com32/lua/src/loadlib.c

   1 /*
   2 ** $Id: loadlib.c,v 1.111.1.1 2013/04/12 18:48:47 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
  12 /*
  13 ** if needed, includes windows header before everything else
  14 */
  15 #if defined(_WIN32)
  16 #include <windows.h>
  17 #endif
  18
  19 /* Base the Lua paths on the Syslinux path */
  20 #ifdef SYSLINUX
  21 #include <fs.h>
  22 #endif
  23
  24 #include <stdlib.h>
  25 #include <string.h>
  26
  27
  28 #define loadlib_c
  29 #define LUA_LIB
  30
  31 #include "lua.h"
  32
  33 #include "lauxlib.h"
  34 #include "lualib.h"
  35
  36
  37 /*
  38 ** LUA_PATH and LUA_CPATH are the names of the environment
  39 ** variables that Lua check to set its paths.
  40 */
  41 #if !defined(LUA_PATH)
  42 #define LUA_PATH        "LUA_PATH"
  43 #endif
  44
  45 #if !defined(LUA_CPATH)
  46 #define LUA_CPATH       "LUA_CPATH"
  47 #endif
  48
  49 #define LUA_PATHSUFFIX          "_" LUA_VERSION_MAJOR "_" LUA_VERSION_MINOR
  50
  51 #define LUA_PATHVERSION         LUA_PATH LUA_PATHSUFFIX
  52 #define LUA_CPATHVERSION        LUA_CPATH LUA_PATHSUFFIX
  53
  54 /*
  55 ** LUA_PATH_SEP is the character that separates templates in a path.
  56 ** LUA_PATH_MARK is the string that marks the substitution points in a
  57 ** template.
  58 ** LUA_EXEC_DIR in a Windows path is replaced by the executable's
  59 ** directory.
  60 ** LUA_IGMARK is a mark to ignore all before it when building the
  61 ** luaopen_ function name.
  62 */
  63 #if !defined (LUA_PATH_SEP)
  64 #define LUA_PATH_SEP            ";"
  65 #endif
  66 #if !defined (LUA_PATH_MARK)
  67 #define LUA_PATH_MARK           "?"
  68 #endif
  69 #if !defined (LUA_EXEC_DIR)
  70 #define LUA_EXEC_DIR            "!"
  71 #endif
  72 #if !defined (LUA_IGMARK)
  73 #define LUA_IGMARK              "-"
  74 #endif
  75
  76
  77 /*
  78 ** LUA_CSUBSEP is the character that replaces dots in submodule names
  79 ** when searching for a C loader.
  80 ** LUA_LSUBSEP is the character that replaces dots in submodule names
  81 ** when searching for a Lua loader.
  82 */
  83 #if !defined(LUA_CSUBSEP)
  84 #define LUA_CSUBSEP             LUA_DIRSEP
  85 #endif
  86
  87 #if !defined(LUA_LSUBSEP)
  88 #define LUA_LSUBSEP             LUA_DIRSEP
  89 #endif
  90
  91
  92 /* prefix for open functions in C libraries */
  93 #define LUA_POF         "luaopen_"
  94
  95 /* separator for open functions in C libraries */
  96 #define LUA_OFSEP       "_"
  97
  98
  99 /* table (in the registry) that keeps handles for all loaded C libraries */
 100 #define CLIBS           "_CLIBS"
 101
 102 #define LIB_FAIL        "open"
 103
 104
 105 /* error codes for ll_loadfunc */
 106 #define ERRLIB          1
 107 #define ERRFUNC         2
 108
 109 #define setprogdir(L)           ((void)0)
 110
 111
 112 /*
 113 ** system-dependent functions
 114 */
 115 static void ll_unloadlib (void *lib);
 116 static void *ll_load (lua_State *L, const char *path, int seeglb);
 117 static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym);
 118
 119
 120
 121 #if defined(LUA_USE_DLOPEN)
 122 /*
 123 ** {========================================================================
 124 ** This is an implementation of loadlib based on the dlfcn interface.
 125 ** The dlfcn interface is available in Linux, SunOS, Solaris, IRIX, FreeBSD,
 126 ** NetBSD, AIX 4.2, HPUX 11, and  probably most other Unix flavors, at least
 127 ** as an emulation layer on top of native functions.
 128 ** =========================================================================
 129 */
 130
 131 #include <dlfcn.h>
 132
 133 static void ll_unloadlib (void *lib) {
 134   dlclose(lib);
 135 }
 136
 137
 138 static void *ll_load (lua_State *L, const char *path, int seeglb) {
 139   void *lib = dlopen(path, RTLD_NOW | (seeglb ? RTLD_GLOBAL : RTLD_LOCAL));
 140   if (lib == NULL) lua_pushstring(L, dlerror());
 141   return lib;
 142 }
 143
 144
 145 static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) {
 146   lua_CFunction f = (lua_CFunction)dlsym(lib, sym);
 147   if (f == NULL) lua_pushstring(L, dlerror());
 148   return f;
 149 }
 150
 151 /* }====================================================== */
 152
 153
 154
 155 #elif defined(LUA_DL_DLL)
 156 /*
 157 ** {======================================================================
 158 ** This is an implementation of loadlib for Windows using native functions.
 159 ** =======================================================================
 160 */
 161
 162 #undef setprogdir
 163
 164 /*
 165 ** optional flags for LoadLibraryEx
 166 */
 167 #if !defined(LUA_LLE_FLAGS)
 168 #define LUA_LLE_FLAGS   0
 169 #endif
 170
 171
 172 static void setprogdir (lua_State *L) {
 173   char buff[MAX_PATH + 1];
 174   char *lb;
 175   DWORD nsize = sizeof(buff)/sizeof(char);
 176   DWORD n = GetModuleFileNameA(NULL, buff, nsize);
 177   if (n == 0 || n == nsize || (lb = strrchr(buff, '\\')) == NULL)
 178     luaL_error(L, "unable to get ModuleFileName");
 179   else {
 180     *lb = '\0';
 181     luaL_gsub(L, lua_tostring(L, -1), LUA_EXEC_DIR, buff);
 182     lua_remove(L, -2);  /* remove original string */
 183   }
 184 }
 185
 186
 187 static void pusherror (lua_State *L) {
 188   int error = GetLastError();
 189   char buffer[128];
 190   if (FormatMessageA(FORMAT_MESSAGE_IGNORE_INSERTS | FORMAT_MESSAGE_FROM_SYSTEM,
 191       NULL, error, 0, buffer, sizeof(buffer)/sizeof(char), NULL))
 192     lua_pushstring(L, buffer);
 193   else
 194     lua_pushfstring(L, "system error %d\n", error);
 195 }
 196
 197 static void ll_unloadlib (void *lib) {
 198   FreeLibrary((HMODULE)lib);
 199 }
 200
 201
 202 static void *ll_load (lua_State *L, const char *path, int seeglb) {
 203   HMODULE lib = LoadLibraryExA(path, NULL, LUA_LLE_FLAGS);
 204   (void)(seeglb);  /* not used: symbols are 'global' by default */
 205   if (lib == NULL) pusherror(L);
 206   return lib;
 207 }
 208
 209
 210 static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) {
 211   lua_CFunction f = (lua_CFunction)GetProcAddress((HMODULE)lib, sym);
 212   if (f == NULL) pusherror(L);
 213   return f;
 214 }
 215
 216 /* }====================================================== */
 217
 218
 219 #elif defined(SYSLINUX)
 220 /*
 221 ** {=========================================================================
 222 ** This is an implementation of loadlib for the Syslinux COM32 module system.
 223 ** ==========================================================================
 224 */
 225
 226 #include <sys/module.h>
 227
 228 static void ll_unloadlib (void *lib) {
 229   module_unload ((struct elf_module *)lib);
 230 }
 231
 232
 233 static void *ll_load (lua_State *L, const char *path, int seeglb) {
 234   int err;
 235   struct elf_module *lib = module_alloc (path);
 236   if (lib == NULL) {
 237     lua_pushstring (L, "module not found");
 238     return NULL;
 239   }
 240   (void)seeglb; /* gcc, ignore it */
 241   err = module_load (lib);
 242   if (err) {
 243     printf ("module load error: %d\n", err);
 244     lua_pushstring (L, "failed to load module");
 245     return NULL;
 246   }
 247   return (void *)lib;
 248 }
 249
 250
 251 static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) {
 252   Elf_Sym *p = module_find_symbol (sym, (struct elf_module *)lib);
 253   if (p == NULL) {
 254     lua_pushstring (L, "symbol not found in module");
 255     return NULL;
 256   }
 257   return (lua_CFunction)module_get_absolute(p->st_value, (struct elf_module *)lib);
 258 }
 259
 260 /* }====================================================== */
 261
 262
 263
 264 #else
 265 /*
 266 ** {======================================================
 267 ** Fallback for other systems
 268 ** =======================================================
 269 */
 270
 271 #undef LIB_FAIL
 272 #define LIB_FAIL        "absent"
 273
 274
 275 #define DLMSG   "dynamic libraries not enabled; check your Lua installation"
 276
 277
 278 static void ll_unloadlib (void *lib) {
 279   (void)(lib);  /* not used */
 280 }
 281
 282
 283 static void *ll_load (lua_State *L, const char *path, int seeglb) {
 284   (void)(path); (void)(seeglb);  /* not used */
 285   lua_pushliteral(L, DLMSG);
 286   return NULL;
 287 }
 288
 289
 290 static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) {
 291   (void)(lib); (void)(sym);  /* not used */
 292   lua_pushliteral(L, DLMSG);
 293   return NULL;
 294 }
 295
 296 /* }====================================================== */
 297 #endif
 298
 299
 300 static void *ll_checkclib (lua_State *L, const char *path) {
 301   void *plib;
 302   lua_getfield(L, LUA_REGISTRYINDEX, CLIBS);
 303   lua_getfield(L, -1, path);
 304   plib = lua_touserdata(L, -1);  /* plib = CLIBS[path] */
 305   lua_pop(L, 2);  /* pop CLIBS table and 'plib' */
 306   return plib;
 307 }
 308
 309
 310 static void ll_addtoclib (lua_State *L, const char *path, void *plib) {
 311   lua_getfield(L, LUA_REGISTRYINDEX, CLIBS);
 312   lua_pushlightuserdata(L, plib);
 313   lua_pushvalue(L, -1);
 314   lua_setfield(L, -3, path);  /* CLIBS[path] = plib */
 315   lua_rawseti(L, -2, luaL_len(L, -2) + 1);  /* CLIBS[#CLIBS + 1] = plib */
 316   lua_pop(L, 1);  /* pop CLIBS table */
 317 }
 318
 319
 320 /*
 321 ** __gc tag method for CLIBS table: calls 'll_unloadlib' for all lib
 322 ** handles in list CLIBS
 323 */
 324 static int gctm (lua_State *L) {
 325   int n = luaL_len(L, 1);
 326   for (; n >= 1; n--) {  /* for each handle, in reverse order */
 327     lua_rawgeti(L, 1, n);  /* get handle CLIBS[n] */
 328     ll_unloadlib(lua_touserdata(L, -1));
 329     lua_pop(L, 1);  /* pop handle */
 330   }
 331   return 0;
 332 }
 333
 334
 335 static int ll_loadfunc (lua_State *L, const char *path, const char *sym) {
 336   void *reg = ll_checkclib(L, path);  /* check loaded C libraries */
 337   if (reg == NULL) {  /* must load library? */
 338     reg = ll_load(L, path, *sym == '*');
 339     if (reg == NULL) return ERRLIB;  /* unable to load library */
 340     ll_addtoclib(L, path, reg);
 341   }
 342   if (*sym == '*') {  /* loading only library (no function)? */
 343     lua_pushboolean(L, 1);  /* return 'true' */
 344     return 0;  /* no errors */
 345   }
 346   else {
 347     lua_CFunction f = ll_sym(L, reg, sym);
 348     if (f == NULL)
 349       return ERRFUNC;  /* unable to find function */
 350     lua_pushcfunction(L, f);  /* else create new function */
 351     return 0;  /* no errors */
 352   }
 353 }
 354
 355
 356 static int ll_loadlib (lua_State *L) {
 357   const char *path = luaL_checkstring(L, 1);
 358   const char *init = luaL_checkstring(L, 2);
 359   int stat = ll_loadfunc(L, path, init);
 360   if (stat == 0)  /* no errors? */
 361     return 1;  /* return the loaded function */
 362   else {  /* error; error message is on stack top */
 363     lua_pushnil(L);
 364     lua_insert(L, -2);
 365     lua_pushstring(L, (stat == ERRLIB) ?  LIB_FAIL : "init");
 366     return 3;  /* return nil, error message, and where */
 367   }
 368 }
 369
 370
 371
 372 /*
 373 ** {======================================================
 374 ** 'require' function
 375 ** =======================================================
 376 */
 377
 378
 379 static int readable (const char *filename) {
 380   FILE *f = fopen(filename, "r");  /* try to open file */
 381   if (f == NULL) return 0;  /* open failed */
 382   fclose(f);
 383   return 1;
 384 }
 385
 386
 387 static const char *pushnexttemplate (lua_State *L, const char *path) {
 388   const char *l;
 389   while (*path == *LUA_PATH_SEP) path++;  /* skip separators */
 390   if (*path == '\0') return NULL;  /* no more templates */
 391   l = strchr(path, *LUA_PATH_SEP);  /* find next separator */
 392   if (l == NULL) l = path + strlen(path);
 393   lua_pushlstring(L, path, l - path);  /* template */
 394   return l;
 395 }
 396
 397
 398 static const char *searchpath (lua_State *L, const char *name,
 399                                              const char *path,
 400                                              const char *sep,
 401                                              const char *dirsep) {
 402   luaL_Buffer msg;  /* to build error message */
 403   luaL_buffinit(L, &msg);
 404   if (*sep != '\0')  /* non-empty separator? */
 405     name = luaL_gsub(L, name, sep, dirsep);  /* replace it by 'dirsep' */
 406   while ((path = pushnexttemplate(L, path)) != NULL) {
 407     const char *filename = luaL_gsub(L, lua_tostring(L, -1),
 408                                      LUA_PATH_MARK, name);
 409     lua_remove(L, -2);  /* remove path template */
 410     if (readable(filename))  /* does file exist and is readable? */
 411       return filename;  /* return that file name */
 412     lua_pushfstring(L, "\n\tno file " LUA_QS, filename);
 413     lua_remove(L, -2);  /* remove file name */
 414     luaL_addvalue(&msg);  /* concatenate error msg. entry */
 415   }
 416   luaL_pushresult(&msg);  /* create error message */
 417   return NULL;  /* not found */
 418 }
 419
 420
 421 static int ll_searchpath (lua_State *L) {
 422   const char *f = searchpath(L, luaL_checkstring(L, 1),
 423                                 luaL_checkstring(L, 2),
 424                                 luaL_optstring(L, 3, "."),
 425                                 luaL_optstring(L, 4, LUA_DIRSEP));
 426   if (f != NULL) return 1;
 427   else {  /* error message is on top of the stack */
 428     lua_pushnil(L);
 429     lua_insert(L, -2);
 430     return 2;  /* return nil + error message */
 431   }
 432 }
 433
 434
 435 static const char *findfile (lua_State *L, const char *name,
 436                                            const char *pname,
 437                                            const char *dirsep) {
 438   const char *path;
 439   lua_getfield(L, lua_upvalueindex(1), pname);
 440   path = lua_tostring(L, -1);
 441   if (path == NULL)
 442     luaL_error(L, LUA_QL("package.%s") " must be a string", pname);
 443   return searchpath(L, name, path, ".", dirsep);
 444 }
 445
 446
 447 static int checkload (lua_State *L, int stat, const char *filename) {
 448   if (stat) {  /* module loaded successfully? */
 449     lua_pushstring(L, filename);  /* will be 2nd argument to module */
 450     return 2;  /* return open function and file name */
 451   }
 452   else
 453     return luaL_error(L, "error loading module " LUA_QS
 454                          " from file " LUA_QS ":\n\t%s",
 455                           lua_tostring(L, 1), filename, lua_tostring(L, -1));
 456 }
 457
 458
 459 static int searcher_Lua (lua_State *L) {
 460   const char *filename;
 461   const char *name = luaL_checkstring(L, 1);
 462   filename = findfile(L, name, "path", LUA_LSUBSEP);
 463   if (filename == NULL) return 1;  /* module not found in this path */
 464   return checkload(L, (luaL_loadfile(L, filename) == LUA_OK), filename);
 465 }
 466
 467
 468 static int loadfunc (lua_State *L, const char *filename, const char *modname) {
 469   const char *funcname;
 470   const char *mark;
 471   modname = luaL_gsub(L, modname, ".", LUA_OFSEP);
 472   mark = strchr(modname, *LUA_IGMARK);
 473   if (mark) {
 474     int stat;
 475     funcname = lua_pushlstring(L, modname, mark - modname);
 476     funcname = lua_pushfstring(L, LUA_POF"%s", funcname);
 477     stat = ll_loadfunc(L, filename, funcname);
 478     if (stat != ERRFUNC) return stat;
 479     modname = mark + 1;  /* else go ahead and try old-style name */
 480   }
 481   funcname = lua_pushfstring(L, LUA_POF"%s", modname);
 482   return ll_loadfunc(L, filename, funcname);
 483 }
 484
 485
 486 static int searcher_C (lua_State *L) {
 487   const char *name = luaL_checkstring(L, 1);
 488   const char *filename = findfile(L, name, "cpath", LUA_CSUBSEP);
 489   if (filename == NULL) return 1;  /* module not found in this path */
 490   return checkload(L, (loadfunc(L, filename, name) == 0), filename);
 491 }
 492
 493
 494 static int searcher_Croot (lua_State *L) {
 495   const char *filename;
 496   const char *name = luaL_checkstring(L, 1);
 497   const char *p = strchr(name, '.');
 498   int stat;
 499   if (p == NULL) return 0;  /* is root */
 500   lua_pushlstring(L, name, p - name);
 501   filename = findfile(L, lua_tostring(L, -1), "cpath", LUA_CSUBSEP);
 502   if (filename == NULL) return 1;  /* root not found */
 503   if ((stat = loadfunc(L, filename, name)) != 0) {
 504     if (stat != ERRFUNC)
 505       return checkload(L, 0, filename);  /* real error */
 506     else {  /* open function not found */
 507       lua_pushfstring(L, "\n\tno module " LUA_QS " in file " LUA_QS,
 508                          name, filename);
 509       return 1;
 510     }
 511   }
 512   lua_pushstring(L, filename);  /* will be 2nd argument to module */
 513   return 2;
 514 }
 515
 516
 517 static int searcher_preload (lua_State *L) {
 518   const char *name = luaL_checkstring(L, 1);
 519   lua_getfield(L, LUA_REGISTRYINDEX, "_PRELOAD");
 520   lua_getfield(L, -1, name);
 521   if (lua_isnil(L, -1))  /* not found? */
 522     lua_pushfstring(L, "\n\tno field package.preload['%s']", name);
 523   return 1;
 524 }
 525
 526
 527 static void findloader (lua_State *L, const char *name) {
 528   int i;
 529   luaL_Buffer msg;  /* to build error message */
 530   luaL_buffinit(L, &msg);
 531   lua_getfield(L, lua_upvalueindex(1), "searchers");  /* will be at index 3 */
 532   if (!lua_istable(L, 3))
 533     luaL_error(L, LUA_QL("package.searchers") " must be a table");
 534   /*  iterate over available searchers to find a loader */
 535   for (i = 1; ; i++) {
 536     lua_rawgeti(L, 3, i);  /* get a searcher */
 537     if (lua_isnil(L, -1)) {  /* no more searchers? */
 538       lua_pop(L, 1);  /* remove nil */
 539       luaL_pushresult(&msg);  /* create error message */
 540       luaL_error(L, "module " LUA_QS " not found:%s",
 541                     name, lua_tostring(L, -1));
 542     }
 543     lua_pushstring(L, name);
 544     lua_call(L, 1, 2);  /* call it */
 545     if (lua_isfunction(L, -2))  /* did it find a loader? */
 546       return;  /* module loader found */
 547     else if (lua_isstring(L, -2)) {  /* searcher returned error message? */
 548       lua_pop(L, 1);  /* remove extra return */
 549       luaL_addvalue(&msg);  /* concatenate error message */
 550     }
 551     else
 552       lua_pop(L, 2);  /* remove both returns */
 553   }
 554 }
 555
 556
 557 static int ll_require (lua_State *L) {
 558   const char *name = luaL_checkstring(L, 1);
 559   lua_settop(L, 1);  /* _LOADED table will be at index 2 */
 560   lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");
 561   lua_getfield(L, 2, name);  /* _LOADED[name] */
 562   if (lua_toboolean(L, -1))  /* is it there? */
 563     return 1;  /* package is already loaded */
 564   /* else must load package */
 565   lua_pop(L, 1);  /* remove 'getfield' result */
 566   findloader(L, name);
 567   lua_pushstring(L, name);  /* pass name as argument to module loader */
 568   lua_insert(L, -2);  /* name is 1st argument (before search data) */
 569   lua_call(L, 2, 1);  /* run loader to load module */
 570   if (!lua_isnil(L, -1))  /* non-nil return? */
 571     lua_setfield(L, 2, name);  /* _LOADED[name] = returned value */
 572   lua_getfield(L, 2, name);
 573   if (lua_isnil(L, -1)) {   /* module did not set a value? */
 574     lua_pushboolean(L, 1);  /* use true as result */
 575     lua_pushvalue(L, -1);  /* extra copy to be returned */
 576     lua_setfield(L, 2, name);  /* _LOADED[name] = true */
 577   }
 578   return 1;
 579 }
 580
 581 /* }====================================================== */
 582
 583
 584
 585 /*
 586 ** {======================================================
 587 ** 'module' function
 588 ** =======================================================
 589 */
 590 #if defined(LUA_COMPAT_MODULE)
 591
 592 /*
 593 ** changes the environment variable of calling function
 594 */
 595 static void set_env (lua_State *L) {
 596   lua_Debug ar;
 597   if (lua_getstack(L, 1, &ar) == 0 ||
 598       lua_getinfo(L, "f", &ar) == 0 ||  /* get calling function */
 599       lua_iscfunction(L, -1))
 600     luaL_error(L, LUA_QL("module") " not called from a Lua function");
 601   lua_pushvalue(L, -2);  /* copy new environment table to top */
 602   lua_setupvalue(L, -2, 1);
 603   lua_pop(L, 1);  /* remove function */
 604 }
 605
 606
 607 static void dooptions (lua_State *L, int n) {
 608   int i;
 609   for (i = 2; i <= n; i++) {
 610     if (lua_isfunction(L, i)) {  /* avoid 'calling' extra info. */
 611       lua_pushvalue(L, i);  /* get option (a function) */
 612       lua_pushvalue(L, -2);  /* module */
 613       lua_call(L, 1, 0);
 614     }
 615   }
 616 }
 617
 618
 619 static void modinit (lua_State *L, const char *modname) {
 620   const char *dot;
 621   lua_pushvalue(L, -1);
 622   lua_setfield(L, -2, "_M");  /* module._M = module */
 623   lua_pushstring(L, modname);
 624   lua_setfield(L, -2, "_NAME");
 625   dot = strrchr(modname, '.');  /* look for last dot in module name */
 626   if (dot == NULL) dot = modname;
 627   else dot++;
 628   /* set _PACKAGE as package name (full module name minus last part) */
 629   lua_pushlstring(L, modname, dot - modname);
 630   lua_setfield(L, -2, "_PACKAGE");
 631 }
 632
 633
 634 static int ll_module (lua_State *L) {
 635   const char *modname = luaL_checkstring(L, 1);
 636   int lastarg = lua_gettop(L);  /* last parameter */
 637   luaL_pushmodule(L, modname, 1);  /* get/create module table */
 638   /* check whether table already has a _NAME field */
 639   lua_getfield(L, -1, "_NAME");
 640   if (!lua_isnil(L, -1))  /* is table an initialized module? */
 641     lua_pop(L, 1);
 642   else {  /* no; initialize it */
 643     lua_pop(L, 1);
 644     modinit(L, modname);
 645   }
 646   lua_pushvalue(L, -1);
 647   set_env(L);
 648   dooptions(L, lastarg);
 649   return 1;
 650 }
 651
 652
 653 static int ll_seeall (lua_State *L) {
 654   luaL_checktype(L, 1, LUA_TTABLE);
 655   if (!lua_getmetatable(L, 1)) {
 656     lua_createtable(L, 0, 1); /* create new metatable */
 657     lua_pushvalue(L, -1);
 658     lua_setmetatable(L, 1);
 659   }
 660   lua_pushglobaltable(L);
 661   lua_setfield(L, -2, "__index");  /* mt.__index = _G */
 662   return 0;
 663 }
 664
 665 #endif
 666 /* }====================================================== */
 667
 668
 669
 670 /* auxiliary mark (for internal use) */
 671 #define AUXMARK         "\1"
 672
 673
 674 #ifdef SYSLINUX
 675 static void setpath (lua_State *L, const char *fieldname, const char *envname1,
 676                                    const char *envname2, const char *def) {
 677   struct path_entry *entry;
 678   luaL_Buffer b;
 679   luaL_buffinit (L, &b);
 680   (void)envname1;
 681   (void)envname2;
 682   list_for_each_entry(entry, &PATH, list) {
 683     const char *e = entry->str;
 684     int need_slash = e[strlen(e)-1] != '/';
 685     void add (const char *stem) {
 686       luaL_addstring (&b, e);
 687       if (need_slash) luaL_addchar (&b, '/');
 688       luaL_addstring (&b, stem);
 689       luaL_addstring (&b, def);
 690       luaL_addchar (&b, ';');
 691     }
 692     add ("?");
 693     add ("?/init");
 694   }
 695   luaL_addstring (&b, "./?");
 696   luaL_addstring (&b, def);
 697   luaL_pushresult (&b);
 698   lua_setfield(L, -2, fieldname);
 699 }
 700 #else
 701 /*
 702 ** return registry.LUA_NOENV as a boolean
 703 */
 704 static int noenv (lua_State *L) {
 705   int b;
 706   lua_getfield(L, LUA_REGISTRYINDEX, "LUA_NOENV");
 707   b = lua_toboolean(L, -1);
 708   lua_pop(L, 1);  /* remove value */
 709   return b;
 710 }
 711
 712
 713 static void setpath (lua_State *L, const char *fieldname, const char *envname1,
 714                                    const char *envname2, const char *def) {
 715   const char *path = getenv(envname1);
 716   if (path == NULL)  /* no environment variable? */
 717     path = getenv(envname2);  /* try alternative name */
 718   if (path == NULL || noenv(L))  /* no environment variable? */
 719     lua_pushstring(L, def);  /* use default */
 720   else {
 721     /* replace ";;" by ";AUXMARK;" and then AUXMARK by default path */
 722     path = luaL_gsub(L, path, LUA_PATH_SEP LUA_PATH_SEP,
 723                               LUA_PATH_SEP AUXMARK LUA_PATH_SEP);
 724     luaL_gsub(L, path, AUXMARK, def);
 725     lua_remove(L, -2);
 726   }
 727   setprogdir(L);
 728   lua_setfield(L, -2, fieldname);
 729 }
 730 #endif
 731
 732
 733 static const luaL_Reg pk_funcs[] = {
 734   {"loadlib", ll_loadlib},
 735   {"searchpath", ll_searchpath},
 736 #if defined(LUA_COMPAT_MODULE)
 737   {"seeall", ll_seeall},
 738 #endif
 739   {NULL, NULL}
 740 };
 741
 742
 743 static const luaL_Reg ll_funcs[] = {
 744 #if defined(LUA_COMPAT_MODULE)
 745   {"module", ll_module},
 746 #endif
 747   {"require", ll_require},
 748   {NULL, NULL}
 749 };
 750
 751
 752 static void createsearcherstable (lua_State *L) {
 753   static const lua_CFunction searchers[] =
 754     {searcher_preload, searcher_Lua, searcher_C, searcher_Croot, NULL};
 755   int i;
 756   /* create 'searchers' table */
 757   lua_createtable(L, sizeof(searchers)/sizeof(searchers[0]) - 1, 0);
 758   /* fill it with pre-defined searchers */
 759   for (i=0; searchers[i] != NULL; i++) {
 760     lua_pushvalue(L, -2);  /* set 'package' as upvalue for all searchers */
 761     lua_pushcclosure(L, searchers[i], 1);
 762     lua_rawseti(L, -2, i+1);
 763   }
 764 }
 765
 766
 767 LUAMOD_API int luaopen_package (lua_State *L) {
 768   /* create table CLIBS to keep track of loaded C libraries */
 769   luaL_getsubtable(L, LUA_REGISTRYINDEX, CLIBS);
 770   lua_createtable(L, 0, 1);  /* metatable for CLIBS */
 771   lua_pushcfunction(L, gctm);
 772   lua_setfield(L, -2, "__gc");  /* set finalizer for CLIBS table */
 773   lua_setmetatable(L, -2);
 774   /* create `package' table */
 775   luaL_newlib(L, pk_funcs);
 776   createsearcherstable(L);
 777 #if defined(LUA_COMPAT_LOADERS)
 778   lua_pushvalue(L, -1);  /* make a copy of 'searchers' table */
 779   lua_setfield(L, -3, "loaders");  /* put it in field `loaders' */
 780 #endif
 781   lua_setfield(L, -2, "searchers");  /* put it in field 'searchers' */
 782   /* set field 'path' */
 783   setpath(L, "path", LUA_PATHVERSION, LUA_PATH, LUA_PATH_DEFAULT);
 784   /* set field 'cpath' */
 785   setpath(L, "cpath", LUA_CPATHVERSION, LUA_CPATH, LUA_CPATH_DEFAULT);
 786   /* store config information */
 787   lua_pushliteral(L, LUA_DIRSEP "\n" LUA_PATH_SEP "\n" LUA_PATH_MARK "\n"
 788                      LUA_EXEC_DIR "\n" LUA_IGMARK "\n");
 789   lua_setfield(L, -2, "config");
 790   /* set field `loaded' */
 791   luaL_getsubtable(L, LUA_REGISTRYINDEX, "_LOADED");
 792   lua_setfield(L, -2, "loaded");
 793   /* set field `preload' */
 794   luaL_getsubtable(L, LUA_REGISTRYINDEX, "_PRELOAD");
 795   lua_setfield(L, -2, "preload");
 796   lua_pushglobaltable(L);
 797   lua_pushvalue(L, -2);  /* set 'package' as upvalue for next lib */
 798   luaL_setfuncs(L, ll_funcs, 1);  /* open lib into global table */
 799   lua_pop(L, 1);  /* pop global table */
 800   return 1;  /* return 'package' table */
 801 }
 802