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wireshark/epan/wslua/wslua_internals.c

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/*
* wslua_internals.c
*
* Wireshark's interface to the Lua Programming Language
*
* This file is for internal WSLUA functions - not ones exposed into Lua.
*
* (c) 2013, Hadriel Kaplan <hadrielk@yahoo.com>
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "config.h"
#include "wslua.h"
WSLUA_API int wslua__concat(lua_State* L) {
/* Concatenate two objects to a string */
if (!luaL_callmeta(L,1,"__tostring"))
lua_pushvalue(L,1);
if (!luaL_callmeta(L,2,"__tostring"))
lua_pushvalue(L,2);
lua_concat(L,2);
return 1;
}
/* like lua_toboolean, except only coerces int, nil, and bool, and errors on other types.
note that normal lua_toboolean returns 1 for any Lua value different from false and
nil; otherwise it returns 0. So a string would give a 0, as would a number of 1.
This function errors if the arg is a string, and sets the boolean to 1 for any
number other than 0. Like toboolean, this returns FALSE if the arg was missing. */
WSLUA_API gboolean wslua_toboolean(lua_State* L, int n) {
gboolean val = FALSE;
if ( lua_isboolean(L,n) || lua_isnil(L,n) || lua_gettop(L) < n ) {
val = lua_toboolean(L,n);
} else if ( lua_type(L,n) == LUA_TNUMBER ) {
int num = (int)luaL_checkinteger(L,n);
val = num != 0 ? TRUE : FALSE;
} else {
luaL_argerror(L,n,"must be a boolean or number");
}
return val;
}
/* like luaL_checkinteger, except for booleans - this does not coerce other types */
WSLUA_API gboolean wslua_checkboolean(lua_State* L, int n) {
if (!lua_isboolean(L,n) ) {
luaL_argerror(L,n,"must be a boolean");
}
return lua_toboolean(L,n);;
}
WSLUA_API gboolean wslua_optbool(lua_State* L, int n, gboolean def) {
gboolean val = FALSE;
if ( lua_isboolean(L,n) ) {
val = lua_toboolean(L,n);
} else if ( lua_isnil(L,n) || lua_gettop(L) < n ){
val = def;
} else {
luaL_argerror(L,n,"must be a boolean");
}
return val;
}
/* like lua_tointeger, except only coerces int, nil, and bool, and errors on other types.
note that normal lua_tointeger does not coerce nil or bool, but does coerce strings. */
WSLUA_API lua_Integer wslua_tointeger(lua_State* L, int n) {
lua_Integer val = 0;
if ( lua_type(L,n) == LUA_TNUMBER) {
val = lua_tointeger(L,n);
} else if ( lua_isboolean(L,n) ) {
val = (lua_Integer) (lua_toboolean(L,n));
} else if ( lua_isnil(L,n) ) {
val = 0;
} else {
luaL_argerror(L,n,"must be a integer, boolean or nil");
}
return val;
}
/* like luaL_optint, except converts/handles Lua booleans as well */
WSLUA_API int wslua_optboolint(lua_State* L, int n, int def) {
int val = 0;
if ( lua_isnumber(L,n) ) {
val = (int)lua_tointeger(L,n);
} else if ( lua_isboolean(L,n) ) {
val = lua_toboolean(L,n) ? 1 : 0;
} else if ( lua_isnil(L,n) || lua_gettop(L) < n ){
val = def;
} else {
luaL_argerror(L,n,"must be a boolean or integer");
}
return val;
}
/* like luaL_checklstring, except no coercion */
WSLUA_API const char* wslua_checklstring_only(lua_State* L, int n, size_t *l) {
if (lua_type(L,n) != LUA_TSTRING) {
luaL_argerror(L,n,"must be a Lua string");
}
return luaL_checklstring(L, n, l);
}
/* like luaL_checkstring, except no coercion */
WSLUA_API const char* wslua_checkstring_only(lua_State* L, int n) {
return wslua_checklstring_only(L, n, NULL);
}
WSLUA_API const gchar* lua_shiftstring(lua_State* L, int i) {
const gchar* p = luaL_checkstring(L, i);
if (p) {
lua_remove(L,i);
return p;
} else {
return NULL;
}
}
/* following is based on the luaL_setfuncs() from Lua 5.2, so we can use it in pre-5.2 */
WSLUA_API void wslua_setfuncs(lua_State *L, const luaL_Reg *l, int nup) {
luaL_checkstack(L, nup, "too many upvalues");
for (; l->name != NULL; l++) { /* fill the table with given functions */
int i;
for (i = 0; i < nup; i++) /* copy upvalues to the top */
lua_pushvalue(L, -nup);
lua_pushcclosure(L, l->func, nup); /* closure with those upvalues */
lua_setfield(L, -(nup + 2), l->name);
}
lua_pop(L, nup); /* remove upvalues */
}
/* identical to lua_getfield but without triggering metamethods
warning: cannot be used directly with negative index (and shouldn't be changed to)
decrement your negative index if you want to use this */
static void lua_rawgetfield(lua_State *L, int idx, const char *k) {
lua_pushstring(L, k);
lua_rawget(L, idx);
}
/* identical to lua_setfield but without triggering metamethods
warning: cannot be used with negative index (and shouldn't be changed to)
decrement your negative index if you want to use this */
static void lua_rawsetfield (lua_State *L, int idx, const char *k) {
lua_pushstring(L, k);
lua_insert(L, -2);
lua_rawset(L, idx);
}
WSLUA_API void wslua_print_stack(char* s, lua_State* L) {
int i;
for (i=1;i<=lua_gettop(L);i++) {
printf("%s-%i: %s\n",s,i,lua_typename (L,lua_type(L, i)));
}
printf("\n");
}
/* C-code function equivalent of the typeof() function we created in Lua.
* The Lua one is for Lua scripts to use, this one is for C-code to use.
*/
const gchar* wslua_typeof_unknown = "UNKNOWN";
const gchar* wslua_typeof(lua_State *L, int idx) {
const gchar *classname = wslua_typeof_unknown;
/* we'll try getting the class name for error reporting*/
if (luaL_getmetafield(L, idx, WSLUA_TYPEOF_FIELD)) {
classname = luaL_optstring(L, -1, wslua_typeof_unknown);
lua_pop(L,1); /* pop __typeof result */
}
else if (lua_type(L,idx) == LUA_TTABLE) {
lua_rawgetfield(L, idx, WSLUA_TYPEOF_FIELD);
classname = luaL_optstring(L, -1, wslua_typeof_unknown);
lua_pop(L,1); /* pop __typeof result */
}
return classname;
}
/* this gets a Lua table of the given name, from the table at the given
* location idx. If it does not get a table, it pops whatever it got
* and returns false.
* warning: cannot be used with pseudo-indeces like LUA_REGISTRYINDEX
*/
gboolean wslua_get_table(lua_State *L, int idx, const gchar *name) {
gboolean result = TRUE;
if (idx < 0) idx--;
lua_rawgetfield(L, idx, name);
if (!lua_istable(L,-1)) {
lua_pop(L,1);
result = FALSE;
}
return result;
}
/* this gets a table field of the given name, from the table at the given
* location idx. If it does not get a field, it pops whatever it got
* and returns false.
* warning: cannot be used with pseudo-indeces like LUA_REGISTRYINDEX
*/
gboolean wslua_get_field(lua_State *L, int idx, const gchar *name) {
gboolean result = TRUE;
if (idx < 0) idx--;
lua_rawgetfield(L, idx, name);
if (lua_isnil(L,-1)) {
lua_pop(L,1);
result = FALSE;
}
return result;
}
/* This verifies/asserts that field 'name' doesn't already exist in table at location idx.
* If it does, this EXITS wireshark, because this is a fundamental programming error.
* As such, this function is only useful for special circumstances, notably
* those that will happen on application start every time, as opposed to
* something that could happen only if a Lua script makes it happen.
*/
void wslua_assert_table_field_new(lua_State *L, int idx, const gchar *name) {
lua_rawgetfield(L, idx, name);
if (!lua_isnil (L, -1)) {
fprintf(stderr, "ERROR: Field %s already exists!\n", name);
exit(1);
}
lua_pop (L, 1); /* pop the nil */ \
}
/* This function is an attribute field __index/__newindex (ie, getter/setter) dispatcher.
* What the heck does that mean? Well, when a Lua script tries to retrieve a
* table/userdata field by doing this:
* local foo = myobj.fieldname
* if 'fieldname' does not exist in the 'myobj' table/userdata, then Lua calls
* the '__index' metamethod of the table/userdata, and puts onto the Lua
* stack the table and fieldname string. So this function here handles that,
* by dispatching that request to the appropriate getter function in the
* __getters table within the metatable of the userdata. That table and
* its functions were populated by the WSLUA_REGISTER_ATTRIBUTES() macro, and
* really by wslua_reg_attributes().
*/
static int wslua_attribute_dispatcher (lua_State *L) {
lua_CFunction cfunc = NULL;
const gchar *fieldname = lua_shiftstring(L,2); /* remove the field name */
const gchar *classname = NULL;
const gchar *type = NULL;
/* the userdata object is at index 1, fieldname was at 2 but no longer,
now we get the getter/setter table at upvalue 1 */
if (!lua_istable(L, lua_upvalueindex(1)))
return luaL_error(L, "Accessor dispatcher cannot retrieve the getter/setter table");
lua_rawgetfield(L, lua_upvalueindex(1), fieldname); /* field's cfunction is now at -1 */
if (!lua_iscfunction(L, -1)) {
lua_pop(L,1); /* pop whatever we got before */
/* check if there's a methods table */
if (lua_istable(L, lua_upvalueindex(2))) {
lua_rawgetfield(L, lua_upvalueindex(2), fieldname);
if (lua_iscfunction(L,-1)) {
/* we found a method for Lua to call, so give it back to Lua */
return 1;
}
lua_pop(L,1); /* pop whatever we got before */
}
classname = wslua_typeof(L, 1);
type = wslua_typeof(L, lua_upvalueindex(1));
lua_pop(L, 1); /* pop the nil/invalid getfield result */
return luaL_error(L, "No such '%s' %s attribute/field for object type '%s'", fieldname, type, classname);
}
cfunc = lua_tocfunction(L, -1);
lua_pop(L, 1); /* pop the cfunction */
/* the stack is now as if it had been calling the getter/setter c-function directly, so do it */
return (*cfunc)(L);
}
/* This function "registers" attribute functions - i.e., getters/setters for Lua objects.
* This way we don't have to write the __index/__newindex function dispatcher for every
* wslua class. Instead, your class should use WSLUA_REGISTER_ATTRIBUTES(classname), which
* ultimately calls this one - it calls it twice: once to register getters, once to register
* setters.
*
* The way this all works is every wslua class has a metatable. One of the fields of that
* metatable is a __index field, used for "getter" access, and a __newindex field used for
* "setter" access. If the __index field's _value_ is a Lua table, then Lua looks
* up that table, as it does for class methods for example; but if the __index field's
* value is a function/cfunction, Lua calls it instead to get/set the field. So
* we use that behavior to access our getters/setters, by creating a table of getter
* cfunctions, saving that as an upvalue of a dispatcher cfunction, and using that
* dispatcher cfunction as the value of the __index field of the metatable of the wslua object.
*
* In some cases, the metatable _index/__newindex will already be a function; for example if
* class methods were registered, then __index will already be a function In that case, we
* move the __methods table to be an upvalue of the attribute dispatcher function. The attribute
* dispatcher will look for it and return the method, if it doesn't find an attribute field.
* The code below makes sure the attribute names don't overlap with method names.
*
* This function assumes there's a class metatable on top of the stack when it's initially called,
* and leaves it on top when done.
*/
int wslua_reg_attributes(lua_State *L, const wslua_attribute_table *t, gboolean is_getter) {
int midx = lua_gettop(L);
const gchar *metafield = is_getter ? "__index" : "__newindex";
int idx;
int nup = 1; /* number of upvalues */
if (!lua_istable(L, midx)) {
fprintf(stderr, "No metatable in the Lua stack when registering attributes!\n");
exit(1);
}
/* check if there's a __index/__newindex table already - could be if this class has methods */
lua_rawgetfield(L, midx, metafield);
if (lua_isnil(L, -1)) {
/* there isn't one, pop the nil */
lua_pop(L,1);
}
else if (lua_istable(L, -1)) {
/* there is one, so make it be the attribute dispatchers upvalue #2 table */
nup = 2;
}
else if (lua_iscfunction(L, -1)) {
/* there's a methods __index dispatcher, copy the __methods table */
lua_pop(L,1); /* pop the cfunction */
lua_rawgetfield(L, midx, "__methods");
if (!lua_istable(L, -1)) {
/* oh oh, something's wrong */
fprintf(stderr, "got a __index cfunction but no __methods table when registering attributes!\n");
exit(1);
}
nup = 2;
}
else {
fprintf(stderr, "'%s' field is not a table in the Lua stack when registering attributes!\n", metafield);
exit(1);
}
/* make our new getter/setter table - we don't need to pop it later */
lua_newtable(L);
idx = lua_gettop(L);
/* fill the getter/setter table with given functions */
for (; t->fieldname != NULL; t++) {
lua_CFunction cfunc = is_getter ? t->getfunc : t->setfunc;
if (cfunc) {
/* if there's a previous methods table, make sure this attribute name doesn't collide */
if (nup > 1) {
lua_rawgetfield(L, -2, t->fieldname);
if (!lua_isnil(L,-1)) {
fprintf(stderr, "'%s' attribute name already exists as method name for the class\n", t->fieldname);
exit(1);
}
lua_pop(L,1); /* pop the nil */
}
lua_pushcfunction(L, cfunc);
lua_rawsetfield(L, idx, t->fieldname);
}
}
/* push the getter/setter table name into its table, for error reporting purposes */
lua_pushstring(L, (is_getter ? "getter" : "setter"));
lua_rawsetfield(L, idx, WSLUA_TYPEOF_FIELD);
/* copy table into the class's metatable, for introspection */
lua_pushvalue(L, idx);
lua_rawsetfield(L, midx, (is_getter ? "__getters" : "__setters"));
if (nup > 1) {
/* we've got more than one upvalue, so move the new getter/setter to the bottom-most of those */
lua_insert(L,-nup);
}
/* we should now be back to having gettter/setter table at -1 (or -2 if there was a previous methods table) */
/* create upvalue of getter/setter table for wslua_attribute_dispatcher function */
lua_pushcclosure(L, wslua_attribute_dispatcher, nup); /* pushes cfunc with upvalue, removes getter/setter table */
lua_rawsetfield(L, midx, metafield); /* sets this dispatch function as __index/__newindex field of metatable */
/* we should now be back to real metatable being on top */
return 0;
}
/* similar to __index metamethod but without triggering more metamethods */
static int wslua__index(lua_State *L) {
const gchar *fieldname = lua_shiftstring(L,2); /* remove the field name */
/* the userdata object or table is at index 1, fieldname was at 2 but no longer,
now we get the metatable, so we can get the methods table */
if (!lua_getmetatable(L,1)) {
/* this should be impossible */
return luaL_error(L, "No such '%s' field", fieldname);
}
lua_rawgetfield(L, 2, "__methods"); /* method table is now at 3 */
lua_remove(L,2); /* remove metatable, methods table is at 2 */
if (!lua_istable(L, -1)) {
const gchar *classname = wslua_typeof(L, 1);
lua_pop(L, 1); /* pop the nil getfield result */
return luaL_error(L, "No such '%s' field for object type '%s'", fieldname, classname);
}
lua_rawgetfield(L, 2, fieldname); /* field's value/function is now at 3 */
lua_remove(L,2); /* remove methods table, field value si at 2 */
if (lua_isnil(L, -1)) {
const gchar *classname = wslua_typeof(L, 1);
lua_pop(L, 1); /* pop the nil getfield result */
return luaL_error(L, "No such '%s' function/method/field for object type '%s'", fieldname, classname);
}
/* we found a method for Lua to call, or a value of some type, so give it back to Lua */
return 1;
}
/*
* This function assumes there's a class methods table at index 1, and its metatable at 2,
* when it's initially called, and leaves them that way when done.
*/
int wslua_set__index(lua_State *L) {
if (!lua_istable(L, 2) || !lua_istable(L, 1)) {
fprintf(stderr, "No metatable or class table in the Lua stack when registering __index!\n");
exit(1);
}
/* push a copy of the class methods table, and set it to be the metatable's __methods field */
lua_pushvalue (L, 1);
lua_rawsetfield(L, 2, "__methods");
/* set the wslua__index to be the __index metamethod */
lua_pushcfunction(L, wslua__index);
lua_rawsetfield(L, 2, "__index");
/* we should now be back to real metatable being on top */
return 0;
}
/* Pushes a hex string of the binary data argument. */
int wslua_bin2hex(lua_State* L, const guint8* data, const guint len, const gboolean lowercase, const gchar* sep) {
luaL_Buffer b;
guint i = 0;
static const char byte_to_str_upper[256][3] = {
"00","01","02","03","04","05","06","07","08","09","0A","0B","0C","0D","0E","0F",
"10","11","12","13","14","15","16","17","18","19","1A","1B","1C","1D","1E","1F",
"20","21","22","23","24","25","26","27","28","29","2A","2B","2C","2D","2E","2F",
"30","31","32","33","34","35","36","37","38","39","3A","3B","3C","3D","3E","3F",
"40","41","42","43","44","45","46","47","48","49","4A","4B","4C","4D","4E","4F",
"50","51","52","53","54","55","56","57","58","59","5A","5B","5C","5D","5E","5F",
"60","61","62","63","64","65","66","67","68","69","6A","6B","6C","6D","6E","6F",
"70","71","72","73","74","75","76","77","78","79","7A","7B","7C","7D","7E","7F",
"80","81","82","83","84","85","86","87","88","89","8A","8B","8C","8D","8E","8F",
"90","91","92","93","94","95","96","97","98","99","9A","9B","9C","9D","9E","9F",
"A0","A1","A2","A3","A4","A5","A6","A7","A8","A9","AA","AB","AC","AD","AE","AF",
"B0","B1","B2","B3","B4","B5","B6","B7","B8","B9","BA","BB","BC","BD","BE","BF",
"C0","C1","C2","C3","C4","C5","C6","C7","C8","C9","CA","CB","CC","CD","CE","CF",
"D0","D1","D2","D3","D4","D5","D6","D7","D8","D9","DA","DB","DC","DD","DE","DF",
"E0","E1","E2","E3","E4","E5","E6","E7","E8","E9","EA","EB","EC","ED","EE","EF",
"F0","F1","F2","F3","F4","F5","F6","F7","F8","F9","FA","FB","FC","FD","FE","FF"
};
static const char byte_to_str_lower[256][3] = {
"00","01","02","03","04","05","06","07","08","09","0a","0b","0c","0d","0e","0f",
"10","11","12","13","14","15","16","17","18","19","1a","1b","1c","1d","1e","1f",
"20","21","22","23","24","25","26","27","28","29","2a","2b","2c","2d","2e","2f",
"30","31","32","33","34","35","36","37","38","39","3a","3b","3c","3d","3e","3f",
"40","41","42","43","44","45","46","47","48","49","4a","4b","4c","4d","4e","4f",
"50","51","52","53","54","55","56","57","58","59","5a","5b","5c","5d","5e","5f",
"60","61","62","63","64","65","66","67","68","69","6a","6b","6c","6d","6e","6f",
"70","71","72","73","74","75","76","77","78","79","7a","7b","7c","7d","7e","7f",
"80","81","82","83","84","85","86","87","88","89","8a","8b","8c","8d","8e","8f",
"90","91","92","93","94","95","96","97","98","99","9a","9b","9c","9d","9e","9f",
"a0","a1","a2","a3","a4","a5","a6","a7","a8","a9","aa","ab","ac","ad","ae","af",
"b0","b1","b2","b3","b4","b5","b6","b7","b8","b9","ba","bb","bc","bd","be","bf",
"c0","c1","c2","c3","c4","c5","c6","c7","c8","c9","ca","cb","cc","cd","ce","cf",
"d0","d1","d2","d3","d4","d5","d6","d7","d8","d9","da","db","dc","dd","de","df",
"e0","e1","e2","e3","e4","e5","e6","e7","e8","e9","ea","eb","ec","ed","ee","ef",
"f0","f1","f2","f3","f4","f5","f6","f7","f8","f9","fa","fb","fc","fd","fe","ff"
};
const char (*byte_to_str)[3] = byte_to_str_upper;
const guint last = len - 1;
if (lowercase) byte_to_str = byte_to_str_lower;
luaL_buffinit(L, &b);
for (i = 0; i < len; i++) {
luaL_addlstring(&b, &(*byte_to_str[data[i]]), 2);
if (sep && i < last) luaL_addstring(&b, sep);
}
luaL_pushresult(&b);
return 1;
}
/* Pushes a binary string of the hex-ascii data argument. */
int wslua_hex2bin(lua_State* L, const char* data, const guint len, const gchar* sep) {
luaL_Buffer b;
guint i = 0;
guint seplen = 0;
gint8 c, d;
static const gint8 str_to_nibble[256] = {
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
0, 1, 2, 3, 4, 5, 6, 7, 8, 9,-1,-1,-1,-1,-1,-1,
-1,10,11,12,13,14,15,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,10,11,12,13,14,15,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1
};
if (sep) seplen = (guint) strlen(sep);
luaL_buffinit(L, &b);
for (i = 0; i < len;) {
c = str_to_nibble[(guchar)data[i]];
if (c < 0) {
if (seplen && strncmp(&data[i], sep, seplen) == 0) {
i += seplen;
continue;
} else {
break;
}
}
d = str_to_nibble[(guchar)data[++i]];
if (d < 0) break;
luaL_addchar(&b, (c * 16) + d);
i++;
}
luaL_pushresult(&b);
return 1;
}
/*
* Editor modelines - http://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 4
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* vi: set shiftwidth=4 tabstop=8 expandtab:
* :indentSize=4:tabSize=8:noTabs=true:
*/
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