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1 /*
2 ** $Id: ldebug.c,v 2.90.1.3 2013/05/16 16:04:15 roberto Exp $
3 ** Debug Interface
4 ** See Copyright Notice in lua.h
5 */
6 
7 
8 #include <stdarg.h>
9 #include <stddef.h>
10 #include <string.h>
11 
12 
13 #define ldebug_c
14 #define LUA_CORE
15 
16 #include "lua.h"
17 
18 #include "lapi.h"
19 #include "lcode.h"
20 #include "ldebug.h"
21 #include "ldo.h"
22 #include "lfunc.h"
23 #include "lobject.h"
24 #include "lopcodes.h"
25 #include "lstate.h"
26 #include "lstring.h"
27 #include "ltable.h"
28 #include "ltm.h"
29 #include "lvm.h"
30 
31 
32 
33 #define noLuaClosure(f)		((f) == NULL || (f)->c.tt == LUA_TCCL)
34 
35 
36 static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name);
37 
38 
currentpc(CallInfo * ci)39 static int currentpc (CallInfo *ci) {
40   lua_assert(isLua(ci));
41   return pcRel(ci->u.l.savedpc, ci_func(ci)->p);
42 }
43 
44 
currentline(CallInfo * ci)45 static int currentline (CallInfo *ci) {
46   return getfuncline(ci_func(ci)->p, currentpc(ci));
47 }
48 
49 
50 /*
51 ** this function can be called asynchronous (e.g. during a signal)
52 */
lua_sethook(lua_State * L,lua_Hook func,int mask,int count)53 LUA_API int lua_sethook (lua_State *L, lua_Hook func, int mask, int count) {
54   if (func == NULL || mask == 0) {  /* turn off hooks? */
55     mask = 0;
56     func = NULL;
57   }
58   if (isLua(L->ci))
59     L->oldpc = L->ci->u.l.savedpc;
60   L->hook = func;
61   L->basehookcount = count;
62   resethookcount(L);
63   L->hookmask = cast_byte(mask);
64   return 1;
65 }
66 
67 
lua_gethook(lua_State * L)68 LUA_API lua_Hook lua_gethook (lua_State *L) {
69   return L->hook;
70 }
71 
72 
lua_gethookmask(lua_State * L)73 LUA_API int lua_gethookmask (lua_State *L) {
74   return L->hookmask;
75 }
76 
77 
lua_gethookcount(lua_State * L)78 LUA_API int lua_gethookcount (lua_State *L) {
79   return L->basehookcount;
80 }
81 
82 
lua_getstack(lua_State * L,int level,lua_Debug * ar)83 LUA_API int lua_getstack (lua_State *L, int level, lua_Debug *ar) {
84   int status;
85   CallInfo *ci;
86   if (level < 0) return 0;  /* invalid (negative) level */
87   lua_lock(L);
88   for (ci = L->ci; level > 0 && ci != &L->base_ci; ci = ci->previous)
89     level--;
90   if (level == 0 && ci != &L->base_ci) {  /* level found? */
91     status = 1;
92     ar->i_ci = ci;
93   }
94   else status = 0;  /* no such level */
95   lua_unlock(L);
96   return status;
97 }
98 
99 
upvalname(Proto * p,int uv)100 static const char *upvalname (Proto *p, int uv) {
101   TString *s = check_exp(uv < p->sizeupvalues, p->upvalues[uv].name);
102   if (s == NULL) return "?";
103   else return getstr(s);
104 }
105 
106 
findvararg(CallInfo * ci,int n,StkId * pos)107 static const char *findvararg (CallInfo *ci, int n, StkId *pos) {
108   int nparams = clLvalue(ci->func)->p->numparams;
109   if (n >= ci->u.l.base - ci->func - nparams)
110     return NULL;  /* no such vararg */
111   else {
112     *pos = ci->func + nparams + n;
113     return "(*vararg)";  /* generic name for any vararg */
114   }
115 }
116 
117 
findlocal(lua_State * L,CallInfo * ci,int n,StkId * pos)118 static const char *findlocal (lua_State *L, CallInfo *ci, int n,
119                               StkId *pos) {
120   const char *name = NULL;
121   StkId base;
122   if (isLua(ci)) {
123     if (n < 0)  /* access to vararg values? */
124       return findvararg(ci, -n, pos);
125     else {
126       base = ci->u.l.base;
127       name = luaF_getlocalname(ci_func(ci)->p, n, currentpc(ci));
128     }
129   }
130   else
131     base = ci->func + 1;
132   if (name == NULL) {  /* no 'standard' name? */
133     StkId limit = (ci == L->ci) ? L->top : ci->next->func;
134     if (limit - base >= n && n > 0)  /* is 'n' inside 'ci' stack? */
135       name = "(*temporary)";  /* generic name for any valid slot */
136     else
137       return NULL;  /* no name */
138   }
139   *pos = base + (n - 1);
140   return name;
141 }
142 
143 
lua_getlocal(lua_State * L,const lua_Debug * ar,int n)144 LUA_API const char *lua_getlocal (lua_State *L, const lua_Debug *ar, int n) {
145   const char *name;
146   lua_lock(L);
147   if (ar == NULL) {  /* information about non-active function? */
148     if (!isLfunction(L->top - 1))  /* not a Lua function? */
149       name = NULL;
150     else  /* consider live variables at function start (parameters) */
151       name = luaF_getlocalname(clLvalue(L->top - 1)->p, n, 0);
152   }
153   else {  /* active function; get information through 'ar' */
154     StkId pos = 0;  /* to avoid warnings */
155     name = findlocal(L, ar->i_ci, n, &pos);
156     if (name) {
157       setobj2s(L, L->top, pos);
158       api_incr_top(L);
159     }
160   }
161   lua_unlock(L);
162   return name;
163 }
164 
165 
lua_setlocal(lua_State * L,const lua_Debug * ar,int n)166 LUA_API const char *lua_setlocal (lua_State *L, const lua_Debug *ar, int n) {
167   StkId pos = 0;  /* to avoid warnings */
168   const char *name = findlocal(L, ar->i_ci, n, &pos);
169   lua_lock(L);
170   if (name)
171     setobjs2s(L, pos, L->top - 1);
172   L->top--;  /* pop value */
173   lua_unlock(L);
174   return name;
175 }
176 
177 
funcinfo(lua_Debug * ar,Closure * cl)178 static void funcinfo (lua_Debug *ar, Closure *cl) {
179   if (noLuaClosure(cl)) {
180     ar->source = "=[C]";
181     ar->linedefined = -1;
182     ar->lastlinedefined = -1;
183     ar->what = "C";
184   }
185   else {
186     Proto *p = cl->l.p;
187     ar->source = p->source ? getstr(p->source) : "=?";
188     ar->linedefined = p->linedefined;
189     ar->lastlinedefined = p->lastlinedefined;
190     ar->what = (ar->linedefined == 0) ? "main" : "Lua";
191   }
192   luaO_chunkid(ar->short_src, ar->source, LUA_IDSIZE);
193 }
194 
195 
collectvalidlines(lua_State * L,Closure * f)196 static void collectvalidlines (lua_State *L, Closure *f) {
197   if (noLuaClosure(f)) {
198     setnilvalue(L->top);
199     api_incr_top(L);
200   }
201   else {
202     int i;
203     TValue v;
204     int *lineinfo = f->l.p->lineinfo;
205     Table *t = luaH_new(L);  /* new table to store active lines */
206     sethvalue(L, L->top, t);  /* push it on stack */
207     api_incr_top(L);
208     setbvalue(&v, 1);  /* boolean 'true' to be the value of all indices */
209     for (i = 0; i < f->l.p->sizelineinfo; i++)  /* for all lines with code */
210       luaH_setint(L, t, lineinfo[i], &v);  /* table[line] = true */
211   }
212 }
213 
214 
auxgetinfo(lua_State * L,const char * what,lua_Debug * ar,Closure * f,CallInfo * ci)215 static int auxgetinfo (lua_State *L, const char *what, lua_Debug *ar,
216                        Closure *f, CallInfo *ci) {
217   int status = 1;
218   for (; *what; what++) {
219     switch (*what) {
220       case 'S': {
221         funcinfo(ar, f);
222         break;
223       }
224       case 'l': {
225         ar->currentline = (ci && isLua(ci)) ? currentline(ci) : -1;
226         break;
227       }
228       case 'u': {
229         ar->nups = (f == NULL) ? 0 : f->c.nupvalues;
230         if (noLuaClosure(f)) {
231           ar->isvararg = 1;
232           ar->nparams = 0;
233         }
234         else {
235           ar->isvararg = f->l.p->is_vararg;
236           ar->nparams = f->l.p->numparams;
237         }
238         break;
239       }
240       case 't': {
241         ar->istailcall = (ci) ? ci->callstatus & CIST_TAIL : 0;
242         break;
243       }
244       case 'n': {
245         /* calling function is a known Lua function? */
246         if (ci && !(ci->callstatus & CIST_TAIL) && isLua(ci->previous))
247           ar->namewhat = getfuncname(L, ci->previous, &ar->name);
248         else
249           ar->namewhat = NULL;
250         if (ar->namewhat == NULL) {
251           ar->namewhat = "";  /* not found */
252           ar->name = NULL;
253         }
254         break;
255       }
256       case 'L':
257       case 'f':  /* handled by lua_getinfo */
258         break;
259       default: status = 0;  /* invalid option */
260     }
261   }
262   return status;
263 }
264 
265 
lua_getinfo(lua_State * L,const char * what,lua_Debug * ar)266 LUA_API int lua_getinfo (lua_State *L, const char *what, lua_Debug *ar) {
267   int status;
268   Closure *cl;
269   CallInfo *ci;
270   StkId func;
271   lua_lock(L);
272   if (*what == '>') {
273     ci = NULL;
274     func = L->top - 1;
275     api_check(L, ttisfunction(func), "function expected");
276     what++;  /* skip the '>' */
277     L->top--;  /* pop function */
278   }
279   else {
280     ci = ar->i_ci;
281     func = ci->func;
282     lua_assert(ttisfunction(ci->func));
283   }
284   cl = ttisclosure(func) ? clvalue(func) : NULL;
285   status = auxgetinfo(L, what, ar, cl, ci);
286   if (strchr(what, 'f')) {
287     setobjs2s(L, L->top, func);
288     api_incr_top(L);
289   }
290   if (strchr(what, 'L'))
291     collectvalidlines(L, cl);
292   lua_unlock(L);
293   return status;
294 }
295 
296 
297 /*
298 ** {======================================================
299 ** Symbolic Execution
300 ** =======================================================
301 */
302 
303 static const char *getobjname (Proto *p, int lastpc, int reg,
304                                const char **name);
305 
306 
307 /*
308 ** find a "name" for the RK value 'c'
309 */
kname(Proto * p,int pc,int c,const char ** name)310 static void kname (Proto *p, int pc, int c, const char **name) {
311   if (ISK(c)) {  /* is 'c' a constant? */
312     TValue *kvalue = &p->k[INDEXK(c)];
313     if (ttisstring(kvalue)) {  /* literal constant? */
314       *name = svalue(kvalue);  /* it is its own name */
315       return;
316     }
317     /* else no reasonable name found */
318   }
319   else {  /* 'c' is a register */
320     const char *what = getobjname(p, pc, c, name); /* search for 'c' */
321     if (what && *what == 'c') {  /* found a constant name? */
322       return;  /* 'name' already filled */
323     }
324     /* else no reasonable name found */
325   }
326   *name = "?";  /* no reasonable name found */
327 }
328 
329 
filterpc(int pc,int jmptarget)330 static int filterpc (int pc, int jmptarget) {
331   if (pc < jmptarget)  /* is code conditional (inside a jump)? */
332     return -1;  /* cannot know who sets that register */
333   else return pc;  /* current position sets that register */
334 }
335 
336 
337 /*
338 ** try to find last instruction before 'lastpc' that modified register 'reg'
339 */
findsetreg(Proto * p,int lastpc,int reg)340 static int findsetreg (Proto *p, int lastpc, int reg) {
341   int pc;
342   int setreg = -1;  /* keep last instruction that changed 'reg' */
343   int jmptarget = 0;  /* any code before this address is conditional */
344   for (pc = 0; pc < lastpc; pc++) {
345     Instruction i = p->code[pc];
346     OpCode op = GET_OPCODE(i);
347     int a = GETARG_A(i);
348     switch (op) {
349       case OP_LOADNIL: {
350         int b = GETARG_B(i);
351         if (a <= reg && reg <= a + b)  /* set registers from 'a' to 'a+b' */
352           setreg = filterpc(pc, jmptarget);
353         break;
354       }
355       case OP_TFORCALL: {
356         if (reg >= a + 2)  /* affect all regs above its base */
357           setreg = filterpc(pc, jmptarget);
358         break;
359       }
360       case OP_CALL:
361       case OP_TAILCALL: {
362         if (reg >= a)  /* affect all registers above base */
363           setreg = filterpc(pc, jmptarget);
364         break;
365       }
366       case OP_JMP: {
367         int b = GETARG_sBx(i);
368         int dest = pc + 1 + b;
369         /* jump is forward and do not skip `lastpc'? */
370         if (pc < dest && dest <= lastpc) {
371           if (dest > jmptarget)
372             jmptarget = dest;  /* update 'jmptarget' */
373         }
374         break;
375       }
376       case OP_TEST: {
377         if (reg == a)  /* jumped code can change 'a' */
378           setreg = filterpc(pc, jmptarget);
379         break;
380       }
381       default:
382         if (testAMode(op) && reg == a)  /* any instruction that set A */
383           setreg = filterpc(pc, jmptarget);
384         break;
385     }
386   }
387   return setreg;
388 }
389 
390 
getobjname(Proto * p,int lastpc,int reg,const char ** name)391 static const char *getobjname (Proto *p, int lastpc, int reg,
392                                const char **name) {
393   int pc;
394   *name = luaF_getlocalname(p, reg + 1, lastpc);
395   if (*name)  /* is a local? */
396     return "local";
397   /* else try symbolic execution */
398   pc = findsetreg(p, lastpc, reg);
399   if (pc != -1) {  /* could find instruction? */
400     Instruction i = p->code[pc];
401     OpCode op = GET_OPCODE(i);
402     switch (op) {
403       case OP_MOVE: {
404         int b = GETARG_B(i);  /* move from 'b' to 'a' */
405         if (b < GETARG_A(i))
406           return getobjname(p, pc, b, name);  /* get name for 'b' */
407         break;
408       }
409       case OP_GETTABUP:
410       case OP_GETTABLE: {
411         int k = GETARG_C(i);  /* key index */
412         int t = GETARG_B(i);  /* table index */
413         const char *vn = (op == OP_GETTABLE)  /* name of indexed variable */
414                          ? luaF_getlocalname(p, t + 1, pc)
415                          : upvalname(p, t);
416         kname(p, pc, k, name);
417         return (vn && strcmp(vn, LUA_ENV) == 0) ? "global" : "field";
418       }
419       case OP_GETUPVAL: {
420         *name = upvalname(p, GETARG_B(i));
421         return "upvalue";
422       }
423       case OP_LOADK:
424       case OP_LOADKX: {
425         int b = (op == OP_LOADK) ? GETARG_Bx(i)
426                                  : GETARG_Ax(p->code[pc + 1]);
427         if (ttisstring(&p->k[b])) {
428           *name = svalue(&p->k[b]);
429           return "constant";
430         }
431         break;
432       }
433       case OP_SELF: {
434         int k = GETARG_C(i);  /* key index */
435         kname(p, pc, k, name);
436         return "method";
437       }
438       default: break;  /* go through to return NULL */
439     }
440   }
441   return NULL;  /* could not find reasonable name */
442 }
443 
444 
getfuncname(lua_State * L,CallInfo * ci,const char ** name)445 static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name) {
446   TMS tm;
447   Proto *p = ci_func(ci)->p;  /* calling function */
448   int pc = currentpc(ci);  /* calling instruction index */
449   Instruction i = p->code[pc];  /* calling instruction */
450   switch (GET_OPCODE(i)) {
451     case OP_CALL:
452     case OP_TAILCALL:  /* get function name */
453       return getobjname(p, pc, GETARG_A(i), name);
454     case OP_TFORCALL: {  /* for iterator */
455       *name = "for iterator";
456        return "for iterator";
457     }
458     /* all other instructions can call only through metamethods */
459     case OP_SELF:
460     case OP_GETTABUP:
461     case OP_GETTABLE: tm = TM_INDEX; break;
462     case OP_SETTABUP:
463     case OP_SETTABLE: tm = TM_NEWINDEX; break;
464     case OP_EQ: tm = TM_EQ; break;
465     case OP_ADD: tm = TM_ADD; break;
466     case OP_SUB: tm = TM_SUB; break;
467     case OP_MUL: tm = TM_MUL; break;
468     case OP_DIV: tm = TM_DIV; break;
469     case OP_MOD: tm = TM_MOD; break;
470     case OP_POW: tm = TM_POW; break;
471     case OP_UNM: tm = TM_UNM; break;
472     case OP_LEN: tm = TM_LEN; break;
473     case OP_LT: tm = TM_LT; break;
474     case OP_LE: tm = TM_LE; break;
475     case OP_CONCAT: tm = TM_CONCAT; break;
476     default:
477       return NULL;  /* else no useful name can be found */
478   }
479   *name = getstr(G(L)->tmname[tm]);
480   return "metamethod";
481 }
482 
483 /* }====================================================== */
484 
485 
486 
487 /*
488 ** only ANSI way to check whether a pointer points to an array
489 ** (used only for error messages, so efficiency is not a big concern)
490 */
isinstack(CallInfo * ci,const TValue * o)491 static int isinstack (CallInfo *ci, const TValue *o) {
492   StkId p;
493   for (p = ci->u.l.base; p < ci->top; p++)
494     if (o == p) return 1;
495   return 0;
496 }
497 
498 
getupvalname(CallInfo * ci,const TValue * o,const char ** name)499 static const char *getupvalname (CallInfo *ci, const TValue *o,
500                                  const char **name) {
501   LClosure *c = ci_func(ci);
502   int i;
503   for (i = 0; i < c->nupvalues; i++) {
504     if (c->upvals[i]->v == o) {
505       *name = upvalname(c->p, i);
506       return "upvalue";
507     }
508   }
509   return NULL;
510 }
511 
512 
luaG_typeerror(lua_State * L,const TValue * o,const char * op)513 l_noret luaG_typeerror (lua_State *L, const TValue *o, const char *op) {
514   CallInfo *ci = L->ci;
515   const char *name = NULL;
516   const char *t = objtypename(o);
517   const char *kind = NULL;
518   if (isLua(ci)) {
519     kind = getupvalname(ci, o, &name);  /* check whether 'o' is an upvalue */
520     if (!kind && isinstack(ci, o))  /* no? try a register */
521       kind = getobjname(ci_func(ci)->p, currentpc(ci),
522                         cast_int(o - ci->u.l.base), &name);
523   }
524   if (kind)
525     luaG_runerror(L, "attempt to %s %s " LUA_QS " (a %s value)",
526                 op, kind, name, t);
527   else
528     luaG_runerror(L, "attempt to %s a %s value", op, t);
529 }
530 
531 
luaG_concaterror(lua_State * L,StkId p1,StkId p2)532 l_noret luaG_concaterror (lua_State *L, StkId p1, StkId p2) {
533   if (ttisstring(p1) || ttisnumber(p1)) p1 = p2;
534   lua_assert(!ttisstring(p1) && !ttisnumber(p1));
535   luaG_typeerror(L, p1, "concatenate");
536 }
537 
538 
luaG_aritherror(lua_State * L,const TValue * p1,const TValue * p2)539 l_noret luaG_aritherror (lua_State *L, const TValue *p1, const TValue *p2) {
540   TValue temp;
541   if (luaV_tonumber(p1, &temp) == NULL)
542     p2 = p1;  /* first operand is wrong */
543   luaG_typeerror(L, p2, "perform arithmetic on");
544 }
545 
546 
luaG_ordererror(lua_State * L,const TValue * p1,const TValue * p2)547 l_noret luaG_ordererror (lua_State *L, const TValue *p1, const TValue *p2) {
548   const char *t1 = objtypename(p1);
549   const char *t2 = objtypename(p2);
550   if (t1 == t2)
551     luaG_runerror(L, "attempt to compare two %s values", t1);
552   else
553     luaG_runerror(L, "attempt to compare %s with %s", t1, t2);
554 }
555 
556 
addinfo(lua_State * L,const char * msg)557 static void addinfo (lua_State *L, const char *msg) {
558   CallInfo *ci = L->ci;
559   if (isLua(ci)) {  /* is Lua code? */
560     char buff[LUA_IDSIZE];  /* add file:line information */
561     int line = currentline(ci);
562     TString *src = ci_func(ci)->p->source;
563     if (src)
564       luaO_chunkid(buff, getstr(src), LUA_IDSIZE);
565     else {  /* no source available; use "?" instead */
566       buff[0] = '?'; buff[1] = '\0';
567     }
568     luaO_pushfstring(L, "%s:%d: %s", buff, line, msg);
569   }
570 }
571 
572 
luaG_errormsg(lua_State * L)573 l_noret luaG_errormsg (lua_State *L) {
574   if (L->errfunc != 0) {  /* is there an error handling function? */
575     StkId errfunc = restorestack(L, L->errfunc);
576     if (!ttisfunction(errfunc)) luaD_throw(L, LUA_ERRERR);
577     setobjs2s(L, L->top, L->top - 1);  /* move argument */
578     setobjs2s(L, L->top - 1, errfunc);  /* push function */
579     L->top++;
580     luaD_call(L, L->top - 2, 1, 0);  /* call it */
581   }
582   luaD_throw(L, LUA_ERRRUN);
583 }
584 
585 
luaG_runerror(lua_State * L,const char * fmt,...)586 l_noret luaG_runerror (lua_State *L, const char *fmt, ...) {
587   va_list argp;
588   va_start(argp, fmt);
589   addinfo(L, luaO_pushvfstring(L, fmt, argp));
590   va_end(argp);
591   luaG_errormsg(L);
592 }
593 
594