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#include <sys/zfs_context.h>
9
10#define ldebug_c
11#define LUA_CORE
12
13#include "lua.h"
14
15#include "lapi.h"
16#include "lcode.h"
17#include "ldebug.h"
18#include "ldo.h"
19#include "lfunc.h"
20#include "lobject.h"
21#include "lopcodes.h"
22#include "lstate.h"
23#include "lstring.h"
24#include "ltable.h"
25#include "ltm.h"
26#include "lvm.h"
27
28
29
30#define noLuaClosure(f)		((f) == NULL || (f)->c.tt == LUA_TCCL)
31
32
33static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name);
34
35
36static int currentpc (CallInfo *ci) {
37  lua_assert(isLua(ci));
38  return pcRel(ci->u.l.savedpc, ci_func(ci)->p);
39}
40
41
42static int currentline (CallInfo *ci) {
43  return getfuncline(ci_func(ci)->p, currentpc(ci));
44}
45
46
47static void swapextra (lua_State *L) {
48  if (L->status == LUA_YIELD) {
49    CallInfo *ci = L->ci;  /* get function that yielded */
50    StkId temp = ci->func;  /* exchange its 'func' and 'extra' values */
51    ci->func = restorestack(L, ci->extra);
52    ci->extra = savestack(L, temp);
53  }
54}
55
56
57/*
58** this function can be called asynchronous (e.g. during a signal)
59*/
60LUA_API int lua_sethook (lua_State *L, lua_Hook func, int mask, int count) {
61  if (func == NULL || mask == 0) {  /* turn off hooks? */
62    mask = 0;
63    func = NULL;
64  }
65  if (isLua(L->ci))
66    L->oldpc = L->ci->u.l.savedpc;
67  L->hook = func;
68  L->basehookcount = count;
69  resethookcount(L);
70  L->hookmask = cast_byte(mask);
71  return 1;
72}
73
74
75LUA_API lua_Hook lua_gethook (lua_State *L) {
76  return L->hook;
77}
78
79
80LUA_API int lua_gethookmask (lua_State *L) {
81  return L->hookmask;
82}
83
84
85LUA_API int lua_gethookcount (lua_State *L) {
86  return L->basehookcount;
87}
88
89
90LUA_API int lua_getstack (lua_State *L, int level, lua_Debug *ar) {
91  int status;
92  CallInfo *ci;
93  if (level < 0) return 0;  /* invalid (negative) level */
94  lua_lock(L);
95  for (ci = L->ci; level > 0 && ci != &L->base_ci; ci = ci->previous)
96    level--;
97  if (level == 0 && ci != &L->base_ci) {  /* level found? */
98    status = 1;
99    ar->i_ci = ci;
100  }
101  else status = 0;  /* no such level */
102  lua_unlock(L);
103  return status;
104}
105
106
107static const char *upvalname (Proto *p, int uv) {
108  TString *s = check_exp(uv < p->sizeupvalues, p->upvalues[uv].name);
109  if (s == NULL) return "?";
110  else return getstr(s);
111}
112
113
114static const char *findvararg (CallInfo *ci, int n, StkId *pos) {
115  int nparams = clLvalue(ci->func)->p->numparams;
116  if (n >= ci->u.l.base - ci->func - nparams)
117    return NULL;  /* no such vararg */
118  else {
119    *pos = ci->func + nparams + n;
120    return "(*vararg)";  /* generic name for any vararg */
121  }
122}
123
124
125static const char *findlocal (lua_State *L, CallInfo *ci, int n,
126                              StkId *pos) {
127  const char *name = NULL;
128  StkId base;
129  if (isLua(ci)) {
130    if (n < 0)  /* access to vararg values? */
131      return findvararg(ci, -n, pos);
132    else {
133      base = ci->u.l.base;
134      name = luaF_getlocalname(ci_func(ci)->p, n, currentpc(ci));
135    }
136  }
137  else
138    base = ci->func + 1;
139  if (name == NULL) {  /* no 'standard' name? */
140    StkId limit = (ci == L->ci) ? L->top : ci->next->func;
141    if (limit - base >= n && n > 0)  /* is 'n' inside 'ci' stack? */
142      name = "(*temporary)";  /* generic name for any valid slot */
143    else
144      return NULL;  /* no name */
145  }
146  *pos = base + (n - 1);
147  return name;
148}
149
150
151LUA_API const char *lua_getlocal (lua_State *L, const lua_Debug *ar, int n) {
152  const char *name;
153  lua_lock(L);
154  swapextra(L);
155  if (ar == NULL) {  /* information about non-active function? */
156    if (!isLfunction(L->top - 1))  /* not a Lua function? */
157      name = NULL;
158    else  /* consider live variables at function start (parameters) */
159      name = luaF_getlocalname(clLvalue(L->top - 1)->p, n, 0);
160  }
161  else {  /* active function; get information through 'ar' */
162    StkId pos = 0;  /* to avoid warnings */
163    name = findlocal(L, ar->i_ci, n, &pos);
164    if (name) {
165      setobj2s(L, L->top, pos);
166      api_incr_top(L);
167    }
168  }
169  swapextra(L);
170  lua_unlock(L);
171  return name;
172}
173
174
175LUA_API const char *lua_setlocal (lua_State *L, const lua_Debug *ar, int n) {
176  StkId pos = 0;  /* to avoid warnings */
177  const char *name;
178  lua_lock(L);
179  swapextra(L);
180  name = findlocal(L, ar->i_ci, n, &pos);
181  if (name)
182    setobjs2s(L, pos, L->top - 1);
183  L->top--;  /* pop value */
184  swapextra(L);
185  lua_unlock(L);
186  return name;
187}
188
189
190static void funcinfo (lua_Debug *ar, Closure *cl) {
191  if (noLuaClosure(cl)) {
192    ar->source = "=[C]";
193    ar->linedefined = -1;
194    ar->lastlinedefined = -1;
195    ar->what = "C";
196  }
197  else {
198    Proto *p = cl->l.p;
199    ar->source = p->source ? getstr(p->source) : "=?";
200    ar->linedefined = p->linedefined;
201    ar->lastlinedefined = p->lastlinedefined;
202    ar->what = (ar->linedefined == 0) ? "main" : "Lua";
203  }
204  luaO_chunkid(ar->short_src, ar->source, LUA_IDSIZE);
205}
206
207
208static void collectvalidlines (lua_State *L, Closure *f) {
209  if (noLuaClosure(f)) {
210    setnilvalue(L->top);
211    api_incr_top(L);
212  }
213  else {
214    int i;
215    TValue v;
216    int *lineinfo = f->l.p->lineinfo;
217    Table *t = luaH_new(L);  /* new table to store active lines */
218    sethvalue(L, L->top, t);  /* push it on stack */
219    api_incr_top(L);
220    setbvalue(&v, 1);  /* boolean 'true' to be the value of all indices */
221    for (i = 0; i < f->l.p->sizelineinfo; i++)  /* for all lines with code */
222      luaH_setint(L, t, lineinfo[i], &v);  /* table[line] = true */
223  }
224}
225
226
227static int auxgetinfo (lua_State *L, const char *what, lua_Debug *ar,
228                       Closure *f, CallInfo *ci) {
229  int status = 1;
230  for (; *what; what++) {
231    switch (*what) {
232      case 'S': {
233        funcinfo(ar, f);
234        break;
235      }
236      case 'l': {
237        ar->currentline = (ci && isLua(ci)) ? currentline(ci) : -1;
238        break;
239      }
240      case 'u': {
241        ar->nups = (f == NULL) ? 0 : f->c.nupvalues;
242        if (noLuaClosure(f)) {
243          ar->isvararg = 1;
244          ar->nparams = 0;
245        }
246        else {
247          ar->isvararg = f->l.p->is_vararg;
248          ar->nparams = f->l.p->numparams;
249        }
250        break;
251      }
252      case 't': {
253        ar->istailcall = (ci) ? ci->callstatus & CIST_TAIL : 0;
254        break;
255      }
256      case 'n': {
257        /* calling function is a known Lua function? */
258        if (ci && !(ci->callstatus & CIST_TAIL) && isLua(ci->previous))
259          ar->namewhat = getfuncname(L, ci->previous, &ar->name);
260        else
261          ar->namewhat = NULL;
262        if (ar->namewhat == NULL) {
263          ar->namewhat = "";  /* not found */
264          ar->name = NULL;
265        }
266        break;
267      }
268      case 'L':
269      case 'f':  /* handled by lua_getinfo */
270        break;
271      default: status = 0;  /* invalid option */
272    }
273  }
274  return status;
275}
276
277
278LUA_API int lua_getinfo (lua_State *L, const char *what, lua_Debug *ar) {
279  int status;
280  Closure *cl;
281  CallInfo *ci;
282  StkId func;
283  lua_lock(L);
284  swapextra(L);
285  if (*what == '>') {
286    ci = NULL;
287    func = L->top - 1;
288    api_check(L, ttisfunction(func), "function expected");
289    what++;  /* skip the '>' */
290    L->top--;  /* pop function */
291  }
292  else {
293    ci = ar->i_ci;
294    func = ci->func;
295    lua_assert(ttisfunction(ci->func));
296  }
297  cl = ttisclosure(func) ? clvalue(func) : NULL;
298  status = auxgetinfo(L, what, ar, cl, ci);
299  if (strchr(what, 'f')) {
300    setobjs2s(L, L->top, func);
301    api_incr_top(L);
302  }
303  swapextra(L);
304  if (strchr(what, 'L'))
305    collectvalidlines(L, cl);
306  lua_unlock(L);
307  return status;
308}
309
310
311/*
312** {======================================================
313** Symbolic Execution
314** =======================================================
315*/
316
317static const char *getobjname (Proto *p, int lastpc, int reg,
318                               const char **name);
319
320
321/*
322** find a "name" for the RK value 'c'
323*/
324static void kname (Proto *p, int pc, int c, const char **name) {
325  if (ISK(c)) {  /* is 'c' a constant? */
326    TValue *kvalue = &p->k[INDEXK(c)];
327    if (ttisstring(kvalue)) {  /* literal constant? */
328      *name = svalue(kvalue);  /* it is its own name */
329      return;
330    }
331    /* else no reasonable name found */
332  }
333  else {  /* 'c' is a register */
334    const char *what = getobjname(p, pc, c, name); /* search for 'c' */
335    if (what && *what == 'c') {  /* found a constant name? */
336      return;  /* 'name' already filled */
337    }
338    /* else no reasonable name found */
339  }
340  *name = "?";  /* no reasonable name found */
341}
342
343
344static int filterpc (int pc, int jmptarget) {
345  if (pc < jmptarget)  /* is code conditional (inside a jump)? */
346    return -1;  /* cannot know who sets that register */
347  else return pc;  /* current position sets that register */
348}
349
350
351/*
352** try to find last instruction before 'lastpc' that modified register 'reg'
353*/
354static int findsetreg (Proto *p, int lastpc, int reg) {
355  int pc;
356  int setreg = -1;  /* keep last instruction that changed 'reg' */
357  int jmptarget = 0;  /* any code before this address is conditional */
358  for (pc = 0; pc < lastpc; pc++) {
359    Instruction i = p->code[pc];
360    OpCode op = GET_OPCODE(i);
361    int a = GETARG_A(i);
362    switch (op) {
363      case OP_LOADNIL: {
364        int b = GETARG_B(i);
365        if (a <= reg && reg <= a + b)  /* set registers from 'a' to 'a+b' */
366          setreg = filterpc(pc, jmptarget);
367        break;
368      }
369      case OP_TFORCALL: {
370        if (reg >= a + 2)  /* affect all regs above its base */
371          setreg = filterpc(pc, jmptarget);
372        break;
373      }
374      case OP_CALL:
375      case OP_TAILCALL: {
376        if (reg >= a)  /* affect all registers above base */
377          setreg = filterpc(pc, jmptarget);
378        break;
379      }
380      case OP_JMP: {
381        int b = GETARG_sBx(i);
382        int dest = pc + 1 + b;
383        /* jump is forward and do not skip `lastpc'? */
384        if (pc < dest && dest <= lastpc) {
385          if (dest > jmptarget)
386            jmptarget = dest;  /* update 'jmptarget' */
387        }
388        break;
389      }
390      case OP_TEST: {
391        if (reg == a)  /* jumped code can change 'a' */
392          setreg = filterpc(pc, jmptarget);
393        break;
394      }
395      default:
396        if (testAMode(op) && reg == a)  /* any instruction that set A */
397          setreg = filterpc(pc, jmptarget);
398        break;
399    }
400  }
401  return setreg;
402}
403
404
405static const char *getobjname (Proto *p, int lastpc, int reg,
406                               const char **name) {
407  int pc;
408  *name = luaF_getlocalname(p, reg + 1, lastpc);
409  if (*name)  /* is a local? */
410    return "local";
411  /* else try symbolic execution */
412  pc = findsetreg(p, lastpc, reg);
413  if (pc != -1) {  /* could find instruction? */
414    Instruction i = p->code[pc];
415    OpCode op = GET_OPCODE(i);
416    switch (op) {
417      case OP_MOVE: {
418        int b = GETARG_B(i);  /* move from 'b' to 'a' */
419        if (b < GETARG_A(i))
420          return getobjname(p, pc, b, name);  /* get name for 'b' */
421        break;
422      }
423      case OP_GETTABUP:
424      case OP_GETTABLE: {
425        int k = GETARG_C(i);  /* key index */
426        int t = GETARG_B(i);  /* table index */
427        const char *vn = (op == OP_GETTABLE)  /* name of indexed variable */
428                         ? luaF_getlocalname(p, t + 1, pc)
429                         : upvalname(p, t);
430        kname(p, pc, k, name);
431        return (vn && strcmp(vn, LUA_ENV) == 0) ? "global" : "field";
432      }
433      case OP_GETUPVAL: {
434        *name = upvalname(p, GETARG_B(i));
435        return "upvalue";
436      }
437      case OP_LOADK:
438      case OP_LOADKX: {
439        int b = (op == OP_LOADK) ? GETARG_Bx(i)
440                                 : GETARG_Ax(p->code[pc + 1]);
441        if (ttisstring(&p->k[b])) {
442          *name = svalue(&p->k[b]);
443          return "constant";
444        }
445        break;
446      }
447      case OP_SELF: {
448        int k = GETARG_C(i);  /* key index */
449        kname(p, pc, k, name);
450        return "method";
451      }
452      default: break;  /* go through to return NULL */
453    }
454  }
455  return NULL;  /* could not find reasonable name */
456}
457
458
459static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name) {
460  TMS tm;
461  Proto *p = ci_func(ci)->p;  /* calling function */
462  int pc = currentpc(ci);  /* calling instruction index */
463  Instruction i = p->code[pc];  /* calling instruction */
464  switch (GET_OPCODE(i)) {
465    case OP_CALL:
466    case OP_TAILCALL:  /* get function name */
467      return getobjname(p, pc, GETARG_A(i), name);
468    case OP_TFORCALL: {  /* for iterator */
469      *name = "for iterator";
470       return "for iterator";
471    }
472    /* all other instructions can call only through metamethods */
473    case OP_SELF:
474    case OP_GETTABUP:
475    case OP_GETTABLE: tm = TM_INDEX; break;
476    case OP_SETTABUP:
477    case OP_SETTABLE: tm = TM_NEWINDEX; break;
478    case OP_EQ: tm = TM_EQ; break;
479    case OP_ADD: tm = TM_ADD; break;
480    case OP_SUB: tm = TM_SUB; break;
481    case OP_MUL: tm = TM_MUL; break;
482    case OP_DIV: tm = TM_DIV; break;
483    case OP_MOD: tm = TM_MOD; break;
484    case OP_POW: tm = TM_POW; break;
485    case OP_UNM: tm = TM_UNM; break;
486    case OP_LEN: tm = TM_LEN; break;
487    case OP_LT: tm = TM_LT; break;
488    case OP_LE: tm = TM_LE; break;
489    case OP_CONCAT: tm = TM_CONCAT; break;
490    default:
491      return NULL;  /* else no useful name can be found */
492  }
493  *name = getstr(G(L)->tmname[tm]);
494  return "metamethod";
495}
496
497/* }====================================================== */
498
499
500
501/*
502** only ANSI way to check whether a pointer points to an array
503** (used only for error messages, so efficiency is not a big concern)
504*/
505static int isinstack (CallInfo *ci, const TValue *o) {
506  StkId p;
507  for (p = ci->u.l.base; p < ci->top; p++)
508    if (o == p) return 1;
509  return 0;
510}
511
512
513static const char *getupvalname (CallInfo *ci, const TValue *o,
514                                 const char **name) {
515  LClosure *c = ci_func(ci);
516  int i;
517  for (i = 0; i < c->nupvalues; i++) {
518    if (c->upvals[i]->v == o) {
519      *name = upvalname(c->p, i);
520      return "upvalue";
521    }
522  }
523  return NULL;
524}
525
526
527l_noret luaG_typeerror (lua_State *L, const TValue *o, const char *op) {
528  CallInfo *ci = L->ci;
529  const char *name = NULL;
530  const char *t = objtypename(o);
531  const char *kind = NULL;
532  if (isLua(ci)) {
533    kind = getupvalname(ci, o, &name);  /* check whether 'o' is an upvalue */
534    if (!kind && isinstack(ci, o))  /* no? try a register */
535      kind = getobjname(ci_func(ci)->p, currentpc(ci),
536                        cast_int(o - ci->u.l.base), &name);
537  }
538  if (kind)
539    luaG_runerror(L, "attempt to %s %s " LUA_QS " (a %s value)",
540                op, kind, name, t);
541  else
542    luaG_runerror(L, "attempt to %s a %s value", op, t);
543}
544
545
546l_noret luaG_concaterror (lua_State *L, StkId p1, StkId p2) {
547  if (ttisstring(p1) || ttisnumber(p1)) p1 = p2;
548  lua_assert(!ttisstring(p1) && !ttisnumber(p1));
549  luaG_typeerror(L, p1, "concatenate");
550}
551
552
553l_noret luaG_aritherror (lua_State *L, const TValue *p1, const TValue *p2) {
554  TValue temp;
555  if (luaV_tonumber(p1, &temp) == NULL)
556    p2 = p1;  /* first operand is wrong */
557  luaG_typeerror(L, p2, "perform arithmetic on");
558}
559
560
561l_noret luaG_ordererror (lua_State *L, const TValue *p1, const TValue *p2) {
562  const char *t1 = objtypename(p1);
563  const char *t2 = objtypename(p2);
564  if (t1 == t2)
565    luaG_runerror(L, "attempt to compare two %s values", t1);
566  else
567    luaG_runerror(L, "attempt to compare %s with %s", t1, t2);
568}
569
570
571static void addinfo (lua_State *L, const char *msg) {
572  CallInfo *ci = L->ci;
573  if (isLua(ci)) {  /* is Lua code? */
574    char buff[LUA_IDSIZE];  /* add file:line information */
575    int line = currentline(ci);
576    TString *src = ci_func(ci)->p->source;
577    if (src)
578      luaO_chunkid(buff, getstr(src), LUA_IDSIZE);
579    else {  /* no source available; use "?" instead */
580      buff[0] = '?'; buff[1] = '\0';
581    }
582    luaO_pushfstring(L, "%s:%d: %s", buff, line, msg);
583  }
584}
585
586
587l_noret luaG_errormsg (lua_State *L) {
588  if (L->errfunc != 0) {  /* is there an error handling function? */
589    StkId errfunc = restorestack(L, L->errfunc);
590    if (!ttisfunction(errfunc)) luaD_throw(L, LUA_ERRERR);
591    setobjs2s(L, L->top, L->top - 1);  /* move argument */
592    setobjs2s(L, L->top - 1, errfunc);  /* push function */
593    L->top++;
594    luaD_call(L, L->top - 2, 1, 0);  /* call it */
595  }
596  luaD_throw(L, LUA_ERRRUN);
597}
598
599
600l_noret luaG_runerror (lua_State *L, const char *fmt, ...) {
601  va_list argp;
602  va_start(argp, fmt);
603  addinfo(L, luaO_pushvfstring(L, fmt, argp));
604  va_end(argp);
605  luaG_errormsg(L);
606}
607
608