/*
** $Id: loadlib.c,v 1.111.1.1 2013/04/12 18:48:47 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.
*/

/*
** if needed, includes windows header before everything else
*/
#if defined(_WIN32)
#include <windows.h>
#endif

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

#define loadlib_c
#define LUA_LIB

#include "lua.h"

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

/*
** LUA_PATH and LUA_CPATH are the names of the environment
** variables that Lua check to set its paths.
*/
#if !defined(LUA_PATH)
#define LUA_PATH "LUA_PATH"
#endif

#if !defined(LUA_CPATH)
#define LUA_CPATH "LUA_CPATH"
#endif

#define LUA_PATHSUFFIX "_" LUA_VERSION_MAJOR "_" LUA_VERSION_MINOR

#define LUA_PATHVERSION LUA_PATH LUA_PATHSUFFIX
#define LUA_CPATHVERSION LUA_CPATH LUA_PATHSUFFIX

/*
** LUA_PATH_SEP is the character that separates templates in a path.
** LUA_PATH_MARK is the string that marks the substitution points in a
** template.
** LUA_EXEC_DIR in a Windows path is replaced by the executable's
** directory.
** LUA_IGMARK is a mark to ignore all before it when building the
** luaopen_ function name.
*/
#if !defined(LUA_PATH_SEP)
#define LUA_PATH_SEP ";"
#endif
#if !defined(LUA_PATH_MARK)
#define LUA_PATH_MARK "?"
#endif
#if !defined(LUA_EXEC_DIR)
#define LUA_EXEC_DIR "!"
#endif
#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 "_"

/* table (in the registry) that keeps handles for all loaded C libraries */
#define CLIBS "_CLIBS"

#define LIB_FAIL "open"

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

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

/*
** system-dependent functions
*/
static void ll_unloadlib(void *lib);
static void *ll_load(lua_State *L, const char *path, int seeglb);
static lua_CFunction ll_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>

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

static void *ll_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 ll_sym(lua_State *L, void *lib, const char *sym)
{
	lua_CFunction f = (lua_CFunction)dlsym(lib, sym);
	if (f == NULL) lua_pushstring(L, dlerror());
	return f;
}

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

#elif defined(LUA_DL_DLL)
/*
** {======================================================================
** This is an implementation of loadlib for Windows using native functions.
** =======================================================================
*/

#undef setprogdir

/*
** optional flags for LoadLibraryEx
*/
#if !defined(LUA_LLE_FLAGS)
#define LUA_LLE_FLAGS 0
#endif

static void setprogdir(lua_State *L)
{
	char buff[MAX_PATH + 1];
	char *lb;
	DWORD nsize = sizeof(buff) / sizeof(char);
	DWORD n = GetModuleFileNameA(NULL, buff, nsize);
	if (n == 0 || n == nsize || (lb = strrchr(buff, '\\')) == NULL)
		luaL_error(L, "unable to get ModuleFileName");
	else
	{
		*lb = '\0';
		luaL_gsub(L, lua_tostring(L, -1), LUA_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 ll_unloadlib(void *lib)
{
	FreeLibrary((HMODULE)lib);
}

static void *ll_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 ll_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 ll_unloadlib(void *lib)
{
	(void)(lib); /* not used */
}

static void *ll_load(lua_State *L, const char *path, int seeglb)
{
	(void)(path);
	(void)(seeglb); /* not used */
	lua_pushliteral(L, DLMSG);
	return NULL;
}

static lua_CFunction ll_sym(lua_State *L, void *lib, const char *sym)
{
	(void)(lib);
	(void)(sym); /* not used */
	lua_pushliteral(L, DLMSG);
	return NULL;
}

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

static void *ll_checkclib(lua_State *L, const char *path)
{
	void *plib;
	lua_getfield(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;
}

static void ll_addtoclib(lua_State *L, const char *path, void *plib)
{
	lua_getfield(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 'll_unloadlib' for all lib
** handles in list CLIBS
*/
static int gctm(lua_State *L)
{
	int n = luaL_len(L, 1);
	for (; n >= 1; n--)
	{                         /* for each handle, in reverse order */
		lua_rawgeti(L, 1, n); /* get handle CLIBS[n] */
		ll_unloadlib(lua_touserdata(L, -1));
		lua_pop(L, 1); /* pop handle */
	}
	return 0;
}

static int ll_loadfunc(lua_State *L, const char *path, const char *sym)
{
	void *reg = ll_checkclib(L, path); /* check loaded C libraries */
	if (reg == NULL)
	{ /* must load library? */
		reg = ll_load(L, path, *sym == '*');
		if (reg == NULL) return ERRLIB; /* unable to load library */
		ll_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 = ll_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 = ll_loadfunc(L, path, init);
	if (stat == 0) /* no errors? */
		return 1;  /* return the loaded function */
	else
	{ /* error; error message is on stack top */
		lua_pushnil(L);
		lua_insert(L, -2);
		lua_pushstring(L, (stat == ERRLIB) ? LIB_FAIL : "init");
		return 3; /* return nil, error message, and where */
	}
}

/*
** {======================================================
** 'require' function
** =======================================================
*/

static int readable(const char *filename)
{
	FILE *f = fopen(filename, "r"); /* try to open file */
	if (f == NULL) return 0;        /* open failed */
	fclose(f);
	return 1;
}

static const char *pushnexttemplate(lua_State *L, const char *path)
{
	const char *l;
	while (*path == *LUA_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 " LUA_QS, 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, LUA_QL("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 " LUA_QS " from file " LUA_QS ":\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);
}

static int loadfunc(lua_State *L, const char *filename, const char *modname)
{
	const char *funcname;
	const char *mark;
	modname = luaL_gsub(L, modname, ".", LUA_OFSEP);
	mark = strchr(modname, *LUA_IGMARK);
	if (mark)
	{
		int stat;
		funcname = lua_pushlstring(L, modname, mark - modname);
		funcname = lua_pushfstring(L, LUA_POF "%s", funcname);
		stat = ll_loadfunc(L, filename, funcname);
		if (stat != ERRFUNC) return stat;
		modname = mark + 1; /* else go ahead and try old-style name */
	}
	funcname = lua_pushfstring(L, LUA_POF "%s", modname);
	return ll_loadfunc(L, filename, funcname);
}

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 " LUA_QS " in file " LUA_QS,
							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, "_PRELOAD");
	lua_getfield(L, -1, name);
	if (lua_isnil(L, -1)) /* not found? */
		lua_pushfstring(L, "\n\tno field package.preload['%s']", name);
	return 1;
}

static void findloader(lua_State *L, const char *name)
{
	int i;
	luaL_Buffer msg; /* to build error message */
	luaL_buffinit(L, &msg);
	lua_getfield(L, lua_upvalueindex(1), "searchers"); /* will be at index 3 */
	if (!lua_istable(L, 3))
		luaL_error(L, LUA_QL("package.searchers") " must be a table");
	/*  iterate over available searchers to find a loader */
	for (i = 1;; i++)
	{
		lua_rawgeti(L, 3, i); /* get a searcher */
		if (lua_isnil(L, -1))
		{                          /* no more searchers? */
			lua_pop(L, 1);         /* remove nil */
			luaL_pushresult(&msg); /* create error message */
			luaL_error(L, "module " LUA_QS " 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, "_LOADED");
	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 */
	lua_getfield(L, 2, name);
	if (lua_isnil(L, -1))
	{                             /* module did not set a value? */
		lua_pushboolean(L, 1);    /* use true as result */
		lua_pushvalue(L, -1);     /* extra copy to be returned */
		lua_setfield(L, 2, name); /* _LOADED[name] = true */
	}
	return 1;
}

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

/*
** {======================================================
** 'module' function
** =======================================================
*/
#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, LUA_QL("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 */
	lua_getfield(L, -1, "_NAME");
	if (!lua_isnil(L, -1)) /* is table an initialized module? */
		lua_pop(L, 1);
	else
	{ /* no; initialize it */
		lua_pop(L, 1);
		modinit(L, modname);
	}
	lua_pushvalue(L, -1);
	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
/* }====================================================== */

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

/*
** 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;
}

static void setpath(lua_State *L, const char *fieldname, const char *envname1,
					const char *envname2, const char *def)
{
	const char *path = getenv(envname1);
	if (path == NULL)             /* no environment variable? */
		path = getenv(envname2);  /* try alternative name */
	if (path == NULL || noenv(L)) /* no environment variable? */
		lua_pushstring(L, def);   /* use default */
	else
	{
		/* replace ";;" by ";AUXMARK;" and then AUXMARK by default path */
		path = luaL_gsub(L, path, LUA_PATH_SEP LUA_PATH_SEP,
						 LUA_PATH_SEP AUXMARK LUA_PATH_SEP);
		luaL_gsub(L, path, AUXMARK, def);
		lua_remove(L, -2);
	}
	setprogdir(L);
	lua_setfield(L, -2, fieldname);
}

static const luaL_Reg pk_funcs[] = {
	{"loadlib", ll_loadlib},
	{"searchpath", ll_searchpath},
#if defined(LUA_COMPAT_MODULE)
	{"seeall", ll_seeall},
#endif
	{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 pre-defined 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);
	}
}

LUAMOD_API int luaopen_package(lua_State *L)
{
	/* create table CLIBS to keep track of loaded C libraries */
	luaL_getsubtable(L, LUA_REGISTRYINDEX, CLIBS);
	lua_createtable(L, 0, 1); /* metatable for CLIBS */
	lua_pushcfunction(L, gctm);
	lua_setfield(L, -2, "__gc"); /* set finalizer for CLIBS table */
	lua_setmetatable(L, -2);
	/* create `package' table */
	luaL_newlib(L, pk_funcs);
	createsearcherstable(L);
#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' */
	/* set field 'path' */
	setpath(L, "path", LUA_PATHVERSION, LUA_PATH, LUA_PATH_DEFAULT);
	/* set field 'cpath' */
	setpath(L, "cpath", LUA_CPATHVERSION, LUA_CPATH, 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, "_LOADED");
	lua_setfield(L, -2, "loaded");
	/* set field `preload' */
	luaL_getsubtable(L, LUA_REGISTRYINDEX, "_PRELOAD");
	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 */
}
