Line data Source code
1 : /*
2 : ** $Id: ldo.c,v 2.108.1.3 2013/11/08 18:22:50 roberto Exp $
3 : ** Stack and Call structure of Lua
4 : ** See Copyright Notice in lua.h
5 : */
6 :
7 :
8 : #include <setjmp.h>
9 : #include <stdlib.h>
10 : #include <string.h>
11 :
12 : #define ldo_c
13 : #define LUA_CORE
14 :
15 : #include "lua.h"
16 :
17 : #include "lapi.h"
18 : #include "ldebug.h"
19 : #include "ldo.h"
20 : #include "lfunc.h"
21 : #include "lgc.h"
22 : #include "lmem.h"
23 : #include "lobject.h"
24 : #include "lopcodes.h"
25 : #include "lparser.h"
26 : #include "lstate.h"
27 : #include "lstring.h"
28 : #include "ltable.h"
29 : #include "ltm.h"
30 : #include "lundump.h"
31 : #include "lvm.h"
32 : #include "lzio.h"
33 :
34 :
35 :
36 :
37 : /*
38 : ** {======================================================
39 : ** Error-recovery functions
40 : ** =======================================================
41 : */
42 :
43 : /*
44 : ** LUAI_THROW/LUAI_TRY define how Lua does exception handling. By
45 : ** default, Lua handles errors with exceptions when compiling as
46 : ** C++ code, with _longjmp/_setjmp when asked to use them, and with
47 : ** longjmp/setjmp otherwise.
48 : */
49 : #if !defined(LUAI_THROW)
50 :
51 : #if defined(__cplusplus) && !defined(LUA_USE_LONGJMP)
52 : /* C++ exceptions */
53 : #define LUAI_THROW(L,c) throw(c)
54 : #define LUAI_TRY(L,c,a) \
55 : try { a } catch(...) { if ((c)->status == 0) (c)->status = -1; }
56 : #define luai_jmpbuf int /* dummy variable */
57 :
58 : #elif defined(LUA_USE_ULONGJMP)
59 : /* in Unix, try _longjmp/_setjmp (more efficient) */
60 : #define LUAI_THROW(L,c) _longjmp((c)->b, 1)
61 : #define LUAI_TRY(L,c,a) if (_setjmp((c)->b) == 0) { a }
62 : #define luai_jmpbuf jmp_buf
63 :
64 : #else
65 : /* default handling with long jumps */
66 : #define LUAI_THROW(L,c) longjmp((c)->b, 1)
67 : #define LUAI_TRY(L,c,a) if (setjmp((c)->b) == 0) { a }
68 : #define luai_jmpbuf jmp_buf
69 :
70 : #endif
71 :
72 : #endif
73 :
74 :
75 :
76 : /* chain list of long jump buffers */
77 : struct lua_longjmp {
78 : struct lua_longjmp *previous;
79 : luai_jmpbuf b;
80 : volatile int status; /* error code */
81 : };
82 :
83 :
84 396 : static void seterrorobj (lua_State *L, int errcode, StkId oldtop) {
85 396 : switch (errcode) {
86 0 : case LUA_ERRMEM: { /* memory error? */
87 0 : setsvalue2s(L, oldtop, G(L)->memerrmsg); /* reuse preregistered msg. */
88 0 : break;
89 : }
90 1 : case LUA_ERRERR: {
91 1 : setsvalue2s(L, oldtop, luaS_newliteral(L, "error in error handling"));
92 1 : break;
93 : }
94 395 : default: {
95 395 : setobjs2s(L, oldtop, L->top - 1); /* error message on current top */
96 395 : break;
97 : }
98 : }
99 396 : L->top = oldtop + 1;
100 396 : }
101 :
102 :
103 6349 : l_noret luaD_throw (lua_State *L, int errcode) {
104 6349 : if (L->errorJmp) { /* thread has an error handler? */
105 6349 : L->errorJmp->status = errcode; /* set status */
106 6349 : LUAI_THROW(L, L->errorJmp); /* jump to it */
107 : }
108 : else { /* thread has no error handler */
109 0 : L->status = cast_byte(errcode); /* mark it as dead */
110 0 : if (G(L)->mainthread->errorJmp) { /* main thread has a handler? */
111 0 : setobjs2s(L, G(L)->mainthread->top++, L->top - 1); /* copy error obj. */
112 0 : luaD_throw(G(L)->mainthread, errcode); /* re-throw in main thread */
113 : }
114 : else { /* no handler at all; abort */
115 0 : if (G(L)->panic) { /* panic function? */
116 : lua_unlock(L);
117 0 : G(L)->panic(L); /* call it (last chance to jump out) */
118 : }
119 0 : abort();
120 : }
121 : }
122 : }
123 :
124 :
125 7878 : int luaD_rawrunprotected (lua_State *L, Pfunc f, void *ud) {
126 7878 : unsigned short oldnCcalls = L->nCcalls;
127 : struct lua_longjmp lj;
128 7878 : lj.status = LUA_OK;
129 7878 : lj.previous = L->errorJmp; /* chain new error handler */
130 7878 : L->errorJmp = &lj;
131 7878 : LUAI_TRY(L, &lj,
132 : (*f)(L, ud);
133 : );
134 7851 : L->errorJmp = lj.previous; /* restore old error handler */
135 7851 : L->nCcalls = oldnCcalls;
136 7851 : return lj.status;
137 : }
138 :
139 : /* }====================================================== */
140 :
141 :
142 941 : static void correctstack (lua_State *L, TValue *oldstack) {
143 : CallInfo *ci;
144 : GCObject *up;
145 941 : L->top = (L->top - oldstack) + L->stack;
146 2731 : for (up = L->openupval; up != NULL; up = up->gch.next)
147 1790 : gco2uv(up)->v = (gco2uv(up)->v - oldstack) + L->stack;
148 5798 : for (ci = L->ci; ci != NULL; ci = ci->previous) {
149 4857 : ci->top = (ci->top - oldstack) + L->stack;
150 4857 : ci->func = (ci->func - oldstack) + L->stack;
151 4857 : if (isLua(ci))
152 2462 : ci->u.l.base = (ci->u.l.base - oldstack) + L->stack;
153 : }
154 941 : }
155 :
156 :
157 : /* some space for error handling */
158 : #define ERRORSTACKSIZE (LUAI_MAXSTACK + 200)
159 :
160 :
161 941 : void luaD_reallocstack (lua_State *L, int newsize) {
162 941 : TValue *oldstack = L->stack;
163 941 : int lim = L->stacksize;
164 : lua_assert(newsize <= LUAI_MAXSTACK || newsize == ERRORSTACKSIZE);
165 : lua_assert(L->stack_last - L->stack == L->stacksize - EXTRA_STACK);
166 941 : luaM_reallocvector(L, L->stack, L->stacksize, newsize, TValue);
167 24871 : for (; lim < newsize; lim++)
168 23930 : setnilvalue(L->stack + lim); /* erase new segment */
169 941 : L->stacksize = newsize;
170 941 : L->stack_last = L->stack + newsize - EXTRA_STACK;
171 941 : correctstack(L, oldstack);
172 941 : }
173 :
174 :
175 432 : void luaD_growstack (lua_State *L, int n) {
176 432 : int size = L->stacksize;
177 432 : if (size > LUAI_MAXSTACK) /* error after extra size? */
178 0 : luaD_throw(L, LUA_ERRERR);
179 : else {
180 432 : int needed = cast_int(L->top - L->stack) + n + EXTRA_STACK;
181 432 : int newsize = 2 * size;
182 432 : if (newsize > LUAI_MAXSTACK) newsize = LUAI_MAXSTACK;
183 432 : if (newsize < needed) newsize = needed;
184 432 : if (newsize > LUAI_MAXSTACK) { /* stack overflow? */
185 0 : luaD_reallocstack(L, ERRORSTACKSIZE);
186 0 : luaG_runerror(L, "stack overflow");
187 : }
188 : else
189 432 : luaD_reallocstack(L, newsize);
190 : }
191 432 : }
192 :
193 :
194 596 : static int stackinuse (lua_State *L) {
195 : CallInfo *ci;
196 596 : StkId lim = L->top;
197 3312 : for (ci = L->ci; ci != NULL; ci = ci->previous) {
198 : lua_assert(ci->top <= L->stack_last);
199 2716 : if (lim < ci->top) lim = ci->top;
200 : }
201 596 : return cast_int(lim - L->stack) + 1; /* part of stack in use */
202 : }
203 :
204 :
205 596 : void luaD_shrinkstack (lua_State *L) {
206 596 : int inuse = stackinuse(L);
207 596 : int goodsize = inuse + (inuse / 8) + 2*EXTRA_STACK;
208 596 : if (goodsize > LUAI_MAXSTACK) goodsize = LUAI_MAXSTACK;
209 596 : if (inuse > LUAI_MAXSTACK || /* handling stack overflow? */
210 596 : goodsize >= L->stacksize) /* would grow instead of shrink? */
211 : condmovestack(L); /* don't change stack (change only for debugging) */
212 : else
213 509 : luaD_reallocstack(L, goodsize); /* shrink it */
214 596 : }
215 :
216 :
217 464 : void luaD_hook (lua_State *L, int event, int line) {
218 464 : lua_Hook hook = L->hook;
219 464 : if (hook && L->allowhook) {
220 227 : CallInfo *ci = L->ci;
221 227 : ptrdiff_t top = savestack(L, L->top);
222 227 : ptrdiff_t ci_top = savestack(L, ci->top);
223 : lua_Debug ar;
224 227 : ar.event = event;
225 227 : ar.currentline = line;
226 227 : ar.i_ci = ci;
227 227 : luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */
228 227 : ci->top = L->top + LUA_MINSTACK;
229 : lua_assert(ci->top <= L->stack_last);
230 227 : L->allowhook = 0; /* cannot call hooks inside a hook */
231 227 : ci->callstatus |= CIST_HOOKED;
232 : lua_unlock(L);
233 227 : (*hook)(L, &ar);
234 : lua_lock(L);
235 : lua_assert(!L->allowhook);
236 227 : L->allowhook = 1;
237 227 : ci->top = restorestack(L, ci_top);
238 227 : L->top = restorestack(L, top);
239 227 : ci->callstatus &= ~CIST_HOOKED;
240 : }
241 464 : }
242 :
243 :
244 290 : static void callhook (lua_State *L, CallInfo *ci) {
245 290 : int hook = LUA_HOOKCALL;
246 290 : ci->u.l.savedpc++; /* hooks assume 'pc' is already incremented */
247 290 : if (isLua(ci->previous) &&
248 148 : GET_OPCODE(*(ci->previous->u.l.savedpc - 1)) == OP_TAILCALL) {
249 0 : ci->callstatus |= CIST_TAIL;
250 0 : hook = LUA_HOOKTAILCALL;
251 : }
252 290 : luaD_hook(L, hook, -1);
253 290 : ci->u.l.savedpc--; /* correct 'pc' */
254 290 : }
255 :
256 :
257 466 : static StkId adjust_varargs (lua_State *L, Proto *p, int actual) {
258 : int i;
259 466 : int nfixargs = p->numparams;
260 : StkId base, fixed;
261 : lua_assert(actual >= nfixargs);
262 : /* move fixed parameters to final position */
263 466 : luaD_checkstack(L, p->maxstacksize); /* check again for new 'base' */
264 466 : fixed = L->top - actual; /* first fixed argument */
265 466 : base = L->top; /* final position of first argument */
266 487 : for (i=0; i<nfixargs; i++) {
267 21 : setobjs2s(L, L->top++, fixed + i);
268 21 : setnilvalue(fixed + i);
269 : }
270 466 : return base;
271 : }
272 :
273 :
274 7 : static StkId tryfuncTM (lua_State *L, StkId func) {
275 7 : const TValue *tm = luaT_gettmbyobj(L, func, TM_CALL);
276 : StkId p;
277 7 : ptrdiff_t funcr = savestack(L, func);
278 7 : if (!ttisfunction(tm))
279 3 : luaG_typeerror(L, func, "call");
280 : /* Open a hole inside the stack at `func' */
281 12 : for (p = L->top; p > func; p--) setobjs2s(L, p, p-1);
282 4 : incr_top(L);
283 4 : func = restorestack(L, funcr); /* previous call may change stack */
284 4 : setobj2s(L, func, tm); /* tag method is the new function to be called */
285 4 : return func;
286 : }
287 :
288 :
289 :
290 : #define next_ci(L) (L->ci = (L->ci->next ? L->ci->next : luaE_extendCI(L)))
291 :
292 :
293 : /*
294 : ** returns true if function has been executed (C function)
295 : */
296 129484 : int luaD_precall (lua_State *L, StkId func, int nresults) {
297 : lua_CFunction f;
298 : CallInfo *ci;
299 : int n; /* number of arguments (Lua) or returns (C) */
300 129484 : ptrdiff_t funcr = savestack(L, func);
301 129484 : switch (ttype(func)) {
302 104878 : case LUA_TLCF: /* light C function */
303 104878 : f = fvalue(func);
304 104878 : goto Cfunc;
305 761 : case LUA_TCCL: { /* C closure */
306 761 : f = clCvalue(func)->f;
307 105639 : Cfunc:
308 105639 : luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */
309 105639 : ci = next_ci(L); /* now 'enter' new function */
310 105639 : ci->nresults = nresults;
311 105639 : ci->func = restorestack(L, funcr);
312 105639 : ci->top = L->top + LUA_MINSTACK;
313 : lua_assert(ci->top <= L->stack_last);
314 105639 : ci->callstatus = 0;
315 105639 : luaC_checkGC(L); /* stack grow uses memory */
316 105639 : if (L->hookmask & LUA_MASKCALL)
317 142 : luaD_hook(L, LUA_HOOKCALL, -1);
318 : lua_unlock(L);
319 105639 : n = (*f)(L); /* do the actual call */
320 : lua_lock(L);
321 : api_checknelems(L, n);
322 99496 : luaD_poscall(L, L->top - n);
323 99496 : return 1;
324 : }
325 23838 : case LUA_TLCL: { /* Lua function: prepare its call */
326 : StkId base;
327 23838 : Proto *p = clLvalue(func)->p;
328 23838 : n = cast_int(L->top - func) - 1; /* number of real arguments */
329 23838 : luaD_checkstack(L, p->maxstacksize);
330 24597 : for (; n < p->numparams; n++)
331 759 : setnilvalue(L->top++); /* complete missing arguments */
332 23838 : if (!p->is_vararg) {
333 23372 : func = restorestack(L, funcr);
334 23372 : base = func + 1;
335 : }
336 : else {
337 466 : base = adjust_varargs(L, p, n);
338 466 : func = restorestack(L, funcr); /* previous call can change stack */
339 : }
340 23838 : ci = next_ci(L); /* now 'enter' new function */
341 23838 : ci->nresults = nresults;
342 23838 : ci->func = func;
343 23838 : ci->u.l.base = base;
344 23838 : ci->top = base + p->maxstacksize;
345 : lua_assert(ci->top <= L->stack_last);
346 23838 : ci->u.l.savedpc = p->code; /* starting point */
347 23838 : ci->callstatus = CIST_LUA;
348 23838 : L->top = ci->top;
349 23838 : luaC_checkGC(L); /* stack grow uses memory */
350 23838 : if (L->hookmask & LUA_MASKCALL)
351 290 : callhook(L, ci);
352 23838 : return 0;
353 : }
354 7 : default: { /* not a function */
355 7 : func = tryfuncTM(L, func); /* retry with 'function' tag method */
356 4 : return luaD_precall(L, func, nresults); /* now it must be a function */
357 : }
358 : }
359 : }
360 :
361 :
362 127814 : int luaD_poscall (lua_State *L, StkId firstResult) {
363 : StkId res;
364 : int wanted, i;
365 127814 : CallInfo *ci = L->ci;
366 127814 : if (L->hookmask & (LUA_MASKRET | LUA_MASKLINE)) {
367 0 : if (L->hookmask & LUA_MASKRET) {
368 0 : ptrdiff_t fr = savestack(L, firstResult); /* hook may change stack */
369 0 : luaD_hook(L, LUA_HOOKRET, -1);
370 0 : firstResult = restorestack(L, fr);
371 : }
372 0 : L->oldpc = ci->previous->u.l.savedpc; /* 'oldpc' for caller function */
373 : }
374 127814 : res = ci->func; /* res == final position of 1st result */
375 127814 : wanted = ci->nresults;
376 127814 : L->ci = ci = ci->previous; /* back to caller */
377 : /* move results to correct place */
378 279685 : for (i = wanted; i != 0 && firstResult < L->top; i--)
379 151871 : setobjs2s(L, res++, firstResult++);
380 134496 : while (i-- > 0)
381 6682 : setnilvalue(res++);
382 127814 : L->top = res;
383 127814 : return (wanted - LUA_MULTRET); /* 0 iff wanted == LUA_MULTRET */
384 : }
385 :
386 :
387 : /*
388 : ** Call a function (C or Lua). The function to be called is at *func.
389 : ** The arguments are on the stack, right after the function.
390 : ** When returns, all the results are on the stack, starting at the original
391 : ** function position.
392 : */
393 57361 : void luaD_call (lua_State *L, StkId func, int nResults, int allowyield) {
394 57361 : if (++L->nCcalls >= LUAI_MAXCCALLS) {
395 0 : if (L->nCcalls == LUAI_MAXCCALLS)
396 0 : luaG_runerror(L, "C stack overflow");
397 0 : else if (L->nCcalls >= (LUAI_MAXCCALLS + (LUAI_MAXCCALLS>>3)))
398 0 : luaD_throw(L, LUA_ERRERR); /* error while handing stack error */
399 : }
400 57361 : if (!allowyield) L->nny++;
401 57361 : if (!luaD_precall(L, func, nResults)) /* is a Lua function? */
402 7016 : luaV_execute(L); /* call it */
403 56979 : if (!allowyield) L->nny--;
404 56979 : L->nCcalls--;
405 56979 : }
406 :
407 :
408 2 : static void finishCcall (lua_State *L) {
409 2 : CallInfo *ci = L->ci;
410 : int n;
411 : lua_assert(ci->u.c.k != NULL); /* must have a continuation */
412 : lua_assert(L->nny == 0);
413 2 : if (ci->callstatus & CIST_YPCALL) { /* was inside a pcall? */
414 2 : ci->callstatus &= ~CIST_YPCALL; /* finish 'lua_pcall' */
415 2 : L->errfunc = ci->u.c.old_errfunc;
416 : }
417 : /* finish 'lua_callk'/'lua_pcall' */
418 2 : adjustresults(L, ci->nresults);
419 : /* call continuation function */
420 2 : if (!(ci->callstatus & CIST_STAT)) /* no call status? */
421 2 : ci->u.c.status = LUA_YIELD; /* 'default' status */
422 : lua_assert(ci->u.c.status != LUA_OK);
423 2 : ci->callstatus = (ci->callstatus & ~(CIST_YPCALL | CIST_STAT)) | CIST_YIELDED;
424 : lua_unlock(L);
425 2 : n = (*ci->u.c.k)(L);
426 : lua_lock(L);
427 : api_checknelems(L, n);
428 : /* finish 'luaD_precall' */
429 2 : luaD_poscall(L, L->top - n);
430 2 : }
431 :
432 :
433 5950 : static void unroll (lua_State *L, void *ud) {
434 : UNUSED(ud);
435 : for (;;) {
436 5969 : if (L->ci == &L->base_ci) /* stack is empty? */
437 13 : return; /* coroutine finished normally */
438 5956 : if (!isLua(L->ci)) /* C function? */
439 2 : finishCcall(L);
440 : else { /* Lua function */
441 5954 : luaV_finishOp(L); /* finish interrupted instruction */
442 5954 : luaV_execute(L); /* execute down to higher C 'boundary' */
443 : }
444 : }
445 : }
446 :
447 :
448 : /*
449 : ** check whether thread has a suspended protected call
450 : */
451 2 : static CallInfo *findpcall (lua_State *L) {
452 : CallInfo *ci;
453 8 : for (ci = L->ci; ci != NULL; ci = ci->previous) { /* search for a pcall */
454 6 : if (ci->callstatus & CIST_YPCALL)
455 0 : return ci;
456 : }
457 2 : return NULL; /* no pending pcall */
458 : }
459 :
460 :
461 2 : static int recover (lua_State *L, int status) {
462 : StkId oldtop;
463 2 : CallInfo *ci = findpcall(L);
464 2 : if (ci == NULL) return 0; /* no recovery point */
465 : /* "finish" luaD_pcall */
466 0 : oldtop = restorestack(L, ci->extra);
467 0 : luaF_close(L, oldtop);
468 0 : seterrorobj(L, status, oldtop);
469 0 : L->ci = ci;
470 0 : L->allowhook = ci->u.c.old_allowhook;
471 0 : L->nny = 0; /* should be zero to be yieldable */
472 0 : luaD_shrinkstack(L);
473 0 : L->errfunc = ci->u.c.old_errfunc;
474 0 : ci->callstatus |= CIST_STAT; /* call has error status */
475 0 : ci->u.c.status = status; /* (here it is) */
476 0 : return 1; /* continue running the coroutine */
477 : }
478 :
479 :
480 : /*
481 : ** signal an error in the call to 'resume', not in the execution of the
482 : ** coroutine itself. (Such errors should not be handled by any coroutine
483 : ** error handler and should not kill the coroutine.)
484 : */
485 0 : static l_noret resume_error (lua_State *L, const char *msg, StkId firstArg) {
486 0 : L->top = firstArg; /* remove args from the stack */
487 0 : setsvalue2s(L, L->top, luaS_new(L, msg)); /* push error message */
488 0 : api_incr_top(L);
489 0 : luaD_throw(L, -1); /* jump back to 'lua_resume' */
490 : }
491 :
492 :
493 : /*
494 : ** do the work for 'lua_resume' in protected mode
495 : */
496 5970 : static void resume (lua_State *L, void *ud) {
497 5970 : int nCcalls = L->nCcalls;
498 5970 : StkId firstArg = cast(StkId, ud);
499 5970 : CallInfo *ci = L->ci;
500 5970 : if (nCcalls >= LUAI_MAXCCALLS)
501 0 : resume_error(L, "C stack overflow", firstArg);
502 5970 : if (L->status == LUA_OK) { /* may be starting a coroutine */
503 20 : if (ci != &L->base_ci) /* not in base level? */
504 0 : resume_error(L, "cannot resume non-suspended coroutine", firstArg);
505 : /* coroutine is in base level; start running it */
506 20 : if (!luaD_precall(L, firstArg - 1, LUA_MULTRET)) /* Lua function? */
507 20 : luaV_execute(L); /* call it */
508 : }
509 5950 : else if (L->status != LUA_YIELD)
510 0 : resume_error(L, "cannot resume dead coroutine", firstArg);
511 : else { /* resuming from previous yield */
512 5950 : L->status = LUA_OK;
513 5950 : ci->func = restorestack(L, ci->extra);
514 5950 : if (isLua(ci)) /* yielded inside a hook? */
515 0 : luaV_execute(L); /* just continue running Lua code */
516 : else { /* 'common' yield */
517 5950 : if (ci->u.c.k != NULL) { /* does it have a continuation? */
518 : int n;
519 0 : ci->u.c.status = LUA_YIELD; /* 'default' status */
520 0 : ci->callstatus |= CIST_YIELDED;
521 : lua_unlock(L);
522 0 : n = (*ci->u.c.k)(L); /* call continuation */
523 : lua_lock(L);
524 : api_checknelems(L, n);
525 0 : firstArg = L->top - n; /* yield results come from continuation */
526 : }
527 5950 : luaD_poscall(L, firstArg); /* finish 'luaD_precall' */
528 : }
529 5950 : unroll(L, NULL);
530 : }
531 : lua_assert(nCcalls == L->nCcalls);
532 15 : }
533 :
534 :
535 5970 : LUA_API int lua_resume (lua_State *L, lua_State *from, int nargs) {
536 : int status;
537 5970 : int oldnny = L->nny; /* save 'nny' */
538 : lua_lock(L);
539 : luai_userstateresume(L, nargs);
540 5970 : L->nCcalls = (from) ? from->nCcalls + 1 : 1;
541 5970 : L->nny = 0; /* allow yields */
542 : api_checknelems(L, (L->status == LUA_OK) ? nargs + 1 : nargs);
543 5970 : status = luaD_rawrunprotected(L, resume, L->top - nargs);
544 5970 : if (status == -1) /* error calling 'lua_resume'? */
545 0 : status = LUA_ERRRUN;
546 : else { /* yield or regular error */
547 5970 : while (status != LUA_OK && status != LUA_YIELD) { /* error? */
548 2 : if (recover(L, status)) /* recover point? */
549 0 : status = luaD_rawrunprotected(L, unroll, NULL); /* run continuation */
550 : else { /* unrecoverable error */
551 2 : L->status = cast_byte(status); /* mark thread as `dead' */
552 2 : seterrorobj(L, status, L->top);
553 2 : L->ci->top = L->top;
554 2 : break;
555 : }
556 : }
557 : lua_assert(status == L->status);
558 : }
559 5970 : L->nny = oldnny; /* restore 'nny' */
560 5970 : L->nCcalls--;
561 : lua_assert(L->nCcalls == ((from) ? from->nCcalls : 0));
562 : lua_unlock(L);
563 5970 : return status;
564 : }
565 :
566 :
567 5954 : LUA_API int lua_yieldk (lua_State *L, int nresults, int ctx, lua_CFunction k) {
568 5954 : CallInfo *ci = L->ci;
569 : luai_userstateyield(L, nresults);
570 : lua_lock(L);
571 : api_checknelems(L, nresults);
572 5954 : if (L->nny > 0) {
573 1 : if (L != G(L)->mainthread)
574 0 : luaG_runerror(L, "attempt to yield across a C-call boundary");
575 : else
576 1 : luaG_runerror(L, "attempt to yield from outside a coroutine");
577 : }
578 5953 : L->status = LUA_YIELD;
579 5953 : ci->extra = savestack(L, ci->func); /* save current 'func' */
580 5953 : if (isLua(ci)) { /* inside a hook? */
581 : api_check(L, k == NULL, "hooks cannot continue after yielding");
582 : }
583 : else {
584 5953 : if ((ci->u.c.k = k) != NULL) /* is there a continuation? */
585 0 : ci->u.c.ctx = ctx; /* save context */
586 5953 : ci->func = L->top - nresults - 1; /* protect stack below results */
587 5953 : luaD_throw(L, LUA_YIELD);
588 : }
589 : lua_assert(ci->callstatus & CIST_HOOKED); /* must be inside a hook */
590 : lua_unlock(L);
591 0 : return 0; /* return to 'luaD_hook' */
592 : }
593 :
594 :
595 1789 : int luaD_pcall (lua_State *L, Pfunc func, void *u,
596 : ptrdiff_t old_top, ptrdiff_t ef) {
597 : int status;
598 1789 : CallInfo *old_ci = L->ci;
599 1789 : lu_byte old_allowhooks = L->allowhook;
600 1789 : unsigned short old_nny = L->nny;
601 1789 : ptrdiff_t old_errfunc = L->errfunc;
602 1789 : L->errfunc = ef;
603 1789 : status = luaD_rawrunprotected(L, func, u);
604 1762 : if (status != LUA_OK) { /* an error occurred? */
605 394 : StkId oldtop = restorestack(L, old_top);
606 394 : luaF_close(L, oldtop); /* close possible pending closures */
607 394 : seterrorobj(L, status, oldtop);
608 394 : L->ci = old_ci;
609 394 : L->allowhook = old_allowhooks;
610 394 : L->nny = old_nny;
611 394 : luaD_shrinkstack(L);
612 : }
613 1762 : L->errfunc = old_errfunc;
614 1762 : return status;
615 : }
616 :
617 :
618 :
619 : /*
620 : ** Execute a protected parser.
621 : */
622 : struct SParser { /* data to `f_parser' */
623 : ZIO *z;
624 : Mbuffer buff; /* dynamic structure used by the scanner */
625 : Dyndata dyd; /* dynamic structures used by the parser */
626 : const char *mode;
627 : const char *name;
628 : };
629 :
630 :
631 512 : static void checkmode (lua_State *L, const char *mode, const char *x) {
632 512 : if (mode && strchr(mode, x[0]) == NULL) {
633 3 : luaO_pushfstring(L,
634 : "attempt to load a %s chunk (mode is " LUA_QS ")", x, mode);
635 3 : luaD_throw(L, LUA_ERRSYNTAX);
636 : }
637 509 : }
638 :
639 :
640 513 : static void f_parser (lua_State *L, void *ud) {
641 : int i;
642 : Closure *cl;
643 513 : struct SParser *p = cast(struct SParser *, ud);
644 513 : int c = zgetc(p->z); /* read first character */
645 512 : if (c == LUA_SIGNATURE[0]) {
646 15 : checkmode(L, p->mode, "binary");
647 14 : cl = luaU_undump(L, p->z, &p->buff, p->name);
648 : }
649 : else {
650 497 : checkmode(L, p->mode, "text");
651 495 : cl = luaY_parser(L, p->z, &p->buff, &p->dyd, p->name, c);
652 : }
653 : lua_assert(cl->l.nupvalues == cl->l.p->sizeupvalues);
654 929 : for (i = 0; i < cl->l.nupvalues; i++) { /* initialize upvalues */
655 464 : UpVal *up = luaF_newupval(L);
656 464 : cl->l.upvals[i] = up;
657 464 : luaC_objbarrier(L, cl, up);
658 : }
659 465 : }
660 :
661 :
662 513 : int luaD_protectedparser (lua_State *L, ZIO *z, const char *name,
663 : const char *mode) {
664 : struct SParser p;
665 : int status;
666 513 : L->nny++; /* cannot yield during parsing */
667 513 : p.z = z; p.name = name; p.mode = mode;
668 513 : p.dyd.actvar.arr = NULL; p.dyd.actvar.size = 0;
669 513 : p.dyd.gt.arr = NULL; p.dyd.gt.size = 0;
670 513 : p.dyd.label.arr = NULL; p.dyd.label.size = 0;
671 513 : luaZ_initbuffer(L, &p.buff);
672 513 : status = luaD_pcall(L, f_parser, &p, savestack(L, L->top), L->errfunc);
673 513 : luaZ_freebuffer(L, &p.buff);
674 513 : luaM_freearray(L, p.dyd.actvar.arr, p.dyd.actvar.size);
675 513 : luaM_freearray(L, p.dyd.gt.arr, p.dyd.gt.size);
676 513 : luaM_freearray(L, p.dyd.label.arr, p.dyd.label.size);
677 513 : L->nny--;
678 513 : return status;
679 : }
680 :
681 :
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