP) path++;  /* skip separators */
427   if (*path == '\0') return NULL;  /* no more templates */
428   l = strchr(path, *LUA_PATH_SEP);  /* find next separator */
429   if (l == NULL) l = path + strlen(path);
430   lua_pushlstring(L, path, l - path);  /* template */
431   return l;
432 }
433 
434 
searchpath(lua_State * L,const char * name,const char * path,const char * sep,const char * dirsep)435 static const char *searchpath (lua_State *L, const char *name,
436                                              const char *path,
437                                              const char *sep,
438                                              const char *dirsep) {
439   luaL_Buffer msg;  /* to build error message */
440   luaL_buffinit(L, &msg);
441   if (*sep != '\0')  /* non-empty separator? */
442     name = luaL_gsub(L, name, sep, dirsep);  /* replace it by 'dirsep' */
443   while ((path = pushnexttemplate(L, path)) != NULL) {
444     const char *filename = luaL_gsub(L, lua_tostring(L, -1),
445                                      LUA_PATH_MARK, name);
446     lua_remove(L, -2);  /* remove path template */
447     if (readable(filename))  /* does file exist and is readable? */
448       return filename;  /* return that file name */
449     lua_pushfstring(L, "\n\tno file '%s'", filename);
450     lua_remove(L, -2);  /* remove file name */
451     luaL_addvalue(&msg);  /* concatenate error msg. entry */
452   }
453   luaL_pushresult(&msg);  /* create error message */
454   return NULL;  /* not found */
455 }
456 
457 
ll_searchpath(lua_State * L)458 static int ll_searchpath (lua_State *L) {
459   const char *f = searchpath(L, luaL_checkstring(L, 1),
460                                 luaL_checkstring(L, 2),
461                                 luaL_optstring(L, 3, "."),
462                                 luaL_optstring(L, 4, LUA_DIRSEP));
463   if (f != NULL) return 1;
464   else {  /* error message is on top of the stack */
465     lua_pushnil(L);
466     lua_insert(L, -2);
467     return 2;  /* return nil + error message */
468   }
469 }
470 
471 
findfile(lua_State * L,const char * name,const char * pname,const char * dirsep)472 static const char *findfile (lua_State *L, const char *name,
473                                            const char *pname,
474                                            const char *dirsep) {
475   const char *path;
476   lua_getfield(L, lua_upvalueindex(1), pname);
477   path = lua_tostring(L, -1);
478   if (path == NULL)
479     luaL_error(L, "'package.%s' must be a string", pname);
480   return searchpath(L, name, path, ".", dirsep);
481 }
482 
483 
checkload(lua_State * L,int stat,const char * filename)484 static int checkload (lua_State *L, int stat, const char *filename) {
485   if (stat) {  /* module loaded successfully? */
486     lua_pushstring(L, filename);  /* will be 2nd argument to module */
487     return 2;  /* return open function and file name */
488   }
489   else
490     return luaL_error(L, "error loading module '%s' from file '%s':\n\t%s",
491                           lua_tostring(L, 1), filename, lua_tostring(L, -1));
492 }
493 
494 
searcher_Lua(lua_State * L)495 static int searcher_Lua (lua_State *L) {
496   const char *filename;
497   const char *name = luaL_checkstring(L, 1);
498   filename = findfile(L, name, "path", LUA_LSUBSEP);
499   if (filename == NULL) return 1;  /* module not found in this path */
500   return checkload(L, (luaL_loadfile(L, filename) == LUA_OK), filename);
501 }
502 
503 
504 /*
505 ** Try to find a load function for module 'modname' at file 'filename'.
506 ** First, change '.' to '_' in 'modname'; then, if 'modname' has
507 ** the form X-Y (that is, it has an "ignore mark"), build a function
508 ** name "luaopen_X" and look for it. (For compatibility, if that
509 ** fails, it also tries "luaopen_Y".) If there is no ignore mark,
510 ** look for a function named "luaopen_modname".
511 */
loadfunc(lua_State * L,const char * filename,const char * modname)512 static int loadfunc (lua_State *L, const char *filename, const char *modname) {
513   const char *openfunc;
514   const char *mark;
515   modname = luaL_gsub(L, modname, ".", LUA_OFSEP);
516   mark = strchr(modname, *LUA_IGMARK);
517   if (mark) {
518     int stat;
519     openfunc = lua_pushlstring(L, modname, mark - modname);
520     openfunc = lua_pushfstring(L, LUA_POF"%s", openfunc);
521     stat = lookforfunc(L, filename, openfunc);
522     if (stat != ERRFUNC) return stat;
523     modname = mark + 1;  /* else go ahead and try old-style name */
524   }
525   openfunc = lua_pushfstring(L, LUA_POF"%s", modname);
526   return lookforfunc(L, filename, openfunc);
527 }
528 
529 
searcher_C(lua_State * L)530 static int searcher_C (lua_State *L) {
531   const char *name = luaL_checkstring(L, 1);
532   const char *filename = findfile(L, name, "cpath", LUA_CSUBSEP);
533   if (filename == NULL) return 1;  /* module not found in this path */
534   return checkload(L, (loadfunc(L, filename, name) == 0), filename);
535 }
536 
537 
searcher_Croot(lua_State * L)538 static int searcher_Croot (lua_State *L) {
539   const char *filename;
540   const char *name = luaL_checkstring(L, 1);
541   const char *p = strchr(name, '.');
542   int stat;
543   if (p == NULL) return 0;  /* is root */
544   lua_pushlstring(L, name, p - name);
545   filename = findfile(L, lua_tostring(L, -1), "cpath", LUA_CSUBSEP);
546   if (filename == NULL) return 1;  /* root not found */
547   if ((stat = loadfunc(L, filename, name)) != 0) {
548     if (stat != ERRFUNC)
549       return checkload(L, 0, filename);  /* real error */
550     else {  /* open function not found */
551       lua_pushfstring(L, "\n\tno module '%s' in file '%s'", name, filename);
552       return 1;
553     }
554   }
555   lua_pushstring(L, filename);  /* will be 2nd argument to module */
556   return 2;
557 }
558 
559 
searcher_preload(lua_State * L)560 static int searcher_preload (lua_State *L) {
561   const char *name = luaL_checkstring(L, 1);
562   lua_getfield(L, LUA_REGISTRYINDEX, LUA_PRELOAD_TABLE);
563   if (lua_getfield(L, -1, name) == LUA_TNIL)  /* not found? */
564     lua_pushfstring(L, "\n\tno field package.preload['%s']", name);
565   return 1;
566 }
567 
568 
findloader(lua_State * L,const char * name)569 static void findloader (lua_State *L, const char *name) {
570   int i;
571   luaL_Buffer msg;  /* to build error message */
572   luaL_buffinit(L, &msg);
573   /* push 'package.searchers' to index 3 in the stack */
574   if (lua_getfield(L, lua_upvalueindex(1), "searchers") != LUA_TTABLE)
575     luaL_error(L, "'package.searchers' must be a table");
576   /*  iterate over available searchers to find a loader */
577   for (i = 1; ; i++) {
578     if (lua_rawgeti(L, 3, i) == LUA_TNIL) {  /* no more searchers? */
579       lua_pop(L, 1);  /* remove nil */
580       luaL_pushresult(&msg);  /* create error message */
581       luaL_error(L, "module '%s' not found:%s", name, lua_tostring(L, -1));
582     }
583     lua_pushstring(L, name);
584     lua_call(L, 1, 2);  /* call it */
585     if (lua_isfunction(L, -2))  /* did it find a loader? */
586       return;  /* module loader found */
587     else if (lua_isstring(L, -2)) {  /* searcher returned error message? */
588       lua_pop(L, 1);  /* remove extra return */
589       luaL_addvalue(&msg);  /* concatenate error message */
590     }
591     else
592       lua_pop(L, 2);  /* remove both returns */
593   }
594 }
595 
596 
ll_require(lua_State * L)597 static int ll_require (lua_State *L) {
598   const char *name = luaL_checkstring(L, 1);
599   lua_settop(L, 1);  /* LOADED table will be at index 2 */
600   lua_getfield(L, LUA_REGISTRYINDEX, LUA_LOADED_TABLE);
601   lua_getfield(L, 2, name);  /* LOADED[name] */
602   if (lua_toboolean(L, -1))  /* is it there? */
603     return 1;  /* package is already loaded */
604   /* else must load package */
605   lua_pop(L, 1);  /* remove 'getfield' result */
606   findloader(L, name);
607   lua_pushstring(L, name);  /* pass name as argument to module loader */
608   lua_insert(L, -2);  /* name is 1st argument (before search data) */
609   lua_call(L, 2, 1);  /* run loader to load module */
610   if (!lua_isnil(L, -1))  /* non-nil return? */
611     lua_setfield(L, 2, name);  /* LOADED[name] = returned value */
612   if (lua_getfield(L, 2, name) == LUA_TNIL) {   /* module set no value? */
613     lua_pushboolean(L, 1);  /* use true as result */
614     lua_pushvalue(L, -1);  /* extra copy to be returned */
615     lua_setfield(L, 2, name);  /* LOADED[name] = true */
616   }
617   return 1;
618 }
619 
620 /* }====================================================== */
621 
622 
623 
624 /*
625 ** {======================================================
626 ** 'module' function
627 ** =======================================================
628 */
629 #if defined(LUA_COMPAT_MODULE)
630 
631 /*
632 ** changes the environment variable of calling function
633 */
set_env(lua_State * L)634 static void set_env (lua_State *L) {
635   lua_Debug ar;
636   if (lua_getstack(L, 1, &ar) == 0 ||
637       lua_getinfo(L, "f", &ar) == 0 ||  /* get calling function */
638       lua_iscfunction(L, -1))
639     luaL_error(L, "'module' not called from a Lua function");
640   lua_pushvalue(L, -2);  /* copy new environment table to top */
641   lua_setupvalue(L, -2, 1);
642   lua_pop(L, 1);  /* remove function */
643 }
644 
645 
dooptions(lua_State * L,int n)646 static void dooptions (lua_State *L, int n) {
647   int i;
648   for (i = 2; i <= n; i++) {
649     if (lua_isfunction(L, i)) {  /* avoid 'calling' extra info. */
650       lua_pushvalue(L, i);  /* get option (a function) */
651       lua_pushvalue(L, -2);  /* module */
652       lua_call(L, 1, 0);
653     }
654   }
655 }
656 
657 
modinit(lua_State * L,const char * modname)658 static void modinit (lua_State *L, const char *modname) {
659   const char *dot;
660   lua_pushvalue(L, -1);
661   lua_setfield(L, -2, "_M");  /* module._M = module */
662   lua_pushstring(L, modname);
663   lua_setfield(L, -2, "_NAME");
664   dot = strrchr(modname, '.');  /* look for last dot in module name */
665   if (dot == NULL) dot = modname;
666   else dot++;
667   /* set _PACKAGE as package name (full module name minus last part) */
668   lua_pushlstring(L, modname, dot - modname);
669   lua_setfield(L, -2, "_PACKAGE");
670 }
671 
672 
ll_module(lua_State * L)673 static int ll_module (lua_State *L) {
674   const char *modname = luaL_checkstring(L, 1);
675   int lastarg = lua_gettop(L);  /* last parameter */
676   luaL_pushmodule(L, modname, 1);  /* get/create module table */
677   /* check whether table already has a _NAME field */
678   if (lua_getfield(L, -1, "_NAME") != LUA_TNIL)
679     lua_pop(L, 1);  /* table is an initialized module */
680   else {  /* no; initialize it */
681     lua_pop(L, 1);
682     modinit(L, modname);
683   }
684   lua_pushvalue(L, -1);
685   set_env(L);
686   dooptions(L, lastarg);
687   return 1;
688 }
689 
690 
ll_seeall(lua_State * L)691 static int ll_seeall (lua_State *L) {
692   luaL_checktype(L, 1, LUA_TTABLE);
693   if (!lua_getmetatable(L, 1)) {
694     lua_createtable(L, 0, 1); /* create new metatable */
695     lua_pushvalue(L, -1);
696     lua_setmetatable(L, 1);
697   }
698   lua_pushglobaltable(L);
699   lua_setfield(L, -2, "__index");  /* mt.__index = _G */
700   return 0;
701 }
702 
703 #endif
704 /* }====================================================== */
705 
706 
707 
708 static const luaL_Reg pk_funcs[] = {
709   {"loadlib", ll_loadlib},
710   {"searchpath", ll_searchpath},
711 #if defined(LUA_COMPAT_MODULE)
712   {"seeall", ll_seeall},
713 #endif
714   /* placeholders */
715   {"preload", NULL},
716   {"cpath", NULL},
717   {"path", NULL},
718   {"searchers", NULL},
719   {"loaded", NULL},
720   {NULL, NULL}
721 };
722 
723 
724 static const luaL_Reg ll_funcs[] = {
725 #if defined(LUA_COMPAT_MODULE)
726   {"module", ll_module},
727 #endif
728   {"require", ll_require},
729   {NULL, NULL}
730 };
731 
732 
createsearcherstable(lua_State * L)733 static void createsearcherstable (lua_State *L) {
734   static const lua_CFunction searchers[] =
735     {searcher_preload, searcher_Lua, searcher_C, searcher_Croot, NULL};
736   int i;
737   /* create 'searchers' table */
738   lua_createtable(L, sizeof(searchers)/sizeof(searchers[0]) - 1, 0);
739   /* fill it with predefined searchers */
740   for (i=0; searchers[i] != NULL; i++) {
741     lua_pushvalue(L, -2);  /* set 'package' as upvalue for all searchers */
742     lua_pushcclosure(L, searchers[i], 1);
743     lua_rawseti(L, -2, i+1);
744   }
745 #if defined(LUA_COMPAT_LOADERS)
746   lua_pushvalue(L, -1);  /* make a copy of 'searchers' table */
747   lua_setfield(L, -3, "loaders");  /* put it in field 'loaders' */
748 #endif
749   lua_setfield(L, -2, "searchers");  /* put it in field 'searchers' */
750 }
751 
752 
753 /*
754 ** create table CLIBS to keep track of loaded C libraries,
755 ** setting a finalizer to close all libraries when closing state.
756 */
createclibstable(lua_State * L)757 static void createclibstable (lua_State *L) {
758   lua_newtable(L);  /* create CLIBS table */
759   lua_createtable(L, 0, 1);  /* create metatable for CLIBS */
760   lua_pushcfunction(L, gctm);
761   lua_setfield(L, -2, "__gc");  /* set finalizer for CLIBS table */
762   lua_setmetatable(L, -2);
763   lua_rawsetp(L, LUA_REGISTRYINDEX, &CLIBS);  /* set CLIBS table in registry */
764 }
765 
766 
luaopen_package(lua_State * L)767 LUAMOD_API int luaopen_package (lua_State *L) {
768   createclibstable(L);
769   luaL_newlib(L, pk_funcs);  /* create 'package' table */
770   createsearcherstable(L);
771   /* set paths */
772   setpath(L, "path", LUA_PATH_VAR, LUA_PATH_DEFAULT);
773   setpath(L, "cpath", LUA_CPATH_VAR, LUA_CPATH_DEFAULT);
774   /* store config information */
775   lua_pushliteral(L, LUA_DIRSEP "\n" LUA_PATH_SEP "\n" LUA_PATH_MARK "\n"
776                      LUA_EXEC_DIR "\n" LUA_IGMARK "\n");
777   lua_setfield(L, -2, "config");
778   /* set field 'loaded' */
779   luaL_getsubtable(L, LUA_REGISTRYINDEX, LUA_LOADED_TABLE);
780   lua_setfield(L, -2, "loaded");
781   /* set field 'preload' */
782   luaL_getsubtable(L, LUA_REGISTRYINDEX, LUA_PRELOAD_TABLE);
783   lua_setfield(L, -2, "preload");
784   lua_pushglobaltable(L);
785   lua_pushvalue(L, -2);  /* set 'package' as upvalue for next lib */
786   luaL_setfuncs(L, ll_funcs, 1);  /* open lib into global table */
787   lua_pop(L, 1);  /* pop global table */
788   return 1;  /* return 'package' table */
789 }
790 
791