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  1. /*
  2. ** $Id: ldebug.c,v 2.29.1.6 2008/05/08 16:56:26 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. static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name);
  34.  
  35.  
  36. static int currentpc (lua_State *L, CallInfo *ci) {
  37.   if (!isLua(ci)) return -1;  /* function is not a Lua function? */
  38.   if (ci == L->ci)
  39.     ci->savedpc = L->savedpc;
  40.   return pcRel(ci->savedpc, ci_func(ci)->l.p);
  41. }
  42.  
  43.  
  44. static int currentline (lua_State *L, CallInfo *ci) {
  45.   int pc = currentpc(L, ci);
  46.   if (pc < 0)
  47.     return -1;  /* only active lua functions have current-line information */
  48.   else
  49.     return getline(ci_func(ci)->l.p, pc);
  50. }
  51.  
  52.  
  53. /*
  54. ** this function can be called asynchronous (e.g. during a signal)
  55. */
  56. LUA_API int lua_sethook (lua_State *L, lua_Hook func, int mask, int count) {
  57.   if (func == NULL || mask == 0) {  /* turn off hooks? */
  58.     mask = 0;
  59.     func = NULL;
  60.   }
  61.   L->hook = func;
  62.   L->basehookcount = count;
  63.   resethookcount(L);
  64.   L->hookmask = cast_byte(mask);
  65.   return 1;
  66. }
  67.  
  68.  
  69. LUA_API lua_Hook lua_gethook (lua_State *L) {
  70.   return L->hook;
  71. }
  72.  
  73.  
  74. LUA_API int lua_gethookmask (lua_State *L) {
  75.   return L->hookmask;
  76. }
  77.  
  78.  
  79. LUA_API int lua_gethookcount (lua_State *L) {
  80.   return L->basehookcount;
  81. }
  82.  
  83.  
  84. LUA_API int lua_getstack (lua_State *L, int level, lua_Debug *ar) {
  85.   int status;
  86.   CallInfo *ci;
  87.   lua_lock(L);
  88.   for (ci = L->ci; level > 0 && ci > L->base_ci; ci--) {
  89.     level--;
  90.     if (f_isLua(ci))  /* Lua function? */
  91.       level -= ci->tailcalls;  /* skip lost tail calls */
  92.   }
  93.   if (level == 0 && ci > L->base_ci) {  /* level found? */
  94.     status = 1;
  95.     ar->i_ci = cast_int(ci - L->base_ci);
  96.   }
  97.   else if (level < 0) {  /* level is of a lost tail call? */
  98.     status = 1;
  99.     ar->i_ci = 0;
  100.   }
  101.   else status = 0;  /* no such level */
  102.   lua_unlock(L);
  103.   return status;
  104. }
  105.  
  106.  
  107. static Proto *getluaproto (CallInfo *ci) {
  108.   return (isLua(ci) ? ci_func(ci)->l.p : NULL);
  109. }
  110.  
  111.  
  112. static const char *findlocal (lua_State *L, CallInfo *ci, int n) {
  113.   const char *name;
  114.   Proto *fp = getluaproto(ci);
  115.   if (fp && (name = luaF_getlocalname(fp, n, currentpc(L, ci))) != NULL)
  116.     return name;  /* is a local variable in a Lua function */
  117.   else {
  118.     StkId limit = (ci == L->ci) ? L->top : (ci+1)->func;
  119.     if (limit - ci->base >= n && n > 0)  /* is 'n' inside 'ci' stack? */
  120.       return "(*temporary)";
  121.     else
  122.       return NULL;
  123.   }
  124. }
  125.  
  126.  
  127. LUA_API const char *lua_getlocal (lua_State *L, const lua_Debug *ar, int n) {
  128.   CallInfo *ci = L->base_ci + ar->i_ci;
  129.   const char *name = findlocal(L, ci, n);
  130.   lua_lock(L);
  131.   if (name)
  132.       luaA_pushobject(L, ci->base + (n - 1));
  133.   lua_unlock(L);
  134.   return name;
  135. }
  136.  
  137.  
  138. LUA_API const char *lua_setlocal (lua_State *L, const lua_Debug *ar, int n) {
  139.   CallInfo *ci = L->base_ci + ar->i_ci;
  140.   const char *name = findlocal(L, ci, n);
  141.   lua_lock(L);
  142.   if (name)
  143.       setobjs2s(L, ci->base + (n - 1), L->top - 1);
  144.   L->top--;  /* pop value */
  145.   lua_unlock(L);
  146.   return name;
  147. }
  148.  
  149.  
  150. static void funcinfo (lua_Debug *ar, Closure *cl) {
  151.   if (cl->c.isC) {
  152.     ar->source = "=[C]";
  153.     ar->linedefined = -1;
  154.     ar->lastlinedefined = -1;
  155.     ar->what = "C";
  156.   }
  157.   else {
  158.     ar->source = getstr(cl->l.p->source);
  159.     ar->linedefined = cl->l.p->linedefined;
  160.     ar->lastlinedefined = cl->l.p->lastlinedefined;
  161.     ar->what = (ar->linedefined == 0) ? "main" : "Lua";
  162.   }
  163.   luaO_chunkid(ar->short_src, ar->source, LUA_IDSIZE);
  164. }
  165.  
  166.  
  167. static void info_tailcall (lua_Debug *ar) {
  168.   ar->name = ar->namewhat = "";
  169.   ar->what = "tail";
  170.   ar->lastlinedefined = ar->linedefined = ar->currentline = -1;
  171.   ar->source = "=(tail call)";
  172.   luaO_chunkid(ar->short_src, ar->source, LUA_IDSIZE);
  173.   ar->nups = 0;
  174. }
  175.  
  176.  
  177. static void collectvalidlines (lua_State *L, Closure *f) {
  178.   if (f == NULL || f->c.isC) {
  179.     setnilvalue(L->top);
  180.   }
  181.   else {
  182.     Table *t = luaH_new(L, 0, 0);
  183.     int *lineinfo = f->l.p->lineinfo;
  184.     int i;
  185.     for (i=0; i<f->l.p->sizelineinfo; i++)
  186.       setbvalue(luaH_setnum(L, t, lineinfo[i]), 1);
  187.     sethvalue(L, L->top, t);
  188.   }
  189.   incr_top(L);
  190. }
  191.  
  192.  
  193. static int auxgetinfo (lua_State *L, const char *what, lua_Debug *ar,
  194.                     Closure *f, CallInfo *ci) {
  195.   int status = 1;
  196.   if (f == NULL) {
  197.     info_tailcall(ar);
  198.     return status;
  199.   }
  200.   for (; *what; what++) {
  201.     switch (*what) {
  202.       case 'S': {
  203.         funcinfo(ar, f);
  204.         break;
  205.       }
  206.       case 'l': {
  207.         ar->currentline = (ci) ? currentline(L, ci) : -1;
  208.         break;
  209.       }
  210.       case 'u': {
  211.         ar->nups = f->c.nupvalues;
  212.         break;
  213.       }
  214.       case 'n': {
  215.         ar->namewhat = (ci) ? getfuncname(L, ci, &ar->name) : NULL;
  216.         if (ar->namewhat == NULL) {
  217.           ar->namewhat = "";  /* not found */
  218.           ar->name = NULL;
  219.         }
  220.         break;
  221.       }
  222.       case 'L':
  223.       case 'f':  /* handled by lua_getinfo */
  224.         break;
  225.       default: status = 0;  /* invalid option */
  226.     }
  227.   }
  228.   return status;
  229. }
  230.  
  231.  
  232. LUA_API int lua_getinfo (lua_State *L, const char *what, lua_Debug *ar) {
  233.   int status;
  234.   Closure *f = NULL;
  235.   CallInfo *ci = NULL;
  236.   lua_lock(L);
  237.   if (*what == '>') {
  238.     StkId func = L->top - 1;
  239.     luai_apicheck(L, ttisfunction(func));
  240.     what++;  /* skip the '>' */
  241.     f = clvalue(func);
  242.     L->top--;  /* pop function */
  243.   }
  244.   else if (ar->i_ci != 0) {  /* no tail call? */
  245.     ci = L->base_ci + ar->i_ci;
  246.     lua_assert(ttisfunction(ci->func));
  247.     f = clvalue(ci->func);
  248.   }
  249.   status = auxgetinfo(L, what, ar, f, ci);
  250.   if (strchr(what, 'f')) {
  251.     if (f == NULL) setnilvalue(L->top);
  252.     else setclvalue(L, L->top, f);
  253.     incr_top(L);
  254.   }
  255.   if (strchr(what, 'L'))
  256.     collectvalidlines(L, f);
  257.   lua_unlock(L);
  258.   return status;
  259. }
  260.  
  261.  
  262. /*
  263. ** {======================================================
  264. ** Symbolic Execution and code checker
  265. ** =======================================================
  266. */
  267.  
  268. #define check(x)                if (!(x)) return 0;
  269.  
  270. #define checkjump(pt,pc)        check(0 <= pc && pc < pt->sizecode)
  271.  
  272. #define checkreg(pt,reg)        check((reg) < (pt)->maxstacksize)
  273.  
  274.  
  275.  
  276. static int precheck (const Proto *pt) {
  277.   check(pt->maxstacksize <= MAXSTACK);
  278.   check(pt->numparams+(pt->is_vararg & VARARG_HASARG) <= pt->maxstacksize);
  279.   check(!(pt->is_vararg & VARARG_NEEDSARG) ||
  280.               (pt->is_vararg & VARARG_HASARG));
  281.   check(pt->sizeupvalues <= pt->nups);
  282.   check(pt->sizelineinfo == pt->sizecode || pt->sizelineinfo == 0);
  283.   check(pt->sizecode > 0 && GET_OPCODE(pt->code[pt->sizecode-1]) == OP_RETURN);
  284.   return 1;
  285. }
  286.  
  287.  
  288. #define checkopenop(pt,pc)      luaG_checkopenop((pt)->code[(pc)+1])
  289.  
  290. int luaG_checkopenop (Instruction i) {
  291.   switch (GET_OPCODE(i)) {
  292.     case OP_CALL:
  293.     case OP_TAILCALL:
  294.     case OP_RETURN:
  295.     case OP_SETLIST: {
  296.       check(GETARG_B(i) == 0);
  297.       return 1;
  298.     }
  299.     default: return 0;  /* invalid instruction after an open call */
  300.   }
  301. }
  302.  
  303.  
  304. static int checkArgMode (const Proto *pt, int r, enum OpArgMask mode) {
  305.   switch (mode) {
  306.     case OpArgN: check(r == 0); break;
  307.     case OpArgU: break;
  308.     case OpArgR: checkreg(pt, r); break;
  309.     case OpArgK:
  310.       check(ISK(r) ? INDEXK(r) < pt->sizek : r < pt->maxstacksize);
  311.       break;
  312.   }
  313.   return 1;
  314. }
  315.  
  316.  
  317. static Instruction symbexec (const Proto *pt, int lastpc, int reg) {
  318.   int pc;
  319.   int last;  /* stores position of last instruction that changed `reg' */
  320.   last = pt->sizecode-1;  /* points to final return (a `neutral' instruction) */
  321.   check(precheck(pt));
  322.   for (pc = 0; pc < lastpc; pc++) {
  323.     Instruction i = pt->code[pc];
  324.     OpCode op = GET_OPCODE(i);
  325.     int a = GETARG_A(i);
  326.     int b = 0;
  327.     int c = 0;
  328.     check(op < NUM_OPCODES);
  329.     checkreg(pt, a);
  330.     switch (getOpMode(op)) {
  331.       case iABC: {
  332.         b = GETARG_B(i);
  333.         c = GETARG_C(i);
  334.         check(checkArgMode(pt, b, getBMode(op)));
  335.         check(checkArgMode(pt, c, getCMode(op)));
  336.         break;
  337.       }
  338.       case iABx: {
  339.         b = GETARG_Bx(i);
  340.         if (getBMode(op) == OpArgK) check(b < pt->sizek);
  341.         break;
  342.       }
  343.       case iAsBx: {
  344.         b = GETARG_sBx(i);
  345.         if (getBMode(op) == OpArgR) {
  346.           int dest = pc+1+b;
  347.           check(0 <= dest && dest < pt->sizecode);
  348.           if (dest > 0) {
  349.             int j;
  350.             /* check that it does not jump to a setlist count; this
  351.                is tricky, because the count from a previous setlist may
  352.                have the same value of an invalid setlist; so, we must
  353.                go all the way back to the first of them (if any) */
  354.             for (j = 0; j < dest; j++) {
  355.               Instruction d = pt->code[dest-1-j];
  356.               if (!(GET_OPCODE(d) == OP_SETLIST && GETARG_C(d) == 0)) break;
  357.             }
  358.             /* if 'j' is even, previous value is not a setlist (even if
  359.                it looks like one) */
  360.             check((j&1) == 0);
  361.           }
  362.         }
  363.         break;
  364.       }
  365.     }
  366.     if (testAMode(op)) {
  367.       if (a == reg) last = pc;  /* change register `a' */
  368.     }
  369.     if (testTMode(op)) {
  370.       check(pc+2 < pt->sizecode);  /* check skip */
  371.       check(GET_OPCODE(pt->code[pc+1]) == OP_JMP);
  372.     }
  373.     switch (op) {
  374.       case OP_LOADBOOL: {
  375.         if (c == 1) {  /* does it jump? */
  376.           check(pc+2 < pt->sizecode);  /* check its jump */
  377.           check(GET_OPCODE(pt->code[pc+1]) != OP_SETLIST ||
  378.                 GETARG_C(pt->code[pc+1]) != 0);
  379.         }
  380.         break;
  381.       }
  382.       case OP_LOADNIL: {
  383.         if (a <= reg && reg <= b)
  384.           last = pc;  /* set registers from `a' to `b' */
  385.         break;
  386.       }
  387.       case OP_GETUPVAL:
  388.       case OP_SETUPVAL: {
  389.         check(b < pt->nups);
  390.         break;
  391.       }
  392.       case OP_GETGLOBAL:
  393.       case OP_SETGLOBAL: {
  394.         check(ttisstring(&pt->k[b]));
  395.         break;
  396.       }
  397.       case OP_SELF: {
  398.         checkreg(pt, a+1);
  399.         if (reg == a+1) last = pc;
  400.         break;
  401.       }
  402.       case OP_CONCAT: {
  403.         check(b < c);  /* at least two operands */
  404.         break;
  405.       }
  406.       case OP_TFORLOOP: {
  407.         check(c >= 1);  /* at least one result (control variable) */
  408.         checkreg(pt, a+2+c);  /* space for results */
  409.         if (reg >= a+2) last = pc;  /* affect all regs above its base */
  410.         break;
  411.       }
  412.       case OP_FORLOOP:
  413.       case OP_FORPREP:
  414.         checkreg(pt, a+3);
  415.         /* go through */
  416.       case OP_JMP: {
  417.         int dest = pc+1+b;
  418.         /* not full check and jump is forward and do not skip `lastpc'? */
  419.         if (reg != NO_REG && pc < dest && dest <= lastpc)
  420.           pc += b;  /* do the jump */
  421.         break;
  422.       }
  423.       case OP_CALL:
  424.       case OP_TAILCALL: {
  425.         if (b != 0) {
  426.           checkreg(pt, a+b-1);
  427.         }
  428.         c--;  /* c = num. returns */
  429.         if (c == LUA_MULTRET) {
  430.           check(checkopenop(pt, pc));
  431.         }
  432.         else if (c != 0)
  433.           checkreg(pt, a+c-1);
  434.         if (reg >= a) last = pc;  /* affect all registers above base */
  435.         break;
  436.       }
  437.       case OP_RETURN: {
  438.         b--;  /* b = num. returns */
  439.         if (b > 0) checkreg(pt, a+b-1);
  440.         break;
  441.       }
  442.       case OP_SETLIST: {
  443.         if (b > 0) checkreg(pt, a + b);
  444.         if (c == 0) {
  445.           pc++;
  446.           check(pc < pt->sizecode - 1);
  447.         }
  448.         break;
  449.       }
  450.       case OP_CLOSURE: {
  451.         int nup, j;
  452.         check(b < pt->sizep);
  453.         nup = pt->p[b]->nups;
  454.         check(pc + nup < pt->sizecode);
  455.         for (j = 1; j <= nup; j++) {
  456.           OpCode op1 = GET_OPCODE(pt->code[pc + j]);
  457.           check(op1 == OP_GETUPVAL || op1 == OP_MOVE);
  458.         }
  459.         if (reg != NO_REG)  /* tracing? */
  460.           pc += nup;  /* do not 'execute' these pseudo-instructions */
  461.         break;
  462.       }
  463.       case OP_VARARG: {
  464.         check((pt->is_vararg & VARARG_ISVARARG) &&
  465.              !(pt->is_vararg & VARARG_NEEDSARG));
  466.         b--;
  467.         if (b == LUA_MULTRET) check(checkopenop(pt, pc));
  468.         checkreg(pt, a+b-1);
  469.         break;
  470.       }
  471.       default: break;
  472.     }
  473.   }
  474.   return pt->code[last];
  475. }
  476.  
  477. #undef check
  478. #undef checkjump
  479. #undef checkreg
  480.  
  481. /* }====================================================== */
  482.  
  483.  
  484. int luaG_checkcode (const Proto *pt) {
  485.   return (symbexec(pt, pt->sizecode, NO_REG) != 0);
  486. }
  487.  
  488.  
  489. static const char *kname (Proto *p, int c) {
  490.   if (ISK(c) && ttisstring(&p->k[INDEXK(c)]))
  491.     return svalue(&p->k[INDEXK(c)]);
  492.   else
  493.     return "?";
  494. }
  495.  
  496.  
  497. static const char *getobjname (lua_State *L, CallInfo *ci, int stackpos,
  498.                                const char **name) {
  499.   if (isLua(ci)) {  /* a Lua function? */
  500.     Proto *p = ci_func(ci)->l.p;
  501.     int pc = currentpc(L, ci);
  502.     Instruction i;
  503.     *name = luaF_getlocalname(p, stackpos+1, pc);
  504.     if (*name)  /* is a local? */
  505.       return "local";
  506.     i = symbexec(p, pc, stackpos);  /* try symbolic execution */
  507.     lua_assert(pc != -1);
  508.     switch (GET_OPCODE(i)) {
  509.       case OP_GETGLOBAL: {
  510.         int g = GETARG_Bx(i);  /* global index */
  511.         lua_assert(ttisstring(&p->k[g]));
  512.         *name = svalue(&p->k[g]);
  513.         return "global";
  514.       }
  515.       case OP_MOVE: {
  516.         int a = GETARG_A(i);
  517.         int b = GETARG_B(i);  /* move from `b' to `a' */
  518.         if (b < a)
  519.           return getobjname(L, ci, b, name);  /* get name for `b' */
  520.         break;
  521.       }
  522.       case OP_GETTABLE: {
  523.         int k = GETARG_C(i);  /* key index */
  524.         *name = kname(p, k);
  525.         return "field";
  526.       }
  527.       case OP_GETUPVAL: {
  528.         int u = GETARG_B(i);  /* upvalue index */
  529.         *name = p->upvalues ? getstr(p->upvalues[u]) : "?";
  530.         return "upvalue";
  531.       }
  532.       case OP_SELF: {
  533.         int k = GETARG_C(i);  /* key index */
  534.         *name = kname(p, k);
  535.         return "method";
  536.       }
  537.       default: break;
  538.     }
  539.   }
  540.   return NULL;  /* no useful name found */
  541. }
  542.  
  543.  
  544. static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name) {
  545.   Instruction i;
  546.   if ((isLua(ci) && ci->tailcalls > 0) || !isLua(ci - 1))
  547.     return NULL;  /* calling function is not Lua (or is unknown) */
  548.   ci--;  /* calling function */
  549.   i = ci_func(ci)->l.p->code[currentpc(L, ci)];
  550.   if (GET_OPCODE(i) == OP_CALL || GET_OPCODE(i) == OP_TAILCALL ||
  551.       GET_OPCODE(i) == OP_TFORLOOP)
  552.     return getobjname(L, ci, GETARG_A(i), name);
  553.   else
  554.     return NULL;  /* no useful name can be found */
  555. }
  556.  
  557.  
  558. /* only ANSI way to check whether a pointer points to an array */
  559. static int isinstack (CallInfo *ci, const TValue *o) {
  560.   StkId p;
  561.   for (p = ci->base; p < ci->top; p++)
  562.     if (o == p) return 1;
  563.   return 0;
  564. }
  565.  
  566.  
  567. void luaG_typeerror (lua_State *L, const TValue *o, const char *op) {
  568.   const char *name = NULL;
  569.   const char *t = luaT_typenames[ttype(o)];
  570.   const char *kind = (isinstack(L->ci, o)) ?
  571.                          getobjname(L, L->ci, cast_int(o - L->base), &name) :
  572.                          NULL;
  573.   if (kind)
  574.     luaG_runerror(L, "attempt to %s %s " LUA_QS " (a %s value)",
  575.                 op, kind, name, t);
  576.   else
  577.     luaG_runerror(L, "attempt to %s a %s value", op, t);
  578. }
  579.  
  580.  
  581. void luaG_concaterror (lua_State *L, StkId p1, StkId p2) {
  582.   if (ttisstring(p1) || ttisnumber(p1)) p1 = p2;
  583.   lua_assert(!ttisstring(p1) && !ttisnumber(p1));
  584.   luaG_typeerror(L, p1, "concatenate");
  585. }
  586.  
  587.  
  588. void luaG_aritherror (lua_State *L, const TValue *p1, const TValue *p2) {
  589.   TValue temp;
  590.   if (luaV_tonumber(p1, &temp) == NULL)
  591.     p2 = p1;  /* first operand is wrong */
  592.   luaG_typeerror(L, p2, "perform arithmetic on");
  593. }
  594.  
  595.  
  596. int luaG_ordererror (lua_State *L, const TValue *p1, const TValue *p2) {
  597.   const char *t1 = luaT_typenames[ttype(p1)];
  598.   const char *t2 = luaT_typenames[ttype(p2)];
  599.   if (t1[2] == t2[2])
  600.     luaG_runerror(L, "attempt to compare two %s values", t1);
  601.   else
  602.     luaG_runerror(L, "attempt to compare %s with %s", t1, t2);
  603.   return 0;
  604. }
  605.  
  606.  
  607. static void addinfo (lua_State *L, const char *msg) {
  608.   CallInfo *ci = L->ci;
  609.   if (isLua(ci)) {  /* is Lua code? */
  610.     char buff[LUA_IDSIZE];  /* add file:line information */
  611.     int line = currentline(L, ci);
  612.     luaO_chunkid(buff, getstr(getluaproto(ci)->source), LUA_IDSIZE);
  613.     luaO_pushfstring(L, "%s:%d: %s", buff, line, msg);
  614.   }
  615. }
  616.  
  617.  
  618. void luaG_errormsg (lua_State *L) {
  619.   if (L->errfunc != 0) {  /* is there an error handling function? */
  620.     StkId errfunc = restorestack(L, L->errfunc);
  621.     if (!ttisfunction(errfunc)) luaD_throw(L, LUA_ERRERR);
  622.     setobjs2s(L, L->top, L->top - 1);  /* move argument */
  623.     setobjs2s(L, L->top - 1, errfunc);  /* push function */
  624.     incr_top(L);
  625.     luaD_call(L, L->top - 2, 1);  /* call it */
  626.   }
  627.   luaD_throw(L, LUA_ERRRUN);
  628. }
  629.  
  630.  
  631. void luaG_runerror (lua_State *L, const char *fmt, ...) {
  632.   va_list argp;
  633.   va_start(argp, fmt);
  634.   addinfo(L, luaO_pushvfstring(L, fmt, argp));
  635.   va_end(argp);
  636.   luaG_errormsg(L);
  637. }
  638.  
  639.