text: /*
  ** $Id: loadlib.c,v 1.130 2017/01/12 17:14:26 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 Windows, and a stub for other
  ** systems.
  */
  
  #define loadlib_c
  #define LUA_LIB
  
  #include "lprefix.h"
  
  
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  
  #include "lua.h"
  
  #include "lauxlib.h"
  #include "lualib.h"
  
  
  /*
  ** LUA_IGMARK is a mark to ignore all before it when building the
  ** luaopen_ function name.
  */
  #if !defined (LUA_IGMARK)
  #define LUA_IGMARK      "-"
  #endif
  
  
  /*
  ** LUA_CSUBSEP is the character that replaces dots in submodule names
  ** when searching for a C loader.
  ** LUA_LSUBSEP is the character that replaces dots in submodule names
  ** when searching for a Lua loader.
  */
  #if !defined(LUA_CSUBSEP)
  #define LUA_CSUBSEP     LUA_DIRSEP
  #endif
  
  #if !defined(LUA_LSUBSEP)
  #define LUA_LSUBSEP     LUA_DIRSEP
  #endif
  
  
  /* prefix for open functions in C libraries */
  #define LUA_POF     "luaopen_"
  
  /* separator for open functions in C libraries */
  #define LUA_OFSEP   "_"
  
  
  /*
  ** unique key for table in the registry that keeps handles
  ** for all loaded C libraries
  */
  static const int CLIBS = 0;
  
  #define LIB_FAIL    "open"
  
  
  #define setprogdir(L)           ((void)0)
  
  
  /*
  ** system-dependent functions
  */
  
  /*
  ** unload library 'lib'
  */
  static void lsys_unloadlib( void* lib );
  
  /*
  ** load C library in file 'path'. If 'seeglb', load with all names in
  ** the library global.
  ** Returns the library; in case of error, returns NULL plus an
  ** error string in the stack.
  */
  static void* lsys_load( lua_State* L, const char* path, int seeglb );
  
  /*
  ** Try to find a function named 'sym' in library 'lib'.
  ** Returns the function; in case of error, returns NULL plus an
  ** error string in the stack.
  */
  static lua_CFunction lsys_sym( lua_State* L, void* lib, const char* sym );
  
  
  
  
  #if defined(LUA_USE_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>
  
  /*
  ** Macro to convert pointer-to-void* to pointer-to-function. This cast
  ** is undefined according to ISO C, but POSIX assumes that it works.
  ** (The '__extension__' in gnu compilers is only to avoid warnings.)
  */
  #if defined(__GNUC__)
  #define cast_func(p) (__extension__ (lua_CFunction)(p))
  #else
  #define cast_func(p) ((lua_CFunction)(p))
  #endif
  
  
  static void lsys_unloadlib( void* lib ) {
      dlclose( lib );
  }
  
  
  static void* lsys_load( lua_State* L, const char* path, int seeglb ) {
      void* lib = dlopen( path, RTLD_NOW | ( seeglb ? RTLD_GLOBAL : RTLD_LOCAL ) );
  
      if ( lib == NULL ) {
          lua_pushstring( L, dlerror() );
      }
  
      return lib;
  }
  
  
  static lua_CFunction lsys_sym( lua_State* L, void* lib, const char* sym ) {
      lua_CFunction f = cast_func( 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>
  
  
  /*
  ** optional flags for LoadLibraryEx
  */
  #if !defined(LUA_LLE_FLAGS)
  #define LUA_LLE_FLAGS   0
  #endif
  
  
  #undef setprogdir
  
  
  /*
  ** Replace in the path (on the top of the stack) any occurrence
  ** of LUA_EXEC_DIR with the executable's path.
  */
  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 ); /* get exec. name */
  
      if ( n == 0 || n == nsize || ( lb = strrchr( buff, '\\' ) ) == NULL ) {
          luaL_error( L, "unable to get ModuleFileName" );
      }
      else {
          *lb = '\0';  /* cut name on the last '\\' to get the path */
          luaL_gsub( L, lua_tostring( L, -1 ), LUA_EXEC_DIR, 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 ) / sizeof( char ), NULL ) ) {
          lua_pushstring( L, buffer );
      }
      else {
          lua_pushfstring( L, "system error %d\n", error );
      }
  }
  
  static void lsys_unloadlib( void* lib ) {
      FreeLibrary( ( HMODULE )lib );
  }
  
  
  static void* lsys_load( lua_State* L, const char* path, int seeglb ) {
      HMODULE lib = LoadLibraryExA( path, NULL, LUA_LLE_FLAGS );
      ( void )( seeglb ); /* not used: symbols are 'global' by default */
  
      if ( lib == NULL ) {
          pusherror( L );
      }
  
      return lib;
  }
  
  
  static lua_CFunction lsys_sym( lua_State* L, void* lib, const char* sym ) {
      lua_CFunction f = ( lua_CFunction )GetProcAddress( ( HMODULE )lib, sym );
  
      if ( f == NULL ) {
          pusherror( L );
      }
  
      return f;
  }
  
  /* }====================================================== */
  
  
  #else               /* }{ */
  /*
  ** {======================================================
  ** Fallback for other systems
  ** =======================================================
  */
  
  #undef LIB_FAIL
  #define LIB_FAIL    "absent"
  
  
  #define DLMSG   "dynamic libraries not enabled; check your Lua installation"
  
  
  static void lsys_unloadlib( void* lib ) {
      ( void )( lib ); /* not used */
  }
  
  
  static void* lsys_load( lua_State* L, const char* path, int seeglb ) {
      ( void )( path );
      ( void )( seeglb ); /* not used */
      lua_pushliteral( L, DLMSG );
      return NULL;
  }
  
  
  static lua_CFunction lsys_sym( lua_State* L, void* lib, const char* sym ) {
      ( void )( lib );
      ( void )( sym ); /* not used */
      lua_pushliteral( L, DLMSG );
      return NULL;
  }
  
  /* }====================================================== */
  #endif              /* } */
  
  
  /*
  ** {==================================================================
  ** Set Paths
  ** ===================================================================
  */
  
  /*
  ** LUA_PATH_VAR and LUA_CPATH_VAR are the names of the environment
  ** variables that Lua check to set its paths.
  */
  #if !defined(LUA_PATH_VAR)
  #define LUA_PATH_VAR    "LUA_PATH"
  #endif
  
  #if !defined(LUA_CPATH_VAR)
  #define LUA_CPATH_VAR   "LUA_CPATH"
  #endif
  
  
  #define AUXMARK         "\1"    /* auxiliary mark */
  
  
  /*
  ** return registry.LUA_NOENV as a boolean
  */
  static int noenv( lua_State* L ) {
      int b;
      lua_getfield( L, LUA_REGISTRYINDEX, "LUA_NOENV" );
      b = lua_toboolean( L, -1 );
      lua_pop( L, 1 ); /* remove value */
      return b;
  }
  
  
  /*
  ** Set a path
  */
  static void setpath( lua_State* L, const char* fieldname,
                       const char* envname,
                       const char* dft ) {
      const char* nver = lua_pushfstring( L, "%s%s", envname, LUA_VERSUFFIX );
      const char* path = getenv( nver ); /* use versioned name */
  
      if ( path == NULL ) { /* no environment variable? */
          path = getenv( envname );    /* try unversioned name */
      }
  
      if ( path == NULL || noenv( L ) ) { /* no environment variable? */
          lua_pushstring( L, dft );    /* use default */
      }
      else {
          /* replace ";;" by ";AUXMARK;" and then AUXMARK by default path */
          path = luaL_gsub( L, path, LUA_PATH_SEP LUA_PATH_SEP,
                            LUA_PATH_SEP AUXMARK LUA_PATH_SEP );
          luaL_gsub( L, path, AUXMARK, dft );
          lua_remove( L, -2 ); /* remove result from 1st 'gsub' */
      }
  
      setprogdir( L );
      lua_setfield( L, -3, fieldname ); /* package[fieldname] = path value */
      lua_pop( L, 1 ); /* pop versioned variable name */
  }
  
  /* }================================================================== */
  
  
  /*
  ** return registry.CLIBS[path]
  */
  static void* checkclib( lua_State* L, const char* path ) {
      void* plib;
      lua_rawgetp( L, LUA_REGISTRYINDEX, &CLIBS );
      lua_getfield( L, -1, path );
      plib = lua_touserdata( L, -1 ); /* plib = CLIBS[path] */
      lua_pop( L, 2 ); /* pop CLIBS table and 'plib' */
      return plib;
  }
  
  
  /*
  ** registry.CLIBS[path] = plib        -- for queries
  ** registry.CLIBS[#CLIBS + 1] = plib  -- also keep a list of all libraries
  */
  static void addtoclib( lua_State* L, const char* path, void* plib ) {
      lua_rawgetp( L, LUA_REGISTRYINDEX, &CLIBS );
      lua_pushlightuserdata( L, plib );
      lua_pushvalue( L, -1 );
      lua_setfield( L, -3, path ); /* CLIBS[path] = plib */
      lua_rawseti( L, -2, luaL_len( L, -2 ) + 1 ); /* CLIBS[#CLIBS + 1] = plib */
      lua_pop( L, 1 ); /* pop CLIBS table */
  }
  
  
  /*
  ** __gc tag method for CLIBS table: calls 'lsys_unloadlib' for all lib
  ** handles in list CLIBS
  */
  static int gctm( lua_State* L ) {
      lua_Integer n = luaL_len( L, 1 );
  
      for ( ; n >= 1; n-- ) { /* for each handle, in reverse order */
          lua_rawgeti( L, 1, n ); /* get handle CLIBS[n] */
          lsys_unloadlib( lua_touserdata( L, -1 ) );
          lua_pop( L, 1 ); /* pop handle */
      }
  
      return 0;
  }
  
  
  
  /* error codes for 'lookforfunc' */
  #define ERRLIB      1
  #define ERRFUNC     2
  
  /*
  ** Look for a C function named 'sym' in a dynamically loaded library
  ** 'path'.
  ** First, check whether the library is already loaded; if not, try
  ** to load it.
  ** Then, if 'sym' is '*', return true (as library has been loaded).
  ** Otherwise, look for symbol 'sym' in the library and push a
  ** C function with that symbol.
  ** Return 0 and 'true' or a function in the stack; in case of
  ** errors, return an error code and an error message in the stack.
  */
  static int lookforfunc( lua_State* L, const char* path, const char* sym ) {
      void* reg = checkclib( L, path ); /* check loaded C libraries */
  
      if ( reg == NULL ) { /* must load library? */
          reg = lsys_load( L, path, *sym == '*' ); /* global symbols if 'sym'=='*' */
  
          if ( reg == NULL ) {
              return ERRLIB;    /* unable to load library */
          }
  
          addtoclib( L, path, reg );
      }
  
      if ( *sym == '*' ) { /* loading only library (no function)? */
          lua_pushboolean( L, 1 ); /* return 'true' */
          return 0;  /* no errors */
      }
      else {
          lua_CFunction f = lsys_sym( L, reg, sym );
  
          if ( f == NULL ) {
              return ERRFUNC;    /* unable to find function */
          }
  
          lua_pushcfunction( L, f ); /* else create new function */
          return 0;  /* no errors */
      }
  }
  
  
  static int ll_loadlib( lua_State* L ) {
      const char* path = luaL_checkstring( L, 1 );
      const char* init = luaL_checkstring( L, 2 );
      int stat = lookforfunc( 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_PATH_SEP ) {
          path++;    /* skip separators */
      }
  
      if ( *path == '\0' ) {
          return NULL;    /* no more templates */
      }
  
      l = strchr( path, *LUA_PATH_SEP ); /* find next separator */
  
      if ( l == NULL ) {
          l = path + strlen( path );
      }
  
      lua_pushlstring( L, path, l - path ); /* template */
      return l;
  }
  
  
  static const char* searchpath( lua_State* L, const char* name,
                                 const char* path,
                                 const char* sep,
                                 const char* dirsep ) {
      luaL_Buffer msg;  /* to build error message */
      luaL_buffinit( L, &msg );
  
      if ( *sep != '\0' ) { /* non-empty separator? */
          name = luaL_gsub( L, name, sep, dirsep );    /* replace it by 'dirsep' */
      }
  
      while ( ( path = pushnexttemplate( L, path ) ) != NULL ) {
          const char* 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 '%s'", filename );
          lua_remove( L, -2 ); /* remove file name */
          luaL_addvalue( &msg ); /* concatenate error msg. entry */
      }
  
      luaL_pushresult( &msg ); /* create error message */
      return NULL;  /* not found */
  }
  
  
  static int ll_searchpath( lua_State* L ) {
      const char* f = searchpath( L, luaL_checkstring( L, 1 ),
                                  luaL_checkstring( L, 2 ),
                                  luaL_optstring( L, 3, "." ),
                                  luaL_optstring( L, 4, LUA_DIRSEP ) );
  
      if ( f != NULL ) {
          return 1;
      }
      else {  /* error message is on top of the stack */
          lua_pushnil( L );
          lua_insert( L, -2 );
          return 2;  /* return nil + error message */
      }
  }
  
  
  static const char* findfile( lua_State* L, const char* name,
                               const char* pname,
                               const char* dirsep ) {
      const char* path;
      lua_getfield( L, lua_upvalueindex( 1 ), pname );
      path = lua_tostring( L, -1 );
  
      if ( path == NULL ) {
          luaL_error( L, "'package.%s' must be a string", pname );
      }
  
      return searchpath( L, name, path, ".", dirsep );
  }
  
  
  static int checkload( lua_State* L, int stat, const char* filename ) {
      if ( stat ) { /* module loaded successfully? */
          lua_pushstring( L, filename ); /* will be 2nd argument to module */
          return 2;  /* return open function and file name */
      }
      else
          return luaL_error( L, "error loading module '%s' from file '%s':\n\t%s",
                             lua_tostring( L, 1 ), filename, lua_tostring( L, -1 ) );
  }
  
  
  static int searcher_Lua( lua_State* L ) {
      const char* filename;
      const char* name = luaL_checkstring( L, 1 );
      filename = findfile( L, name, "path", LUA_LSUBSEP );
  
      if ( filename == NULL ) {
          return 1;    /* module not found in this path */
      }
  
      return checkload( L, ( luaL_loadfile( L, filename ) == LUA_OK ), filename );
  }
  
  
  /*
  ** Try to find a load function for module 'modname' at file 'filename'.
  ** First, change '.' to '_' in 'modname'; then, if 'modname' has
  ** the form X-Y (that is, it has an "ignore mark"), build a function
  ** name "luaopen_X" and look for it. (For compatibility, if that
  ** fails, it also tries "luaopen_Y".) If there is no ignore mark,
  ** look for a function named "luaopen_modname".
  */
  static int loadfunc( lua_State* L, const char* filename, const char* modname ) {
      const char* openfunc;
      const char* mark;
      modname = luaL_gsub( L, modname, ".", LUA_OFSEP );
      mark = strchr( modname, *LUA_IGMARK );
  
      if ( mark ) {
          int stat;
          openfunc = lua_pushlstring( L, modname, mark - modname );
          openfunc = lua_pushfstring( L, LUA_POF"%s", openfunc );
          stat = lookforfunc( L, filename, openfunc );
  
          if ( stat != ERRFUNC ) {
              return stat;
          }
  
          modname = mark + 1;  /* else go ahead and try old-style name */
      }
  
      openfunc = lua_pushfstring( L, LUA_POF"%s", modname );
      return lookforfunc( L, filename, openfunc );
  }
  
  
  static int searcher_C( lua_State* L ) {
      const char* name = luaL_checkstring( L, 1 );
      const char* filename = findfile( L, name, "cpath", LUA_CSUBSEP );
  
      if ( filename == NULL ) {
          return 1;    /* module not found in this path */
      }
  
      return checkload( L, ( loadfunc( L, filename, name ) == 0 ), filename );
  }
  
  
  static int searcher_Croot( lua_State* L ) {
      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", LUA_CSUBSEP );
  
      if ( filename == NULL ) {
          return 1;    /* root not found */
      }
  
      if ( ( stat = loadfunc( L, filename, name ) ) != 0 ) {
          if ( stat != ERRFUNC ) {
              return checkload( L, 0, filename );    /* real error */
          }
          else {  /* open function not found */
              lua_pushfstring( L, "\n\tno module '%s' in file '%s'", name, filename );
              return 1;
          }
      }
  
      lua_pushstring( L, filename ); /* will be 2nd argument to module */
      return 2;
  }
  
  
  static int searcher_preload( lua_State* L ) {
      const char* name = luaL_checkstring( L, 1 );
      lua_getfield( L, LUA_REGISTRYINDEX, LUA_PRELOAD_TABLE );
  
      if ( lua_getfield( L, -1, name ) == LUA_TNIL ) { /* not found? */
          lua_pushfstring( L, "\n\tno field package.preload['%s']", name );
      }
  
      return 1;
  }
  
  
  static void findloader( lua_State* L, const char* name ) {
      int i;
      luaL_Buffer msg;  /* to build error message */
      luaL_buffinit( L, &msg );
  
      /* push 'package.searchers' to index 3 in the stack */
      if ( lua_getfield( L, lua_upvalueindex( 1 ), "searchers" ) != LUA_TTABLE ) {
          luaL_error( L, "'package.searchers' must be a table" );
      }
  
      /*  iterate over available searchers to find a loader */
      for ( i = 1; ; i++ ) {
          if ( lua_rawgeti( L, 3, i ) == LUA_TNIL ) { /* no more searchers? */
              lua_pop( L, 1 ); /* remove nil */
              luaL_pushresult( &msg ); /* create error message */
              luaL_error( L, "module '%s' not found:%s", name, lua_tostring( L, -1 ) );
          }
  
          lua_pushstring( L, name );
          lua_call( L, 1, 2 ); /* call it */
  
          if ( lua_isfunction( L, -2 ) ) { /* did it find a loader? */
              return;    /* module loader found */
          }
          else if ( lua_isstring( L, -2 ) ) { /* searcher returned error message? */
              lua_pop( L, 1 ); /* remove extra return */
              luaL_addvalue( &msg ); /* concatenate error message */
          }
          else {
              lua_pop( L, 2 );    /* remove both returns */
          }
      }
  }
  
  
  static int ll_require( lua_State* L ) {
      const char* name = luaL_checkstring( L, 1 );
      lua_settop( L, 1 ); /* LOADED table will be at index 2 */
      lua_getfield( L, LUA_REGISTRYINDEX, LUA_LOADED_TABLE );
      lua_getfield( L, 2, name ); /* LOADED[name] */
  
      if ( lua_toboolean( L, -1 ) ) { /* is it there? */
          return 1;    /* package is already loaded */
      }
  
      /* else must load package */
      lua_pop( L, 1 ); /* remove 'getfield' result */
      findloader( L, name );
      lua_pushstring( L, name ); /* pass name as argument to module loader */
      lua_insert( L, -2 ); /* name is 1st argument (before search data) */
      lua_call( L, 2, 1 ); /* run loader to load module */
  
      if ( !lua_isnil( L, -1 ) ) { /* non-nil return? */
          lua_setfield( L, 2, name );    /* LOADED[name] = returned value */
      }
  
      if ( lua_getfield( L, 2, name ) == LUA_TNIL ) { /* module set no 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
  ** =======================================================
  */
  #if defined(LUA_COMPAT_MODULE)
  
  /*
  ** changes the environment variable of calling function
  */
  static void set_env( 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, "'module' not called from a Lua function" );
      }
  
      lua_pushvalue( L, -2 ); /* copy new environment table to top */
      lua_setupvalue( L, -2, 1 );
      lua_pop( L, 1 ); /* remove function */
  }
  
  
  static void dooptions( lua_State* L, int n ) {
      int i;
  
      for ( i = 2; i <= n; i++ ) {
          if ( lua_isfunction( L, i ) ) { /* avoid 'calling' extra info. */
              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 lastarg = lua_gettop( L ); /* last parameter */
      luaL_pushmodule( L, modname, 1 ); /* get/create module table */
  
      /* check whether table already has a _NAME field */
      if ( lua_getfield( L, -1, "_NAME" ) != LUA_TNIL ) {
          lua_pop( L, 1 );    /* table is an initialized module */
      }
      else {  /* no; initialize it */
          lua_pop( L, 1 );
          modinit( L, modname );
      }
  
      lua_pushvalue( L, -1 );
      set_env( L );
      dooptions( L, lastarg );
      return 1;
  }
  
  
  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_pushglobaltable( L );
      lua_setfield( L, -2, "__index" ); /* mt.__index = _G */
      return 0;
  }
  
  #endif
  /* }====================================================== */
  
  
  
  static const luaL_Reg pk_funcs[] = {
      {"loadlib", ll_loadlib},
      {"searchpath", ll_searchpath},
  #if defined(LUA_COMPAT_MODULE)
      {"seeall", ll_seeall},
  #endif
      /* placeholders */
      {"preload", NULL},
      {"cpath", NULL},
      {"path", NULL},
      {"searchers", NULL},
      {"loaded", NULL},
      {NULL, NULL}
  };
  
  
  static const luaL_Reg ll_funcs[] = {
  #if defined(LUA_COMPAT_MODULE)
      {"module", ll_module},
  #endif
      {"require", ll_require},
      {NULL, NULL}
  };
  
  
  static void createsearcherstable( lua_State* L ) {
      static const lua_CFunction searchers[] =
      {searcher_preload, searcher_Lua, searcher_C, searcher_Croot, NULL};
      int i;
      /* create 'searchers' table */
      lua_createtable( L, sizeof( searchers ) / sizeof( searchers[0] ) - 1, 0 );
  
      /* fill it with predefined searchers */
      for ( i = 0; searchers[i] != NULL; i++ ) {
          lua_pushvalue( L, -2 ); /* set 'package' as upvalue for all searchers */
          lua_pushcclosure( L, searchers[i], 1 );
          lua_rawseti( L, -2, i + 1 );
      }
  
  #if defined(LUA_COMPAT_LOADERS)
      lua_pushvalue( L, -1 ); /* make a copy of 'searchers' table */
      lua_setfield( L, -3, "loaders" ); /* put it in field 'loaders' */
  #endif
      lua_setfield( L, -2, "searchers" ); /* put it in field 'searchers' */
  }
  
  
  /*
  ** create table CLIBS to keep track of loaded C libraries,
  ** setting a finalizer to close all libraries when closing state.
  */
  static void createclibstable( lua_State* L ) {
      lua_newtable( L ); /* create CLIBS table */
      lua_createtable( L, 0, 1 ); /* create metatable for CLIBS */
      lua_pushcfunction( L, gctm );
      lua_setfield( L, -2, "__gc" ); /* set finalizer for CLIBS table */
      lua_setmetatable( L, -2 );
      lua_rawsetp( L, LUA_REGISTRYINDEX, &CLIBS ); /* set CLIBS table in registry */
  }
  
  
  LUAMOD_API int luaopen_package( lua_State* L ) {
      createclibstable( L );
      luaL_newlib( L, pk_funcs ); /* create 'package' table */
      createsearcherstable( L );
      /* set paths */
      setpath( L, "path", LUA_PATH_VAR, LUA_PATH_DEFAULT );
      setpath( L, "cpath", LUA_CPATH_VAR, LUA_CPATH_DEFAULT );
      /* store config information */
      lua_pushliteral( L, LUA_DIRSEP "\n" LUA_PATH_SEP "\n" LUA_PATH_MARK "\n"
                       LUA_EXEC_DIR "\n" LUA_IGMARK "\n" );
      lua_setfield( L, -2, "config" );
      /* set field 'loaded' */
      luaL_getsubtable( L, LUA_REGISTRYINDEX, LUA_LOADED_TABLE );
      lua_setfield( L, -2, "loaded" );
      /* set field 'preload' */
      luaL_getsubtable( L, LUA_REGISTRYINDEX, LUA_PRELOAD_TABLE );
      lua_setfield( L, -2, "preload" );
      lua_pushglobaltable( L );
      lua_pushvalue( L, -2 ); /* set 'package' as upvalue for next lib */
      luaL_setfuncs( L, ll_funcs, 1 ); /* open lib into global table */
      lua_pop( L, 1 ); /* pop global table */
      return 1;  /* return 'package' table */
  }
  
  