Line data Source code
1 : /*
2 : ** $Id: ldo.c,v 2.157.1.1 2017/04/19 17:20:42 roberto Exp $
3 : ** Stack and Call structure of Lua
4 : ** See Copyright Notice in lua.h
5 : */
6 :
7 : #define ldo_c
8 : #define LUA_CORE
9 :
10 : #include "lprefix.h"
11 :
12 :
13 : #include <AP_HAL/ap_setjmp.h>
14 : #include <stdlib.h>
15 : #include <string.h>
16 :
17 : #include "lua.h"
18 :
19 : #include "lapi.h"
20 : #include "ldebug.h"
21 : #include "ldo.h"
22 : #include "lfunc.h"
23 : #include "lgc.h"
24 : #include "lmem.h"
25 : #include "lobject.h"
26 : #include "lopcodes.h"
27 : #include "lparser.h"
28 : #include "lstate.h"
29 : #include "lstring.h"
30 : #include "ltable.h"
31 : #include "ltm.h"
32 : #include "lundump.h"
33 : #include "lvm.h"
34 : #include "lzio.h"
35 :
36 : // lua code does lots of casting, these warnings are not helpful
37 : #pragma GCC diagnostic ignored "-Wcast-align"
38 :
39 : #define errorstatus(s) ((s) > LUA_YIELD)
40 :
41 :
42 : /*
43 : ** {======================================================
44 : ** Error-recovery functions
45 : ** =======================================================
46 : */
47 :
48 : /*
49 : ** LUAI_THROW/LUAI_TRY define how Lua does exception handling. By
50 : ** default, Lua handles errors with exceptions when compiling as
51 : ** C++ code, with _longjmp/_setjmp when asked to use them, and with
52 : ** longjmp/setjmp otherwise.
53 : */
54 : #if !defined(LUAI_THROW) /* { */
55 :
56 : #if defined(__cplusplus) && !defined(LUA_USE_LONGJMP) /* { */
57 :
58 : /* C++ exceptions */
59 : #define LUAI_THROW(L,c) throw(c)
60 : #define LUAI_TRY(L,c,a) \
61 : try { a } catch(...) { if ((c)->status == 0) (c)->status = -1; }
62 : #define luai_jmpbuf int /* dummy variable */
63 :
64 : #elif defined(LUA_USE_POSIX) /* }{ */
65 :
66 : /* in POSIX, try _longjmp/_setjmp (more efficient) */
67 : #define LUAI_THROW(L,c) _longjmp((c)->b, 1)
68 : #define LUAI_TRY(L,c,a) if (_setjmp((c)->b) == 0) { a }
69 : #define luai_jmpbuf jmp_buf
70 :
71 : #else /* }{ */
72 :
73 : /* ISO C handling with long jumps */
74 : #define LUAI_THROW(L,c) ap_longjmp((c)->b, 1)
75 : #define LUAI_TRY(L,c,a) if (ap_setjmp((c)->b) == 0) { a }
76 : #define luai_jmpbuf ap_jmp_buf
77 :
78 : #endif /* } */
79 :
80 : #endif /* } */
81 :
82 :
83 :
84 : /* chain list of long jump buffers */
85 : struct lua_longjmp {
86 : struct lua_longjmp *previous;
87 : luai_jmpbuf b;
88 : volatile int status; /* error code */
89 : };
90 :
91 :
92 58 : static void seterrorobj (lua_State *L, int errcode, StkId oldtop) {
93 58 : switch (errcode) {
94 0 : case LUA_ERRMEM: { /* memory error? */
95 0 : setsvalue2s(L, oldtop, G(L)->memerrmsg); /* reuse preregistered msg. */
96 0 : break;
97 : }
98 0 : case LUA_ERRERR: {
99 0 : setsvalue2s(L, oldtop, luaS_newliteral(L, "error in error handling"));
100 0 : break;
101 : }
102 58 : default: {
103 58 : setobjs2s(L, oldtop, L->top - 1); /* error message on current top */
104 58 : break;
105 : }
106 : }
107 58 : L->top = oldtop + 1;
108 58 : }
109 :
110 :
111 58 : l_noret luaD_throw (lua_State *L, int errcode) {
112 58 : if (L->errorJmp) { /* thread has an error handler? */
113 58 : L->errorJmp->status = errcode; /* set status */
114 58 : LUAI_THROW(L, L->errorJmp); /* jump to it */
115 : }
116 : else { /* thread has no error handler */
117 0 : global_State *g = G(L);
118 0 : L->status = cast_byte(errcode); /* mark it as dead */
119 0 : if (g->mainthread->errorJmp) { /* main thread has a handler? */
120 0 : setobjs2s(L, g->mainthread->top++, L->top - 1); /* copy error obj. */
121 0 : luaD_throw(g->mainthread, errcode); /* re-throw in main thread */
122 : }
123 : else { /* no handler at all; abort */
124 0 : if (g->panic) { /* panic function? */
125 0 : seterrorobj(L, errcode, L->top); /* assume EXTRA_STACK */
126 0 : if (L->ci->top < L->top)
127 0 : L->ci->top = L->top; /* pushing msg. can break this invariant */
128 : lua_unlock(L);
129 0 : g->panic(L); /* call panic function (last chance to jump out) */
130 : }
131 0 : lua_abort();
132 : }
133 : }
134 : }
135 :
136 :
137 263742 : int luaD_rawrunprotected (lua_State *L, Pfunc f, void *ud) {
138 263742 : unsigned short oldnCcalls = L->nCcalls;
139 : struct lua_longjmp lj;
140 263742 : lj.status = LUA_OK;
141 263742 : lj.previous = L->errorJmp; /* chain new error handler */
142 263742 : L->errorJmp = &lj;
143 263742 : LUAI_TRY(L, &lj,
144 : (*f)(L, ud);
145 : );
146 263695 : L->errorJmp = lj.previous; /* restore old error handler */
147 263695 : L->nCcalls = oldnCcalls;
148 263695 : return lj.status;
149 : }
150 :
151 : /* }====================================================== */
152 :
153 :
154 : /*
155 : ** {==================================================================
156 : ** Stack reallocation
157 : ** ===================================================================
158 : */
159 184821 : static void correctstack (lua_State *L, TValue *oldstack) {
160 : CallInfo *ci;
161 : UpVal *up;
162 184821 : L->top = (L->top - oldstack) + L->stack;
163 185204 : for (up = L->openupval; up != NULL; up = up->u.open.next)
164 383 : up->v = (up->v - oldstack) + L->stack;
165 719625 : for (ci = L->ci; ci != NULL; ci = ci->previous) {
166 534804 : ci->top = (ci->top - oldstack) + L->stack;
167 534804 : ci->func = (ci->func - oldstack) + L->stack;
168 534804 : if (isLua(ci))
169 137751 : ci->u.l.base = (ci->u.l.base - oldstack) + L->stack;
170 : }
171 184821 : }
172 :
173 :
174 : /* some space for error handling */
175 : #define ERRORSTACKSIZE (LUAI_MAXSTACK + 200)
176 :
177 :
178 184821 : void luaD_reallocstack (lua_State *L, int newsize) {
179 184821 : TValue *oldstack = L->stack;
180 184821 : int lim = L->stacksize;
181 : lua_assert(newsize <= LUAI_MAXSTACK || newsize == ERRORSTACKSIZE);
182 : lua_assert(L->stack_last - L->stack == L->stacksize - EXTRA_STACK);
183 184821 : luaM_reallocvector(L, L->stack, L->stacksize, newsize, TValue);
184 3688304 : for (; lim < newsize; lim++)
185 3503483 : setnilvalue(L->stack + lim); /* erase new segment */
186 184821 : L->stacksize = newsize;
187 184821 : L->stack_last = L->stack + newsize - EXTRA_STACK;
188 184821 : correctstack(L, oldstack);
189 184821 : }
190 :
191 :
192 94907 : void luaD_growstack (lua_State *L, int n) {
193 94907 : int size = L->stacksize;
194 94907 : if (size > LUAI_MAXSTACK) /* error after extra size? */
195 0 : luaD_throw(L, LUA_ERRERR);
196 : else {
197 94907 : int needed = cast_int(L->top - L->stack) + n + EXTRA_STACK;
198 94907 : int newsize = 2 * size;
199 94907 : if (newsize > LUAI_MAXSTACK) newsize = LUAI_MAXSTACK;
200 94907 : if (newsize < needed) newsize = needed;
201 94907 : if (newsize > LUAI_MAXSTACK) { /* stack overflow? */
202 0 : luaD_reallocstack(L, ERRORSTACKSIZE);
203 0 : luaG_runerror(L, "stack overflow");
204 : }
205 : else
206 94907 : luaD_reallocstack(L, newsize);
207 : }
208 94907 : }
209 :
210 :
211 90721 : static int stackinuse (lua_State *L) {
212 : CallInfo *ci;
213 90721 : StkId lim = L->top;
214 272549 : for (ci = L->ci; ci != NULL; ci = ci->previous) {
215 181828 : if (lim < ci->top) lim = ci->top;
216 : }
217 : lua_assert(lim <= L->stack_last);
218 90721 : return cast_int(lim - L->stack) + 1; /* part of stack in use */
219 : }
220 :
221 :
222 90721 : void luaD_shrinkstack (lua_State *L) {
223 90721 : int inuse = stackinuse(L);
224 90721 : int goodsize = inuse + (inuse / 8) + 2*EXTRA_STACK;
225 90721 : if (goodsize > LUAI_MAXSTACK)
226 0 : goodsize = LUAI_MAXSTACK; /* respect stack limit */
227 90721 : if (L->stacksize > LUAI_MAXSTACK) /* had been handling stack overflow? */
228 0 : luaE_freeCI(L); /* free all CIs (list grew because of an error) */
229 : else
230 90721 : luaE_shrinkCI(L); /* shrink list */
231 : /* if thread is currently not handling a stack overflow and its
232 : good size is smaller than current size, shrink its stack */
233 90721 : if (inuse <= (LUAI_MAXSTACK - EXTRA_STACK) &&
234 90721 : goodsize < L->stacksize)
235 89914 : luaD_reallocstack(L, goodsize);
236 : else /* don't change stack */
237 : condmovestack(L,{},{}); /* (change only for debugging) */
238 90721 : }
239 :
240 :
241 2454 : void luaD_inctop (lua_State *L) {
242 2454 : luaD_checkstack(L, 1);
243 2454 : L->top++;
244 2454 : }
245 :
246 : /* }================================================================== */
247 :
248 :
249 : /*
250 : ** Call a hook for the given event. Make sure there is a hook to be
251 : ** called. (Both 'L->hook' and 'L->hookmask', which triggers this
252 : ** function, can be changed asynchronously by signals.)
253 : */
254 1 : void luaD_hook (lua_State *L, int event, int line) {
255 1 : lua_Hook hook = L->hook;
256 1 : if (hook && L->allowhook) { /* make sure there is a hook */
257 1 : CallInfo *ci = L->ci;
258 1 : ptrdiff_t top = savestack(L, L->top);
259 1 : ptrdiff_t ci_top = savestack(L, ci->top);
260 : lua_Debug ar;
261 1 : ar.event = event;
262 1 : ar.currentline = line;
263 1 : ar.i_ci = ci;
264 1 : luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */
265 1 : ci->top = L->top + LUA_MINSTACK;
266 : lua_assert(ci->top <= L->stack_last);
267 1 : L->allowhook = 0; /* cannot call hooks inside a hook */
268 1 : ci->callstatus |= CIST_HOOKED;
269 : lua_unlock(L);
270 1 : (*hook)(L, &ar);
271 : lua_lock(L);
272 : lua_assert(!L->allowhook);
273 0 : L->allowhook = 1;
274 0 : ci->top = restorestack(L, ci_top);
275 0 : L->top = restorestack(L, top);
276 0 : ci->callstatus &= ~CIST_HOOKED;
277 : }
278 0 : }
279 :
280 :
281 0 : static void callhook (lua_State *L, CallInfo *ci) {
282 0 : int hook = LUA_HOOKCALL;
283 0 : ci->u.l.savedpc++; /* hooks assume 'pc' is already incremented */
284 0 : if (isLua(ci->previous) &&
285 0 : GET_OPCODE(*(ci->previous->u.l.savedpc - 1)) == OP_TAILCALL) {
286 0 : ci->callstatus |= CIST_TAIL;
287 0 : hook = LUA_HOOKTAILCALL;
288 : }
289 0 : luaD_hook(L, hook, -1);
290 0 : ci->u.l.savedpc--; /* correct 'pc' */
291 0 : }
292 :
293 :
294 155 : static StkId adjust_varargs (lua_State *L, Proto *p, int actual) {
295 : int i;
296 155 : int nfixargs = p->numparams;
297 : StkId base, fixed;
298 : /* move fixed parameters to final position */
299 155 : fixed = L->top - actual; /* first fixed argument */
300 155 : base = L->top; /* final position of first argument */
301 225 : for (i = 0; i < nfixargs && i < actual; i++) {
302 70 : setobjs2s(L, L->top++, fixed + i);
303 70 : setnilvalue(fixed + i); /* erase original copy (for GC) */
304 : }
305 155 : for (; i < nfixargs; i++)
306 0 : setnilvalue(L->top++); /* complete missing arguments */
307 155 : return base;
308 : }
309 :
310 :
311 : /*
312 : ** Check whether __call metafield of 'func' is a function. If so, put
313 : ** it in stack below original 'func' so that 'luaD_precall' can call
314 : ** it. Raise an error if __call metafield is not a function.
315 : */
316 114 : static void tryfuncTM (lua_State *L, StkId func) {
317 114 : const TValue *tm = luaT_gettmbyobj(L, func, TM_CALL);
318 : StkId p;
319 114 : if (!ttisfunction(tm))
320 2 : luaG_typeerror(L, func, "call");
321 : /* Open a hole inside the stack at 'func' */
322 1120 : for (p = L->top; p > func; p--)
323 1008 : setobjs2s(L, p, p-1);
324 112 : L->top++; /* slot ensured by caller */
325 112 : setobj2s(L, func, tm); /* tag method is the new function to be called */
326 112 : }
327 :
328 :
329 : /*
330 : ** Given 'nres' results at 'firstResult', move 'wanted' of them to 'res'.
331 : ** Handle most typical cases (zero results for commands, one result for
332 : ** expressions, multiple results for tail calls/single parameters)
333 : ** separated.
334 : */
335 10796855 : static int moveresults (lua_State *L, const TValue *firstResult, StkId res,
336 : int nres, int wanted) {
337 10796855 : switch (wanted) { /* handle typical cases separately */
338 1117547 : case 0: break; /* nothing to move */
339 7988874 : case 1: { /* one result needed */
340 7988874 : if (nres == 0) /* no results? */
341 12030 : firstResult = luaO_nilobject; /* adjust with nil */
342 7988874 : setobjs2s(L, res, firstResult); /* move it to proper place */
343 7988874 : break;
344 : }
345 744898 : case LUA_MULTRET: {
346 : int i;
347 1553148 : for (i = 0; i < nres; i++) /* move all results to correct place */
348 808250 : setobjs2s(L, res + i, firstResult + i);
349 744898 : L->top = res + nres;
350 744898 : return 0; /* wanted == LUA_MULTRET */
351 : }
352 945536 : default: {
353 : int i;
354 945536 : if (wanted <= nres) { /* enough results? */
355 2676454 : for (i = 0; i < wanted; i++) /* move wanted results to correct place */
356 1806988 : setobjs2s(L, res + i, firstResult + i);
357 : }
358 : else { /* not enough results; use all of them plus nils */
359 147289 : for (i = 0; i < nres; i++) /* move all results to correct place */
360 71219 : setobjs2s(L, res + i, firstResult + i);
361 161446 : for (; i < wanted; i++) /* complete wanted number of results */
362 85376 : setnilvalue(res + i);
363 : }
364 945536 : break;
365 : }
366 : }
367 10051957 : L->top = res + wanted; /* top points after the last result */
368 10051957 : return 1;
369 : }
370 :
371 :
372 : /*
373 : ** Finishes a function call: calls hook if necessary, removes CallInfo,
374 : ** moves current number of results to proper place; returns 0 iff call
375 : ** wanted multiple (variable number of) results.
376 : */
377 10796855 : int luaD_poscall (lua_State *L, CallInfo *ci, StkId firstResult, int nres) {
378 : StkId res;
379 10796855 : int wanted = ci->nresults;
380 10796855 : if (L->hookmask & (LUA_MASKRET | LUA_MASKLINE)) {
381 0 : if (L->hookmask & LUA_MASKRET) {
382 0 : ptrdiff_t fr = savestack(L, firstResult); /* hook may change stack */
383 0 : luaD_hook(L, LUA_HOOKRET, -1);
384 0 : firstResult = restorestack(L, fr);
385 : }
386 0 : L->oldpc = ci->previous->u.l.savedpc; /* 'oldpc' for caller function */
387 : }
388 10796855 : res = ci->func; /* res == final position of 1st result */
389 10796855 : L->ci = ci->previous; /* back to caller */
390 : /* move results to proper place */
391 10796855 : return moveresults(L, firstResult, res, nres, wanted);
392 : }
393 :
394 :
395 :
396 : #define next_ci(L) (L->ci = (L->ci->next ? L->ci->next : luaE_extendCI(L)))
397 :
398 :
399 : /* macro to check stack size, preserving 'p' */
400 : #define checkstackp(L,n,p) \
401 : luaD_checkstackaux(L, n, \
402 : ptrdiff_t t__ = savestack(L, p); /* save 'p' */ \
403 : luaC_checkGC(L), /* stack grow uses memory */ \
404 : p = restorestack(L, t__)) /* 'pos' part: restore 'p' */
405 :
406 :
407 : /*
408 : ** Prepares a function call: checks the stack, creates a new CallInfo
409 : ** entry, fills in the relevant information, calls hook if needed.
410 : ** If function is a C function, does the call, too. (Otherwise, leave
411 : ** the execution ('luaV_execute') to the caller, to allow stackless
412 : ** calls.) Returns true iff function has been executed (C function).
413 : */
414 10932449 : int luaD_precall (lua_State *L, StkId func, int nresults) {
415 : lua_CFunction f;
416 : CallInfo *ci;
417 10932449 : switch (ttype(func)) {
418 73 : case LUA_TCCL: /* C closure */
419 73 : f = clCvalue(func)->f;
420 73 : goto Cfunc;
421 7759790 : case LUA_TLCF: /* light C function */
422 7759790 : f = fvalue(func);
423 7759863 : Cfunc: {
424 : int n; /* number of returns */
425 7759863 : checkstackp(L, LUA_MINSTACK, func); /* ensure minimum stack size */
426 7759863 : ci = next_ci(L); /* now 'enter' new function */
427 7759863 : ci->nresults = nresults;
428 7759863 : ci->func = func;
429 7759863 : ci->top = L->top + LUA_MINSTACK;
430 : lua_assert(ci->top <= L->stack_last);
431 7759863 : ci->callstatus = 0;
432 7759863 : if (L->hookmask & LUA_MASKCALL)
433 0 : luaD_hook(L, LUA_HOOKCALL, -1);
434 : lua_unlock(L);
435 7759863 : n = (*f)(L); /* do the actual call */
436 : lua_lock(L);
437 : api_checknelems(L, n);
438 7759769 : luaD_poscall(L, ci, L->top - n, n);
439 7759769 : return 1;
440 : }
441 3172472 : case LUA_TLCL: { /* Lua function: prepare its call */
442 : StkId base;
443 3172472 : Proto *p = clLvalue(func)->p;
444 3172472 : int n = cast_int(L->top - func) - 1; /* number of real arguments */
445 3172472 : int fsize = p->maxstacksize; /* frame size */
446 3172472 : checkstackp(L, fsize, func);
447 3172472 : if (p->is_vararg)
448 155 : base = adjust_varargs(L, p, n);
449 : else { /* non vararg function */
450 3192455 : for (; n < p->numparams; n++)
451 20138 : setnilvalue(L->top++); /* complete missing arguments */
452 3172317 : base = func + 1;
453 : }
454 3172472 : ci = next_ci(L); /* now 'enter' new function */
455 3172472 : ci->nresults = nresults;
456 3172472 : ci->func = func;
457 3172472 : ci->u.l.base = base;
458 3172472 : L->top = ci->top = base + fsize;
459 : lua_assert(ci->top <= L->stack_last);
460 3172472 : ci->u.l.savedpc = p->code; /* starting point */
461 3172472 : ci->callstatus = CIST_LUA;
462 3172472 : if (L->hookmask & LUA_MASKCALL)
463 0 : callhook(L, ci);
464 3172472 : return 0;
465 : }
466 114 : default: { /* not a function */
467 114 : checkstackp(L, 1, func); /* ensure space for metamethod */
468 114 : tryfuncTM(L, func); /* try to get '__call' metamethod */
469 112 : return luaD_precall(L, func, nresults); /* now it must be a function */
470 : }
471 : }
472 : }
473 :
474 :
475 : /*
476 : ** Check appropriate error for stack overflow ("regular" overflow or
477 : ** overflow while handling stack overflow). If 'nCalls' is larger than
478 : ** LUAI_MAXCCALLS (which means it is handling a "regular" overflow) but
479 : ** smaller than 9/8 of LUAI_MAXCCALLS, does not report an error (to
480 : ** allow overflow handling to work)
481 : */
482 0 : static void stackerror (lua_State *L) {
483 0 : if (L->nCcalls == LUAI_MAXCCALLS)
484 0 : luaG_runerror(L, "C stack overflow");
485 0 : else if (L->nCcalls >= (LUAI_MAXCCALLS + (LUAI_MAXCCALLS>>3)))
486 0 : luaD_throw(L, LUA_ERRERR); /* error while handing stack error */
487 0 : }
488 :
489 :
490 : /*
491 : ** Call a function (C or Lua). The function to be called is at *func.
492 : ** The arguments are on the stack, right after the function.
493 : ** When returns, all the results are on the stack, starting at the original
494 : ** function position.
495 : */
496 3775720 : void luaD_call (lua_State *L, StkId func, int nResults) {
497 3775720 : if (++L->nCcalls >= LUAI_MAXCCALLS)
498 0 : stackerror(L);
499 3775720 : if (!luaD_precall(L, func, nResults)) /* is a Lua function? */
500 117719 : luaV_execute(L); /* call it */
501 3775615 : L->nCcalls--;
502 3775615 : }
503 :
504 :
505 : /*
506 : ** Similar to 'luaD_call', but does not allow yields during the call
507 : */
508 118082 : void luaD_callnoyield (lua_State *L, StkId func, int nResults) {
509 118082 : L->nny++;
510 118082 : luaD_call(L, func, nResults);
511 117977 : L->nny--;
512 117977 : }
513 :
514 :
515 : /*
516 : ** Completes the execution of an interrupted C function, calling its
517 : ** continuation function.
518 : */
519 0 : static void finishCcall (lua_State *L, int status) {
520 0 : CallInfo *ci = L->ci;
521 : int n;
522 : /* must have a continuation and must be able to call it */
523 : lua_assert(ci->u.c.k != NULL && L->nny == 0);
524 : /* error status can only happen in a protected call */
525 : lua_assert((ci->callstatus & CIST_YPCALL) || status == LUA_YIELD);
526 0 : if (ci->callstatus & CIST_YPCALL) { /* was inside a pcall? */
527 0 : ci->callstatus &= ~CIST_YPCALL; /* continuation is also inside it */
528 0 : L->errfunc = ci->u.c.old_errfunc; /* with the same error function */
529 : }
530 : /* finish 'lua_callk'/'lua_pcall'; CIST_YPCALL and 'errfunc' already
531 : handled */
532 0 : adjustresults(L, ci->nresults);
533 : lua_unlock(L);
534 0 : n = (*ci->u.c.k)(L, status, ci->u.c.ctx); /* call continuation function */
535 : lua_lock(L);
536 : api_checknelems(L, n);
537 0 : luaD_poscall(L, ci, L->top - n, n); /* finish 'luaD_precall' */
538 0 : }
539 :
540 :
541 : /*
542 : ** Executes "full continuation" (everything in the stack) of a
543 : ** previously interrupted coroutine until the stack is empty (or another
544 : ** interruption long-jumps out of the loop). If the coroutine is
545 : ** recovering from an error, 'ud' points to the error status, which must
546 : ** be passed to the first continuation function (otherwise the default
547 : ** status is LUA_YIELD).
548 : */
549 0 : static void unroll (lua_State *L, void *ud) {
550 0 : if (ud != NULL) /* error status? */
551 0 : finishCcall(L, *(int *)ud); /* finish 'lua_pcallk' callee */
552 0 : while (L->ci != &L->base_ci) { /* something in the stack */
553 0 : if (!isLua(L->ci)) /* C function? */
554 0 : finishCcall(L, LUA_YIELD); /* complete its execution */
555 : else { /* Lua function */
556 0 : luaV_finishOp(L); /* finish interrupted instruction */
557 0 : luaV_execute(L); /* execute down to higher C 'boundary' */
558 : }
559 : }
560 0 : }
561 :
562 :
563 : /*
564 : ** Try to find a suspended protected call (a "recover point") for the
565 : ** given thread.
566 : */
567 0 : static CallInfo *findpcall (lua_State *L) {
568 : CallInfo *ci;
569 0 : for (ci = L->ci; ci != NULL; ci = ci->previous) { /* search for a pcall */
570 0 : if (ci->callstatus & CIST_YPCALL)
571 0 : return ci;
572 : }
573 0 : return NULL; /* no pending pcall */
574 : }
575 :
576 :
577 : /*
578 : ** Recovers from an error in a coroutine. Finds a recover point (if
579 : ** there is one) and completes the execution of the interrupted
580 : ** 'luaD_pcall'. If there is no recover point, returns zero.
581 : */
582 0 : static int recover (lua_State *L, int status) {
583 : StkId oldtop;
584 0 : CallInfo *ci = findpcall(L);
585 0 : if (ci == NULL) return 0; /* no recovery point */
586 : /* "finish" luaD_pcall */
587 0 : oldtop = restorestack(L, ci->extra);
588 0 : luaF_close(L, oldtop);
589 0 : seterrorobj(L, status, oldtop);
590 0 : L->ci = ci;
591 0 : L->allowhook = getoah(ci->callstatus); /* restore original 'allowhook' */
592 0 : L->nny = 0; /* should be zero to be yieldable */
593 0 : luaD_shrinkstack(L);
594 0 : L->errfunc = ci->u.c.old_errfunc;
595 0 : return 1; /* continue running the coroutine */
596 : }
597 :
598 :
599 : /*
600 : ** Signal an error in the call to 'lua_resume', not in the execution
601 : ** of the coroutine itself. (Such errors should not be handled by any
602 : ** coroutine error handler and should not kill the coroutine.)
603 : */
604 0 : static int resume_error (lua_State *L, const char *msg, int narg) {
605 0 : L->top -= narg; /* remove args from the stack */
606 0 : setsvalue2s(L, L->top, luaS_new(L, msg)); /* push error message */
607 0 : api_incr_top(L);
608 : lua_unlock(L);
609 0 : return LUA_ERRRUN;
610 : }
611 :
612 :
613 : /*
614 : ** Do the work for 'lua_resume' in protected mode. Most of the work
615 : ** depends on the status of the coroutine: initial state, suspended
616 : ** inside a hook, or regularly suspended (optionally with a continuation
617 : ** function), plus erroneous cases: non-suspended coroutine or dead
618 : ** coroutine.
619 : */
620 0 : static void resume (lua_State *L, void *ud) {
621 0 : int n = *(cast(int*, ud)); /* number of arguments */
622 0 : StkId firstArg = L->top - n; /* first argument */
623 0 : CallInfo *ci = L->ci;
624 0 : if (L->status == LUA_OK) { /* starting a coroutine? */
625 0 : if (!luaD_precall(L, firstArg - 1, LUA_MULTRET)) /* Lua function? */
626 0 : luaV_execute(L); /* call it */
627 : }
628 : else { /* resuming from previous yield */
629 : lua_assert(L->status == LUA_YIELD);
630 0 : L->status = LUA_OK; /* mark that it is running (again) */
631 0 : ci->func = restorestack(L, ci->extra);
632 0 : if (isLua(ci)) /* yielded inside a hook? */
633 0 : luaV_execute(L); /* just continue running Lua code */
634 : else { /* 'common' yield */
635 0 : if (ci->u.c.k != NULL) { /* does it have a continuation function? */
636 : lua_unlock(L);
637 0 : n = (*ci->u.c.k)(L, LUA_YIELD, ci->u.c.ctx); /* call continuation */
638 : lua_lock(L);
639 : api_checknelems(L, n);
640 0 : firstArg = L->top - n; /* yield results come from continuation */
641 : }
642 0 : luaD_poscall(L, ci, firstArg, n); /* finish 'luaD_precall' */
643 : }
644 0 : unroll(L, NULL); /* run continuation */
645 : }
646 0 : }
647 :
648 :
649 0 : LUA_API int lua_resume (lua_State *L, lua_State *from, int nargs) {
650 : int status;
651 0 : unsigned short oldnny = L->nny; /* save "number of non-yieldable" calls */
652 : lua_lock(L);
653 0 : if (L->status == LUA_OK) { /* may be starting a coroutine */
654 0 : if (L->ci != &L->base_ci) /* not in base level? */
655 0 : return resume_error(L, "cannot resume non-suspended coroutine", nargs);
656 : }
657 0 : else if (L->status != LUA_YIELD)
658 0 : return resume_error(L, "cannot resume dead coroutine", nargs);
659 0 : L->nCcalls = (from) ? from->nCcalls + 1 : 1;
660 0 : if (L->nCcalls >= LUAI_MAXCCALLS)
661 0 : return resume_error(L, "C stack overflow", nargs);
662 : luai_userstateresume(L, nargs);
663 0 : L->nny = 0; /* allow yields */
664 : api_checknelems(L, (L->status == LUA_OK) ? nargs + 1 : nargs);
665 0 : status = luaD_rawrunprotected(L, resume, &nargs);
666 0 : if (status == -1) /* error calling 'lua_resume'? */
667 0 : status = LUA_ERRRUN;
668 : else { /* continue running after recoverable errors */
669 0 : while (errorstatus(status) && recover(L, status)) {
670 : /* unroll continuation */
671 0 : status = luaD_rawrunprotected(L, unroll, &status);
672 : }
673 0 : if (errorstatus(status)) { /* unrecoverable error? */
674 0 : L->status = cast_byte(status); /* mark thread as 'dead' */
675 0 : seterrorobj(L, status, L->top); /* push error message */
676 0 : L->ci->top = L->top;
677 : }
678 : else lua_assert(status == L->status); /* normal end or yield */
679 : }
680 0 : L->nny = oldnny; /* restore 'nny' */
681 0 : L->nCcalls--;
682 : lua_assert(L->nCcalls == ((from) ? from->nCcalls : 0));
683 : lua_unlock(L);
684 0 : return status;
685 : }
686 :
687 :
688 0 : LUA_API int lua_isyieldable (lua_State *L) {
689 0 : return (L->nny == 0);
690 : }
691 :
692 :
693 0 : LUA_API int lua_yieldk (lua_State *L, int nresults, lua_KContext ctx,
694 : lua_KFunction k) {
695 0 : CallInfo *ci = L->ci;
696 : luai_userstateyield(L, nresults);
697 : lua_lock(L);
698 : api_checknelems(L, nresults);
699 0 : if (L->nny > 0) {
700 0 : if (L != G(L)->mainthread)
701 0 : luaG_runerror(L, "attempt to yield across a C-call boundary");
702 : else
703 0 : luaG_runerror(L, "attempt to yield from outside a coroutine");
704 : }
705 0 : L->status = LUA_YIELD;
706 0 : ci->extra = savestack(L, ci->func); /* save current 'func' */
707 0 : if (isLua(ci)) { /* inside a hook? */
708 : api_check(L, k == NULL, "hooks cannot continue after yielding");
709 : }
710 : else {
711 0 : if ((ci->u.c.k = k) != NULL) /* is there a continuation? */
712 0 : ci->u.c.ctx = ctx; /* save context */
713 0 : ci->func = L->top - nresults - 1; /* protect stack below results */
714 0 : luaD_throw(L, LUA_YIELD);
715 : }
716 : lua_assert(ci->callstatus & CIST_HOOKED); /* must be inside a hook */
717 : lua_unlock(L);
718 0 : return 0; /* return to 'luaD_hook' */
719 : }
720 :
721 :
722 118148 : int luaD_pcall (lua_State *L, Pfunc func, void *u,
723 : ptrdiff_t old_top, ptrdiff_t ef) {
724 : int status;
725 118148 : CallInfo *old_ci = L->ci;
726 118148 : lu_byte old_allowhooks = L->allowhook;
727 118148 : unsigned short old_nny = L->nny;
728 118148 : ptrdiff_t old_errfunc = L->errfunc;
729 118148 : L->errfunc = ef;
730 118148 : status = luaD_rawrunprotected(L, func, u);
731 118101 : if (status != LUA_OK) { /* an error occurred? */
732 58 : StkId oldtop = restorestack(L, old_top);
733 58 : luaF_close(L, oldtop); /* close possible pending closures */
734 58 : seterrorobj(L, status, oldtop);
735 58 : L->ci = old_ci;
736 58 : L->allowhook = old_allowhooks;
737 58 : L->nny = old_nny;
738 58 : luaD_shrinkstack(L);
739 : }
740 118101 : L->errfunc = old_errfunc;
741 118101 : return status;
742 : }
743 :
744 :
745 :
746 : /*
747 : ** Execute a protected parser.
748 : */
749 : struct SParser { /* data to 'f_parser' */
750 : ZIO *z;
751 : Mbuffer buff; /* dynamic structure used by the scanner */
752 : Dyndata dyd; /* dynamic structures used by the parser */
753 : const char *mode;
754 : const char *name;
755 : };
756 :
757 :
758 120 : static void checkmode (lua_State *L, const char *mode, const char *x) {
759 120 : if (mode && strchr(mode, x[0]) == NULL) {
760 0 : luaO_pushfstring(L,
761 : "attempt to load a %s chunk (mode is '%s')", x, mode);
762 0 : luaD_throw(L, LUA_ERRSYNTAX);
763 : }
764 120 : }
765 :
766 :
767 120 : static void f_parser (lua_State *L, void *ud) {
768 : LClosure *cl;
769 120 : struct SParser *p = cast(struct SParser *, ud);
770 120 : int c = zgetc(p->z); /* read first character */
771 : #if LUA_SUPPORT_LOAD_BINARY
772 : // support loading pre-compiled luac
773 : if (c == LUA_SIGNATURE[0]) {
774 : checkmode(L, p->mode, "binary");
775 : cl = luaU_undump(L, p->z, p->name);
776 : }
777 : else
778 : #endif
779 : {
780 120 : checkmode(L, p->mode, "text");
781 120 : cl = luaY_parser(L, p->z, &p->buff, &p->dyd, p->name, c);
782 : }
783 : lua_assert(cl->nupvalues == cl->p->sizeupvalues);
784 120 : luaF_initupvals(L, cl);
785 120 : }
786 :
787 :
788 120 : int luaD_protectedparser (lua_State *L, ZIO *z, const char *name,
789 : const char *mode) {
790 : struct SParser p;
791 : int status;
792 120 : L->nny++; /* cannot yield during parsing */
793 120 : p.z = z; p.name = name; p.mode = mode;
794 120 : p.dyd.actvar.arr = NULL; p.dyd.actvar.size = 0;
795 120 : p.dyd.gt.arr = NULL; p.dyd.gt.size = 0;
796 120 : p.dyd.label.arr = NULL; p.dyd.label.size = 0;
797 120 : luaZ_initbuffer(L, &p.buff);
798 120 : status = luaD_pcall(L, f_parser, &p, savestack(L, L->top), L->errfunc);
799 120 : luaZ_freebuffer(L, &p.buff);
800 120 : luaM_freearray(L, p.dyd.actvar.arr, p.dyd.actvar.size);
801 120 : luaM_freearray(L, p.dyd.gt.arr, p.dyd.gt.size);
802 120 : luaM_freearray(L, p.dyd.label.arr, p.dyd.label.size);
803 120 : L->nny--;
804 120 : return status;
805 : }
806 :
807 :
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