ldblib.c
(5.3.6)
/*
** $Id: ldblib.c,v 1.151.1.1 2017/04/19 17:20:42 roberto Exp $
** Interface from Lua to its debug API
** See Copyright Notice in lua.h
*/
#define ldblib_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"
/*
** The hook table at registry[&HOOKKEY] maps threads to their current
** hook function. (We only need the unique address of 'HOOKKEY'.)
*/
static const int HOOKKEY = 0;
/*
** If L1 != L, L1 can be in any state, and therefore there are no
** guarantees about its stack space; any push in L1 must be
** checked.
*/
static void checkstack (lua_State *L, lua_State *L1, int n) {
if (L != L1 && !lua_checkstack(L1, n))
luaL_error(L, "stack overflow");
}
static int db_getregistry (lua_State *L) {
lua_pushvalue(L, LUA_REGISTRYINDEX);
return 1;
}
static int db_getmetatable (lua_State *L) {
luaL_checkany(L, 1);
if (!lua_getmetatable(L, 1)) {
lua_pushnil(L); /* no metatable */
}
return 1;
}
static int db_setmetatable (lua_State *L) {
int t = lua_type(L, 2);
luaL_argcheck(L, t == LUA_TNIL || t == LUA_TTABLE, 2,
"nil or table expected");
lua_settop(L, 2);
lua_setmetatable(L, 1);
return 1; /* return 1st argument */
}
static int db_getuservalue (lua_State *L) {
if (lua_type(L, 1) != LUA_TUSERDATA)
lua_pushnil(L);
else
lua_getuservalue(L, 1);
return 1;
}
static int db_setuservalue (lua_State *L) {
luaL_checktype(L, 1, LUA_TUSERDATA);
luaL_checkany(L, 2);
lua_settop(L, 2);
lua_setuservalue(L, 1);
return 1;
}
/*
** Auxiliary function used by several library functions: check for
** an optional thread as function's first argument and set 'arg' with
** 1 if this argument is present (so that functions can skip it to
** access their other arguments)
*/
static lua_State *getthread (lua_State *L, int *arg) {
if (lua_isthread(L, 1)) {
*arg = 1;
return lua_tothread(L, 1);
}
else {
*arg = 0;
return L; /* function will operate over current thread */
}
}
/*
** Variations of 'lua_settable', used by 'db_getinfo' to put results
** from 'lua_getinfo' into result table. Key is always a string;
** value can be a string, an int, or a boolean.
*/
static void settabss (lua_State *L, const char *k, const char *v) {
lua_pushstring(L, v);
lua_setfield(L, -2, k);
}
static void settabsi (lua_State *L, const char *k, int v) {
lua_pushinteger(L, v);
lua_setfield(L, -2, k);
}
static void settabsb (lua_State *L, const char *k, int v) {
lua_pushboolean(L, v);
lua_setfield(L, -2, k);
}
/*
** In function 'db_getinfo', the call to 'lua_getinfo' may push
** results on the stack; later it creates the result table to put
** these objects. Function 'treatstackoption' puts the result from
** 'lua_getinfo' on top of the result table so that it can call
** 'lua_setfield'.
*/
static void treatstackoption (lua_State *L, lua_State *L1, const char *fname) {
if (L == L1)
lua_rotate(L, -2, 1); /* exchange object and table */
else
lua_xmove(L1, L, 1); /* move object to the "main" stack */
lua_setfield(L, -2, fname); /* put object into table */
}
/*
** Calls 'lua_getinfo' and collects all results in a new table.
** L1 needs stack space for an optional input (function) plus
** two optional outputs (function and line table) from function
** 'lua_getinfo'.
*/
static int db_getinfo (lua_State *L) {
lua_Debug ar;
int arg;
lua_State *L1 = getthread(L, &arg);
const char *options = luaL_optstring(L, arg+2, "flnStu");
checkstack(L, L1, 3);
if (lua_isfunction(L, arg + 1)) { /* info about a function? */
options = lua_pushfstring(L, ">%s", options); /* add '>' to 'options' */
lua_pushvalue(L, arg + 1); /* move function to 'L1' stack */
lua_xmove(L, L1, 1);
}
else { /* stack level */
if (!lua_getstack(L1, (int)luaL_checkinteger(L, arg + 1), &ar)) {
lua_pushnil(L); /* level out of range */
return 1;
}
}
if (!lua_getinfo(L1, options, &ar))
return luaL_argerror(L, arg+2, "invalid option");
lua_newtable(L); /* table to collect results */
if (strchr(options, 'S')) {
settabss(L, "source", ar.source);
settabss(L, "short_src", ar.short_src);
settabsi(L, "linedefined", ar.linedefined);
settabsi(L, "lastlinedefined", ar.lastlinedefined);
settabss(L, "what", ar.what);
}
if (strchr(options, 'l'))
settabsi(L, "currentline", ar.currentline);
if (strchr(options, 'u')) {
settabsi(L, "nups", ar.nups);
settabsi(L, "nparams", ar.nparams);
settabsb(L, "isvararg", ar.isvararg);
}
if (strchr(options, 'n')) {
settabss(L, "name", ar.name);
settabss(L, "namewhat", ar.namewhat);
}
if (strchr(options, 't'))
settabsb(L, "istailcall", ar.istailcall);
if (strchr(options, 'L'))
treatstackoption(L, L1, "activelines");
if (strchr(options, 'f'))
treatstackoption(L, L1, "func");
return 1; /* return table */
}
static int db_getlocal (lua_State *L) {
int arg;
lua_State *L1 = getthread(L, &arg);
lua_Debug ar;
const char *name;
int nvar = (int)luaL_checkinteger(L, arg + 2); /* local-variable index */
if (lua_isfunction(L, arg + 1)) { /* function argument? */
lua_pushvalue(L, arg + 1); /* push function */
lua_pushstring(L, lua_getlocal(L, NULL, nvar)); /* push local name */
return 1; /* return only name (there is no value) */
}
else { /* stack-level argument */
int level = (int)luaL_checkinteger(L, arg + 1);
if (!lua_getstack(L1, level, &ar)) /* out of range? */
return luaL_argerror(L, arg+1, "level out of range");
checkstack(L, L1, 1);
name = lua_getlocal(L1, &ar, nvar);
if (name) {
lua_xmove(L1, L, 1); /* move local value */
lua_pushstring(L, name); /* push name */
lua_rotate(L, -2, 1); /* re-order */
return 2;
}
else {
lua_pushnil(L); /* no name (nor value) */
return 1;
}
}
}
static int db_setlocal (lua_State *L) {
int arg;
const char *name;
lua_State *L1 = getthread(L, &arg);
lua_Debug ar;
int level = (int)luaL_checkinteger(L, arg + 1);
int nvar = (int)luaL_checkinteger(L, arg + 2);
if (!lua_getstack(L1, level, &ar)) /* out of range? */
return luaL_argerror(L, arg+1, "level out of range");
luaL_checkany(L, arg+3);
lua_settop(L, arg+3);
checkstack(L, L1, 1);
lua_xmove(L, L1, 1);
name = lua_setlocal(L1, &ar, nvar);
if (name == NULL)
lua_pop(L1, 1); /* pop value (if not popped by 'lua_setlocal') */
lua_pushstring(L, name);
return 1;
}
/*
** get (if 'get' is true) or set an upvalue from a closure
*/
static int auxupvalue (lua_State *L, int get) {
const char *name;
int n = (int)luaL_checkinteger(L, 2); /* upvalue index */
luaL_checktype(L, 1, LUA_TFUNCTION); /* closure */
name = get ? lua_getupvalue(L, 1, n) : lua_setupvalue(L, 1, n);
if (name == NULL) return 0;
lua_pushstring(L, name);
lua_insert(L, -(get+1)); /* no-op if get is false */
return get + 1;
}
static int db_getupvalue (lua_State *L) {
return auxupvalue(L, 1);
}
static int db_setupvalue (lua_State *L) {
luaL_checkany(L, 3);
return auxupvalue(L, 0);
}
/*
** Check whether a given upvalue from a given closure exists and
** returns its index
*/
static int checkupval (lua_State *L, int argf, int argnup) {
int nup = (int)luaL_checkinteger(L, argnup); /* upvalue index */
luaL_checktype(L, argf, LUA_TFUNCTION); /* closure */
luaL_argcheck(L, (lua_getupvalue(L, argf, nup) != NULL), argnup,
"invalid upvalue index");
return nup;
}
static int db_upvalueid (lua_State *L) {
int n = checkupval(L, 1, 2);
lua_pushlightuserdata(L, lua_upvalueid(L, 1, n));
return 1;
}
static int db_upvaluejoin (lua_State *L) {
int n1 = checkupval(L, 1, 2);
int n2 = checkupval(L, 3, 4);
luaL_argcheck(L, !lua_iscfunction(L, 1), 1, "Lua function expected");
luaL_argcheck(L, !lua_iscfunction(L, 3), 3, "Lua function expected");
lua_upvaluejoin(L, 1, n1, 3, n2);
return 0;
}
/*
** Call hook function registered at hook table for the current
** thread (if there is one)
*/
static void hookf (lua_State *L, lua_Debug *ar) {
static const char *const hooknames[] =
{"call", "return", "line", "count", "tail call"};
lua_rawgetp(L, LUA_REGISTRYINDEX, &HOOKKEY);
lua_pushthread(L);
if (lua_rawget(L, -2) == LUA_TFUNCTION) { /* is there a hook function? */
lua_pushstring(L, hooknames[(int)ar->event]); /* push event name */
if (ar->currentline >= 0)
lua_pushinteger(L, ar->currentline); /* push current line */
else lua_pushnil(L);
lua_assert(lua_getinfo(L, "lS", ar));
lua_call(L, 2, 0); /* call hook function */
}
}
/*
** Convert a string mask (for 'sethook') into a bit mask
*/
static int makemask (const char *smask, int count) {
int mask = 0;
if (strchr(smask, 'c')) mask |= LUA_MASKCALL;
if (strchr(smask, 'r')) mask |= LUA_MASKRET;
if (strchr(smask, 'l')) mask |= LUA_MASKLINE;
if (count > 0) mask |= LUA_MASKCOUNT;
return mask;
}
/*
** Convert a bit mask (for 'gethook') into a string mask
*/
static char *unmakemask (int mask, char *smask) {
int i = 0;
if (mask & LUA_MASKCALL) smask[i++] = 'c';
if (mask & LUA_MASKRET) smask[i++] = 'r';
if (mask & LUA_MASKLINE) smask[i++] = 'l';
smask[i] = '\0';
return smask;
}
static int db_sethook (lua_State *L) {
int arg, mask, count;
lua_Hook func;
lua_State *L1 = getthread(L, &arg);
if (lua_isnoneornil(L, arg+1)) { /* no hook? */
lua_settop(L, arg+1);
func = NULL; mask = 0; count = 0; /* turn off hooks */
}
else {
const char *smask = luaL_checkstring(L, arg+2);
luaL_checktype(L, arg+1, LUA_TFUNCTION);
count = (int)luaL_optinteger(L, arg + 3, 0);
func = hookf; mask = makemask(smask, count);
}
if (lua_rawgetp(L, LUA_REGISTRYINDEX, &HOOKKEY) == LUA_TNIL) {
lua_createtable(L, 0, 2); /* create a hook table */
lua_pushvalue(L, -1);
lua_rawsetp(L, LUA_REGISTRYINDEX, &HOOKKEY); /* set it in position */
lua_pushstring(L, "k");
lua_setfield(L, -2, "__mode"); /** hooktable.__mode = "k" */
lua_pushvalue(L, -1);
lua_setmetatable(L, -2); /* setmetatable(hooktable) = hooktable */
}
checkstack(L, L1, 1);
lua_pushthread(L1); lua_xmove(L1, L, 1); /* key (thread) */
lua_pushvalue(L, arg + 1); /* value (hook function) */
lua_rawset(L, -3); /* hooktable[L1] = new Lua hook */
lua_sethook(L1, func, mask, count);
return 0;
}
static int db_gethook (lua_State *L) {
int arg;
lua_State *L1 = getthread(L, &arg);
char buff[5];
int mask = lua_gethookmask(L1);
lua_Hook hook = lua_gethook(L1);
if (hook == NULL) /* no hook? */
lua_pushnil(L);
else if (hook != hookf) /* external hook? */
lua_pushliteral(L, "external hook");
else { /* hook table must exist */
lua_rawgetp(L, LUA_REGISTRYINDEX, &HOOKKEY);
checkstack(L, L1, 1);
lua_pushthread(L1); lua_xmove(L1, L, 1);
lua_rawget(L, -2); /* 1st result = hooktable[L1] */
lua_remove(L, -2); /* remove hook table */
}
lua_pushstring(L, unmakemask(mask, buff)); /* 2nd result = mask */
lua_pushinteger(L, lua_gethookcount(L1)); /* 3rd result = count */
return 3;
}
static int db_debug (lua_State *L) {
for (;;) {
char buffer[250];
lua_writestringerror("%s", "lua_debug> ");
if (fgets(buffer, sizeof(buffer), stdin) == 0 ||
strcmp(buffer, "cont\n") == 0)
return 0;
if (luaL_loadbuffer(L, buffer, strlen(buffer), "=(debug command)") ||
lua_pcall(L, 0, 0, 0))
lua_writestringerror("%s\n", lua_tostring(L, -1));
lua_settop(L, 0); /* remove eventual returns */
}
}
static int db_traceback (lua_State *L) {
int arg;
lua_State *L1 = getthread(L, &arg);
const char *msg = lua_tostring(L, arg + 1);
if (msg == NULL && !lua_isnoneornil(L, arg + 1)) /* non-string 'msg'? */
lua_pushvalue(L, arg + 1); /* return it untouched */
else {
int level = (int)luaL_optinteger(L, arg + 2, (L == L1) ? 1 : 0);
luaL_traceback(L, L1, msg, level);
}
return 1;
}
static const luaL_Reg dblib[] = {
{"debug", db_debug},
{"getuservalue", db_getuservalue},
{"gethook", db_gethook},
{"getinfo", db_getinfo},
{"getlocal", db_getlocal},
{"getregistry", db_getregistry},
{"getmetatable", db_getmetatable},
{"getupvalue", db_getupvalue},
{"upvaluejoin", db_upvaluejoin},
{"upvalueid", db_upvalueid},
{"setuservalue", db_setuservalue},
{"sethook", db_sethook},
{"setlocal", db_setlocal},
{"setmetatable", db_setmetatable},
{"setupvalue", db_setupvalue},
{"traceback", db_traceback},
{NULL, NULL}
};
LUAMOD_API int luaopen_debug (lua_State *L) {
luaL_newlib(L, dblib);
return 1;
}