1 /*
2 ** $Id: ldblib.c $
3 ** Interface from Lua to its debug API
4 ** See Copyright Notice in lua.h
5 */
6
7 #define ldblib_c
8 #define LUA_LIB
9
10 #include "lprefix.h"
11
12
13 #include <stdio.h>
14 #include <stdlib.h>
15 #include <string.h>
16
17 #include "lua.h"
18
19 #include "lauxlib.h"
20 #include "lualib.h"
21
22
23 /*
24 ** The hook table at registry[HOOKKEY] maps threads to their current
25 ** hook function.
26 */
27 static const char *const HOOKKEY = "_HOOKKEY";
28
29
30 /*
31 ** If L1 != L, L1 can be in any state, and therefore there are no
32 ** guarantees about its stack space; any push in L1 must be
33 ** checked.
34 */
checkstack(lua_State * L,lua_State * L1,int n)35 static void checkstack (lua_State *L, lua_State *L1, int n) {
36 if (l_unlikely(L != L1 && !lua_checkstack(L1, n)))
37 luaL_error(L, "stack overflow");
38 }
39
40
db_getregistry(lua_State * L)41 static int db_getregistry (lua_State *L) {
42 lua_pushvalue(L, LUA_REGISTRYINDEX);
43 return 1;
44 }
45
46
db_getmetatable(lua_State * L)47 static int db_getmetatable (lua_State *L) {
48 luaL_checkany(L, 1);
49 if (!lua_getmetatable(L, 1)) {
50 lua_pushnil(L); /* no metatable */
51 }
52 return 1;
53 }
54
55
db_setmetatable(lua_State * L)56 static int db_setmetatable (lua_State *L) {
57 int t = lua_type(L, 2);
58 luaL_argexpected(L, t == LUA_TNIL || t == LUA_TTABLE, 2, "nil or table");
59 lua_settop(L, 2);
60 lua_setmetatable(L, 1);
61 return 1; /* return 1st argument */
62 }
63
64
db_getuservalue(lua_State * L)65 static int db_getuservalue (lua_State *L) {
66 int n = (int)luaL_optinteger(L, 2, 1);
67 if (lua_type(L, 1) != LUA_TUSERDATA)
68 luaL_pushfail(L);
69 else if (lua_getiuservalue(L, 1, n) != LUA_TNONE) {
70 lua_pushboolean(L, 1);
71 return 2;
72 }
73 return 1;
74 }
75
76
db_setuservalue(lua_State * L)77 static int db_setuservalue (lua_State *L) {
78 int n = (int)luaL_optinteger(L, 3, 1);
79 luaL_checktype(L, 1, LUA_TUSERDATA);
80 luaL_checkany(L, 2);
81 lua_settop(L, 2);
82 if (!lua_setiuservalue(L, 1, n))
83 luaL_pushfail(L);
84 return 1;
85 }
86
87
88 /*
89 ** Auxiliary function used by several library functions: check for
90 ** an optional thread as function's first argument and set 'arg' with
91 ** 1 if this argument is present (so that functions can skip it to
92 ** access their other arguments)
93 */
getthread(lua_State * L,int * arg)94 static lua_State *getthread (lua_State *L, int *arg) {
95 if (lua_isthread(L, 1)) {
96 *arg = 1;
97 return lua_tothread(L, 1);
98 }
99 else {
100 *arg = 0;
101 return L; /* function will operate over current thread */
102 }
103 }
104
105
106 /*
107 ** Variations of 'lua_settable', used by 'db_getinfo' to put results
108 ** from 'lua_getinfo' into result table. Key is always a string;
109 ** value can be a string, an int, or a boolean.
110 */
settabss(lua_State * L,const char * k,const char * v)111 static void settabss (lua_State *L, const char *k, const char *v) {
112 lua_pushstring(L, v);
113 lua_setfield(L, -2, k);
114 }
115
settabsi(lua_State * L,const char * k,int v)116 static void settabsi (lua_State *L, const char *k, int v) {
117 lua_pushinteger(L, v);
118 lua_setfield(L, -2, k);
119 }
120
settabsb(lua_State * L,const char * k,int v)121 static void settabsb (lua_State *L, const char *k, int v) {
122 lua_pushboolean(L, v);
123 lua_setfield(L, -2, k);
124 }
125
126
127 /*
128 ** In function 'db_getinfo', the call to 'lua_getinfo' may push
129 ** results on the stack; later it creates the result table to put
130 ** these objects. Function 'treatstackoption' puts the result from
131 ** 'lua_getinfo' on top of the result table so that it can call
132 ** 'lua_setfield'.
133 */
treatstackoption(lua_State * L,lua_State * L1,const char * fname)134 static void treatstackoption (lua_State *L, lua_State *L1, const char *fname) {
135 if (L == L1)
136 lua_rotate(L, -2, 1); /* exchange object and table */
137 else
138 lua_xmove(L1, L, 1); /* move object to the "main" stack */
139 lua_setfield(L, -2, fname); /* put object into table */
140 }
141
142
143 /*
144 ** Calls 'lua_getinfo' and collects all results in a new table.
145 ** L1 needs stack space for an optional input (function) plus
146 ** two optional outputs (function and line table) from function
147 ** 'lua_getinfo'.
148 */
db_getinfo(lua_State * L)149 static int db_getinfo (lua_State *L) {
150 lua_Debug ar;
151 int arg;
152 lua_State *L1 = getthread(L, &arg);
153 const char *options = luaL_optstring(L, arg+2, "flnSrtu");
154 checkstack(L, L1, 3);
155 luaL_argcheck(L, options[0] != '>', arg + 2, "invalid option '>'");
156 if (lua_isfunction(L, arg + 1)) { /* info about a function? */
157 options = lua_pushfstring(L, ">%s", options); /* add '>' to 'options' */
158 lua_pushvalue(L, arg + 1); /* move function to 'L1' stack */
159 lua_xmove(L, L1, 1);
160 }
161 else { /* stack level */
162 if (!lua_getstack(L1, (int)luaL_checkinteger(L, arg + 1), &ar)) {
163 luaL_pushfail(L); /* level out of range */
164 return 1;
165 }
166 }
167 if (!lua_getinfo(L1, options, &ar))
168 return luaL_argerror(L, arg+2, "invalid option");
169 lua_newtable(L); /* table to collect results */
170 if (strchr(options, 'S')) {
171 lua_pushlstring(L, ar.source, ar.srclen);
172 lua_setfield(L, -2, "source");
173 settabss(L, "short_src", ar.short_src);
174 settabsi(L, "linedefined", ar.linedefined);
175 settabsi(L, "lastlinedefined", ar.lastlinedefined);
176 settabss(L, "what", ar.what);
177 }
178 if (strchr(options, 'l'))
179 settabsi(L, "currentline", ar.currentline);
180 if (strchr(options, 'u')) {
181 settabsi(L, "nups", ar.nups);
182 settabsi(L, "nparams", ar.nparams);
183 settabsb(L, "isvararg", ar.isvararg);
184 }
185 if (strchr(options, 'n')) {
186 settabss(L, "name", ar.name);
187 settabss(L, "namewhat", ar.namewhat);
188 }
189 if (strchr(options, 'r')) {
190 settabsi(L, "ftransfer", ar.ftransfer);
191 settabsi(L, "ntransfer", ar.ntransfer);
192 }
193 if (strchr(options, 't'))
194 settabsb(L, "istailcall", ar.istailcall);
195 if (strchr(options, 'L'))
196 treatstackoption(L, L1, "activelines");
197 if (strchr(options, 'f'))
198 treatstackoption(L, L1, "func");
199 return 1; /* return table */
200 }
201
202
db_getlocal(lua_State * L)203 static int db_getlocal (lua_State *L) {
204 int arg;
205 lua_State *L1 = getthread(L, &arg);
206 int nvar = (int)luaL_checkinteger(L, arg + 2); /* local-variable index */
207 if (lua_isfunction(L, arg + 1)) { /* function argument? */
208 lua_pushvalue(L, arg + 1); /* push function */
209 lua_pushstring(L, lua_getlocal(L, NULL, nvar)); /* push local name */
210 return 1; /* return only name (there is no value) */
211 }
212 else { /* stack-level argument */
213 lua_Debug ar;
214 const char *name;
215 int level = (int)luaL_checkinteger(L, arg + 1);
216 if (l_unlikely(!lua_getstack(L1, level, &ar))) /* out of range? */
217 return luaL_argerror(L, arg+1, "level out of range");
218 checkstack(L, L1, 1);
219 name = lua_getlocal(L1, &ar, nvar);
220 if (name) {
221 lua_xmove(L1, L, 1); /* move local value */
222 lua_pushstring(L, name); /* push name */
223 lua_rotate(L, -2, 1); /* re-order */
224 return 2;
225 }
226 else {
227 luaL_pushfail(L); /* no name (nor value) */
228 return 1;
229 }
230 }
231 }
232
233
db_setlocal(lua_State * L)234 static int db_setlocal (lua_State *L) {
235 int arg;
236 const char *name;
237 lua_State *L1 = getthread(L, &arg);
238 lua_Debug ar;
239 int level = (int)luaL_checkinteger(L, arg + 1);
240 int nvar = (int)luaL_checkinteger(L, arg + 2);
241 if (l_unlikely(!lua_getstack(L1, level, &ar))) /* out of range? */
242 return luaL_argerror(L, arg+1, "level out of range");
243 luaL_checkany(L, arg+3);
244 lua_settop(L, arg+3);
245 checkstack(L, L1, 1);
246 lua_xmove(L, L1, 1);
247 name = lua_setlocal(L1, &ar, nvar);
248 if (name == NULL)
249 lua_pop(L1, 1); /* pop value (if not popped by 'lua_setlocal') */
250 lua_pushstring(L, name);
251 return 1;
252 }
253
254
255 /*
256 ** get (if 'get' is true) or set an upvalue from a closure
257 */
auxupvalue(lua_State * L,int get)258 static int auxupvalue (lua_State *L, int get) {
259 const char *name;
260 int n = (int)luaL_checkinteger(L, 2); /* upvalue index */
261 luaL_checktype(L, 1, LUA_TFUNCTION); /* closure */
262 name = get ? lua_getupvalue(L, 1, n) : lua_setupvalue(L, 1, n);
263 if (name == NULL) return 0;
264 lua_pushstring(L, name);
265 lua_insert(L, -(get+1)); /* no-op if get is false */
266 return get + 1;
267 }
268
269
db_getupvalue(lua_State * L)270 static int db_getupvalue (lua_State *L) {
271 return auxupvalue(L, 1);
272 }
273
274
db_setupvalue(lua_State * L)275 static int db_setupvalue (lua_State *L) {
276 luaL_checkany(L, 3);
277 return auxupvalue(L, 0);
278 }
279
280
281 /*
282 ** Check whether a given upvalue from a given closure exists and
283 ** returns its index
284 */
checkupval(lua_State * L,int argf,int argnup,int * pnup)285 static void *checkupval (lua_State *L, int argf, int argnup, int *pnup) {
286 void *id;
287 int nup = (int)luaL_checkinteger(L, argnup); /* upvalue index */
288 luaL_checktype(L, argf, LUA_TFUNCTION); /* closure */
289 id = lua_upvalueid(L, argf, nup);
290 if (pnup) {
291 luaL_argcheck(L, id != NULL, argnup, "invalid upvalue index");
292 *pnup = nup;
293 }
294 return id;
295 }
296
297
db_upvalueid(lua_State * L)298 static int db_upvalueid (lua_State *L) {
299 void *id = checkupval(L, 1, 2, NULL);
300 if (id != NULL)
301 lua_pushlightuserdata(L, id);
302 else
303 luaL_pushfail(L);
304 return 1;
305 }
306
307
db_upvaluejoin(lua_State * L)308 static int db_upvaluejoin (lua_State *L) {
309 int n1, n2;
310 checkupval(L, 1, 2, &n1);
311 checkupval(L, 3, 4, &n2);
312 luaL_argcheck(L, !lua_iscfunction(L, 1), 1, "Lua function expected");
313 luaL_argcheck(L, !lua_iscfunction(L, 3), 3, "Lua function expected");
314 lua_upvaluejoin(L, 1, n1, 3, n2);
315 return 0;
316 }
317
318
319 /*
320 ** Call hook function registered at hook table for the current
321 ** thread (if there is one)
322 */
hookf(lua_State * L,lua_Debug * ar)323 static void hookf (lua_State *L, lua_Debug *ar) {
324 static const char *const hooknames[] =
325 {"call", "return", "line", "count", "tail call"};
326 lua_getfield(L, LUA_REGISTRYINDEX, HOOKKEY);
327 lua_pushthread(L);
328 if (lua_rawget(L, -2) == LUA_TFUNCTION) { /* is there a hook function? */
329 lua_pushstring(L, hooknames[(int)ar->event]); /* push event name */
330 if (ar->currentline >= 0)
331 lua_pushinteger(L, ar->currentline); /* push current line */
332 else lua_pushnil(L);
333 lua_assert(lua_getinfo(L, "lS", ar));
334 lua_call(L, 2, 0); /* call hook function */
335 }
336 }
337
338
339 /*
340 ** Convert a string mask (for 'sethook') into a bit mask
341 */
makemask(const char * smask,int count)342 static int makemask (const char *smask, int count) {
343 int mask = 0;
344 if (strchr(smask, 'c')) mask |= LUA_MASKCALL;
345 if (strchr(smask, 'r')) mask |= LUA_MASKRET;
346 if (strchr(smask, 'l')) mask |= LUA_MASKLINE;
347 if (count > 0) mask |= LUA_MASKCOUNT;
348 return mask;
349 }
350
351
352 /*
353 ** Convert a bit mask (for 'gethook') into a string mask
354 */
unmakemask(int mask,char * smask)355 static char *unmakemask (int mask, char *smask) {
356 int i = 0;
357 if (mask & LUA_MASKCALL) smask[i++] = 'c';
358 if (mask & LUA_MASKRET) smask[i++] = 'r';
359 if (mask & LUA_MASKLINE) smask[i++] = 'l';
360 smask[i] = '\0';
361 return smask;
362 }
363
364
db_sethook(lua_State * L)365 static int db_sethook (lua_State *L) {
366 int arg, mask, count;
367 lua_Hook func;
368 lua_State *L1 = getthread(L, &arg);
369 if (lua_isnoneornil(L, arg+1)) { /* no hook? */
370 lua_settop(L, arg+1);
371 func = NULL; mask = 0; count = 0; /* turn off hooks */
372 }
373 else {
374 const char *smask = luaL_checkstring(L, arg+2);
375 luaL_checktype(L, arg+1, LUA_TFUNCTION);
376 count = (int)luaL_optinteger(L, arg + 3, 0);
377 func = hookf; mask = makemask(smask, count);
378 }
379 if (!luaL_getsubtable(L, LUA_REGISTRYINDEX, HOOKKEY)) {
380 /* table just created; initialize it */
381 lua_pushliteral(L, "k");
382 lua_setfield(L, -2, "__mode"); /** hooktable.__mode = "k" */
383 lua_pushvalue(L, -1);
384 lua_setmetatable(L, -2); /* metatable(hooktable) = hooktable */
385 }
386 checkstack(L, L1, 1);
387 lua_pushthread(L1); lua_xmove(L1, L, 1); /* key (thread) */
388 lua_pushvalue(L, arg + 1); /* value (hook function) */
389 lua_rawset(L, -3); /* hooktable[L1] = new Lua hook */
390 lua_sethook(L1, func, mask, count);
391 return 0;
392 }
393
394
db_gethook(lua_State * L)395 static int db_gethook (lua_State *L) {
396 int arg;
397 lua_State *L1 = getthread(L, &arg);
398 char buff[5];
399 int mask = lua_gethookmask(L1);
400 lua_Hook hook = lua_gethook(L1);
401 if (hook == NULL) { /* no hook? */
402 luaL_pushfail(L);
403 return 1;
404 }
405 else if (hook != hookf) /* external hook? */
406 lua_pushliteral(L, "external hook");
407 else { /* hook table must exist */
408 lua_getfield(L, LUA_REGISTRYINDEX, HOOKKEY);
409 checkstack(L, L1, 1);
410 lua_pushthread(L1); lua_xmove(L1, L, 1);
411 lua_rawget(L, -2); /* 1st result = hooktable[L1] */
412 lua_remove(L, -2); /* remove hook table */
413 }
414 lua_pushstring(L, unmakemask(mask, buff)); /* 2nd result = mask */
415 lua_pushinteger(L, lua_gethookcount(L1)); /* 3rd result = count */
416 return 3;
417 }
418
419
db_debug(lua_State * L)420 static int db_debug (lua_State *L) {
421 for (;;) {
422 char buffer[250];
423 lua_writestringerror("%s", "lua_debug> ");
424 if (fgets(buffer, sizeof(buffer), stdin) == NULL ||
425 strcmp(buffer, "cont\n") == 0)
426 return 0;
427 if (luaL_loadbuffer(L, buffer, strlen(buffer), "=(debug command)") ||
428 lua_pcall(L, 0, 0, 0))
429 lua_writestringerror("%s\n", luaL_tolstring(L, -1, NULL));
430 lua_settop(L, 0); /* remove eventual returns */
431 }
432 }
433
434
db_traceback(lua_State * L)435 static int db_traceback (lua_State *L) {
436 int arg;
437 lua_State *L1 = getthread(L, &arg);
438 const char *msg = lua_tostring(L, arg + 1);
439 if (msg == NULL && !lua_isnoneornil(L, arg + 1)) /* non-string 'msg'? */
440 lua_pushvalue(L, arg + 1); /* return it untouched */
441 else {
442 int level = (int)luaL_optinteger(L, arg + 2, (L == L1) ? 1 : 0);
443 luaL_traceback(L, L1, msg, level);
444 }
445 return 1;
446 }
447
448
db_setcstacklimit(lua_State * L)449 static int db_setcstacklimit (lua_State *L) {
450 int limit = (int)luaL_checkinteger(L, 1);
451 int res = lua_setcstacklimit(L, limit);
452 lua_pushinteger(L, res);
453 return 1;
454 }
455
456
457 static const luaL_Reg dblib[] = {
458 {"debug", db_debug},
459 {"getuservalue", db_getuservalue},
460 {"gethook", db_gethook},
461 {"getinfo", db_getinfo},
462 {"getlocal", db_getlocal},
463 {"getregistry", db_getregistry},
464 {"getmetatable", db_getmetatable},
465 {"getupvalue", db_getupvalue},
466 {"upvaluejoin", db_upvaluejoin},
467 {"upvalueid", db_upvalueid},
468 {"setuservalue", db_setuservalue},
469 {"sethook", db_sethook},
470 {"setlocal", db_setlocal},
471 {"setmetatable", db_setmetatable},
472 {"setupvalue", db_setupvalue},
473 {"traceback", db_traceback},
474 {"setcstacklimit", db_setcstacklimit},
475 {NULL, NULL}
476 };
477
478
luaopen_debug(lua_State * L)479 LUAMOD_API int luaopen_debug (lua_State *L) {
480 luaL_newlib(L, dblib);
481 return 1;
482 }
483
484