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#define ldo_c 9#define LUA_CORE 10 11#include <sys/lua/lua.h> 12#include <sys/asm_linkage.h> 13 14#include "lapi.h" 15#include "ldebug.h" 16#include "ldo.h" 17#include "lfunc.h" 18#include "lgc.h" 19#include "lmem.h" 20#include "lobject.h" 21#include "lopcodes.h" 22#include "lparser.h" 23#include "lstate.h" 24#include "lstring.h" 25#include "ltable.h" 26#include "ltm.h" 27#include "lvm.h" 28#include "lzio.h" 29 30 31/* Return the number of bytes available on the stack. */ 32#if defined (_KERNEL) && defined(__linux__) 33#include <asm/current.h> 34static intptr_t stack_remaining(void) { 35 intptr_t local; 36 local = (intptr_t)&local - (intptr_t)current->stack; 37 return local; 38} 39#elif defined (_KERNEL) && defined(__FreeBSD__) 40#include <sys/pcpu.h> 41static intptr_t stack_remaining(void) { 42 intptr_t local; 43 local = (intptr_t)&local - (intptr_t)curthread->td_kstack; 44 return local; 45} 46#else 47static intptr_t stack_remaining(void) { 48 return INTPTR_MAX; 49} 50#endif 51 52/* 53** {====================================================== 54** Error-recovery functions 55** ======================================================= 56*/ 57 58/* 59** LUAI_THROW/LUAI_TRY define how Lua does exception handling. By 60** default, Lua handles errors with exceptions when compiling as 61** C++ code, with _longjmp/_setjmp when asked to use them, and with 62** longjmp/setjmp otherwise. 63*/ 64#if !defined(LUAI_THROW) 65 66#ifdef _KERNEL 67 68#ifdef __linux__ 69#if defined(__i386__) 70#define JMP_BUF_CNT 6 71#elif defined(__x86_64__) 72#define JMP_BUF_CNT 8 73#elif defined(__sparc__) && defined(__arch64__) 74#define JMP_BUF_CNT 6 75#elif defined(__powerpc__) 76#define JMP_BUF_CNT 26 77#elif defined(__aarch64__) 78#define JMP_BUF_CNT 64 79#elif defined(__arm__) 80#define JMP_BUF_CNT 65 81#elif defined(__mips__) 82#define JMP_BUF_CNT 12 83#elif defined(__s390x__) 84#define JMP_BUF_CNT 18 85#elif defined(__riscv) 86#define JMP_BUF_CNT 64 87#elif defined(__loongarch_lp64) 88#define JMP_BUF_CNT 64 89#else 90#define JMP_BUF_CNT 1 91#endif 92 93typedef struct _label_t { long long unsigned val[JMP_BUF_CNT]; } label_t; 94 95int ASMABI setjmp(label_t *) __attribute__ ((__nothrow__)); 96extern __attribute__((noreturn)) void ASMABI longjmp(label_t *); 97 98#define LUAI_THROW(L,c) longjmp(&(c)->b) 99#define LUAI_TRY(L,c,a) if (setjmp(&(c)->b) == 0) { a } 100#define luai_jmpbuf label_t 101 102/* unsupported arches will build but not be able to run lua programs */ 103#if JMP_BUF_CNT == 1 104int setjmp (label_t *buf) { 105 return 1; 106} 107 108void longjmp (label_t * buf) { 109 for (;;); 110} 111#endif 112#else 113#define LUAI_THROW(L,c) longjmp((c)->b, 1) 114#define LUAI_TRY(L,c,a) if (setjmp((c)->b) == 0) { a } 115#define luai_jmpbuf jmp_buf 116#endif 117 118#else /* _KERNEL */ 119 120#if defined(__cplusplus) && !defined(LUA_USE_LONGJMP) 121/* C++ exceptions */ 122#define LUAI_THROW(L,c) throw(c) 123#define LUAI_TRY(L,c,a) \ 124 try { a } catch(...) { if ((c)->status == 0) (c)->status = -1; } 125#define luai_jmpbuf int /* dummy variable */ 126 127#elif defined(LUA_USE_ULONGJMP) 128/* in Unix, try _longjmp/_setjmp (more efficient) */ 129#define LUAI_THROW(L,c) _longjmp((c)->b, 1) 130#define LUAI_TRY(L,c,a) if (_setjmp((c)->b) == 0) { a } 131#define luai_jmpbuf jmp_buf 132 133#else 134/* default handling with long jumps */ 135#define LUAI_THROW(L,c) longjmp((c)->b, 1) 136#define LUAI_TRY(L,c,a) if (setjmp((c)->b) == 0) { a } 137#define luai_jmpbuf jmp_buf 138 139#endif 140 141#endif /* _KERNEL */ 142 143#endif /* LUAI_THROW */ 144 145 146/* chain list of long jump buffers */ 147struct lua_longjmp { 148 struct lua_longjmp *previous; 149 luai_jmpbuf b; 150 volatile int status; /* error code */ 151}; 152 153 154static void seterrorobj (lua_State *L, int errcode, StkId oldtop) { 155 switch (errcode) { 156 case LUA_ERRMEM: { /* memory error? */ 157 setsvalue2s(L, oldtop, G(L)->memerrmsg); /* reuse preregistered msg. */ 158 break; 159 } 160 case LUA_ERRERR: { 161 setsvalue2s(L, oldtop, luaS_newliteral(L, "error in error handling")); 162 break; 163 } 164 default: { 165 setobjs2s(L, oldtop, L->top - 1); /* error message on current top */ 166 break; 167 } 168 } 169 L->top = oldtop + 1; 170} 171 172/* 173 * Silence infinite recursion warning which was added to -Wall in gcc 12.1 174 */ 175#if defined(__GNUC__) && !defined(__clang__) && \ 176 defined(HAVE_KERNEL_INFINITE_RECURSION) 177#pragma GCC diagnostic push 178#pragma GCC diagnostic ignored "-Winfinite-recursion" 179#endif 180 181l_noret luaD_throw (lua_State *L, int errcode) { 182 if (L->errorJmp) { /* thread has an error handler? */ 183 L->errorJmp->status = errcode; /* set status */ 184 LUAI_THROW(L, L->errorJmp); /* jump to it */ 185 } 186 else { /* thread has no error handler */ 187 L->status = cast_byte(errcode); /* mark it as dead */ 188 if (G(L)->mainthread->errorJmp) { /* main thread has a handler? */ 189 setobjs2s(L, G(L)->mainthread->top++, L->top - 1); /* copy error obj. */ 190 luaD_throw(G(L)->mainthread, errcode); /* re-throw in main thread */ 191 } 192 else { /* no handler at all; abort */ 193 if (G(L)->panic) { /* panic function? */ 194 lua_unlock(L); 195 G(L)->panic(L); /* call it (last chance to jump out) */ 196 } 197 panic("no error handler"); 198 } 199 } 200} 201 202#if defined(__GNUC__) && !defined(__clang__) && \ 203 defined(HAVE_INFINITE_RECURSION) 204#pragma GCC diagnostic pop 205#endif 206 207 208int luaD_rawrunprotected (lua_State *L, Pfunc f, void *ud) { 209 unsigned short oldnCcalls = L->nCcalls; 210 struct lua_longjmp lj; 211 lj.status = LUA_OK; 212 lj.previous = L->errorJmp; /* chain new error handler */ 213 L->errorJmp = &lj; 214 LUAI_TRY(L, &lj, 215 (*f)(L, ud); 216 ); 217 L->errorJmp = lj.previous; /* restore old error handler */ 218 L->nCcalls = oldnCcalls; 219 return lj.status; 220} 221 222/* }====================================================== */ 223 224 225static void correctstack (lua_State *L, TValue *oldstack) { 226 CallInfo *ci; 227 GCObject *up; 228 L->top = (L->top - oldstack) + L->stack; 229 for (up = L->openupval; up != NULL; up = up->gch.next) 230 gco2uv(up)->v = (gco2uv(up)->v - oldstack) + L->stack; 231 for (ci = L->ci; ci != NULL; ci = ci->previous) { 232 ci->top = (ci->top - oldstack) + L->stack; 233 ci->func = (ci->func - oldstack) + L->stack; 234 if (isLua(ci)) 235 ci->u.l.base = (ci->u.l.base - oldstack) + L->stack; 236 } 237} 238 239 240/* some space for error handling */ 241#define ERRORSTACKSIZE (LUAI_MAXSTACK + 200) 242 243 244void luaD_reallocstack (lua_State *L, int newsize) { 245 TValue *oldstack = L->stack; 246 int lim = L->stacksize; 247 lua_assert(newsize <= LUAI_MAXSTACK || newsize == ERRORSTACKSIZE); 248 lua_assert(L->stack_last - L->stack == L->stacksize - EXTRA_STACK); 249 luaM_reallocvector(L, L->stack, L->stacksize, newsize, TValue); 250 for (; lim < newsize; lim++) 251 setnilvalue(L->stack + lim); /* erase new segment */ 252 L->stacksize = newsize; 253 L->stack_last = L->stack + newsize - EXTRA_STACK; 254 correctstack(L, oldstack); 255} 256 257 258void luaD_growstack (lua_State *L, int n) { 259 int size = L->stacksize; 260 if (size > LUAI_MAXSTACK) /* error after extra size? */ 261 luaD_throw(L, LUA_ERRERR); 262 else { 263 int needed = cast_int(L->top - L->stack) + n + EXTRA_STACK; 264 int newsize = 2 * size; 265 if (newsize > LUAI_MAXSTACK) newsize = LUAI_MAXSTACK; 266 if (newsize < needed) newsize = needed; 267 if (newsize > LUAI_MAXSTACK) { /* stack overflow? */ 268 luaD_reallocstack(L, ERRORSTACKSIZE); 269 luaG_runerror(L, "stack overflow"); 270 } 271 else 272 luaD_reallocstack(L, newsize); 273 } 274} 275 276 277static int stackinuse (lua_State *L) { 278 CallInfo *ci; 279 StkId lim = L->top; 280 for (ci = L->ci; ci != NULL; ci = ci->previous) { 281 lua_assert(ci->top <= L->stack_last); 282 if (lim < ci->top) lim = ci->top; 283 } 284 return cast_int(lim - L->stack) + 1; /* part of stack in use */ 285} 286 287 288void luaD_shrinkstack (lua_State *L) { 289 int inuse = stackinuse(L); 290 int goodsize = inuse + (inuse / 8) + 2*EXTRA_STACK; 291 if (goodsize > LUAI_MAXSTACK) goodsize = LUAI_MAXSTACK; 292 if (inuse > LUAI_MAXSTACK || /* handling stack overflow? */ 293 goodsize >= L->stacksize) /* would grow instead of shrink? */ 294 condmovestack(L); /* don't change stack (change only for debugging) */ 295 else 296 luaD_reallocstack(L, goodsize); /* shrink it */ 297} 298 299 300void luaD_hook (lua_State *L, int event, int line) { 301 lua_Hook hook = L->hook; 302 if (hook && L->allowhook) { 303 CallInfo *ci = L->ci; 304 ptrdiff_t top = savestack(L, L->top); 305 ptrdiff_t ci_top = savestack(L, ci->top); 306 lua_Debug ar; 307 ar.event = event; 308 ar.currentline = line; 309 ar.i_ci = ci; 310 luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */ 311 ci->top = L->top + LUA_MINSTACK; 312 lua_assert(ci->top <= L->stack_last); 313 L->allowhook = 0; /* cannot call hooks inside a hook */ 314 ci->callstatus |= CIST_HOOKED; 315 lua_unlock(L); 316 (*hook)(L, &ar); 317 lua_lock(L); 318 lua_assert(!L->allowhook); 319 L->allowhook = 1; 320 ci->top = restorestack(L, ci_top); 321 L->top = restorestack(L, top); 322 ci->callstatus &= ~CIST_HOOKED; 323 } 324} 325 326 327static void callhook (lua_State *L, CallInfo *ci) { 328 int hook = LUA_HOOKCALL; 329 ci->u.l.savedpc++; /* hooks assume 'pc' is already incremented */ 330 if (isLua(ci->previous) && 331 GET_OPCODE(*(ci->previous->u.l.savedpc - 1)) == OP_TAILCALL) { 332 ci->callstatus |= CIST_TAIL; 333 hook = LUA_HOOKTAILCALL; 334 } 335 luaD_hook(L, hook, -1); 336 ci->u.l.savedpc--; /* correct 'pc' */ 337} 338 339 340static StkId adjust_varargs (lua_State *L, Proto *p, int actual) { 341 int i; 342 int nfixargs = p->numparams; 343 StkId base, fixed; 344 lua_assert(actual >= nfixargs); 345 /* move fixed parameters to final position */ 346 luaD_checkstack(L, p->maxstacksize); /* check again for new 'base' */ 347 fixed = L->top - actual; /* first fixed argument */ 348 base = L->top; /* final position of first argument */ 349 for (i=0; i<nfixargs; i++) { 350 setobjs2s(L, L->top++, fixed + i); 351 setnilvalue(fixed + i); 352 } 353 return base; 354} 355 356 357static StkId tryfuncTM (lua_State *L, StkId func) { 358 const TValue *tm = luaT_gettmbyobj(L, func, TM_CALL); 359 StkId p; 360 ptrdiff_t funcr = savestack(L, func); 361 if (!ttisfunction(tm)) 362 luaG_typeerror(L, func, "call"); 363 /* Open a hole inside the stack at `func' */ 364 for (p = L->top; p > func; p--) setobjs2s(L, p, p-1); 365 incr_top(L); 366 func = restorestack(L, funcr); /* previous call may change stack */ 367 setobj2s(L, func, tm); /* tag method is the new function to be called */ 368 return func; 369} 370 371 372 373#define next_ci(L) (L->ci = (L->ci->next ? L->ci->next : luaE_extendCI(L))) 374 375 376/* 377** returns true if function has been executed (C function) 378*/ 379int luaD_precall (lua_State *L, StkId func, int nresults) { 380 lua_CFunction f; 381 CallInfo *ci; 382 int n; /* number of arguments (Lua) or returns (C) */ 383 ptrdiff_t funcr = savestack(L, func); 384 switch (ttype(func)) { 385 case LUA_TLCF: /* light C function */ 386 f = fvalue(func); 387 goto Cfunc; 388 case LUA_TCCL: { /* C closure */ 389 f = clCvalue(func)->f; 390 Cfunc: 391 luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */ 392 ci = next_ci(L); /* now 'enter' new function */ 393 ci->nresults = nresults; 394 ci->func = restorestack(L, funcr); 395 ci->top = L->top + LUA_MINSTACK; 396 lua_assert(ci->top <= L->stack_last); 397 ci->callstatus = 0; 398 luaC_checkGC(L); /* stack grow uses memory */ 399 if (L->hookmask & LUA_MASKCALL) 400 luaD_hook(L, LUA_HOOKCALL, -1); 401 lua_unlock(L); 402 n = (*f)(L); /* do the actual call */ 403 lua_lock(L); 404 api_checknelems(L, n); 405 luaD_poscall(L, L->top - n); 406 return 1; 407 } 408 case LUA_TLCL: { /* Lua function: prepare its call */ 409 StkId base; 410 Proto *p = clLvalue(func)->p; 411 n = cast_int(L->top - func) - 1; /* number of real arguments */ 412 luaD_checkstack(L, p->maxstacksize + p->numparams); 413 for (; n < p->numparams; n++) 414 setnilvalue(L->top++); /* complete missing arguments */ 415 if (!p->is_vararg) { 416 func = restorestack(L, funcr); 417 base = func + 1; 418 } 419 else { 420 base = adjust_varargs(L, p, n); 421 func = restorestack(L, funcr); /* previous call can change stack */ 422 } 423 ci = next_ci(L); /* now 'enter' new function */ 424 ci->nresults = nresults; 425 ci->func = func; 426 ci->u.l.base = base; 427 ci->top = base + p->maxstacksize; 428 lua_assert(ci->top <= L->stack_last); 429 ci->u.l.savedpc = p->code; /* starting point */ 430 ci->callstatus = CIST_LUA; 431 L->top = ci->top; 432 luaC_checkGC(L); /* stack grow uses memory */ 433 if (L->hookmask & LUA_MASKCALL) 434 callhook(L, ci); 435 return 0; 436 } 437 default: { /* not a function */ 438 func = tryfuncTM(L, func); /* retry with 'function' tag method */ 439 return luaD_precall(L, func, nresults); /* now it must be a function */ 440 } 441 } 442} 443 444 445int luaD_poscall (lua_State *L, StkId firstResult) { 446 StkId res; 447 int wanted, i; 448 CallInfo *ci = L->ci; 449 if (L->hookmask & (LUA_MASKRET | LUA_MASKLINE)) { 450 if (L->hookmask & LUA_MASKRET) { 451 ptrdiff_t fr = savestack(L, firstResult); /* hook may change stack */ 452 luaD_hook(L, LUA_HOOKRET, -1); 453 firstResult = restorestack(L, fr); 454 } 455 L->oldpc = ci->previous->u.l.savedpc; /* 'oldpc' for caller function */ 456 } 457 res = ci->func; /* res == final position of 1st result */ 458 wanted = ci->nresults; 459 L->ci = ci->previous; /* back to caller */ 460 /* move results to correct place */ 461 for (i = wanted; i != 0 && firstResult < L->top; i--) 462 setobjs2s(L, res++, firstResult++); 463 while (i-- > 0) 464 setnilvalue(res++); 465 L->top = res; 466 return (wanted - LUA_MULTRET); /* 0 iff wanted == LUA_MULTRET */ 467} 468 469 470/* 471** Call a function (C or Lua). The function to be called is at *func. 472** The arguments are on the stack, right after the function. 473** When returns, all the results are on the stack, starting at the original 474** function position. 475*/ 476void luaD_call (lua_State *L, StkId func, int nResults, int allowyield) { 477 if (++L->nCcalls >= LUAI_MAXCCALLS) { 478 if (L->nCcalls == LUAI_MAXCCALLS) 479 luaG_runerror(L, "C stack overflow"); 480 else if (L->nCcalls >= (LUAI_MAXCCALLS + (LUAI_MAXCCALLS>>3))) 481 luaD_throw(L, LUA_ERRERR); /* error while handling stack error */ 482 } 483 intptr_t remaining = stack_remaining(); 484 if (L->runerror == 0 && remaining < LUAI_MINCSTACK) 485 luaG_runerror(L, "C stack overflow"); 486 if (L->runerror != 0 && remaining < LUAI_MINCSTACK / 2) 487 luaD_throw(L, LUA_ERRERR); /* error while handling stack error */ 488 if (!allowyield) L->nny++; 489 if (!luaD_precall(L, func, nResults)) /* is a Lua function? */ 490 luaV_execute(L); /* call it */ 491 if (!allowyield) L->nny--; 492 L->nCcalls--; 493} 494 495 496static void finishCcall (lua_State *L) { 497 CallInfo *ci = L->ci; 498 int n; 499 lua_assert(ci->u.c.k != NULL); /* must have a continuation */ 500 lua_assert(L->nny == 0); 501 if (ci->callstatus & CIST_YPCALL) { /* was inside a pcall? */ 502 ci->callstatus &= ~CIST_YPCALL; /* finish 'lua_pcall' */ 503 L->errfunc = ci->u.c.old_errfunc; 504 } 505 /* finish 'lua_callk'/'lua_pcall' */ 506 adjustresults(L, ci->nresults); 507 /* call continuation function */ 508 if (!(ci->callstatus & CIST_STAT)) /* no call status? */ 509 ci->u.c.status = LUA_YIELD; /* 'default' status */ 510 lua_assert(ci->u.c.status != LUA_OK); 511 ci->callstatus = (ci->callstatus & ~(CIST_YPCALL | CIST_STAT)) | CIST_YIELDED; 512 lua_unlock(L); 513 n = (*ci->u.c.k)(L); 514 lua_lock(L); 515 api_checknelems(L, n); 516 /* finish 'luaD_precall' */ 517 luaD_poscall(L, L->top - n); 518} 519 520 521static void unroll (lua_State *L, void *ud) { 522 UNUSED(ud); 523 for (;;) { 524 if (L->ci == &L->base_ci) /* stack is empty? */ 525 return; /* coroutine finished normally */ 526 if (!isLua(L->ci)) /* C function? */ 527 finishCcall(L); 528 else { /* Lua function */ 529 luaV_finishOp(L); /* finish interrupted instruction */ 530 luaV_execute(L); /* execute down to higher C 'boundary' */ 531 } 532 } 533} 534 535 536/* 537** check whether thread has a suspended protected call 538*/ 539static CallInfo *findpcall (lua_State *L) { 540 CallInfo *ci; 541 for (ci = L->ci; ci != NULL; ci = ci->previous) { /* search for a pcall */ 542 if (ci->callstatus & CIST_YPCALL) 543 return ci; 544 } 545 return NULL; /* no pending pcall */ 546} 547 548 549static int recover (lua_State *L, int status) { 550 StkId oldtop; 551 CallInfo *ci = findpcall(L); 552 if (ci == NULL) return 0; /* no recovery point */ 553 /* "finish" luaD_pcall */ 554 oldtop = restorestack(L, ci->extra); 555 luaF_close(L, oldtop); 556 seterrorobj(L, status, oldtop); 557 L->ci = ci; 558 L->allowhook = ci->u.c.old_allowhook; 559 L->nny = 0; /* should be zero to be yieldable */ 560 luaD_shrinkstack(L); 561 L->errfunc = ci->u.c.old_errfunc; 562 ci->callstatus |= CIST_STAT; /* call has error status */ 563 ci->u.c.status = status; /* (here it is) */ 564 return 1; /* continue running the coroutine */ 565} 566 567 568/* 569** signal an error in the call to 'resume', not in the execution of the 570** coroutine itself. (Such errors should not be handled by any coroutine 571** error handler and should not kill the coroutine.) 572*/ 573static l_noret resume_error (lua_State *L, const char *msg, StkId firstArg) { 574 L->top = firstArg; /* remove args from the stack */ 575 setsvalue2s(L, L->top, luaS_new(L, msg)); /* push error message */ 576 api_incr_top(L); 577 luaD_throw(L, -1); /* jump back to 'lua_resume' */ 578} 579 580 581/* 582** do the work for 'lua_resume' in protected mode 583*/ 584static void resume_cb (lua_State *L, void *ud) { 585 int nCcalls = L->nCcalls; 586 StkId firstArg = cast(StkId, ud); 587 CallInfo *ci = L->ci; 588 if (nCcalls >= LUAI_MAXCCALLS) 589 resume_error(L, "C stack overflow", firstArg); 590 if (L->status == LUA_OK) { /* may be starting a coroutine */ 591 if (ci != &L->base_ci) /* not in base level? */ 592 resume_error(L, "cannot resume non-suspended coroutine", firstArg); 593 /* coroutine is in base level; start running it */ 594 if (!luaD_precall(L, firstArg - 1, LUA_MULTRET)) /* Lua function? */ 595 luaV_execute(L); /* call it */ 596 } 597 else if (L->status != LUA_YIELD) 598 resume_error(L, "cannot resume dead coroutine", firstArg); 599 else { /* resuming from previous yield */ 600 L->status = LUA_OK; 601 ci->func = restorestack(L, ci->extra); 602 if (isLua(ci)) /* yielded inside a hook? */ 603 luaV_execute(L); /* just continue running Lua code */ 604 else { /* 'common' yield */ 605 if (ci->u.c.k != NULL) { /* does it have a continuation? */ 606 int n; 607 ci->u.c.status = LUA_YIELD; /* 'default' status */ 608 ci->callstatus |= CIST_YIELDED; 609 lua_unlock(L); 610 n = (*ci->u.c.k)(L); /* call continuation */ 611 lua_lock(L); 612 api_checknelems(L, n); 613 firstArg = L->top - n; /* yield results come from continuation */ 614 } 615 luaD_poscall(L, firstArg); /* finish 'luaD_precall' */ 616 } 617 unroll(L, NULL); 618 } 619 lua_assert(nCcalls == L->nCcalls); 620} 621 622 623LUA_API int lua_resume (lua_State *L, lua_State *from, int nargs) { 624 int status; 625 int oldnny = L->nny; /* save 'nny' */ 626 lua_lock(L); 627 luai_userstateresume(L, nargs); 628 L->nCcalls = (from) ? from->nCcalls + 1 : 1; 629 L->nny = 0; /* allow yields */ 630 api_checknelems(L, (L->status == LUA_OK) ? nargs + 1 : nargs); 631 status = luaD_rawrunprotected(L, resume_cb, L->top - nargs); 632 if (status == -1) /* error calling 'lua_resume'? */ 633 status = LUA_ERRRUN; 634 else { /* yield or regular error */ 635 while (status != LUA_OK && status != LUA_YIELD) { /* error? */ 636 if (recover(L, status)) /* recover point? */ 637 status = luaD_rawrunprotected(L, unroll, NULL); /* run continuation */ 638 else { /* unrecoverable error */ 639 L->status = cast_byte(status); /* mark thread as `dead' */ 640 seterrorobj(L, status, L->top); 641 L->ci->top = L->top; 642 break; 643 } 644 } 645 lua_assert(status == L->status); 646 } 647 L->nny = oldnny; /* restore 'nny' */ 648 L->nCcalls--; 649 lua_assert(L->nCcalls == ((from) ? from->nCcalls : 0)); 650 lua_unlock(L); 651 return status; 652} 653 654 655LUA_API int lua_yieldk (lua_State *L, int nresults, int ctx, lua_CFunction k) { 656 CallInfo *ci = L->ci; 657 luai_userstateyield(L, nresults); 658 lua_lock(L); 659 api_checknelems(L, nresults); 660 if (L->nny > 0) { 661 if (L != G(L)->mainthread) 662 luaG_runerror(L, "attempt to yield across a C-call boundary"); 663 else 664 luaG_runerror(L, "attempt to yield from outside a coroutine"); 665 } 666 L->status = LUA_YIELD; 667 ci->extra = savestack(L, ci->func); /* save current 'func' */ 668 if (isLua(ci)) { /* inside a hook? */ 669 api_check(L, k == NULL, "hooks cannot continue after yielding"); 670 } 671 else { 672 if ((ci->u.c.k = k) != NULL) /* is there a continuation? */ 673 ci->u.c.ctx = ctx; /* save context */ 674 ci->func = L->top - nresults - 1; /* protect stack below results */ 675 luaD_throw(L, LUA_YIELD); 676 } 677 lua_assert(ci->callstatus & CIST_HOOKED); /* must be inside a hook */ 678 lua_unlock(L); 679 return 0; /* return to 'luaD_hook' */ 680} 681 682 683int luaD_pcall (lua_State *L, Pfunc func, void *u, 684 ptrdiff_t old_top, ptrdiff_t ef) { 685 int status; 686 CallInfo *old_ci = L->ci; 687 lu_byte old_allowhooks = L->allowhook; 688 unsigned short old_nny = L->nny; 689 ptrdiff_t old_errfunc = L->errfunc; 690 L->errfunc = ef; 691 status = luaD_rawrunprotected(L, func, u); 692 if (status != LUA_OK) { /* an error occurred? */ 693 StkId oldtop = restorestack(L, old_top); 694 luaF_close(L, oldtop); /* close possible pending closures */ 695 seterrorobj(L, status, oldtop); 696 L->ci = old_ci; 697 L->allowhook = old_allowhooks; 698 L->nny = old_nny; 699 luaD_shrinkstack(L); 700 } 701 L->errfunc = old_errfunc; 702 return status; 703} 704 705 706 707/* 708** Execute a protected parser. 709*/ 710struct SParser { /* data to `f_parser' */ 711 ZIO *z; 712 Mbuffer buff; /* dynamic structure used by the scanner */ 713 Dyndata dyd; /* dynamic structures used by the parser */ 714 const char *mode; 715 const char *name; 716}; 717 718 719static void checkmode (lua_State *L, const char *mode, const char *x) { 720 if (mode && strchr(mode, x[0]) == NULL) { 721 luaO_pushfstring(L, 722 "attempt to load a %s chunk (mode is " LUA_QS ")", x, mode); 723 luaD_throw(L, LUA_ERRSYNTAX); 724 } 725} 726 727 728static void f_parser (lua_State *L, void *ud) { 729 int i; 730 Closure *cl; 731 struct SParser *p = cast(struct SParser *, ud); 732 int c = zgetc(p->z); /* read first character */ 733 lua_assert(c != LUA_SIGNATURE[0]); /* binary not supported */ 734 checkmode(L, p->mode, "text"); 735 cl = luaY_parser(L, p->z, &p->buff, &p->dyd, p->name, c); 736 lua_assert(cl->l.nupvalues == cl->l.p->sizeupvalues); 737 for (i = 0; i < cl->l.nupvalues; i++) { /* initialize upvalues */ 738 UpVal *up = luaF_newupval(L); 739 cl->l.upvals[i] = up; 740 luaC_objbarrier(L, cl, up); 741 } 742} 743 744 745int luaD_protectedparser (lua_State *L, ZIO *z, const char *name, 746 const char *mode) { 747 struct SParser p; 748 int status; 749 L->nny++; /* cannot yield during parsing */ 750 p.z = z; p.name = name; p.mode = mode; 751 p.dyd.actvar.arr = NULL; p.dyd.actvar.size = 0; 752 p.dyd.gt.arr = NULL; p.dyd.gt.size = 0; 753 p.dyd.label.arr = NULL; p.dyd.label.size = 0; 754 luaZ_initbuffer(L, &p.buff); 755 status = luaD_pcall(L, f_parser, &p, savestack(L, L->top), L->errfunc); 756 luaZ_freebuffer(L, &p.buff); 757 luaM_freearray(L, p.dyd.actvar.arr, p.dyd.actvar.size); 758 luaM_freearray(L, p.dyd.gt.arr, p.dyd.gt.size); 759 luaM_freearray(L, p.dyd.label.arr, p.dyd.label.size); 760 L->nny--; 761 return status; 762} 763