module/lua/ldebug.c

   1 /*
   2 ** $Id: ldebug.c,v 2.90.1.4 2015/02/19 17:05:13 roberto Exp $
   3 ** Debug Interface
   4 ** See Copyright Notice in lua.h
   5 */
   6
   7
   8 #define ldebug_c
   9 #define LUA_CORE
  10
  11 #include <sys/lua/lua.h>
  12
  13 #include "lapi.h"
  14 #include "lcode.h"
  15 #include "ldebug.h"
  16 #include "ldo.h"
  17 #include "lfunc.h"
  18 #include "lobject.h"
  19 #include "lopcodes.h"
  20 #include "lstate.h"
  21 #include "lstring.h"
  22 #include "ltable.h"
  23 #include "ltm.h"
  24 #include "lvm.h"
  25
  26
  27
  28 #define noLuaClosure(f)         ((f) == NULL || (f)->c.tt == LUA_TCCL)
  29
  30
  31 static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name);
  32
  33
  34 static int currentpc (CallInfo *ci) {
  35   lua_assert(isLua(ci));
  36   return pcRel(ci->u.l.savedpc, ci_func(ci)->p);
  37 }
  38
  39
  40 static int currentline (CallInfo *ci) {
  41   return getfuncline(ci_func(ci)->p, currentpc(ci));
  42 }
  43
  44
  45 static void swapextra (lua_State *L) {
  46   if (L->status == LUA_YIELD) {
  47     CallInfo *ci = L->ci;  /* get function that yielded */
  48     StkId temp = ci->func;  /* exchange its 'func' and 'extra' values */
  49     ci->func = restorestack(L, ci->extra);
  50     ci->extra = savestack(L, temp);
  51   }
  52 }
  53
  54
  55 /*
  56 ** this function can be called asynchronous (e.g. during a signal)
  57 */
  58 LUA_API int lua_sethook (lua_State *L, lua_Hook func, int mask, int count) {
  59   if (func == NULL || mask == 0) {  /* turn off hooks? */
  60     mask = 0;
  61     func = NULL;
  62   }
  63   if (isLua(L->ci))
  64     L->oldpc = L->ci->u.l.savedpc;
  65   L->hook = func;
  66   L->basehookcount = count;
  67   resethookcount(L);
  68   L->hookmask = cast_byte(mask);
  69   return 1;
  70 }
  71
  72
  73 LUA_API lua_Hook lua_gethook (lua_State *L) {
  74   return L->hook;
  75 }
  76
  77
  78 LUA_API int lua_gethookmask (lua_State *L) {
  79   return L->hookmask;
  80 }
  81
  82
  83 LUA_API int lua_gethookcount (lua_State *L) {
  84   return L->basehookcount;
  85 }
  86
  87
  88 LUA_API int lua_getstack (lua_State *L, int level, lua_Debug *ar) {
  89   int status;
  90   CallInfo *ci;
  91   if (level < 0) return 0;  /* invalid (negative) level */
  92   lua_lock(L);
  93   for (ci = L->ci; level > 0 && ci != &L->base_ci; ci = ci->previous)
  94     level--;
  95   if (level == 0 && ci != &L->base_ci) {  /* level found? */
  96     status = 1;
  97     ar->i_ci = ci;
  98   }
  99   else status = 0;  /* no such level */
 100   lua_unlock(L);
 101   return status;
 102 }
 103
 104
 105 static const char *upvalname (Proto *p, int uv) {
 106   TString *s = check_exp(uv < p->sizeupvalues, p->upvalues[uv].name);
 107   if (s == NULL) return "?";
 108   else return getstr(s);
 109 }
 110
 111
 112 static const char *findvararg (CallInfo *ci, int n, StkId *pos) {
 113   int nparams = clLvalue(ci->func)->p->numparams;
 114   if (n >= ci->u.l.base - ci->func - nparams)
 115     return NULL;  /* no such vararg */
 116   else {
 117     *pos = ci->func + nparams + n;
 118     return "(*vararg)";  /* generic name for any vararg */
 119   }
 120 }
 121
 122
 123 static const char *findlocal (lua_State *L, CallInfo *ci, int n,
 124                               StkId *pos) {
 125   const char *name = NULL;
 126   StkId base;
 127   if (isLua(ci)) {
 128     if (n < 0)  /* access to vararg values? */
 129       return findvararg(ci, -n, pos);
 130     else {
 131       base = ci->u.l.base;
 132       name = luaF_getlocalname(ci_func(ci)->p, n, currentpc(ci));
 133     }
 134   }
 135   else
 136     base = ci->func + 1;
 137   if (name == NULL) {  /* no 'standard' name? */
 138     StkId limit = (ci == L->ci) ? L->top : ci->next->func;
 139     if (limit - base >= n && n > 0)  /* is 'n' inside 'ci' stack? */
 140       name = "(*temporary)";  /* generic name for any valid slot */
 141     else
 142       return NULL;  /* no name */
 143   }
 144   *pos = base + (n - 1);
 145   return name;
 146 }
 147
 148
 149 LUA_API const char *lua_getlocal (lua_State *L, const lua_Debug *ar, int n) {
 150   const char *name;
 151   lua_lock(L);
 152   swapextra(L);
 153   if (ar == NULL) {  /* information about non-active function? */
 154     if (!isLfunction(L->top - 1))  /* not a Lua function? */
 155       name = NULL;
 156     else  /* consider live variables at function start (parameters) */
 157       name = luaF_getlocalname(clLvalue(L->top - 1)->p, n, 0);
 158   }
 159   else {  /* active function; get information through 'ar' */
 160     StkId pos = 0;  /* to avoid warnings */
 161     name = findlocal(L, ar->i_ci, n, &pos);
 162     if (name) {
 163       setobj2s(L, L->top, pos);
 164       api_incr_top(L);
 165     }
 166   }
 167   swapextra(L);
 168   lua_unlock(L);
 169   return name;
 170 }
 171
 172
 173 LUA_API const char *lua_setlocal (lua_State *L, const lua_Debug *ar, int n) {
 174   StkId pos = 0;  /* to avoid warnings */
 175   const char *name;
 176   lua_lock(L);
 177   swapextra(L);
 178   name = findlocal(L, ar->i_ci, n, &pos);
 179   if (name)
 180     setobjs2s(L, pos, L->top - 1);
 181   L->top--;  /* pop value */
 182   swapextra(L);
 183   lua_unlock(L);
 184   return name;
 185 }
 186
 187
 188 static void funcinfo (lua_Debug *ar, Closure *cl) {
 189   if (noLuaClosure(cl)) {
 190     ar->source = "=[C]";
 191     ar->linedefined = -1;
 192     ar->lastlinedefined = -1;
 193     ar->what = "C";
 194   }
 195   else {
 196     Proto *p = cl->l.p;
 197     ar->source = p->source ? getstr(p->source) : "=?";
 198     ar->linedefined = p->linedefined;
 199     ar->lastlinedefined = p->lastlinedefined;
 200     ar->what = (ar->linedefined == 0) ? "main" : "Lua";
 201   }
 202   luaO_chunkid(ar->short_src, ar->source, LUA_IDSIZE);
 203 }
 204
 205
 206 static void collectvalidlines (lua_State *L, Closure *f) {
 207   if (noLuaClosure(f)) {
 208     setnilvalue(L->top);
 209     api_incr_top(L);
 210   }
 211   else {
 212     int i;
 213     TValue v;
 214     int *lineinfo = f->l.p->lineinfo;
 215     Table *t = luaH_new(L);  /* new table to store active lines */
 216     sethvalue(L, L->top, t);  /* push it on stack */
 217     api_incr_top(L);
 218     setbvalue(&v, 1);  /* boolean 'true' to be the value of all indices */
 219     for (i = 0; i < f->l.p->sizelineinfo; i++)  /* for all lines with code */
 220       luaH_setint(L, t, lineinfo[i], &v);  /* table[line] = true */
 221   }
 222 }
 223
 224
 225 static int auxgetinfo (lua_State *L, const char *what, lua_Debug *ar,
 226                        Closure *f, CallInfo *ci) {
 227   int status = 1;
 228   for (; *what; what++) {
 229     switch (*what) {
 230       case 'S': {
 231         funcinfo(ar, f);
 232         break;
 233       }
 234       case 'l': {
 235         ar->currentline = (ci && isLua(ci)) ? currentline(ci) : -1;
 236         break;
 237       }
 238       case 'u': {
 239         ar->nups = (f == NULL) ? 0 : f->c.nupvalues;
 240         if (noLuaClosure(f)) {
 241           ar->isvararg = 1;
 242           ar->nparams = 0;
 243         }
 244         else {
 245           ar->isvararg = f->l.p->is_vararg;
 246           ar->nparams = f->l.p->numparams;
 247         }
 248         break;
 249       }
 250       case 't': {
 251         ar->istailcall = (ci) ? ci->callstatus & CIST_TAIL : 0;
 252         break;
 253       }
 254       case 'n': {
 255         /* calling function is a known Lua function? */
 256         if (ci && !(ci->callstatus & CIST_TAIL) && isLua(ci->previous))
 257           ar->namewhat = getfuncname(L, ci->previous, &ar->name);
 258         else
 259           ar->namewhat = NULL;
 260         if (ar->namewhat == NULL) {
 261           ar->namewhat = "";  /* not found */
 262           ar->name = NULL;
 263         }
 264         break;
 265       }
 266       case 'L':
 267       case 'f':  /* handled by lua_getinfo */
 268         break;
 269       default: status = 0;  /* invalid option */
 270     }
 271   }
 272   return status;
 273 }
 274
 275
 276 LUA_API int lua_getinfo (lua_State *L, const char *what, lua_Debug *ar) {
 277   int status;
 278   Closure *cl;
 279   CallInfo *ci;
 280   StkId func;
 281   lua_lock(L);
 282   swapextra(L);
 283   if (*what == '>') {
 284     ci = NULL;
 285     func = L->top - 1;
 286     api_check(L, ttisfunction(func), "function expected");
 287     what++;  /* skip the '>' */
 288     L->top--;  /* pop function */
 289   }
 290   else {
 291     ci = ar->i_ci;
 292     func = ci->func;
 293     lua_assert(ttisfunction(ci->func));
 294   }
 295   cl = ttisclosure(func) ? clvalue(func) : NULL;
 296   status = auxgetinfo(L, what, ar, cl, ci);
 297   if (strchr(what, 'f')) {
 298     setobjs2s(L, L->top, func);
 299     api_incr_top(L);
 300   }
 301   swapextra(L);
 302   if (strchr(what, 'L'))
 303     collectvalidlines(L, cl);
 304   lua_unlock(L);
 305   return status;
 306 }
 307
 308
 309 /*
 310 ** {======================================================
 311 ** Symbolic Execution
 312 ** =======================================================
 313 */
 314
 315 static const char *getobjname (Proto *p, int lastpc, int reg,
 316                                const char **name);
 317
 318
 319 /*
 320 ** find a "name" for the RK value 'c'
 321 */
 322 static void kname (Proto *p, int pc, int c, const char **name) {
 323   if (ISK(c)) {  /* is 'c' a constant? */
 324     TValue *kvalue = &p->k[INDEXK(c)];
 325     if (ttisstring(kvalue)) {  /* literal constant? */
 326       *name = svalue(kvalue);  /* it is its own name */
 327       return;
 328     }
 329     /* else no reasonable name found */
 330   }
 331   else {  /* 'c' is a register */
 332     const char *what = getobjname(p, pc, c, name); /* search for 'c' */
 333     if (what && *what == 'c') {  /* found a constant name? */
 334       return;  /* 'name' already filled */
 335     }
 336     /* else no reasonable name found */
 337   }
 338   *name = "?";  /* no reasonable name found */
 339 }
 340
 341
 342 static int filterpc (int pc, int jmptarget) {
 343   if (pc < jmptarget)  /* is code conditional (inside a jump)? */
 344     return -1;  /* cannot know who sets that register */
 345   else return pc;  /* current position sets that register */
 346 }
 347
 348
 349 /*
 350 ** try to find last instruction before 'lastpc' that modified register 'reg'
 351 */
 352 static int findsetreg (Proto *p, int lastpc, int reg) {
 353   int pc;
 354   int setreg = -1;  /* keep last instruction that changed 'reg' */
 355   int jmptarget = 0;  /* any code before this address is conditional */
 356   for (pc = 0; pc < lastpc; pc++) {
 357     Instruction i = p->code[pc];
 358     OpCode op = GET_OPCODE(i);
 359     int a = GETARG_A(i);
 360     switch (op) {
 361       case OP_LOADNIL: {
 362         int b = GETARG_B(i);
 363         if (a <= reg && reg <= a + b)  /* set registers from 'a' to 'a+b' */
 364           setreg = filterpc(pc, jmptarget);
 365         break;
 366       }
 367       case OP_TFORCALL: {
 368         if (reg >= a + 2)  /* affect all regs above its base */
 369           setreg = filterpc(pc, jmptarget);
 370         break;
 371       }
 372       case OP_CALL:
 373       case OP_TAILCALL: {
 374         if (reg >= a)  /* affect all registers above base */
 375           setreg = filterpc(pc, jmptarget);
 376         break;
 377       }
 378       case OP_JMP: {
 379         int b = GETARG_sBx(i);
 380         int dest = pc + 1 + b;
 381         /* jump is forward and do not skip `lastpc'? */
 382         if (pc < dest && dest <= lastpc) {
 383           if (dest > jmptarget)
 384             jmptarget = dest;  /* update 'jmptarget' */
 385         }
 386         break;
 387       }
 388       case OP_TEST: {
 389         if (reg == a)  /* jumped code can change 'a' */
 390           setreg = filterpc(pc, jmptarget);
 391         break;
 392       }
 393       default:
 394         if (testAMode(op) && reg == a)  /* any instruction that set A */
 395           setreg = filterpc(pc, jmptarget);
 396         break;
 397     }
 398   }
 399   return setreg;
 400 }
 401
 402
 403 static const char *getobjname (Proto *p, int lastpc, int reg,
 404                                const char **name) {
 405   int pc;
 406   *name = luaF_getlocalname(p, reg + 1, lastpc);
 407   if (*name)  /* is a local? */
 408     return "local";
 409   /* else try symbolic execution */
 410   pc = findsetreg(p, lastpc, reg);
 411   if (pc != -1) {  /* could find instruction? */
 412     Instruction i = p->code[pc];
 413     OpCode op = GET_OPCODE(i);
 414     switch (op) {
 415       case OP_MOVE: {
 416         int b = GETARG_B(i);  /* move from 'b' to 'a' */
 417         if (b < GETARG_A(i))
 418           return getobjname(p, pc, b, name);  /* get name for 'b' */
 419         break;
 420       }
 421       case OP_GETTABUP:
 422       case OP_GETTABLE: {
 423         int k = GETARG_C(i);  /* key index */
 424         int t = GETARG_B(i);  /* table index */
 425         const char *vn = (op == OP_GETTABLE)  /* name of indexed variable */
 426                          ? luaF_getlocalname(p, t + 1, pc)
 427                          : upvalname(p, t);
 428         kname(p, pc, k, name);
 429         return (vn && strcmp(vn, LUA_ENV) == 0) ? "global" : "field";
 430       }
 431       case OP_GETUPVAL: {
 432         *name = upvalname(p, GETARG_B(i));
 433         return "upvalue";
 434       }
 435       case OP_LOADK:
 436       case OP_LOADKX: {
 437         int b = (op == OP_LOADK) ? GETARG_Bx(i)
 438                                  : GETARG_Ax(p->code[pc + 1]);
 439         if (ttisstring(&p->k[b])) {
 440           *name = svalue(&p->k[b]);
 441           return "constant";
 442         }
 443         break;
 444       }
 445       case OP_SELF: {
 446         int k = GETARG_C(i);  /* key index */
 447         kname(p, pc, k, name);
 448         return "method";
 449       }
 450       default: break;  /* go through to return NULL */
 451     }
 452   }
 453   return NULL;  /* could not find reasonable name */
 454 }
 455
 456
 457 static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name) {
 458   TMS tm;
 459   Proto *p = ci_func(ci)->p;  /* calling function */
 460   int pc = currentpc(ci);  /* calling instruction index */
 461   Instruction i = p->code[pc];  /* calling instruction */
 462   switch (GET_OPCODE(i)) {
 463     case OP_CALL:
 464     case OP_TAILCALL:  /* get function name */
 465       return getobjname(p, pc, GETARG_A(i), name);
 466     case OP_TFORCALL: {  /* for iterator */
 467       *name = "for iterator";
 468        return "for iterator";
 469     }
 470     /* all other instructions can call only through metamethods */
 471     case OP_SELF:
 472     case OP_GETTABUP:
 473     case OP_GETTABLE: tm = TM_INDEX; break;
 474     case OP_SETTABUP:
 475     case OP_SETTABLE: tm = TM_NEWINDEX; break;
 476     case OP_EQ: tm = TM_EQ; break;
 477     case OP_ADD: tm = TM_ADD; break;
 478     case OP_SUB: tm = TM_SUB; break;
 479     case OP_MUL: tm = TM_MUL; break;
 480     case OP_DIV: tm = TM_DIV; break;
 481     case OP_MOD: tm = TM_MOD; break;
 482     case OP_POW: tm = TM_POW; break;
 483     case OP_UNM: tm = TM_UNM; break;
 484     case OP_LEN: tm = TM_LEN; break;
 485     case OP_LT: tm = TM_LT; break;
 486     case OP_LE: tm = TM_LE; break;
 487     case OP_CONCAT: tm = TM_CONCAT; break;
 488     default:
 489       return NULL;  /* else no useful name can be found */
 490   }
 491   *name = getstr(G(L)->tmname[tm]);
 492   return "metamethod";
 493 }
 494
 495 /* }====================================================== */
 496
 497
 498
 499 /*
 500 ** only ANSI way to check whether a pointer points to an array
 501 ** (used only for error messages, so efficiency is not a big concern)
 502 */
 503 static int isinstack (CallInfo *ci, const TValue *o) {
 504   StkId p;
 505   for (p = ci->u.l.base; p < ci->top; p++)
 506     if (o == p) return 1;
 507   return 0;
 508 }
 509
 510
 511 static const char *getupvalname (CallInfo *ci, const TValue *o,
 512                                  const char **name) {
 513   LClosure *c = ci_func(ci);
 514   int i;
 515   for (i = 0; i < c->nupvalues; i++) {
 516     if (c->upvals[i]->v == o) {
 517       *name = upvalname(c->p, i);
 518       return "upvalue";
 519     }
 520   }
 521   return NULL;
 522 }
 523
 524
 525 l_noret luaG_typeerror (lua_State *L, const TValue *o, const char *op) {
 526   CallInfo *ci = L->ci;
 527   const char *name = NULL;
 528   const char *t = objtypename(o);
 529   const char *kind = NULL;
 530   if (isLua(ci)) {
 531     kind = getupvalname(ci, o, &name);  /* check whether 'o' is an upvalue */
 532     if (!kind && isinstack(ci, o))  /* no? try a register */
 533       kind = getobjname(ci_func(ci)->p, currentpc(ci),
 534                         cast_int(o - ci->u.l.base), &name);
 535   }
 536   if (kind)
 537     luaG_runerror(L, "attempt to %s %s " LUA_QS " (a %s value)",
 538                 op, kind, name, t);
 539   else
 540     luaG_runerror(L, "attempt to %s a %s value", op, t);
 541 }
 542
 543
 544 l_noret luaG_concaterror (lua_State *L, StkId p1, StkId p2) {
 545   if (ttisstring(p1) || ttisnumber(p1)) p1 = p2;
 546   lua_assert(!ttisstring(p1) && !ttisnumber(p1));
 547   luaG_typeerror(L, p1, "concatenate");
 548 }
 549
 550
 551 l_noret luaG_aritherror (lua_State *L, const TValue *p1, const TValue *p2) {
 552   TValue temp;
 553   if (luaV_tonumber(p1, &temp) == NULL)
 554     p2 = p1;  /* first operand is wrong */
 555   luaG_typeerror(L, p2, "perform arithmetic on");
 556 }
 557
 558
 559 l_noret luaG_ordererror (lua_State *L, const TValue *p1, const TValue *p2) {
 560   const char *t1 = objtypename(p1);
 561   const char *t2 = objtypename(p2);
 562   if (t1 == t2)
 563     luaG_runerror(L, "attempt to compare two %s values", t1);
 564   else
 565     luaG_runerror(L, "attempt to compare %s with %s", t1, t2);
 566 }
 567
 568
 569 static void addinfo (lua_State *L, const char *msg) {
 570   CallInfo *ci = L->ci;
 571   if (isLua(ci)) {  /* is Lua code? */
 572     char buff[LUA_IDSIZE];  /* add file:line information */
 573     int line = currentline(ci);
 574     TString *src = ci_func(ci)->p->source;
 575     if (src)
 576       luaO_chunkid(buff, getstr(src), LUA_IDSIZE);
 577     else {  /* no source available; use "?" instead */
 578       buff[0] = '?'; buff[1] = '\0';
 579     }
 580     luaO_pushfstring(L, "%s:%d: %s", buff, line, msg);
 581   }
 582 }
 583
 584
 585 l_noret luaG_errormsg (lua_State *L) {
 586   if (L->errfunc != 0) {  /* is there an error handling function? */
 587     StkId errfunc = restorestack(L, L->errfunc);
 588     if (!ttisfunction(errfunc)) luaD_throw(L, LUA_ERRERR);
 589     setobjs2s(L, L->top, L->top - 1);  /* move argument */
 590     setobjs2s(L, L->top - 1, errfunc);  /* push function */
 591     L->top++;
 592     luaD_call(L, L->top - 2, 1, 0);  /* call it */
 593   }
 594   luaD_throw(L, LUA_ERRRUN);
 595 }
 596
 597
 598 l_noret luaG_runerror (lua_State *L, const char *fmt, ...) {
 599   L->runerror++;
 600   va_list argp;
 601   va_start(argp, fmt);
 602   addinfo(L, luaO_pushvfstring(L, fmt, argp));
 603   va_end(argp);
 604   luaG_errormsg(L);
 605   L->runerror--;
 606 }